Ovarian follicular growth in Morada Nova sheep supplemented with crude glycerin before mating

Abstract

This study was aimed to investigate the follicular growth of Morada Nova sheep supplemented with crude glycerin before mating. Eighteen ewes were subjected to follicular wave and estrus synchronization with three injections of D-cloprostenol administered via IM, on days -14, -7 and -1 before mating. Animals were randomized into two groups, the control (n = 9), which received an oral drench of solution of 200 mL of saline solution, and the glycerin group (n = 9), which was supplied with 200 mL glycerol (n = 9), administered as an oral drench of crude glycerin in saline solution (9:1), 1h after morning feeding. Glycerin was supplied for 6 days, beginning 7 days from the mate. Growth follicular pattern was monitored daily by transrectal ultrasonography during the period of glycerin supplementation. Blood samples were taken during glycerin administration for progesterone and glucose analysis. There was a significant increase (P < 0.001) in blood glucose after supplementation with glycerin (mean of 66.2 ± 1.3 vs 56.5 ± 0.8 mg/dL). The greater availability of energy near to ovulation was beneficial to Morada Nova ewes, leading to a significant increase (P < 0.001) of large follicles (> 3 mm). At diagnosis of pregnancy, it was observed that approximately 87% (13/15) (87.5% control group vs. 85.7% glycerin group) of the ewes were pregnant. The group treated with glycerin presented an increase of more than 40% of prolificacy (1.7 ± 0.3 vs. 1.2 ± 0.2; P=0.21). In conclusion, the monitoring of follicular growth reveals that crude glycerin increases the follicular population of Morada Nova ewes, when applied before mating.