Major

Animal Science and Technology

Advisor

Dr. Maria Hoffman

Advisor Department

Animal and Veterinary Science

Date

5-2018

Comments

For this project, 35 adult Holstein cows were split into two groups based on the amount of milk produced during their previous lactation. Specifically, cows that produced ≥ 25,792 kg of milk were classified as high producers and cows that produced ≤ 18,896 kg of milk were classified as low producers. Blood samples from their corresponding calves were then collected within 24 hours of birth. Calves born to low and high producing dams are referred to as LOW and HIGH respectively. Total serum triglycerides and total cholesterol were analyzed at the University of Missouri Veterinary Diagnostic Laboratory and oxidative stress was measured using a plasma protein carbonyl assay. Data were analyzed in SAS using PROC MIXED with maternal milk production as a covariate and differences were considered statistically significant when P ≤ 0.05 and a tendency when 0.05 < P ≤ 0.10. Efficiency of TG absorption appears to be gender dependent. Additionally, these data suggest that LOW female calves are absorbing more lipid from colostrum than HIGH female calves which could aid in maintaining energy balance. Completion of this project has allowed me to expand my career and heighten my knowledge of research and laboratory work to the level that is expected of veterinary students. Since I will be a veterinary student starting next fall, I feel prepared and confident that I will be able to partake in research throughout my veterinary school experience. Additionally, gaining knowledge and experience about this subject matter was important to me, since I will be treating livestock clinically and knowledge of calf health will allow me to approach situations differently and more effectively than if I never had the chance to carry out this research.

Keywords

Veterinary Medicine, Maternal Programming, Neonatal Health, Milk Production, Total Cholesterol, Circulating Triglycerides

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

The efficiency of the dairy industry relies heavily on the production of healthy calves. However, dairy operations experience high rates of calf mortality due to digestive and respiratory issues. One factor that could predispose calves to disease is the effects of maternal programming caused by high maternal milk production during pregnancy. We hypothesized that calves born to high producing dams will exhibit increased oxidative stress as well as increased circulating triglyceride and total cholesterol concentrations. Cows (n = 17) that produced ≥ 14,865 kg of milk during their lactations were classified as high producers. Alternately, cows (n = 18) that produced ≤ 10,069 kg of milk during their lactation were classified as low producers. At parturition, blood samples from the corresponding calves were collected within 24 hrs of birth (n = 5 to 13 per group per gender). Calves born to low and high producing dams will be referred to as LOW and HIGH respectively. Total serum triglycerides (TG) and total cholesterol (TC) were analyzed at the University of Missouri Veterinary Diagnostic Laboratory. Oxidative stress was measured using a plasma protein carbonyl assay (Sigma-Aldrich, St. Louis, MO). Data were analyzed in SAS using maternal milk production as a covariate. Differences were considered statistically significant when P ≤ 0.05 and a tendency when P > 0.05 ≤ 0.10. No effect of maternal milk production by gender was observed for circulating TC concentrations or plasma protein carbonyl concentrations when comparing LOW calves with HIGH calves for the gender by treatment interaction (P ≥ 0.42). However, LOW female calves had greater circulating TG concentrations (34.23 ± 1.65 mg/dL) when compared with LOW male calves (18.24 ± 2.37 mg/dL; P < 0.01), HIGH male (21.98 ± 2.06 mg/dL; P = 0.08) and HIGH female calves (19.57 ± 3.36 mg/dL; P = 0.06). In newborn calves, the small intestine has a vital role in facilitating passive transfer as well as nutrient absorption. If disrupted, this could impact calf health and metabolism. In conclusion, efficiency of TG absorption appears to be gender dependent. Additionally, these data suggest that LOW female calves are absorbing more lipid from colostrum than HIGH female calves which could aid in maintaining energy balance. A future study will evaluate histological changes in the gastrointestinal tract of calf neonates born to HIGH and LOW producing dams to better understand changes to lipid absorption and passive transfer.

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