Master of Science, The Ohio State University, 1967, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1966, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2017, Veterinary Preventive Medicine

A proper transition from gestation to lactation, ensuring a strong immune system and appropriate metabolic functioning, is critical to optimize health and performance of dairy cows and, therefore, promoting best animal welfare and profitability of dairy herds. Health events during the periparturient period such as dystocia and metritis produce important economic losses in dairy farms, and affect the welfare of dairy cows. Furthermore, several studies have suggested that the administration of nonsteroidal anti-inflammatory drugs (i.e., NSAIDs) after parturition decreased discomfort in the early postpartum period, and improved the welfare and performance of dairy cows. The aims of the present dissertation were to assess the effects of oral administration of acetylsalicylic acid following parturition on pain, inflammation, stress, behavior and productivity in postpartum dairy cows (Chapters 3 and 4); and the effects of metritis on physiological and behavioral responses in postpartum dairy cows (Chapter 5). The first two specific aims (Chapters 3 and 4) were performed in three large organic dairy farms where cows were treated with acetylsalicylic acid (ASP) or a placebo (PLC) following parturition. The results from this study showed that treatment with ASP may decrease pain and inflammation in dairy cows after parturition. Furthermore, cows treated with ASP tended to be more active (higher number of steps) and produced more milk compared to PLC cows. These results suggest that a short-duration treatment with ASP following parturition can improve welfare and productivity of dairy cows; thus, contributing to address some of the biggest challenges in the dairy industry. Furthermore, analysis by calving difficulty revealed that cows that experienced dystocic births behaved differently compared to cows that experienced normal births regardless of treatment. These findings revealed new knowledge on the behavior of dairy cows that experience dystocia, and suggest that the (open full item for complete abstract)

Committee: Gustavo Schuenemann (Advisor); Santiago Bas (Committee Member); Katy Proudfoot (Committee Member); Marco Coutinho da Silva (Committee Member) Subjects: Veterinary Services

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1976, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1975, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1958, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1958, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Master of Science, The Ohio State University, 2016, Veterinary Preventive Medicine

The objective of the present study was to assess the effect of postpartum uterine diseases on milk yield (kg/day), and milk components (percent fat and protein, and SCC). Lactating cows (n = 3,217) from 2 dairy herds were screened for retained placenta (RP; >24 hours after parturition), metritis (MET) within 20 days in milk (DIM), and clinical endometritis (CE) at 26 ± 3 DIM. Milk yield and components from the DHIA test-days up to 305 DIM and reproductive performance at first service were collected. Weekly, a list of cows was obtained using on-farm computer records screened for RP, MET, and CE. Parity (lactations 1, 2 and =3) of cows was accounted for milk yield, milk components, and reproduction. The statistical analyses were performed using MIXED (milk yield and components), GLIMMIX (risk factors associated with uterine diseases and reproduction), and CORR (correlation of risk factors with uterine diseases) procedures of SAS. Cows diagnosed with MET or CE had a negative effect on milk yield, increased milk fat percentage and SCC, and reduced reproductive performance at first service. Regardless of parity, lactating cows diagnosed with MET and CE had significantly reduced milk yield (by 2 to 3 kg/cow/day) for at least one of the first 4 DHIA tests (P < 0.05), but no difference was observed in subsequent tests. For the first 2 DHIA tests relative to calving, lactating cows diagnosed with MET and CE had significantly higher SCC and fat content compared with cows without MET and CE (P < 0.05). Milk protein content was not different between cows with or without uterine diseases. Cows with MET and CE had increased (P < 0.05) DIM to first service and significantly lower (P < 0.05) pregnancies to first service compared with cows without MET and CE, regardless of parity. In conclusion, uterine diseases (MET and CE) decreased milk yield and altered milk components (primarily SCC and fat) early in lactation; Furthermore, MET and CE were substantial risk factors for reduced r (open full item for complete abstract)

Committee: Gustavo Schuenemann (Advisor); William Weiss (Committee Member); Hans Bothe (Committee Member); Santiago Bas (Committee Member) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 2007, Veterinary Preventive Medicine

The research herein evaluates the effect that antimicrobials used at the end of lactation have on udder health in the subsequent lactation. The first section of this dissertation discusses the importance of the dry period for the mammary gland and its relevance for production of high quality milk in the following lactation. The second section addresses the importance of sampling strategy and interpretation of microbiological culture results in the diagnoses of intramammary infections. The third section evaluates the utility of farm records and quality milk indicators in the identification of infected cows at the end of lactation. The fourth section evaluates the effect of the selective use of antimicrobials at the end of lactation on occurrence of clinical mastitis and on milk yield in the lactation after treatment. The present study evaluated the effect of somatic cell count levels at the end of lactation on the occurrence of clinical mastitis and milk yield. Cows with an elevated somatic cell count at the end of lactation had an increased hazard of contracting clinical mastitis and they had reduced milk yield in the following lactation even though they received antimicrobial treatment. For cows with low somatic cell counts at the end of lactation, the effect of antimicrobial dry cow therapy on the occurrence of clinical mastitis depended on the number of lactations. Increased hazard of contracting clinical mastitis for uninfected second lactation cows treated at dry-off was observed. The effect of dry cow therapy on the milk yield of uninfected cows was shown to be variable from farm to farm, with no effect, an increase, or a decrease in milk yield, depending on the farm. Results indicate the importance of careful consideration of farm characteristics and level of somatic cell counts at the end of lactation before advising the use of antimicrobials.

Committee: Paivi Rajala-Schultz (Advisor) Subjects: Biology, Veterinary Science