Date of Award
5-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Animal and Veterinary Sciences
Committee Chair/Advisor
Dr. Susan Duckett
Committee Member
Dr. Susan Duckett
Committee Member
Dr. Eliot Jesch
Committee Member
Dr. Matais Aguerre
Abstract
Cross-bred ewes carrying twins, confirmed via ultrasound, were split into two groups: nutrient-restricted (NR), n=15, and control (CON), n=16. On day (d) 86, at 60% of the NRC requirements, nutrient restriction began and lasted until parturition, at which point ewes were placed back onto a regular diet. After parturition, milk samples and lamb weights were taken on days 1, 7, 14, and 21. Milk lipids were then extracted using modified methods proposed by Hara and Radin (1978). Lipid samples were weighed and then methylated following the procedure outlined by Lock and colleagues (2013). Methylated samples were then analyzed by gas chromatography. Retention times were compared to the retention times of standards to identify the numerous fatty acids within each sample. Fatty acid amounts were put on a percentage basis. Using a repeated measures model, lamb weights, milk yield, and fatty acid percent were analyzed through SAS. Milk yield had a day effect (P = 0.023), with day one having the highest yield. While no difference was seen between groups, NR ewes had lower milk yields for each sampling day. Lamb weight also had a day effect (P < .0001). All sample days were significantly different from one another, with an upward trend, as one would expect. While no difference was seen between the two groups, the NR lambs were consistently higher in body weight for each sampling day. Fatty acids on a g/100g basis had a treatment-by-day effect (p=.0290). The fatty acid percentage was highest in day one samples (NR>CON)—and lowest in day 14 NR samples. Twenty-seven different fatty acids (FA) were analyzed for any significance among treatment, day, and treatment by day. The FAs were examined individually and in groups such as total medium/short-chain fatty acids, long-chain fatty acids, and branched-chain fatty acids. FAs shorter than sixteen carbons had a day effect (P = 0.015). The total number of FAs greater than sixteen carbs was not significantly different in treatment or day or treatment-by-day, and branched chain fatty acids had a treatment-by-day effect (P = 0.004). The fatty acids C4:0, C8:0, C18:2, C18:1c9, and C181c12 all had treatment-by-day effects. C10:0, C12:0, C14:0, C16:0, C17:0, C18:0, C18:3, C20:4, C20:5, Iso-C14:0, Anteiso-C15:0, Iso-C16:0, C18:1t11, C18:2 c9,t11, C22:5, and C22:6 all had day effects. Some fatty acids showed no significant differences regarding treatment, day, or treatment-by-day. These fatty acids are C15:0, C14:1, C18:1t9, C18:1t10, and C18:1c11. Another prominent fatty acid in milk, C6:0, was absent from the milk samples in both NR and CON ewes.
Recommended Citation
Murray, Dakota, "The Effects of Pre-Parturient Nutrient Restriction on Milk Production, Milk Fat Percentage, Milk Fatty Acid Profile, And Lamb Growth in Sheep" (2024). All Theses. 4315.
https://open.clemson.edu/all_theses/4315