Advisors/Committee Members: Harvey, Walter R.

▼ To increase the adoption of artificial insemination (AI) in cattle, timed-AI (TAI) programs in which AI is performed without the necessity of estrous detection, were developed. With the ability to manipulate the estrous cycle and follicular development concurrent with the enhancement of these approaches, much has been learned about the factors during follicular development that affect fertility. In some approaches, it has been clearly demonstrated that the diameter of the ovulatory follicle has a major effect on fertility. Others have shown that fertility is influenced by the length of proestrus. More recent data suggests that age of the ovulatory follicle may also impact fertility; however this has not been investigated in beef cattle. In the first experiment, age of ovulatory follicle and its effect on conception rate were investigated in beef heifers in Montana (MT) and Ohio (OH). The animal model used created a difference in follicle age of approximately 3 d between treatments (“young” follicle, YF; and “mature” follicle, MF). Ultrasonography was performed to assess follicular characteristics and development, and for pregnancy status. AI was performed approximately 12 h after onset of estrus. Interval to estrus was greater and follicle diameter at AI was smaller in the YF than in the MF treatment, however no difference was detected in conception rates. In the second experiment, the effect of ovulatory follicle age on pregnancy rate was investigated in beef cows in MT. Follicle age differed by approximately 3 d at the time of AI between treatments (YF and MF). Ultrasonography was performed throughout the experiment for follicular characteristics and pregnancy diagnosis. Estrous detection was performed for 3 d and 4 d in the MF and YF, respectively, followed by AI approximately 12 h later. Cows not detected in estrus during this period, received an injection of GnRH and TAI either at 72 h (MF) or 96 h (YF) after prostaglandin (PGF) administration. Follicle diameter at AI did not differ between treatments; however interval to estrus was greater in the YF than in the MF. Pregnancy rates were similar between treatments. Across treatments, pregnancy rate was greater in cows that were AI after estrus, than cows that received TAI. In conclusion, manipulation of ovulatory follicle age in beef cattle resulted in a longer interval to estrus (heifers and cows), and smaller follicle diameter at AI (heifers) in animals treated in a manner to result in ovulation of younger follicles, but age of the follicle at AI did not influence pregnancy rate. This data suggest that age of the ovulatory follicle is not a major contributor to variation in fertility in beef cattle. Advisors/Committee Members: Day, Michael.

▼ A randombred control turkey line (R 2) was developed in 1966 at the Ohio Agricultural Research and Development Center (OARDC). A sub-line of the R 2 was established in 1969 by selecting solely for body weight at 16 wk (F line). Since the development of the F line, no studies have been conducted to determine if selection has altered the dietary lysine and total sulphur amino acid concentration needed to support the increased body weight. Results of our studies showed that selection for BW alone at 16 wk in the F line has not changed the dietary amino acid concentration needed to support the increased BW gain and that the nutrients required to support the accelerated growth is provided by correlated increases in feed consumption. There are relatively few studies with turkeys that have examined the effect of selection for increased BW and breast muscle size on breast muscle structure/morphology or the interaction between diet and genotype on breast muscle morphology, particularly during younger ages when amino acid requirements are the highest. Growth assays and histological analyses suggest that selection for body weight alone (F line) and body weight in tandem with changes in carcass conformation (commercial turkeys) have altered muscle fiber through reduced muscle fiber diameter and increased muscle fiber number per unit area. There was also a line x lysine interactions on muscle fiber number per unit area. The increase in muscle growth when dietary lysine concentration was increased from 1.45% to 1.60% supports the NRC (1994) recommended concentration of 1.60% lysine in starter diets for poults. There have been relatively few lysine requirement studies that have covered the full productive life of commercial toms (0 to 20 wk). Lysine is the reference amino acid for Ideal Protein ratios and accurately defining the requirement reduces fractional errors in the corresponding ideal protein ratios. Growth assays with commercial toms over a full production cycle showed that the maximal lysine response in 2- to 4-wk, 4- to 8-wk and 16- to 20-wk turkeys were above the NRC (1994) recommended lysine requirement. Threonine is the third limiting amino acid after methionine and lysine in a typical corn-soybean meal diet. A review of the literature shows that only two studies have recommended threonine requirements that covered the full growth cycle for commercial turkeys. Based on the lysine study above, it was our hypothesis that threonine concentrations that support maximal responses in commercial turkeys will increase with increasing dietary lysine concentrations. Growth assays with commercial toms fed four threonine concentrations at two lysine concentrations showed that optimal responses of 2- to 20-wk male turkeys were at lysine and threonine concentrations above the NRC (1994) remmoned requirements. Advisors/Committee Members: Lilburn, Michael.

▼ Chemokines and chemokine receptors play important roles in the migration of lymphocytes to various tissues during health and disease. Experiments were conducted in chickens to investigate, 1. The mRNA amounts of different chemokine receptors in the immune tissues of chickens during inflammatory and non-inflammatory states and 2. The effect of the cytokine, IL-4 on CCR9 mRNA amounts of lymphocytes and on the migration of the lymphoyctes to the gut-associated lymphoid tissue, the cecal tonsils. In healthy chickens, chemokine receptor mRNA amounts of CD4+ and CD8+ cells isolated from the thymus, spleen, cecal tonsils, bursa and blood were studied. CCR7 and CCR8 mRNA amounts were highest in the thymus CD4+ cells, CCR9 mRNA amount was highest in cecal tonsil CD4+ cells and CXCR5 mRNA amount was highest in bursa and thymus CD4+ cells. The CD8+ cells isolated from cecal tonsil had the highest mRNA amount of most receptors studied. Thus the chemokine receptor mRNA amount depended on the organ from which the cells were isolated. In birds injected with an inflammatory compound, namely lipopolysaccharide (LPS), the splenic CCR7 mRNA amount was decreased by approximately 100 times and the bursal CXCR5 mRNA amount was decreased by approximately five-fold at 24 h post-LPS injection. In birds infected with coccidia oocysts (an intestinal pathogen), CCR7 and CXCR5 mRNA amounts of cecal tonsils were approximately 12-fold higher than in the control group at 10 d post-coccidia infection. In vitro immune stimulation of CD4+ cells using a mitogen, concanavalin A (Con A) increased CCR2, CCR4, CCR7, CCR8, and CXCR5 mRNA amounts. In vitro stimulation of CD8+ cells using the Con A increased the CCR4 and CCR6 mRNA amounts and decreased the CCR8 and CXCR4 mRNA amounts, suggesting the role of these receptors in inflammation. The effects of in vitro and in vivo IL-4 supplementation on thymocyte and splenocyte CCR9 mRNA amount and migration were studied. In vitro, IL-4 supplementation (5 ng/ml) upregulated CCR9 mRNA of thymocytes only in the presence of splenocytes. IL-4-treated splenocyte+thymocyte cells when injected in vivo preferentially migrated to cecal tonsils. IL-4 supplementation through in ovo injection of recombinant chicken IL-4 plasmid increased the weight, CCR9 mRNA amount and percentage of CD8+ cells of cecal tonsils. The effects of in ovo administration of IL-4 expression vector on indices of anti-coccidia immune responses were studied. A 15 microgram IL-4 plasmid in ovo injection decreased fecal oocyst shedding, decreased the number of CD8+ cells in the cecal tonsils, and decreased cecal tonsil lymphocyte cell proliferation post-coccidia challenge. Splenic macrophages of chicks hatched from eggs injected with 15 micrograms IL-4 plasmid had higher nitrite production than those of chicks hatched from eggs injected with empty plasmid. Co-administration of IL-4 expression vector with an in ovo coccidia vaccine, improved anti-coccidia immune responses synergistically and improved the body weight gain post-coccidia challenge. This study identified the role of chemokine receptors in chickens during health and disease and identified the possible applications of IL-4 to alter chemokine receptor expression and improve the immune response of chicken following pathogen challenge. Advisors/Committee Members: Selvaraj, Ramesh.

▼ Jersey cattle are recognized as being slower growing and having more yellow fat compared with other breeds, thus limiting the use of this breed for beef production. Because Jerseys are slower growing, they require additional time on feed to achieve acceptable market weights and yield acceptable hot carcass weights. Although Jerseys face challenges, the resulting product has other quality aspects that exceed the general beef population. Gaps in knowledge exist regarding the optimum forage level in finishing diets on growth performance, carcass characteristics, and beef palatability. The objective of this study was to evaluate the effects of forage level (12 vs. 24% sudangrass:alfalfa hay, DM-basis) in steam-flaked, corn-based finishing diets on carcass characteristics, palatability, and retail color stability of Jersey beef. Seventy-nine Jersey steers were blocked by weight and randomly assigned one of the following treatments for a 385-d trial period: Jersey low- 12% (JL; n = 38) or Jersey high- 24% (JH; n = 39) forage, DM-basis. Forty-eight hours postmortem (PM), strip loins were removed, vacuum-packaged, and aged at 3°C for 18 d PM. Following the aging period, steaks from the longissimus muscle were sliced, vacuum-packaged, and frozen (-20°C) until analyzed. Steers fed the low forage diet had greater (P < 0.05) backfat and tended to have greater dressing percent compared to steers fed the high forage diet. Live weight, HCW, LMA, and USDA Yield Grade were not affected (P > 0.05) by forage level. Steers fed the low forage diet on average tended to bring a 6% greater value ($63.73 more per head) compared to steers fed the high forage diet. Objective color (L*, a*, b*) measurements decreased (P < 0.05) over time of display across treatments. There were no differences among treatments for L*; however, overall during retail display JH had greater (P < 0.05) a* and b* values than JL. Subjective color scores increased over time of display and were not affected by forage level. Warner-Bratzler shear force (WBSF) values and cooking loss were not affected by forage level. All measured sensory panel ratings were more favorable for JL steaks than JH steaks. These results suggest that forage level had minimal effects on carcass characteristics, color stability, and beef palatability; however, feeding a low forage diet decreases input cost and results in a greater value carcass. Finishing fed Jersey steers in conventional feeding systems can be accomplished meeting beef industry expectations and result in a high quality beef product. Advisors/Committee Members: Kuber, Paul.

