74 Ovulatory Follicle and Corpus Luteum Development of<i>Bos Taurus</i> Cows Under Nutrient Restriction

Abstract Establishment and maintenance of pregnancy is a central concern to the cattle industry, as it strongly impacts efficiency profitability beef cow-calf operations. The objective this study was determine if nutrient restriction ovulatory follicle size corpus luteum (CL) volume Angus cows enrolled in estrous synchronization. A total 26 were housed at Virginia Tech – Shenandoah Valley Agricultural Research Education Center (SVAREC) equipped with Calan gate system for individual animal intake, stratified by body weight (BW) randomly assigned one two treatments: 1) diet that provided 100% requirements (MTN; n = 13) or 2) providing 70% (REST; 13). Nutrient calculated adjusted weekly based on BW using 2016 NRC version Beef Cattle Requirements Model Software. underwent an acclimation period of4 days exposed nutritional treatments 30 before Body measured daily automated scale, conventional livestock scale beginning end experiment. Cows synchronized 7-day CO-synch + CIDR protocol day -10. An estrus alert patch applied -3 read 0 assess expression estrus. Ultrasonography ovaries performed each event synchronization protocol. Data analyzed MIXED procedure SAS. Initial similar between (P 0.07; 600 ± 32 kg), but MTN compared REST had greater final &amp;lt; 0.01; 687 24 556 27 kg, respectively) average gain (1.35 0.18 -0.72 0.21 kg/d, respectively). Estrus numerically 0.185) (84.62%) than (61.54%) cows. Diameter largest 0.851) insertion (12.6 0.6 mm) removal (12.9 0.4 mm), 60 hours after (14.01 12.37 0.5 mm, Volume CL &amp;gt; 0.01) 5 (3211 ±13 mm3) 7 (5280.3 212 ovulation. In conclusion, during negatively affects diameter follicle, did not affect subsequent mature