Effectiveness of peri-conception low dose of a highly gluconeogenic fast-release supplement in a fixed-time insemination program on ovarian and reproductive outcomes in meat goats.

This study verified the impact of glycerin supplementation during fixed-time insemination on ovarian and reproductive outcomes in meat goats. Fifty-one Anglo-Nubian crossbred does underwent estrus synchronization with 12 days of CIDR, followed by 0.075 mg of d-cloprostenol and 150 IU of eCG. Thirty-six hours after CIDR removal, 100 μg of GnRH was administered, and 18 h later, insemination (AI) was performed via intrauterine laparoscopy. At CIDR insertion, goats were grouped into the Control Group (n = 25) fed a TMR, and the DGS Group (n = 26), where TMR was supplemented with 100 mL of glycerin from CIDR insertion to two weeks after AI. DGS showed a lower diet intake (-13%; P < 0.001) and higher (+ 5.3%; P = 0.026) glucose levels. In the CIDR interval, DGS pregnant goats (DGSPG), presented in the first wave a higher number of growing follicles (P = 0.035) and greater follicular diameters (P < 0.05). After CIDR removal, the DGSPG exhibited a lesser small follicles (P = 0.016), greater follicle size (P = 0.005), and lower number of corpora lutea (P = 0.031). Pregnancy (32.0% vs. 46.2%) and twinning rates (87.5% vs. 66.7%) were similar in Control and DGS groups (P > 0.05). The control group had a higher proportion of non-pregnant goats that were follicular unresponsive during the CIDR interval (P < 0.01). In pregnant animals, no differences (P > 0.05) were found in fetal biometric measurements, kidding rate, or litter size. Glycerin stimulated follicle growth and CL regression before AI but did not promote reproductive effects post-AI.