▼ The primary objective of this experiment was to estimate both maternal and individual heterosis expressed by comparing the Yorkshire and Large White breeds and their crosses. A second objective of the experiment was, based on the estimates of heterosis, to conclude if the two breeds are the same or different. In 1992, a foundation herd of Yorkshire and Large White pigs was established at the Western Branch of the Ohio Agricultural Research and Development Center, in South Charleston, Ohio. Matings among Yorkshire and Large White swine produced pigs to be used in the experiment.Maternal heterosis was estimated by the performance of the litter and the respective sow producing the litter. Females of Yorkshire, Large White and their crosses were mated to Hampshire sires. Preweaning traits used in this analysis included birth weight, number of pigs born, number of pigs born alive, number of stillborn and mummified pigs, 21-day weight, weaning weight and number of pigs weaned. Maternal heterosis was found to exist and be significant (P<.05) for weaning weight (3.07%), average adjusted 21-day weight (3.08%), and average birth weight (3.26%).Individual heterosis was estimated by the performance of individual pigs and average pig performance in pens. Postweaning traits used in this analysis included gain and feed efficiency. Individual heterosis estimates demonstrated crossbred pigs to have gained faster during the testing period than purebred pigs. Crossbred pigs had significant (P<.05) levels of heterosis for gain during the second half of the testing period (4.47%) and for gain during the entire testing period (3.87%).Based on these estimates of heterosis, it is concluded that Yorkshire and Large White swine do in fact represent different populations. While breed differences for many of the traits analyzed were not significant, several differences existed between the Yorkshire and Large White swine. Advisors/Committee Members: Irvin, Dr. Keith M.

▼ A stage–gate process was used to develop a high energy protein supplement that is versatile, economical, nutritional, palatable and shelf-stable. This food item was designed for non-refrigerated tropical areas so that the product could be distributed to hospitals, to sustain disaster relief zones, or be mobilized as short-term aid in food scarcity or unstable food security situations. Nutrition and cost were the two criteria found to be the most important in a survey of hospital patients, medical personnel, and other participants in the general population. A formulation was developed containing a variety of ingredients that were nutritionally desirable, cost effective, flexible, and easily modified to fit local conditions for protracted relief and recovery situations. A production system was developed that: a) reduced the potential microbial load by using a thin diameter product that could be rapidly heated to a temperature that would destroy all detectable microorganisms; b) dehydrated the material to an equilibrium moisture content that would prevent bacterial growth; c) analyzed the vacuum packaged product under simulated storage conditions; and d) established a generic plant production design, HACCP compliance program and label design. Microbial evaluation of processed/stored product indicated no organisms above the typical analytical detection levels. High-resolution electron microscopic evaluation indicated no evidence of remaining muscle structure. Quantity of raw material influenced variations in rheological properties of the emulsion. Extrapolations based on feed consumption during bio-assay evaluation indicated the product increased growth rates consistently in experimental subjects than the three other popular diets currently being used. Chemical evaluation of amino acids, fatty acids, minerals, vitamins, oxidation, energy, water activity and pH, favorably compared with the currently utilized corn meal diet. Cost evaluation of raw ingredients was achieved by benchmark health risk assessment which was economically acceptable. Sensory evaluations by research subjects rated the product superior to the corn meal control. Conjoint analysis by quantitative market research, regulatory issues, global strategy inputs and rapid response emergency interventions found the product showed promise in humanitarian commitments. Advisors/Committee Members: Herbert, Ockerman.

▼ The study evaluated the effects of a 28 d pre-harvest ractopamine (RAC) feeding program on average daily gain (ADG), feed conversion efficiency (FC), backfat (BF) and loin muscle area (LMA), pork loin quality, and cortisol concentration in purebred Berkshire pigs (n = 117) utilizing a randomized complete block design with three treatments (Control (C), 0 ppm; RAC5, 5.0 ppm; RAC10; 10 ppm) in four replicates. Litter-mate pigs were randomly assigned to each of the three treatments within a replicate. Ultrasonic BF and LMA, pig weight, and salivary cortisol concentrations were measured at days 0, 7, 14, 21, and 28 of the feeding period. Blood was collected during harvest at exsanguination for plasma cortisol measurements. Carcass composition and pork quality (NPPC, 2000; visual color, marbling, firmness, and wetness and instrumental measures of ultimate pH and Minolta L*, a*, and b* were assessed at 24h post-harvest. Mixed model procedures of SAS were used in analyses. Fixed effects were treatment, sex, and a treatment x sex interaction, with sex and interaction effects removed if not significant (P > 0.10). Random effects included replication and litter nested within replication. Individual ADG was greater (P < 0.05) for RAC10 when compared with C and RAC5 by d 14 and through d 28, while pigs fed RAC5 had greater ADG than the C from d 1 to 14 and d 1 to 21 (P < 0.05) only. However, when assessed on a pen basis, ADG was not different across the 28 d feeding period. Feeding RAC5 or RAC10 improved pen FC throughout the trial when compared with pens fed the C diet (P < 0.05); however, no differences were observed between RAC5 and RAC10. Serial ultrasonic measures of BF were significantly decreased in RAC10 pigs from 95 to 120 kg of BW when compared to C pigs and from 115 to 120 kg BW when compared to RAC5 pigs. Pigs fed RAC5 had decreased BF from 110 to 120 kg BW when compared to C. Ultrasonic measures of LMA were increased in RAC10 pigs from 105 to 120 kg BW when compared to C, however no differences were seen between RAC5 and RAC10 fed pigs throughout the trial. Carcass LMA of RAC10 was greater than C (P < 0.05) and BF was less than RAC5 and C (P < 0.05). Carcass fat-free lean percentage was greater for pigs fed RAC10 (P < 0.05) when compared with carcasses of pigs fed C and RAC5 diets. Neither RAC5 nor RAC10 diets influenced fresh loin quality, as there were no differences in visual color, marbling, firmness, wetness, or L*. However, ultimate pH was greater for the RAC10 treatment when compared with C. On d 0, baseline cortisol concentrations did not differ between treatment groups. No differences in salivary or plasma cortisol concentrations were observed between treatments regardless of day. Final results indicate feeding ractopamine improved feed conversion efficiency, maintained (RAC5), or improved (RAC10) carcass lean content and, therefore, value without negatively influencing pig cortisol concentrations or pork loin quality. Advisors/Committee Members: Moeller, Steven.

▼ Two experiments, using 140 purebred Berkshires and 60 Berkshire influenced pigs, were conducted to evaluate the influence of dietary energy on growth performance and resulting carcass characteristics of Berkshire and Berkshire influenced pigs. Pigs were blocked by litter and randomly allotted to four pens upon entering the growing-finishing barn to one of four treatments; 6 month low energy (6LE), 6 month standard energy (6ST), 7 month low energy (7LE), and 7 month standard energy (7ST). The 6ST and 7LE treatments were designed to achieve a live weight of approximately 113 kg at time of harvest. Individual pig weights and pen feed disappearance were measured weekly to calculate ADG, ADFI, and G:F. Monthly, carcass composition was assessed using ultrasonic measurement for 10th rib backfat and loin muscle area (LMA). Final ultrasonic measurements for backfat and LMA prior to harvest were utilized for carcass composition characteristics. A three rib section of the longissimus muscle, composed of the 10th, 11th, and 12th, rib and a six square inch belly sample were collected from the right side of each carcass. Each loin section was evaluated for final pH, subjective and objective color, marbling scores, and IMF. A subcutaneous fat sample from each loin and belly were also used to determine SFA, MUFA, and PUFA as indication of fat quality using near-infrared spectroscopy. As expected pigs receiving the low energy diet (6LE and 7LE) had lower (P < 0.05) averaged daily gains than those receiving the standard energy diets (0.61 vs. 0.81, respectively). Across both experiments 6LE pigs had lower (P < 0.05) final weights and produced carcasses with less backfat and loin muscle area (LMA) and 7ST pigs had significantly greater final weights and produced carcasses with greater backfat and LMA. In general, there were minimal differences in quality attributes for the Berkshire and Berkshire influenced pigs in both experiments with the exception of 7ST pigs having greater (P < 0.05) marbling scores supported by numerically higher IMF, and Berkshire 6LE pigs having a greater (P < 0.05) shear force. For both loin and belly fat the 6LE pigs had the lowest concentration of MUFA and the 7ST pigs had the greatest concentration of MUFA with 6ST and 7LE treatments being intermediate to 6LE and 7ST but not significantly different from each other. Although low energy diets did not result in detrimental effects on carcass composition and muscle quality, their negative impacts on growth performance and consequently cost of production do not make them an effective alternative in producing Berkshire or Berkshire influenced pigs for high quality markets. Advisors/Committee Members: Zerby, Henry.

