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商品猪早期因素在预测存活率、后期生长性能和胴体品质中的应用
发布单位:凯发网站
查看次数：8036
时间：2019-08-21Zhikai K Zeng，Pedro E Urriola，Jenelle R Dunkelberger，John M Eggert，Roos Vogelzang，Gerald C Shurson，Lee J Johnston
翻译&校对：上海亘泰实业集团
随着对母猪多产仔数的选育，现代高产母猪通常比低产母猪的产仔数更多，但是低初生重仔猪占比也逐渐提高。然而多大比例的低出生重仔猪会有补偿生长，以及如何在早期鉴定这些猪只，相关的研究几乎没有。本试验的目的在于研究仔猪初生重和早期生长性能对断奶前死亡率、后期生长性能和胴体品质的影响。
试验收集7654头商品猪数据进行分析。使用区组回归模型分析初生重对断奶前存活率的影响，使用一系列混合模型分析初生重（n=7654）对断奶重（n=6777）、保育末期重（n=4805）和出栏重（n=1417）、胴体重和瘦肉率（n=4572）的影响。生长速度根据断奶前＜225g/d和≥225g/d分组，保育阶段根据＜424g/d和≥424g/d分组。断奶前死亡率、生长速度、体重和胴体性状根据标准日龄进行校正，日增重和瘦肉率通过计算得到。
结果显示，区组回归模型的结果表明初生重低于0.99kg和高于0.99kg时，断奶前死亡率和初生重回归方程的斜率有显著差异（P＜0.05）。混合模型的分析结果发现初生重和校正后出栏重、胴体重、瘦肉率之间有正线性相关关系（P＜0.05），母猪胎次与校正后出栏重、胴体重、瘦肉率之间有二次线性相关关系。与哺乳期日增重较高的猪相比，日增重较低的猪初生重提高对校正后出栏重、胴体重的提高更多（P＜0.05）。保育期日增重越大的猪，校正后出栏重和胴体重越大（P＜0.05）。
总之，初生重低于1kg的仔猪断奶前死亡率越高。低初生重仔猪如果在哺乳阶段生长速度低于平均水平可能会丧失补偿生长的能力。
As a result of genetic selection for increased litter size, modern, highly prolific sows often produce large litters with an increased percentage of light birth weight (BiW) piglets compared with less prolific females. However, there is limited information elucidating what proportion of light BiW piglets that express compensatory growth and how these pigs might be identified at a young age. The objective of this study was to analyze the effect of birth weight and early phase growth on preweaning mortality, subsequent growth performance, and carcass characteristics of pigs. Individual records collected on 7,654 commercial crossbred pigs were used for analyses. A segmented regression model was used to analyze the effect of birth weight on preweaning survival and a series of mixed models were used to analyze the effect of birth weight (n = 7,654) group on weights recorded at: weaning (n = 6,777), nursery exit (n = 4,805), and finishing exit (n = 1,417); hot carcass weight (HCW), and lean percentage (n = 4,572). The effect of growth rate group was defined during suckling (< 225 or ≥ 225 g/d) or the nursery phase (< 424 or ≥ 424 g/d). Preweaning mortality, growth rate, BW, and carcass traits were adjusted to a standard age, and ADG and lean percentage were calculated. Results of segmented regression analysis showed that the slope of preweaning mortality on birth weights below 0.99 kg differed (P < 0.05) from the slope of preweaning mortality regressed on birth weights above 0.99 kg. The mixed model analyses showed a positive linear effect (P < 0.05) of BiW and quadratic effect (P < 0.05) of sow parity on age-adjusted finishing weight (FiW), HCW, and lean percentage. The positive influences of increasing BiW were greater (P < 0.05) in age-adjusted FiW and HCW for pigs with slow suckling growth rate compared with those with fast suckling growth rate. Pigs with fast nursery growth rate had greater (P < 0.05) age-adjusted FiW and HCW compared with the slow growing nursery contemporaries. In conclusion, piglets born weighing less than 1 kg were at a higher risk of preweaning mortality than piglets born weighing 1 kg or greater. Light BiW pigs, but not heavy BiW pigs, may lose compensatory growth capability if growth rate during the suckling phase is below the average level.（转自：猪营养国际论坛）
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