Sex-dependent effects of maternal undernutrition on growth performance, carcass characteristics and meat quality of lambs

Abstract

The present study evaluated the sex-specific effects of maternal undernutrition induced by a lower natural pasture allowance (between gestation days 30 and 143) on growth performance, carcass and meat quality of lambs. Thirty-three single-bearing multiparous Corriedale ewes were randomly assigned to two natural pasture allowances: a) Sixteen HPA (high pasture allowance) ewes (eight carrying male and eight carrying female lambs) grazed on 14–20 kg of dry matter (DM)/100 kg of body weight (BW)/day; and b) Seventeen LPA (low pasture allowance) ewes (seven carrying male and ten carrying female lambs) grazed on 6–10 kg of DM/100 kg of BW/day. From gestation day 100 ewes were supplemented with rice bran. From gestation day 143 until weaning all animals grazed on natural pasture with unlimited availability and continued to be supplemented. After weaning lambs were individually ad libitum fed with a mixed diet (alfalfa hay and commercial mixed ration) until slaughtering at 200 days old. High pasture allowance ewes showed greater mean gestational BW (P ˂ 0.01), with differences between groups from day 55 on. Body weight differences between HPA and LPA ewes carrying female fetuses appeared earlier and were more profound (P ˂ 0.05) than those detected between ewes carrying male fetuses. Maternal undernutrition affected male (P = 0.05, sex-by-age-by-treatment and P = 0.01, sex-by-treatment interactions for lactation and fattening periods, respectively) but not female lamb growth. Carcass conformation and meat yield were affected by maternal undernutrition mostly in a sex-dependent manner. Male LPA lambs showed reduced area (P = 0.03, sex-by-treatment interaction) and tended to show reduced perimeter (P = 0.07, sex-by-treatment interaction) of the Longissimus muscle. Male LPA lambs showed narrower (P ˂ 0.01, sex-by-treatment interaction) and tended to show less compact carcasses (P = 0.09, sex-by-treatment interaction) and reduced buttock perimeters (P = 0.08, sex-by-treatment interaction). Sex-dependent muscle weight reduction was found for muscles Gluteobiceps, Supraspinatus and Semitendinosus (P = 0.02, sex-by-treatment interaction), with males but not females being affected. Maternal undernutrition affected meat quality in a sex-dependent manner, generally increasing meat lightness in most muscles from females, but not males. In conclusion, a reduced forage allowance of ewes from gestation day 30 until partum affected growth performance, carcass and meat quality of lambs mostly in a sex-dependent manner. Generally, males born to undernourished ewes grew more slowly and showed poorer quality carcasses and reduced meat yields, while females born to undernourished ewes generally showed brighter meat.