▼ Mammals possess mammary glands which are composed of two tissue types; secretory parenchyma (PAR), and non-secretory stroma. Amount of PAR is positively correlated with milk production. This work contains results from two separate projects. In the first, estrogen signaling in PAR from dairy heifers was more fully characterized using an ovariectomy (OVX) model. In the second, maternal body condition score (BCS) of gestating ewes was imposed as a treatment and PAR characteristics of female progeny were measured. Estrogen regulates bovine mammary growth and development and acts mainly through estrogen receptors (ER), specifically ERα, to regulate estrogen-responsive genes. One such gene, CREB1, has recently been identified, but has not been characterized in bovine mammary tissue. The CREB1 gene codes for cAMP response element-binding protein (CREB). OVX of prepubertal heifers inhibits mammary development while causing an increase in ERα-positive cells, and increased abundance of myoepithelial cells which are identifiable by staining for α-smooth muscle actin (SMA). Our objective was to study the effects of OVX on tissue localization of CREB. PAR samples were obtained from 16 prepubertal heifers in a 2 × 2 factorial experiment. The first factor was ovarian status (intact or OVX); the second factor was estrogen treatment (control or estradiol). OVX was performed at ~4.5 mo of age and estrogen treatments began ~5.5 mo. After 54 h of estrogen treatment, heifers were slaughtered, udders removed and PAR sampled. Tissue sections underwent staining for CREB and ERα, or for CREB and SMA. CREB was more abundant in the luminal and embedded layer compared to the basal layer. Neither OVX, estrogen replacement, nor the combination of the two affected the amount of CREB protein. CREB has previously been identified as being estrogen-responsive at the transcript level. Our data indicate that tissue abundance of CREB protein does not show the same pattern. CREB may play a key role in signaling pathways that influence development of the bovine mammary gland because it was constitutively present in all treatment groups examined. Mammary PAR is formed in utero, so maternal BCS during gestation may affect progeny mammary growth and composition. Pregnant ewes (n = 96; ~80 d of gestation) were grouped based on initial BCS of 2, 3, or 4 (1 to 5 scoring system; 1 = emaciated and 5 = obese). Ewes received gestation diets formulated to maintain initial BCS throughout pregnancy. Post-lambing diet and management were equivalent across treatments. Female progeny (n = 73) were slaughtered at similar BW and age. Udders were removed and mammary tissue subjected to biochemical analyses. Total mammary gland weights did not differ by treatment. However, PAR weight of BCS 2 progeny tended to be greater than that of BCS 3 or BCS 4 progeny. Protein mass within PAR tended to be highest in BCS 2 progeny, as did DNA mass within PAR. Despite detectable differences in PAR due to treatment, no differences in weight or composition of mammary stroma were found. Our observations suggest that BCS during gestation may have important lactation performance implications for female progeny. Advisors/Committee Members: Daniels, Kristy.

▼ Most milk replacers (MR) in the US are formulated to meet the needs of Holstein calves, yet the fatty acid (FA) composition of milk from Jersey cows differs from that of Holstein milk. Most MR use edible lard as the fat source, which contains primarily long-chain fatty acids (LCFA). However, 10.8% of FA in Jersey whole milk are medium-chain fatty acids (MCFA). The objective of this study was to determine whether altering the FA profile of MR with coconut oil (CO), which contains a high concentration of MCFA, to more closely match the FA profile typically found in whole milk from Jersey cows, would improve Jersey calf performance. Male (n = 18) and female (n = 32) Jersey calves were assigned at birth to 1 of 4 liquid diets: 1) pasteurized Jersey saleable whole milk (pSWM; 27.9% CP, 33.5% fat); 2) 29.3% CP, 29.1% fat MR containing 100% of fat as edible lard (100:00); 3) 28.2% CP, 28.0% fat MR containing 20% of fat as CO (80:20); 4) and 28.2% CP, 28.3% fat MR containing 40% of fat as CO (60:40). Calves were fed their respective liquid diet twice daily during wk 1 through 7 and once daily until weaning (approximately wk 8). Calves had ad libitum access to grain and water. Calves were monitored 1 wk post-weaning. Calves were weighed at birth and once a week thereafter. Hip height (HH) and wither height (WH) were taken at birth, and 4, 7, and 9 wk. Grain refusals and fecal and respiratory scores were recorded daily. Average daily gain and BW did not differ by treatment. Calves fed pSWM tended (P = 0.10) to have greater HH than calves fed 80:20 (80.5 vs. 79.7 cm). Coconut oil tended to have a quadratic effect on HH, with calves fed 100:00, 80:20, and 60:40 at 79.2, 79.7, and 78.5 cm, respectively. There was no difference in WH between pSWM and 80:20. Coconut oil had a quadratic effect on WH, with calves fed 100:00, 80:20, and 60:40 at 76.6, 77.5, and 76.5 cm, respectively. Change in HH from birth to 9 wk tended to be greater for calves fed pSWM than calves fed 80:20 (0.218 vs. 0.194 cm/d). Calves fed pSWM had a higher milk DMI intake than calves fed 80:20 (0.523 vs. 0.498 kg/d). There was no effect of CO on milk DMI. Grain DMI and total DMI did not differ among treatments. Calves fed pSWM had an increase in days with a fecal score > 2 compared to calves fed 80:20 (4.24 vs. 2.00 d). Coconut oil had a quadratic effect on fecal score, with calves fed 100:00, 80:20, and 60:40 scouring 4.00, 2.00, and 3.63 d, respectively. Respiratory score did not differ among treatments. In conclusion, DMI and ADG were similar among treatments. However, differences among treatments in skeletal growth and fecal scores are indicative of some possible benefits in MCFA on calf health and performance. Additional data on adipose tissue and liver biopsies may provide further evidence of such benefits. Advisors/Committee Members: Eastridge, Maurice.

▼ A paucity of research is available on the effects of docosahexaenoic (DHA) and arachidonic (AA) acid on hepatic fuel utilization in infants. Pigs serve as suitable models for infants due to many physiological and biological similarities. To evaluate the effect of these fatty acids on partitioning fatty acids and glucose towards utilization or storage, pigs were delivered by cesarean section at 106d and 114d of gestation and umbilical catheters were placed for total parenteral nutrition (TPN). Pigs received either a control, a low polyunsaturated fatty acid (PUFA) (0.3% and 0.63% of total lipids as DHA and AA, respectively), or a high PUFA (5.5% and 12% of total lipids as DHA and AA, respectively) diet. Diets were administered based on pig weight to promote moderate weight gain. Hepatic fatty acid oxidative and glucose oxidative capacities, hepatic carnitine palmitoyltransferase (CPT) I activity and relative transcript amounts, and hepatic phoshofructokinase-1 (PFK-1) activity and relative transcript amounts were determined after 6d. Rates of fatty acid oxidation were similar across TPN regimens in both term and preterm pigs. Additionally, no differences were found between term and preterm pigs. Low PUFA administered term pigs exhibited an increase in CPT I transcript abundance (2 fold) relative to newborn pigs (P=0.031). Preterm pigs displayed increased malonyl-CoA insensitive CPT activity over term pigs in each TPN regimen (p<0.05). Preterm control and high PUFA pigs displayed a reduction in malonyl-CoA insensitive CPT activity as compared preterm low PUFA pigs (P=0.05). Rates of glucose oxidation were increased in term pigs receiving the high PUFA regimen compared to term pigs receiving the control diet (P=0.03). Additionally, term pigs receiving the low and high PUFA regimens displayed increased glucose oxidation relative to their respective preterm dietary counterparts (P<0.0001). Preterm control and high PUFA administered pigs displayed a 2-fold increase in PFK-1 transcript amounts relative to term animals (P<0.05). Term Low PUFA pigs displayed greater PFK-1 activity compared to term control pigs (P=0.03). Among term pigs all dietary treatments displayed a greater rate of glucose oxidation than fatty acid oxidation (P<0.05). Collectively, these findings suggest that fatty acid oxidation is not altered by the presence of DHA/AA in either age group regardless of changes in CPT I expression or activity. In contrast, glucose oxidation in term pigs is increased with increased concentrations of PUFA indicating an age-related PUFA effect on glucose oxidative capacity, which is not reflected in PFK-1 mRNA or activity. Advisors/Committee Members: Lyvers Peffer, Pasha.

▼ The U.S. swine industry has changed dramatically in recent decades and the changes have led to a shift in the manner in which pigs are raised. The use of production contracts has become increasingly popular, which has led to a greater percentage of stockpersons raising pigs only from weaning or feeder size through the end of production. The stockpersons that undertake the production contracts are specialized in the one area of production and may have never worked with pigs in any capacity. Industry changes in size of production units and number of producers marketing hog(s) have been characterized; however, what is not known is information about the stockpersons. Therefore, the aim of this research was to characterize stockpersons in Ohio with regard to their demographics, attitudes, beliefs and their subsequent behavior toward pigs, and the reaction the pigs toward humans as measured by stroll test methodology and cortisol concentrations measured in the saliva. The stockpersons varied with respect to their demographics, their pig experience, other forms of employment besides contract hog production, and, when observed interacting with their pigs, the location from where and how long they observed the pigs in their given facility. In addition, the stroll test response data and cortisol concentration results varied across farms. Furthermore, questionnaire results revealed that there were differences among stockpersons with regard to their attitudes and beliefs about pigs and about working with pigs. With the differences in stockpersons in mind, a pig handling training program, directed specifically at attitudes and beliefs of stockpersons toward pigs, was implemented for a sample half of study participants to determine if the attitudes and the behavior of the stockpersons could be improved. After the implementation of the training program, stockpersons that completed the training program had an improvement in indicator variables related to their positive attitude toward pigs and also increased the neutral behavior characteristics while reducing their negative behaviors toward pigs. Based on the results of the present study, the implementation of a training program, specifically addressing stockpersons raising pigs under a production contracts or raising only finishing stage swine, would be beneficial to the welfare of the pigs under their control and also enhance job satisfaction of the stockpersons. Advisors/Committee Members: Moeller, Steven.

