Milligan Barry N, Dewey Catherine E, de Grau Angel F
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, N1G 2W1, Ont, Canada.
Prev Vet Med. 2002 Dec 18;56(2):119-27. doi: 10.1016/s0167-5877(02)00157-5.
To determine the effect of within-litter neonatal-weight variation on pre-weaning mortality and weight gain, we analyzed piglet survival and weight gain within 400 litters from 10 commercial farms. Neonatal-weight variation (independent of mean neonatal weight, litter size and sow parity) was associated with pre-weaning survival and weaning-weight variation-but not with mean weaning weight. Neonatal piglets with weights well below the range of most of the litter (low-birth-weight piglets) had an increased risk of dying and were unable to obtain normal weight gains by weaning if they survived. These piglets experienced lower survival and poorer weight gain in larger litters. These piglets also tended to have lower survival but normal (albeit low) weaning weights if they survived in litters from middle-aged and old sows. High neonatal-weight variation resulted in lower survival and more variable weaning weights. Small piglets had a greater risk for poor survival and weight gain compared to their heavier litter-mates (a disadvantage that was exacerbated in large litters).
为了确定同窝仔猪出生体重差异对断奶前死亡率和体重增加的影响，我们分析了来自10个商业农场的400窝仔猪的存活情况和体重增加情况。出生体重差异（与平均出生体重、窝产仔数和母猪胎次无关）与断奶前存活率和断奶体重差异有关，但与平均断奶体重无关。出生体重远低于同窝大多数仔猪范围的新生仔猪（低出生体重仔猪）死亡风险增加，且如果存活下来，到断奶时无法获得正常体重增加。这些仔猪在较大窝产仔数中存活率较低，体重增加较差。如果这些仔猪在中年和老年母猪所产窝中存活下来，它们的存活率也往往较低，但断奶体重正常（尽管较低）。出生体重差异大导致存活率降低和断奶体重更不稳定。与较重的同窝仔猪相比，较小的仔猪存活和体重增加情况较差的风险更大（这种劣势在较大窝产仔数中更为明显）。
