Effect of Dietary Protein Level during Estrus Cycle: Nutrient Digestibility, Quality of Embryo and Pregnancy Rate by Embryo Transfer in Thai Crossbred Goats during Hot Season

Abstract

Tis study aimed to evaluate the embryo quality and embryo transfer rate of Thai crossbred goats fed different levels of protein in total mixed rations (TMR) during the hot season. Twenty-four non- pregnant Thai crossbred goats with an average body weight of 26±5.9 kg were assigned with a random complete block design (RCBD). Dietary treatments contained 8, 13, and 18 % crude protein (CP) in TMR. The feeding trial lasted for 42 days. Does (female goat) were scheduled to determine embryo quality by surgical laparotomy and flushing. At the end of the feeding trial, the digestion trial was conducted by the total collection method for a 5-day period. The results showed that the average total feed intake and feed conversion ratio did not differ among all treatments (p ˃ 0.05), however, digestible protein intake had increased from 70.39, 79.77 to 89.11 g/d in 8, 13, and 18 % CP group, respectively. Increasing CP levels in TMR resulted in linearly increased goat final body weight (30.25, 28.75, and 32.00 kg), weight gain (3.00, 4.00, and 4.25 kg), and average daily gain (ADG) (87.84, 114.87 and 121.63 g/d). Embryo quality (1, 1, and 3.5 morular follicle state) and pregnancy of embryo transfer rate (25, 25, and 50 %) of the animal received CP level at 8 and 13 % less than that 18 %. These results indicated that dietary protein level during program superovulation regimen affected the good quality of an embryo and the pregnancy rate in an embryo transfer in Thai crossbred goats.