▼ Two studies were conducted to determine the effect of litter microbiome on the ontogeny of the intestinal microbiome in broilers over a 6-week growth cycle. In the first study, composite (10 random birds/replicate) ileal mucosa and cecal luminal samples from birds reared on both fresh pine shavings and 2-year old reused pine litter were collected at days 7, 14, 21, and 42. At the same times, litter subsamples were also collected and pooled from multiple locations (brood area, along the water and feed lines, and along the walls) within the broiler house. Microbiome DNA was extracted from all samples using the RBB+C method. Bacterial community profiles were compared among samples (ileum, cecum, or litter) based on each litter type using PCR-DGGE. DGGE banding patterns were analyzed using BioNumerics V.5.1 software, and compared among individual samples with UPGMA clustering analysis using the Dice similarity coefficient. The DGGE banding patterns were also analyzed using SAS and principal component analysis (PCA). All these analyses indicated the following: 1) The two litter types appeared to have very distinct microbiomes, with the reused litter having a greater bacterial diversity than the fresh litter; 2) the litter microbiome is more influential on the ileal than the cecal microbiome; 3) all samples (ileal, cecal and litter) exhibit temporal shifts in the bacterial community structure; and, 4) the intestinal microbiome of the chickens raised on the fresh litter becomes similar to that of chickens raised on reused litter by week six. In addition to microbiome structure, further analysis of the chemical composition of the litter and bird performance in subsequent trials is needed to better understand the relationship between the condition of litter and gastrointestinal health of the broiler chicken. In the second study, a 16S rRNA gene clone library was constructed from microbiome DNA extracted from ileal mucosa and cecal lumen of young chicks (7 days of age) placed on fresh pine shavings or 2-year old reused litter, as well as the litter samples. All the recovered 16S rRNA gene sequences were identified by comparison with database sequences and analyzed using phylogenetic programs. As demonstrated in the 16S clone libraries, all samples had distinct microbiomes at day 7. The predominant genera were Lachnospiraceae Incertae Sedis (19.3%), Lactobacillus (18.1%), Enterococcus (3.4%), Faecalibacterium (3.4%), and Staphylococcus (3.2%). Although the co-occurrence of both Lactobacillus and Enterococcus species was seen between the fresh litter and the ileal clones of chicks placed on fresh pine shavings, very few co-occurrences were seen between the reused litter and ileal clones of chicks placed on reused litter. The majority of clones in the cecal library of chicks placed on reused litter were classified as belonging to Ruminococcaceae (60%), while the majority of clones in the cecal library of chicks placed on fresh pine shavings belonged to Lachnospiraceae (58%). Collective analysis of all 476 clones identified 138 operation taxonomic units (OTUs) corresponding to species (defined by 97% sequence identity). Less than 12% (16 OTUs) of these OTUs were ≥97% identical to known bacterial species, while another 4 OTUs (2.9%) were 95-96.9% identical. Another 6 OTUs (4.3%) were 90-94.9% identical to known bacterial species. The remaining 112 (81.2%) OTUs were <90% identical to any known bacterial species within the database. These results suggest that the microbiome in different litter can affect the intestinal microbiome differently, and the majority of the bacteria present in these microbiome remains to be identified. Advisors/Committee Members: Moeller, Steven.

▼ The objective of this study was to determine the effect of the length of the preovulatory period, and consequent alterations of preovulatory plasma estradiol concentrations, on steady-state concentrations of mRNA for ISG15, SPP1 and MX1, and localization and density of nuclear progesterone receptors (PGR) in the uterine endometrium of beef cows slaughtered 17.5 d after GnRH-induced ovulation. Twenty-one non-lactating cows in 2 replicates (Rep 1, n = 10; Rep 2, n = 11) were pre-synchronized to a common day of the estrous cycle and ultrasonographic-guided follicle aspiration was performed 6.2 ± 0.4 d after estrus (d -7 of the experiment). Cows were assigned to receive prostaglandin F2α on either d -3 (high estradiol group, n = 9; Hi-E), or d -2 (low estradiol group, n = 12; Lo-E). All cows received GnRH (100 µg) on d 0 (h 0), resulting in a preovulatory period of either 3 (Hi-E) or 2 (Lo-E) d. On d 7, cows either received no further treatment (Cyclic = C) or were implanted with an embryo (Embryo transferred = ET) resulting in pregnant or cyclic animals. Ovarian ultrasonography was performed on d -7, -3, 0, 2 and 6 to monitor emergence and maximum diameter of the eventual ovulatory follicle and formation of a new corpus luteum after GnRH. Blood samples collected at 12 h intervals from h -72 to h -12 and at h -6 and 0 were used to determine preovulatory concentrations of estradiol. Progesterone concentrations were assessed in samples collected on d -3, -2, 0, 2, 4, 6, 9, 11, 13 and then daily to d 17.5. All cows were slaughtered on d 17.5 and the reproductive tract collected. Cross-sections of uterine endometrium were snap frozen for mRNA analysis using qPCR or placed in paraformaldehyde for immunohistochemistry evaluation of location and density of PGR. In a 2x2 factorial arrangement, where the dependent variables were preovulatory treatment (Hi-E and Lo-E) and pregnancy status (ET and C), cows were grouped in 4 subclasses (Hi-E-ET, Hi-E-C, Lo-E-ET, and Lo-E-C). Only animals in the Hi-E-ET (n = 5) and Lo-E-ET (n = 8) subclasses that had recoverable embryos at slaughter and females in Hi-E-C (n = 4) and Lo-E-C (n = 4) subclasses, that had progesterone concentrations indicative of the presence of a corpus luteum at slaughter were included in subsequent analyses. Steady-state concentration of mRNA for ISG15, MX1 and SSP1 were determined using qPCR with RPL19 mRNA concentration used to adjust for variation in pipetting between samples. Data were analyzed using MIXED procedures of SAS with models that included treatment (Hi-E and Lo-E), reproductive status (ET and C), Rep and interactions for mRNA concentration and staning intensity for PGR. Day (d) was designated the repeated variable for hormone concentrations. Secondary analyses were performed among the subclasses (Hi-E-ET, Lo-E-ET), excluding the cyclic animals. Estradiol concentrations were greater (treatment x h, P < 0.05) in the Hi-E (3.2 ± 0.32 pg/mL) than Lo-E (1.6 ± 0.26 pg/mL) treatment at h - 48. Estradiol concentration did not differ between Hi-E and Lo-E treatments for both peak (10.4 ± 1.6 and 8.3 ± 0.7 pg/mL, respectively; P > 0.1) and AUC (362.5 ± 43.3 and 284.0 ± 25.3 units respectively; P > 0.1).Concentrations of progesterone from d 0 to d 17 were not affected by concentrations of estradiol during the preovulatory period (Hi-E vs. Lo-E) or reproductive status (ET vs. C). Relative amount of mRNA for MX1 was greater (P < 0.05) in ET (9753 ± 24) than C females (221 ± 108), but did not differ between the Hi-E-ET (10.3 ± 2.9) and Lo-E-ET (9.4 ± 2.8) subclasses. ISG15 mRNA was undetectable in 5 of 8 cows in the C group, but in a secondary comparison between pregnant cows, it did not differ between the Hi-E-ET and Lo-E-ET subclasses (4.8 ± 1.1 and 5.9 ± 1.5, respectively). For SPP1, amounts of mRNA were greater (P < 0.05) in the ET (2.93 ± 0.33) than C (1.19 ± 0.33), groups. A treatment by Rep interaction (P < 0.05) was detected for SPP1. In Rep 1, amount of SPP1 was greater (P < 0.05) in the Hi-E-ET than Lo-E-ET subclass (4.2 ± 0.5 and 2.5 ± 0.4, respectively) whereas in Rep 2 the Lo-E-ET (3.35 ± 0.40) tended (P = 0.06) to have greater amounts of SPP1 mRNA than the Hi-E-ET (1.53 ± 0.03) subclass. Across treatments, PGR immunostaining in cell nuclei was not above background in the luminal epithelium was faint in the shallow glandular epithelium, low to moderate in the stroma, and intense in the deep endometrial glandular epithelium. Staining intensity of PGR in the deep glandular epithelium was greater (P < 0.05) for the Lo-E compared to Hi-E treatment and was greater (P < 0.05) in Rep 2 compared to Rep 1. Pregnancy did not affect staining intensity for PGR. In conclusion, alteration of concentrations of estradiol during the preovulatory period did not influence amounts of endometrial mRNA for ISG15 and MX1 in pregnant cows, reduced PGR staining intensity in the Hi-E compared to Lo-E treatment, and had variable effects on amount of mRNA for SPP1. Advisors/Committee Members: Day, Michael.

