大约克、甘肃白猪及其正反杂交猪的同期比较研究1．繁殖性能、肥育性能与胴体品质

对８０头大约克、甘肃白猪及其正反杂交猪进行了纯繁和不同杂交方式的同期对比，并对４０头猪进行了屠宰测定和胴体分析，结果表明外引猪种和本地猪种的生长差异是在６６０ｋｇ体重以后形成。正反杂交效果在不同性状上表现不一。繁殖性能正文优于反交，获得１４％～２２％的杂交优势率；肥育性能反交优于正交，平均日增重和饲料利用率分别获８％和６％的优势率；正反杂交均可显著降低皮厚和板油比率，但反交胴体瘦肉率高，胸体品质优于正交。正反杂交的性状表现向母本回归，两者在生长速度的差异亦是６０ｋｇ体重后形成。

Performance Comparison among Yorkshire,Gansu White Pig,Hybrid Between Direct and Reciprocal CrossⅠ.Reproductive,Fattening Performance and Carcass Quality

The research was conducted to compare the production performance amongpurebreed and two hybrids of Yorkshire, Gansu White Pig and hybrid of reciprocal crosses inthe same feeding period.Forty experimental pig was slaughtered to analyses body measure-ment and carcass composition。The result showed that growing difference was formed afte60 kg weight between exotic breed and national breed.The effect of reciprocal crosses on different characters was rather different.Direct cross had a better reproductive performancethan reciprocal with a 14%～22% heterosis. The effect on fattening performance,reciprocalcross is better than direct with 8%and 6% heterosis of mean daily gain and feed efficiencyrespectively.The skin thickness and suet ratio were all reduced significantly after direct andreciprocal crossing,but carcass lean meat percentages was higher and carcass quality was bet-ter in reciprocal than direct.The performance was regressived towards female parent eitherdirect or reciprocal cross and the difference in growth rate formed after 60 kg weight.