Brumm M C, Ellis M, Johnston L J, Rozeboom D W, Zimmerman D R
Haskell Agricultural Laboratory, University of Nebraska, Concord 68728, USA.
J Anim Sci. 2002 May;80(5):1166-72. doi: 10.2527/2002.8051166x.
Two experiments were conducted to determine the effect of lightweight pig removal and remixing on performance to slaughter. Experiment 1 was a growing-finishing trial utilizing a total of 900 pigs (26.2+/-0.1 kg initial weight) that were sorted and remixed at a mean replicate BW of 72 kg. Experiment 2 was a wean-to-finish trial (17 d mean wean age; 4.8 kg +/- 0.1 BW) utilizing 225 barrows with sorting and remixing occurring 3 wk after weaning. Treatments were 15 pigs/ pen from initial weight to slaughter (15S), 20 pigs/pen from initial weight to time of sort and remix and then reduced to 15 pigs/pen (20/15), and 15 pigs/pen from time of sort and remix to slaughter comprised of the five lightest pigs from each of three 20/15 pens per replicate (15M). Space allocation was 0.56 m2/pig from 26 to 70 kg and 0.74 m2/pig thereafter in Exp. 1. In Exp. 2, pen size was fixed at 2.44 x 4.27 m. In Exp. 1, there was no effect (P > 0.20) of treatment on performance prior to 70 kg. Least squares means for ADG from time of sort and remix to first pig removal from a pen for slaughter at 113 kg were 0.93, 0.87, and 0.91 kg/d for the 20/15, 15M, and 15S treatments, respectively (P < 0.05). When comparing the population represented by the 20/15 + 15M treatments vs the 15S population, there was no difference (P > 0.20) in ADG, ADFI, feed conversion, or carcass lean content. In Exp. 2, pigs in the 20/15 treatment grew slower (P < 0.05) than 15S pigs for the first 21 d (0.20 vs 0.22 kg/d, respectively) with a lower ADFI (P = 0.06) and no difference in feed conversion. When comparing the population represented by the 20/15 + 15M treatments vs the 15S population after sorting and remixing, there was no effect (P > 0.15) of experimental treatments on ADG, ADFI, feed conversion efficiency, carcass lean content, or daily lean gain. These results suggest that removal of lightweight pigs and remixing of the removed pigs into pens of similar-weight pigs is ineffective in improving the overall performance of a population of pigs during the postweaning period.
进行了两项试验以确定去除轻体重猪并重新混群对育肥性能的影响。试验1是一项生长育肥试验，共使用900头猪（初始体重26.2±0.1千克），在平均重复体重达72千克时进行挑选和重新混群。试验2是一项从断奶到育肥的试验（平均断奶日龄17天；体重4.8±0.1千克），使用225头公猪，在断奶后3周进行挑选和重新混群。处理方式为：从初始体重到出栏每栏15头猪（15S）；从初始体重到挑选和重新混群时每栏20头猪，之后减至每栏15头猪（20/15）；从挑选和重新混群时到出栏每栏15头猪，由每个重复中三个20/15栏中最轻的5头猪组成（15M）。试验1中，体重26至70千克时每头猪的空间分配为0.56平方米，之后为0.74平方米。试验2中，栏舍大小固定为2.44×4.27米。试验1中，70千克之前处理方式对性能无影响（P>0.20）。从挑选和重新混群到第一头猪达到113千克出栏时，20/15、15M和15S处理组每栏的平均日增重（ADG）的最小二乘均值分别为0.93、0.87和0.91千克/天（P<0.05）。比较20/15 + 15M处理组与15S组的总体情况，平均日增重、平均日采食量（ADFI）、饲料转化率或胴体瘦肉含量无差异（P>0.20）。试验2中，前21天20/15处理组的猪生长速度比15S组猪慢（P<0.05）（分别为0.20和0.22千克/天），平均日采食量较低（P = 0.06），饲料转化率无差异。比较挑选和重新混群后20/15 + 15M处理组与15S组的总体情况，试验处理对平均日增重、平均日采食量、饲料转化效率、胴体瘦肉含量或每日瘦肉增重无影响（P>0.15）。这些结果表明，去除轻体重猪并将其重新混入体重相近的猪栏中，对提高断奶后猪群的整体性能无效。