▼  Although isotrichid protozoa have been studied for their migratory behavior followed by sedimentation to the ventral reticulum and rumen, it has not been determined whether the more predominant entodiniomorphid species exhibit chemotaxis following feeding and, if so, whether they also have a detrimental effect on the amount of dietary protein that becomes available to the cow. In chapter 3, I hypothesized that chemotaxis toward nutrients is responsible for the attraction of entodiniomorphid protozoa toward feed particles and therefore pass with the potentially digestible particulate phase (or phases if there is a buoyancy delay). In Chapter 3, objectives were to compare dose-responsive chemotaxis by isotrichids and entodiniomorphids to glucose (Experiment 1), glucose or xylose when protozoa were harvested from a fed cow (Experiment 2), peptides of bacterial, protozoal, and soy origin (Experiment 3), or toward glucose when mixed ruminal protozoa were previously incubated for 0, 3, or 6 h in the presence of emulsified polyunsaturated fatty acids (PUFA; Liposyn II). In experiment 1 isotrichid protozoa decreased chemotaxis toward increasing glucose concentration when the cow was fasted. However, entodiniomorphids exhibited chemotaxis to a lesser degree, regardless of feeding, but to similar glucose concentrations as isotrichids. In experiment 2, our results do not support xylose as a major chemotactic molecule that draws protozoa toward non-starch particulate matter in the rumen. Experiment 3 showed that entodiniomorphids are not selectively chemoattracted toward bacterial or protozoal peptides. In experiment 4, despite isotrichid populations being inhibited by fat, chemotaxis to glucose remained unchanged. In contrast, chemotaxis by entodiniomorphids was more complex and glucose tended to recover loss of chemotaxis from PUFA incubation. In chapter 4, the objective of experiment 1 was to test the hypothesis that wortmannin (an inhibitor of phosphatidylinositol-3-kinase) would inhibit growth of single cultures of the rumen protozoa Entodinium caudatum and Epidinium caudatum unless cultures were subsequently rescued dose-responsively by increasing concentrations of insulin added to the culture medium. Results showed dose-responsive insulin recovery from wortmannin inhibition by both cultures. In Experiment 2 of chapter 4, I hypothesized that wortmannin should decrease chemotaxis, insulin should recover chemotaxis in wortmannin-incubated treatments, and sodium nitroprusside (SNP; activates guanylyl cyclase and resultant activation of protein kinase G) should increase chemotaxis toward glucose and peptides as in other ciliate models from aerobic ecosystems, but we expected interactions in insulin would overcome inhibition by WORT but not SNP. Sodium nitroprusside at 500 μM and wortmannin at 200 μM decreased (P < 0.05) random swimming to saline control but both increased (P < 0.05) chemotaxis toward glucose for entodiniomorphids. Sodium nitroprusside at 500 μM and wortmannin at 200 μM decreased chemotaxis toward glucose or peptides on isotrichids. Peptides also decrease chemotaxis on isotrichids. In Experiment 3, we assessed the role of receptor tyrosine kinases (RTK) on rumen protozoal chemotaxis toward glucose using genistein and guanosine triphophate (GTP; universal chemorepellent by ciliates). Neither genistein (reported RTK blocker in other ciliate models) nor GTP affected chemotaxis toward glucose for entodiniomorphids. However, GTP at 100 μM reduced chemotaxis toward glucose for isotrichids. The repellence by GTP was reversed when cells were incubated in the presence of genistein at 40 or 400 μM. In chapter 5, we screened and evaluated dose-responsiveness of various compounds used to study motility of non-rumen ciliates. The current objectives were to evaluate effects and potential interactions among wortmannin (blocking phosphoinositide signaling used in phagocytosis or chemotaxis), insulin (previously rescued wortmannin’s inhibition of cell growth, potentially through a RTK), genistein (RTK blocker, potentially inhibiting chemotaxis), U73122 (inhibitor of phospholipase C, PLC, potentially disrupting Ca++ gradients needed for swimming and turning), and sodium nitroprusside (SNP, protein kinase G activator to enhance turning toward a chemoattractant) preloaded for 3 h in flocculated ruminal fluid maintained anaerobically at 39°C. Chemoattractants were glucose, peptides, and their combination; peptides also were combined with GTP). Isotrichids increased chemotaxis to glucose, which was countered by wortmannin. Peptides were strongly chemorepellent to isotrichids, even in the presence of glucose and especially when preloaded with genistein or SNP. In this study, GTP did not reverse peptide repellence by isotrichids or chemoattraction by entodiniomorphids. For entodiniomorphids, U73122 increased random swimming into saline controls. As in a previous study, wortmannin decreased or did not affect random swimming into saline but enhanced chemotaxis by entodiniomorphids to glucose. Wortmannin’s opposite results for entodiniomorphids versus isotrichids appear to be mediated through differences in vacuolization or, more likely, through RTK signaling. For entodiniomorphids, motility toward chemoattractants appears to be sensitized by energy deprivation (as with wortmannin inhibition of digestive vacuole formation and recycling). Turning toward gradients is mediated through PKG; however, we could not support a direct PLC role because results were opposite of results from other ciliate models. Advisors/Committee Members: Firkins, Jeffrey.

▼ The poultry industry is of great economic importance in the United States. Increasing the muscle yield of poultry is of great interest to the poultry industry, but the mechanisms that control muscle growth and development are not fully understood. Broiler-type chickens and turkey have been shown to have increased muscle yield, especially pectoral muscle (breast muscle), and this increased muscularity has been shown to be due to increased muscle fiber number (hyperplasia) and/or increased muscle fiber size (hypertrophy). Some lines of quail have been shown to have similarly increased pectoral muscle size, and to exhibit hypertrophy or hyperplasia. However, the heavy weight (HW) line of quail has not been characterized, and is of particular interest as previous studies indicate a possible increase in pectoral muscle size relative to body weight compared to a control line. Embryonic and posthatch growth curves are reported here for the HW line as well as a control line (RBC). HW quail show an initially smaller size, but quickly surpass RBC line quail during embryonic growth. At hatch, HW quail are significantly larger than RBC, and continue to grow more quickly than RBC quail, to a 2.3 fold increase compared to RBC at 85 days posthatch. The HW line also shows an increased right pectoralis major (r. p. major) size and weight compared to the RBC line from posthatch day 4, and is a greater percentage of body weight by day 8 posthatch. By day 85 posthatch, the HW r. p. major is 2.7 times larger than that of the RBC. The HW r. p. major has more DNA than the RBC from the day of hatch, indicating the presence of more nuclei, and probably a greater cell number. At day 15 posthatch, the HW r. p. major has 1.6 fold more fibers than the RBC r. p. major, and the mean fiber cross-sectional area is 3.6 fold larger. By day 85, the RBC fiber cross-sectional area is 471.45μm2 and the HW is 839.22μm2. No significant differences were seen in satellite cell proliferation rates at day 6 or 15 posthatch, although the HW line has a greater number of cells at day 6 posthatch. Further study would be required to determine whether satellite cell proliferation differences are a factor in the muscle growth differences seen in HW and RBC quail in earlier or later development. The increased size of HW muscle is due both to hypertrophy and hyperplasia. Advisors/Committee Members: Lee, Kichoon.

▼ Mammary parenchyma (PAR) is present at birth in negligible quantities, undergoes extensive postnatal growth, and will ultimately comprise milk secretory tissue. Over-nutrition in early life may negatively impact future milk yield (MY) by affecting PAR growth. Monitoring in vivo growth of PAR has historically been difficult, necessitating slaughter studies to measure PAR quantity, which precludes measurement of MY. Advances in ultrasound (US) technology warrant revisiting its use as a non-invasive tool to monitor PAR growth in vivo. Holstein heifers (n = 24; 41±1kg initial BW) from a single farm were randomly assigned to 1 of 3 milk replacers (MR) at 2-3d of age. Heifers were fed MR at 660 g/d until weaning at 42d. All MR contained 27% CP (DM basis); fat sources and total fat (DM basis) were as follows: A) only lard, 17% fat, B) animal fat supplemented with 1.25% NeoTect4® (MR, Provimi North America, Brookville, OH), 17% fat, and C) milk fat, 33% fat. Calves had ad libitum access to a common calf starter (20%CP) and water for the duration of the 56d trial. A real time B-mode US with a 7.5MHz convex probe was used to examine two-dimensional (2D) PAR area in all 4 glands of heifers once weekly from 2-3d of age to harvest at 56d. Individual digital images of each gland were saved for further analysis. The left front and left rear glands were also examined by US 24h post-harvest in order to validate final US measurements, and then bisected to produce a sagittal plane view of PAR for comparison to US images. In all cases, 2D areas of PAR were determined using ImageJ software (NIH). Data were analyzed with a mixed model in SAS that accounted for repeated measures. Additionally, 8wk paired data were analyzed using the correlation procedure. PAR areas grew over time (week, P = 0.001) and were not different due to diet (P = 0.947). Initially, PAR area averaged 0.049±0.020 cm2/gland; at day 56 it averaged 0.420 ±0.015 cm2/gland. These values changed over time in a complex pattern (linear, P = 0.001; quadratic, P = 0.001; cubic, P = 0.003). On average, front glands were smaller than rear glands (P = 0.002), while there was no difference between the two front (P = 0.834) or the two rear (P = 0.926) glands. Positive correlations existed between all paired variables analyzed (Bisected PAR area; PAR area ante-mortem from US; PAR area postmortem from US; all r > 0.60). As long as dietary nutrients are not limiting, it seems that PAR growth may rely more on initial tissue foundation within a given animal rather than on dietary manipulation prior to 2 mo of age. Therefore, determination of PAR area in vivo may be useful in distinguishing potential high-producing animals at an early age. Future studies will use US to monitor PAR growth during the preweaning period with later comparison to first lactation MY. Lastly, methodology used here demonstrates that US is an effective tool for measuring weekly changes in PAR area in vivo and may be utilized in future experiments. Advisors/Committee Members: Daniels, Kristy.

