Effects of protein supplementation on Nellore cows' reproductive performance, growth, myogenesis, lipogenesis and intestine development of the progeny

Context. It is hypothesised that protein supplementation in pregnant Nellore cows during the dry season would improve reproductive performance in the next breeding season, as well as growth, myogenesis and intramuscular lipogenesis of the progeny until weaning. Aims. To evaluate the effect of maternal nutrition on cow reproductive performance, as well as on the growth, myogenesis and lipogenesis of the progeny until weaning. Methods. A total of 92 pregnant cows were fed on pasture, and half of the cows were also fed a mineral-protein supplement (36% crude protein) from 124 +/- 21 days of pregnancy to calving. Therefore, two treatments were tested: non-supplemented or supplemented cows. Progeny were weighed after birth, 130 days after birth and at weaning. Six newborn calves from each treatment were slaughtered to collect muscle and jejunum samples to analyse histology and gene expression. In addition, Longissimus thoracis muscle biopsies were collected at 11 days after birth and weaning for gene expression analyses. Key results. Supplemented cows had greater bodyweight (P = 0.03) and body condition score (P = 0.05) during gestation, and the pregnancy rate in the subsequent breeding season had a tendency (P = 0.10) to be greater. The progeny from supplemented cows had greater bodyweight at birth (P = 0.05). However, no differences (P > 0.05) were found in bodyweight at weaning or in the average daily gain during this period. Non-supplemented calves had greater SLC27A4 (P = 0.04) expression and a tendency for greater expression of SLC5A1 (P = 0.08) in the jejunum. Muscle gene expression data showed that progeny from supplemented cows had greater expression of myogenic (WNT10B), adipogenic (PPARG, ZFP423, CD36) and fibrogenic (TGF beta 1) markers at birth and at weaning (P <= 0.10). Conclusions. In conclusion, protein supplementation of pregnant Nellore cows leads to positive effects for subsequent reproductive performance and for muscle development of their progeny. In addition, the progeny from feed-restricted cows increases prenatal intestinal development for better nutrients absorption under a potentially impaired environmental condition. Implications. The use of protein supplementation in pregnant Nellore cows has a positive impact on the production system, increasing productivity in a cow/calf operation.