Effects of short term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

"Ten Sarda dairy ewes (5 with high Body. Condition Score: H-BCS, BCS>2.5; BW. 48.8±5.4 kg; 5 with low BCS: L-BCS, BCS<2.5;. BW 36.2±4.7 kg) were subjected, after 7-day. preliminary (Prel) period, to short-term feed. restriction (FR, 50% of nutrient requirements). for three days followed by refeeding. (Re-Fed, 100% requirements) for three days.. Milk yield and composition (protein, fat, lactose,. MUN, SCC, fatty acids), and blood. parameters (glucose, NEFA, BUN, insulin,. GH, IGF-I, leptin) were monitored. Milk yield. decreased during FR in both BCS groups: at. day 3 it was 38% and 35% of Prel values in HBCS. and L-BCS ewes, respectively, reaching. Prel levels at Re-Fed in both groups. Milk fat. concentration was influenced by BCS¥sampling,. increasing in H-BCS ewes during FR,. but not varying in L-BCS ewes throughout the. trial. During FR, milk protein increased as. milk yield decreased. There was no change in. milk urea nitrogen concentration during FR,. but this decreased in both BCS groups during. Re-Fed. FR modified the FA profile of milk fat. in both BCS groups, increasing LCFA at the. expense of SCFA and MCFA. Some blood. parameters (NEFA, GH and IGF-I) were influenced. by BCS, whereas almost all parameters. were influenced by sampling. There was a. rapid return to initial levels in all parameters. except milk urea, blood urea and insulin at. Re-Fed."