Test Of Meat Performance And Estimation Of Genetic Parameters Of Growth Traits In Dorper×Hu Hybrid Sheep

Dorper sheep is famous meat sheep breed in the world,and is an excellent terminal male parent for cross production of mutton sheep.Hu sheep is a first-class protected local livestock and poultry breed in China,and often used as a hybrid female parent.In order to make full use of the long genetic distance between foreign varieties and local varieties,the potential of good gene complementary effect,and the specialized sheep varieties for meat are cultivated.In this study,we used the binary hybridization between Dorper sheep and Hu sheep to test the meat performance(slaughter performance and meat quality)of hybrid F1(F1),and analyzed the non-genetic factors affecting the growth traits of Dorper×Hu hybrids before weaning,and estimated the genetic parameters.It provides a scientific basis for hybrid breeding of meat sheep and the application of related technologies in China.Twelve 6-month-old Dorper×Hu hybrid F1 sheep(half male and half female)were carried out for slaufhter test.After slaufhter test,samples of mutton from different parts of the muscles(longissimus dorsi,biceps femoris,semitendinosus,triceps)were stored at-20? for meat quality determination;The growth traits of mutton sheep are affected by many factors.In this study,the birth weight,weaning weight and the Type of birth of Dorper sheep,Hu sheep,Dorper×Hu F1,Dorper×Hu hybrid F2(F2)sheep were statistically analyzed.The growth traits were considered based on factors such as breed,gender,birth year and birth season.The phenotype of birth weight and weaning weight(continuous data)was analyzed by variance analysis,which considered the main effect of each factor as well as the secondary interaction of each factor.Poisson regression was used to analyze the Type of birth(counting data).maternal effect models of bisexual traits(birth weight and weaning weight)were used,and parameters were estimated by AIREML and Gibbs sampling methods.The test results are as follows:1.slaughter performance test results: There was no significant difference in pre-slaughter live weight,carcass weight,slaughter rate and bone to meat ratio between male and female sheep of Dorper×Hu F1(P>0.05).The GR value was significantly different between ram and ewe(P<0.01).2.Meat quality test results: In the muscles of Dorper×Hu F1,except the cooked meat rate,there wasno significant difference in the water loss rate in p H1,p H2,shear force and marbling,but there was a certain difference in the muscles of the Dorper×Hu hybrid F1 sheep.The species of amino acid and fatty acid in ram and ewe were abundant,and the contents of Glutamic acid(Glu)and Oleic acid(C18.1N9C)were the highest.There was no significant difference in cholesterol between ram and ewe(P>0.05).3.Analysis results of major non-genetic factors affecting growth traits: Dorper×Hu F1 and Dorper×Hu F2 inherited the characteristics of Dorper sheep,such as birth weight and weaning,as well as the superiority in lambing number of Hu sheep.The birth weight and weaning weight of male lambs were significantly greater than that of female lambs.The weaning weight of lambs born in spring is significantly greater than that of lambs born in other seasons.4.Estimation results of genetic parameters: Based on the two methods of AIREML and Gibbs sampling,the estimated values of the maternal effect genetic parameters of the two traits are basically the same.The direct heritability of the birth weightof Duhu hybrid sheep was 0.37,the maternal heritability was 0.10,the total heritability was 0.21,the direct-maternal additive genetic correlation was-0.73;the direct heritability of the weaning weight was 0.03,and the maternal heritability was 0.44.The total heritability was 0.14,and the direct-maternal additive genetic correlation was-0.66;the genetic correlation between the birth weight and weaning weight was 0.53.In summary,this study compares and analyzes the meat performance of the 6-month-old Dorper×Hu F1,and clarifies the effects of non-genetic factors on the birth weight and weaning weight,estimated the genetic parameters of growth traits of Dorper×Hu hybrid sheep,and provided scientific basis for sheep production management and genetic improvement.