Optimal Cross Combinations For Lamb Production In Sheep And Polymorphism Of Pit-1Gene In Goat

In order to optimize the hybrid pattern of lamb production in alpine pastoral area. A fouryears field experiment was conducted to observe four cross combinations including904individuals（Texel、white suffolk、Bond and Australia Merino were used as male parent，andGansu Alpine Merino was used as female）by the method of artificial insemination from2008to2011. The results of growth observation showed that the weaning weight of Texel F1was27.71kg，being significantly higher than other combinations（P<0.01）；the6-month-old weightof Texel F1was31.04kg，which was higher than Bond、White Suffolk、Australian Merino andcontrol group for8.79%（P<0.05）、14.15%（P<0.01）、18.42%（P<0.01）and33.97%（P<0.01），respectively. The results of slaughter performance indicated that the carass weight、dressingpercentage、net meat percentage、bone weight and loin muscle area of Texel F1were the highest（P<0.05），but the ratio of bone to meat was the least. Meanwhile，the pH value（pH=5.92）and tenderness（22.25N）were better than others. Therefore，the combination of Texel F1can notonly improve the production of Gansu Alpine Merino，and can improve the meat quality，andthen the group of the Texel×Gansu Alpine Merino was the ideal cross combination for lambproduction in alpine pastoral area of Qilian mountains.Genetic polymorphisms of Pit-1gene was analyzed by DNA sequencing and PCR-SSCP inHexi cashmere goat，Longdong cashmere goat，Liaoning cashmere goat and Inner Mongoliacashmere goat including509individuals among four goat populations，and the effects ofgenotype on production traits were also estimated in this study，In order to provide an effectivegenetic markers for goat breeding. The result showed that：（1）Two genotypes（AA and AB）one SNP（c.313A>G），five genotypes（AA、AB、BB、AC and BC）and two SNPs（c.682G>T、c.837C>T）were detected in exon3and exon6of Pit-1gene，respectively.（2）A chi-squareanalysis suggested that all analyzed populations were at Hardy-Weinberg equilibrium，but forthe Inner Mongolia cashmere goat in exon6of Pit-1gene. The genetic diversity analysisrevealed a low polymorphism information content（PIC<0.25）in exon3，and an intermediatepolymorphism information content in exon6among four goat populations（0.25<PIC<0.50），respectively.（3）Using least square analysis，it was showed that individuals with the AAgenotype in exon3had significantly more body weight and production of cashmere than these with AB genotype（P<0.05）. Although there was no significant difference for the bodymeasurement traits（P>0.05），the phenotypic values of the individuals with AB genotype wereobviously less than those with AA genotype. In exon6of Pit-1gene，The least square analysisindicated that body weight and heart girth of individuals with genotype AB were significantlyhigher than that of individuals with genotype BC（P<0.05），and other genotypes was nosignificance in withers height and body length（P>0.05）. Therefore，Pit-1gene is a main effectgene on body weight and cashmere weight，and it can be used as a candidate loci for goatproduction traits.