▼ Dried distillers grains with solubles (DDGS) may be a cheaper source of calories than corn for ruminants. However, including high levels of DDGS in ruminant diets may decrease average daily gain (ADG), decrease marbling, and have negative impacts on health due to the high nitrogen, fat, and sulfur (S) in DDGS. High S can be fatal because it increases rumen H2S concentration which can cause a disorder known as polioencephalomalacia (PEM). Experiments were conducted in cattle and sheep to discover: 1) feeding and management strategies that would allow increased use of DDGS in ruminant diets without negatively affecting feed intake, performance, and carcass characteristics, and 2) methods that would decrease negative effects of high dietary S on feed intake, performance, and rumen H2S concentrations in ruminants consuming DDGS-based diets ad libitum. In the first experiment, increasing intake of the DDGS-based diet to achieve greater ADG during the growing phase increased marbling, while increasing intake of the corn-based diet to increase ADG decreased marbling. These data suggest 65% DDGS are comparable to corn as a source of calories during the growing phase and may be prescription-fed without negatively impacting marbling. To investigate ways to decrease the negative impacts of high S, experiments examined the effects of 3 dietary Cu concentrations on performance, mineral absorption, carcass characteristics, and ruminal S metabolism of cattle fed 60% DDGS diets. Copper supplementation improved feed efficiency; however, the effects of Cu on rumen S metabolism were minimal. Further experiments were conducted to determine the interaction of monensin and forage supplementation for steers fed 60% DDGS. Cattle fed 60% DDGS diets benefited from increased dietary forage and the effects of monensin and forage were additive for ADG and final body weight. Monensin supplementation decreased rumen H2S concentration. Based on this research it was discovered that sulfuric acid in DDGS, not ruminal short chain fatty acids, may cause low rumen pH and influence the maximum dietary inclusion of DDGS. Acid burden impacts health and digestibility of animals. Therefore, the next experiments examined the effects of 0 to 60% dietary DDGS, thus increasing dietary acidity, on growing lamb performance and nutrient digestibility. Lambs fed the 20% DDGS diet had the greatest gains. Increases in dietary DDGS resulted in decreased digestion of DM and fat. Daily urine output increased while urine pH decreased with increasing DDGS suggesting urine is a major route for acid excretion when DDGS-based diets are fed. To buffer this acidity and examine its effect in cattle, additional experiments investigated the dietary inclusion of DDGS and its pretreatment with NaOH on ruminal metabolism. Rumen pH tended to decrease while rumen H2S gas concentrations increased with increasing DDGS inclusion. When DDGS was treated with 2% NaOH, rumen pH increased approximately 0.3 units. These data suggest low rumen pH may be causing reduced intake, growth rate, and increased incidence of PEM when DDGS-based diets are fed. Treating DDGS with 2% NaOH may increase rumen pH thereby decreasing H2S and alleviating PEM. Advisors/Committee Members: Loerch, Steve.

▼ The primary source of protein for milk production is of microbial origin, so increasing microbial protein supply should either increase milk protein or decrease the need for expensive bypass protein. Moreover, improving the consistency of prediction of microbial protein supply decreases the amount of protein that must be fed to the dairy cow, reducing urinary N excretion and decreasing feed costs. Methionine is co-limiting with lysine in most dairy diets. 2-hydroxy-4-(methylthio) butanoic acid (HMBi) is a methionine precursor for bacteria and might be degraded more slowly and, therefore, might be sustained longer over the feeding cycle for bacterial uptake or absorption than methionine itself. To show the effect of HMBi and methionine on bacterial population structure and protein synthesis, we used four continuous culture fermenters inoculated with rumen fluid from two lactating Holstein cows. We fed the cultures a normal dairy ration with a 50/50 ratio of concentrate and alfalfa thrice per day. Our experimental design was a 4x4 Latin square. Our treatments were control (CON), 0.11% HMBi (HMBi), 0.097% methionine (MET), and 0.055% HMBi plus 0.048% methionine (HMBi + MET). All doses were on an equivalent methionine molar basis. We dosed the stable isotopes 1-13C-methionine, 3D-methionine (methyl hydrogens labeled with deuterium) and U-13C-HMBi into the fermenters at six consecutive feedings to trace the incorporation of the carbon skeletons into microbial protein and methylation of substrates by methionine. We also infused NH3-N15 with the buffer during each period to measure efficiency of microbial protein synthesis. The data were compared using three orthogonal contrasts, all methionine treatments versus control and the linear and quadratic responses to methionine substitution by HMBi. Supplementation of methionine and HMBi had no effect on digestibilities of ADF and true OM. NDF and hemicellulose digestibility were linearly affected (P=0.04 and P<0.01, respectively) by supplementation. The flow of non-ammonia N, bacterial N, total N, and non-ammonia, non-bacterial N were not affected. Ammonia N flow tended (P=0.08) to be affected linearly. Concentration of NH3-N tended to be affected linearly (P=0.07) and quadratically (P=0.08). Peptide N was affected linearly (P=0.04) and tended to be affected quadratically (P=0.09). The proportion of bacterial N from NH3-N was affected linearly (P=0.02). Propionate production was affected linearly (P<0.01) and quadratically (P=0.05), and control was greater than the average of the three methionine treatments (P=0.01). Isobutyrate was affected linearly (P=0.05). Isovalerate tended to be affected linearly (P=0.08). Valerate was affected linearly (P<0.01) and quadratically (P=0.05), and control was less (P=0.01) than the average of the three methionine treatments. The production of total VFA was affected linearly (P=0.02). The acetate:propionate tended to be affected linearly (P=0.08) and quadratically (P=0.06). The increase in hemicellulose digestibility due to methionine supplementation indicates a possible increase in activity of hemicellulose degrading bacteria. Though relative changes in population abundance were not detected by DGGE, these bacteria might increase activity to support bacterial growth that is aided by methionine. The changes in VFA production also indicate a possible shift in activity of present populations. Advisors/Committee Members: Firkins, Jeffrey.

▼ The development of systemic and local endotoxin tolerance (ET) in mid-lactation cows that experienced chronic subacute ruminal acidosis (SARA) or acute SARA and subsequent endotoxin mastitis was investigated. Twenty-four Holstein cows, both primiparous and multiparous, were assigned to eight blocks of three cows grouped by milk production, parity, and days in milk. Cows within blocks were randomly assigned to one of three treatments: 1) Control (Con), 2) High grain (Hi; formulated to reduce milk fat), and 3) Acidosis (designed to reduce milk fat for short periods and potentially induce clinical signs of rumen upset during these periods). Con and Hi treatment animals were fed their respective diets throughout the trial. The Acidosis cows were primarily fed the Con diet, but the Acidosis diet was fed for two two-day periods one week apart. Both Hi and Acidosis diet cows experienced SARA as measured by milk fatty acid profile alterations. Hi cows experienced reduced milk fat percentage, increased trans-10-octadecenoic acid, trans-10, cis-12 conjugated linoleic acid, and increased total trans fatty acids. Acidosis cows had increased trans-10-octadecenoic acid and increased total trans fatty acid content during acidosis bouts. On d 20, all cows were challenged via intramammary infusion with 10 µg of lipopolysaccharide (Escherichia coli 0111:B4) in one mammary quarter 3 h after morning milking. No systemic indicators of ET were observed among treatments. Evidence of an ET response at the local level of the mammary gland was observed. Hi diet animals had reduced milk amyloid A concentration at 12 and 24 h post-LPS in comparison with Con diet cows. Acidosis cows also had lower milk amyloid A concentrations than Con diet cows at 12 h. In addition, Hi diet cows had lower peak somatic cell count at 12 h when compared with Con diet cows. Our data suggest cows which experience varying degrees of SARA and subsequent experimental endotoxin mastitis experience endotoxin tolerance at the level of the mammary gland, but not a systemic reduction in inflammatory mediators. Advisors/Committee Members: Hogan, Joseph S.

▼ Grower pigs (n = 237) initially weighing 24.3 kg BW were used to evaluate the effects of reduced micromineral supplementation and varying levels of Fe and Zn on growth, feed efficiency, hematology, carcass characteristics and pork quality. A randomized complete block design with 7 dietary treatments replicated 7 times was used in the study. Treatments consisted of 1) basal diet with no added microminerals, 2) basal + 25% of NRC micromineral requirements, 3) basal + 50% of NRC micromineral requirements, 4) basal + 100% NRC micromineral requirements, 5) basal + 25 ppm Zn, 6) basal + 50 ppm Zn and 7) basal + 50 ppm Fe. Minerals were fed as mineral-proteonates and all diets incorporated organic Se-yeast at 0.3 ppm. When the average pen weight was 55, 80 and 115 kg BW pigs were bled with hemoglobin (Hb) and hematocrit (Hct) determined. At the end of the trial 3 pigs per pen were killed with carcass characteristics and meat quality measurements determined. The ADG, ADFI, and G:F for each of the 3 dietary phases and overall trial were not affected by dietary treatment (P > 0.10). The concentration of Hb and Hct volume were not different (P > 0.10) due to dietary treatment at each of the three dietary phases or the average of the trial. There were no differences in carcass characteristics such as hot carcass weight or fat free lean index (P > 0.10) due to dietary treatment. Loin pH, color (L*, a*, and b*), and moisture loss were not different (P > 0.10) by dietary treatment. The subjective marbling scores and IMF content of loin samples were also not different due to dietary treatment. Firmness scores decreased cubically (P < 0.05) as the level of all microminerals was increased. Also, loins from pigs supplemental Fe had greater (P < 0.05) firmness and wetness scores. These results indicate that there are sufficient microminerals available in a corn-soybean meal based diet to meet the grower-finisher pig’s requirement for growth and hemoglobin synthesis. There are no detrimental effects of reducing micromineral, Zn or Fe supplementation on carcass characteristics and pork quality. Advisors/Committee Members: Mahan, Donald.

