Additional feeding during late gestation improves initial litter weight of lactating sows exposed to high ambient temperature

ABSTRACT The present study investigated the impacts of additional feeding (AF; containing 16% excess feed than control diet in the last two weeks of gestation) during late gestation period and different backfat thickness (BFT) including low (<20 mm) and high (≥20 mm) backfat on reproductive performance, litter size, blood metabolites, hormonal profiles, colostrum, and milk composition of sows from day 90 of gestation to farrowing, and from farrowing to weaning during summer (average 28.3 °C). Fifty-four crossbred sows (Yorkshire × Landrace) were allotted to one of four treatments according to a 2×2 factorial arrangement. There was no AF×BFT interaction for any of the measured variables. The body weight change of sows was decreased for <20 mm in BFT and AF treatments during late gestation and farrowing to weaning periods. The BFT change of sows was higher in AF during late gestation and higher in ≥20 mm BFT during late gestation and farrowing to weaning periods. There were no effects of AF and BFT on the average daily feed intake and weaning-to-oestrus interval; however, sows in AF groups had a greater litter uniformity at birth and initial litter weight. Hormone profiles, colostrum, and milk composition of sows were not different among the treatments. Additional feeding during the last two weeks of gestation increases initial litter size in summer; however, final litter weight is not affected.

摘要：本研究旨在探究妊娠后期（妊娠最后两周）的额外饲喂（additional feeding, AF，相较于对照日粮多添加16%饲粮）与不同背膘厚度（backfat thickness, BFT）组别（低背膘组＜20mm、高背膘组≥20mm）对夏季（平均气温28.3℃）妊娠第90天至分娩、分娩至断奶阶段母猪繁殖性能、产仔数、血液代谢物、激素谱、初乳及乳汁成分的影响。试验选取54头约克夏×兰德瑞斯（Yorkshire × Landrace）杂交母猪，采用2×2析因设计随机分为4个处理组。所有测定指标均未观测到AF与BFT的交互作用。在妊娠后期及分娩至断奶阶段，低背膘组与AF处理组母猪的体重变化量降低。妊娠后期AF处理组母猪的背膘厚度变化量更高，而分娩至断奶阶段高背膘组母猪的背膘厚度变化量更高。AF与BFT对母猪平均日采食量及断奶至发情间隔无影响，但AF组母猪的初生产仔均匀度及初生窝重更高。各处理组母猪的激素谱、初乳及乳汁成分均无差异。妊娠最后两周的额外饲喂可提升夏季母猪的初生产仔数，但对最终窝重无影响。