▼ Two experiments, using 24 purebred Berkshires and 12 commercial crossbred pigs were conducted to evaluate the influence of fresh meat quality found in Berkshire hams with commodity hams, the influence of an early-postmortem, rapid chilling method, and the influence of cooking methodology on the processing yields, cooked color, and texture profile of cured cooked hams. The pigs were harvested at The Ohio State University Meat Science Laboratory. Experiment 1 used a 2 x 2 factorial design to evaluate chilling method and cooking method on resulting cooked ham characteristics. Left hams from the carcasses were assigned randomly to one of the two chilling methods (rapid vs. standard), and the right am was then assigned to the other chilling method. Internal ham temperature was recorded at 0, 2, 4, 8, and 12 h during the postmortem chilling process. An ultimate pH was recorded for both the Semimembranosus and the Biceps femoris muscles at approximately 24 h postmortem. Two measurements were taken in the Semimembranosus and Biceps femoris, lateral and medial, from which the Ham pH was comprised. Hams were injected (target of 125% green weight), macerated, tumbled, and netted. Then half of the hams from each of the two chill methods were assigned to each of the cooking methods (Traditional or Delta-T cooking method) balancing for equal number of left and right side across all treatments. Experiment 2 used a 2 x 2 factorial design to evaluate Berkshire hams vs. commodity hams and cooking method on resulting cooked ham characteristics. All hams were chilled using the standard chill protocol from Experiment 1. Hams were processed and cooked following the procedures used in Experiment 1. In both experiments, pump yield ((green weight / pump weight) x 100), cook yield ((post-cook weight / netted weight) x 100), total yield ((24 h chill weight / green weight) x100) and post-cook weight and 24 h chill yields were measured. A 2.54 cm thick center slice was removed from each cooked ham to collect L*, a*, and b* values and a series of objective texture analysis measures (Warner-Bratzler shear force, hardness, cohesiveness, resilience, and springiness). There were no significant interactions between chill method and cook method in Experiment 1 or between fresh ham source (Berkshire or commodity) and cook method in Experiment 2. Therefore, results for chill method and fresh ham source were analyzed using the 48 hams within Experiment 1 and Experiment 2, respectively, and cook method was analyzed using the pooled results of from both Experiment 1 and Experiment 2. The temperature least squares means of hams subjected to the rapid chill treatment were numerically 0.65, 1.80, 3.11, and 3.09°C less than those of the normal chill at 2, 4, 8, and 12 h, respectively, however, only the difference at 4 h was significantly different (P < 0.05). The rapid chill method did not result in any differences (P > 0.05) in cooked ham characteristics. Commodity type hams from the commercial pigs had a greater (P < 0.05) trimmed green weight compared to Berkshire hams (7.9 vs. 7.3 kg, respectively). Berkshire hams had a 2.5% greater (24.7% vs. 22.3%; P < 0.05) pump yield than the commodity hams, however, there were no differences (P > 0.05) in cook yield (83.3% vs. 83.6%). Berkshire hams produced a greater (P < 0.05; 3.9%) total yield. There were no significant differences in cooked ham slice color, however, ham slices from Berkshire pigs had a more desirable (P < 0.05) Warner-Bratzler shear force (1.71 vs. 1.45 kg) and significantly greater (5.6%) springiness. The hams that were cooked using the Delta-T cooking methodology had a 2.3% greater (P < 0.05) cook yield than hams cooked using the traditional method, however there was no difference (P > 0.05) between cooking methods for total yield. The results for cooked ham slices from the Delta-T method were similar to those cooked via the standard method with the exception of Delta-T Slices having a lower (P < 0.05) a* value (redness; 15.5 vs. 16.2) and greater cohesiveness (3.51 vs. 3.37). Advisors/Committee Members: Zerby, Henry.

Advisors/Committee Members: Cahill, V. R.

▼ The influence of early post-mortem enhancement and the inclusion of dextrose in the brine solution were evaluated using crossbred market lambs (n = 41; average live weight = 46.16kg). Immediately post-harvest, carcasses were fabricated removing the leg and shoulder and then splitting the midsection (intact rack and loin) along the longitudinal axis of the spine. The left side was designated as the treatment side (pre- or post injection) with the right side being the paired control. Enhancement treatments were non-enhancement (control sides), standard solution (water, 2.0% salt and 0.5% tri-polyphosphate; STND) or (water, 2.0% salt, 0.5% tri-polyphosphate and 3% dextrose; DEXT). Loins designated to the pre-rigor treatment were injected with either STND or DEXT approximately 45 min post-mortem and those designated to the post-rigor treatment were injected approximately 24 h postmortem. There was an interaction (P < 0.05) between time of injection and type of solution for pump yield, 24-h purge loss and 48-h yield. Pre-rigor enhanced midsections had greater (P < 0.05) pump yields than the post-rigor enhanced loins. Furthermore, midsections enhanced post-rigor with the STND solution had greater (P < 0.05) pump yields than those enhanced with the DEXT solution. The 24-h purge loss and 48-h yield followed the pattern of pump yield, in that greater pump yields also produced greater 24-h purge loss, but still resulted in greater 48-h yields. After 48-h post harvest, the longissimus was removed from each midsection and sliced into eight, 2.54 cm thick chops, and a pair of chops were then randomly assigned to one of the four aging categories (2, 3, 4, and 7 day) to measure thaw loss, cook loss and slice shear force. In general, thaw loss followed pump yield with greater (P < 0.05) for pre- vs. post-rigor enhancement and greater thaw loss for chops from enhanced midsections vs. control sections. Additionally, there was a trend for thaw loss to increase with additional post-mortem aging. Cook loss was influenced (P < 0.05) by type of solution and followed the pump yield associated with the type of solution with pump yield and corresponding cook loss being STND>DEXT>control. Post-mortem aging had a significant effect on slice shear force values with chops becoming more tender (P < 0.05) with additional aging. No differences (P > 0.05) were observed in tenderness due to timing of injection or type of enhancement solution. As enhancement resulted in increased salable yields without additional detrimental impacts, enhancement may and no detrimental were produced as a result of enhancement, this process may be a viable option for the lamb industry to improve economic viability while targeting increasing consumer demand and market share. Advisors/Committee Members: Moeller, Steven.

▼  Multiple experiments investigated mineral metabolism in the pig with the goal to reduce mineral excretion (environmental impact). The effects of 2 Ca and P levels (Ca:P) and 5 trace mineral (TM) treatments on nursery pig growth and tissue mineral retention were evaluated. Increasing Ca:P reduced Fe and Mn in soft tissues (P < 0.05). Measurements such as BW, G:F, and organ contents of several minerals were unaffected by Ca:P level across TM treatments, but were affected (P < 0.05) when no trace minerals were added to the diet. In conclusion, increasing dietary Ca reduces growth and mineral status, especially when dietary trace mineral content is low. Also investigated were the effects of phytase and the prebiotic inulin on tissue mineralization and apparent mineral digestibility in weanling pigs (Exp. 1) and mineral balance in grower pigs (Exp. 2). Experiment 1 used 3 levels of inulin, 2 levels of phytase, and carbadox (antimicrobial). Experiment 2 used 2 levels of inulin and 2 levels of phytase. Overall, inulin did not affect growth or mineral digestibility. Phytase increased (P < 0.05) growth, tissue mineralization, and Ca and P digestibility. In conclusion, dietary inulin does not affect the mineral status or growth of pigs. Phytase increases growth and mineral bioavailability. Inulin and phytase do not interact to affect mineral status. Four experiments studied Fe requirements of young pigs. Exp. 1 found that, as BW increased, hemoglobin (Hb) and hematocrit (Hct) declined (P < 0.01). Exp. 2 evaluated the following Fe injection protocols: 1) 200 mg Fe at birth; 2) 300 mg Fe at birth; or 3) 200 mg Fe at birth + 100 mg Fe at 10 d. Protocols 2 and 3 resulted in similar Hb and Hct, but both resulted in greater (P < 0.05) Hb and Hct than protocol 1. Exp. 3 used protocols 1 and 3 from Exp. 2. Weaned pigs of each protocol were fed diets supplemented with 0, 80, or 160 ppm Fe. The greater Fe injection group had greater (P < 0.01) Hct through 21 d. As dietary Fe increased, Hct increased on d 14, 21, and 35 (P < 0.01). Dietary Fe increased (P < 0.01) ADG from d 21 to 35 d and 0 to 35 d. Exp. 4 evaluated 3 supplemental levels of dietary Fe (80, 160, and 240 mg/kg diet), 2 injected Fe treatments (200 or 300 mg Fe at birth), and birth weight (< 1.5 or ≥ 1.5 kg). The 300 mg Fe injection resulted in lower BW (P < 0.05). There were also birth weight x injected Fe and birth weight x dietary Fe interactions (P < 0.01) for ADG. Lighter birth weight pigs receiving 200 mg injected Fe had increasing gains to the 240 ppm supplemental dietary Fe, while the growth of light weight pigs injected with 300 mg Fe plateaued at the160 ppm Fe level. In conclusion, Hb and Hct are affected by pig BW, but Fe injected preweaning affects initial postweaning growth. Advisors/Committee Members: Mahan, Donald.

▼ Ruminant animals obtain most of their nutrients from fermentation products produced by a ruminal microbiome. Since the 16S rRNA gene (rrs) was used as a phylogenetic marker in studies of ruminal microbiome, the ruminal microbiome that is not culturable has been identified. Recently microarray or pyrosequencing analysis has been greatly contributed to identifying numerous rrs sequences at the same time. However, few studies have used the microarray or pyrosequencing analysis to investigate the ruminal microbiome. The overall objective of my study was to examine ruminal microbial diversity as affected by dietary modification and to compare microbial diversity between the liquid and adherent fractions using the microarray and pyrosequencing analysis. In the first study (Chapter 3), a meta-analysis of all the rrs sequences of rumen origin deposited in the RDP database was performed. Collectively, 5,271 and 943 OTUs of bacteria and archaea, respectively, were identified at 0.03 phylogenetic distance. The predominant bacterial phyla were Firmicutes and Bacteroidetes, while the largest archaeal phylum was Euryarchaeota. More than 50% of all the bacterial sequences could not be classified into any known genus. In the second study (Chapter 4), select cultured bacteria and uncultured bacteria were quantified using specific real-time PCR assay. The populations of some uncultured bacteria were as abundant as those of major cellulolytic cultured bacteria. In the third study (Chapter 5), the diversity of ruminal microbiome in cattle was examined using rrs clone libraries. Six known rrs clones were used to validate the phylogenetic microarray (Chapter 6). In the fourth study (Chapter 6), a phylogenetic microarray that detects 1,600 OTUs of ruminal bacteria was developed in a 6x5K format based on the OTUs identified in Chapter 3. The utility of the phylogenetic microarray (referred to as RumenArray) was tested in comparative analysis of fractionated bacterial microbiomes obtained from sheep fed two different diets. Species-level OTUs are commonly defined at 0.03 phylogenetic distance based on full-length rrs sequences. However, the current 454 pyrosequencing method is not able to produce full-length rrs sequences. To identify a region or phylogenetic distance that can support species richness estimate as reliably as full-length rrs sequences, in the fifth study I compared datasets of partial rrs sequences corresponding to different variable regions with a dataset of nearly full-length rrs sequences (Chapter 7). The results indicated that the V1-V3 and the V1-V4 regions at 0.04 distance provide more accurate estimates than other partial regions. Based on the results obtained in Chapter 7, pyrosequencing analysis was performed to investigate bacterial diversity in the rumen of cattle as affected by supplementation of monensin or fat in my sixth study (Chapter 8). Supplementary fat resulted in significant shift of bacterial populations when compared to the control diet, but supplementary monensin did not. The overall results of the above studies provided further insights into the microbial microbiome as affected by different diets and different fractions. Integration of RumenArray and pyrosequencing techniques will improve our understanding of the ruminal microbiome and its integration with nutritional studies. Advisors/Committee Members: Morrison, Mark.

▼ This dissertation examined the effects of high dietary levels of organic and inorganic Se on growth performance, toxicity characteristic in grower-finisher pigs and the long term effects on sow performance, and the tissue Se concentration and subsequent toxic symptoms in both the sow and progeny. The experiments demonstrated that feeding a diet containing 5 to 10 ppm inorganic Se (sodium selenite) or 15 ppm organic Se (Se-enriched yeast) resulted in toxic responses in grower-finisher pigs. Serum and tissue Se content increased as dietary Se level increased but was higher when organic Se was fed. Colored hair pigs (red or black) were more resistant to Se toxicity compared to white haired pigs in both Se sources. The excretion of the essential micro-minerals (Zn and Mn) increased in the bile as dietary Se level increased and was higher when pigs were fed inorganic Se. When inorganic Se was fed, Se toxicity occurred at 7 ppm, but at 10 ppm organic Se when fed to reproducing sows. Serum GSH-Px activity of sows and pigs was not affected by dietary Se level or source. Serum GOT activities at the 12 wk period increased as dietary Se level increased and were approximately 2 fold higher when pigs were fed inorganic Se. This suggested increased cellular damage as dietary Se level increased particularly when inorganic Se was fed. Dark colored of bile at high dietary Se levels suggested that hepatic tissue damage occurred. Selenium transfer through the placenta and milk from dam to litter was higher when organic Se was provided during gestation and lactation. Tissue and serum Se concentrations of sows and pigs were higher when sows were fed organic Se. This demonstrated that the labile Se (liver) when the organic Se was provided supported high milk Se concentration. The higher Se transfer from dam to litter consequently increased the Se status of progeny when organic Se was fed. Hoof separation and hair loss in nursing pigs at 14 days of age occurred above 7 ppm Se when sows were fed inorganic Se. When organic Se was provided, only hair loss was observed at 10 ppm Se. Hair Se concentration was a good indicator of Se status, particularly when pigs were fed high levels of Se. Amino acid composition of pig hair was similar among three different colored hair (white, red and black) pigs. Red colored hair of gilts contained more Se and thicker than white colored hair when gilts were fed normal diets containing .3 ppm of inorganic Se. Consequently, Se requirement may differ by breed hair color. Hair Se content and hair diameter were affected by hair location of the body. Advisors/Committee Members: Mahan, Donald C.

▼ Yeast cultures are commonly used in the animal industry as feed supplements. Frequently found in the dairy industry, yeast cultures may enhance intake, digestibility, and milk production. There is little research examining the efficacy when given to beef cows exclusively on a pasture. Yeast (Saccharomyces cerevisiae) culture (YC) was provided in a free-choice vitamin-mineral mix. The effects of YC on organic matter intake (OMI), apparent organic matter digestibility (OMD), neutral detergent fiber degradability (NDFD) and in-situ NDF were examined over three periods (winter, early summer and late summer). There were no differences between the two groups for winter and early summer. OMI (kg/d) was higher (P=0.04) in the YC group (5.69 kg/d) compared to the control group (4.79 kg/d) in late summer. In addition, when intake was corrected for weight, OMI was also higher (P=0.02) for the YC group (11.6 g/kg BW) compared to the control group (9.0 g/kg BW). Similar to OMI, OMD was higher (P=0.04) in the YC group (27.2 %) compared to the control group (21.1%) late summer. NDFD was also higher (P=0.03) in the YC group (39.2 %) compared to the control group (32.3%) late summer. No changes were found in the in-situ degradability of NDF. There was no difference in milk production 60 days in milk (DIM) over two years. However, YC supplemented cows had (P=0.06) higher (5.6 kg) vs. (4.3 kg) 120 DIM estimated milk production in the first year and also had (P=0.05) higher (6.3 kg.) vs. (5.0 kg.) 120 DIM estimated milk production in the second year. No changes were found in calf weight (per day of age), birth weights, or weaning weights. Yeast culture supplements are shown here to have positive production responses to beef cattle on a fescue-based pasture. The responses are focused in the late summer compared to early summer and winter months. Advisors/Committee Members: Boyles, Stephen L.

▼ The onset of adult hazard avoidance behavior (fear motor patterns) occurs during the critical period of development in domesticated canines. In wolves, the onset of adult hazard avoidance behavior occurs at approximately 19 days (Coppinger and Coppinger, 2001). This onset is delayed in domestic dogs, taking place as late as day 72 in the Labrador Retriever (Coppinger and Coppinger, 2001). The objectives of this study were to identify, compare, and contrast the onset and expression of adult hazard avoidance behavior across three breeds of puppies between four and ten weeks of age and examine developmental breed differences in heart rate, behavior, and salivary cortisol concentrations. Ninety-eight puppies were tested within three purebred breeds: Cavalier King Charles Spaniels (n=33), Yorkshire Terriers (n=32), and German Shepherd Dogs (n=33). Data were collected weekly beginning when the puppies were 4-5 weeks of age and continuing until the treatment group puppies demonstrated hazard avoidance behavior, reached ten weeks of age, or left the breeder home. Puppies took part in four tests each visit: a Novel Item Test, Teeter-Totter Test, Step Test, and Loud Noise Test. During each test, the presence or absence of crouching and hazard avoidance behavior were noted. Heart rate was measured initially, following each test, and at the conclusion of the testing period. Saliva samples were also collected to measure salivary cortisol in the puppies prior to testing and 20 minutes following the final test. Our results indicated a significantly (P < 0.05) later onset of hazard avoidance behavior in Cavalier King Charles Spaniels compared to both German Shepherd and Yorkshire Terrier puppies. The proportion of treatment puppies exhibiting hazard avoidance behavior at any point was also significantly (P < 0.01) different: Yorkshire Terriers (82%), Cavalier King Charles Spaniel (53%), and German Shepherds (26%). Yorkshire Terriers demonstrated the highest (P < 0.05) heart rates at five weeks of age, while Cavalier King Charles Spaniel heart rates were the lowest (P < 0.03) from six through eight weeks of age. Significant (P < 0.05) breed differences in puppy mobility were found beginning at six weeks of age, with German Shepherds demonstrating the most mobility and Cavalier King Charles Spaniels the least. There were also significant breed (P < 0.01) differences in the crouch response to the Loud Noise Test, regardless of age, with Cavalier King Charles Spaniels demonstrating the highest incidence of crouching followed by the Yorkshire Terriers. Among treatment puppies of all breeds, the incidence of crouch was significantly (P < 0.01) greater from four to six weeks of age than seven through nine weeks of age, regardless of breed or gender. Puppies that exhibited hazard avoidance behavior also demonstrated a tendency (P < .07) of higher concentrations of cortisol from the post-test salivary collection compared to the pre-test collection. No other puppies (treatment puppies not demonstrating hazard avoidance behavior and control puppies) showed this tendency. The results of this study support the hypothesis that behavioral development and the onset of hazard avoidance behavior vary across breeds of domestic dogs. Advisors/Committee Members: Ottobre, Joseph.