The Research On Performance And Carcass Quality Of Castration Xinjiang Brown Cattle Bulls Beef

In this experiment,21 head of Xinjiang brown cattle at 10-12 months of age which in the same nutritional conditions of feeding were chosen as the experimental cattle, where in,15 steers as the experimental group,6 bulls for the control group.In order to find out the influence of castration on Xinjiang brown cattle meat production performance and carcass quality, ultrasound detection, carcass traits and muscle physicochemical determination techniques and variance analysis, multivariate statistics and regression methods are applied, the conclusion is as follows:A amathematical model which based on the ultrasound detection data was established to forecast the meat production traits in Xinjiang brown cattle,explanatory variables and constants in the model were significant(P<0.05), and after verification, there was no significant difference between the predicted and measured values(P>0.05), shows that the model has strong practicability, can predict the slaughtered meat traits of the Xinjiang brown cattle.The average weight of Xinjiang brown cattle bull group and steers group were 580.62±36.92 kg, 559.80±33.14 kg, there was significant difference between the two groups on weight gain effect(P <0.05), but no significant difference on slaughter rate(P >0.05);The hind legs length and width of carcass of bull group were higher than that of steers group, the difference was extremely significant(P<0.01);And the eye muscle area of bull group is higher than that of steers group, difference was significant(P <0.05), but there were no significant differences on other indexes(P >0.05) between them;Show that the body height growth rate of bull higher than that of steers,especially the legs and waist muscles grow more easily,compared steers.In addition, in the flesh bright degree of the meat, steer group was significantly higher than that of the bull group(P<0.05), the fat color of steers group was white, which of bull group was slightly yellower than that of steers group, there was no significant difference(P >0.05), In the aspect of marbling traits steer group was significantly higher than that of the bull group(P<0.05),and in the aspect of cooking loss, shear force and PH value,steer group beef were significantly less than bull group(P <0.05), and the beef moisture of steers group was significantly higher than that of bull group(P <0.05).It show that Xinjiang brown cattle steers have advantages of better fat deposition, more bright color, less cooking loss, smaller shear force, higher moisture content and richer marbling, suitable for high grade beef production.The results show,there was a extremely significant negative correlation between the castration and carcass traits in the ham girth and leg length(r2=-0.591,-0.816; P<0.01)and a significant correlation between castration and meat quality traits of carcass in marbling and fat color(r2=0.760, P <0.01;r2=-0.476, P <0.01);Therefore,we can concluded that castration has a decisive influence on the meat production performance and growth and high-grade meat production of beef cattle.In various parts of the high-grade and high-quality beef division, the performance of meat was generally measured with back fat thickness, loin eye area,carcass weight accuracy and practical to the cattle.This study shows that, there was significant and extremely significant correlation(r2=0.568(P <0.05), r2=-0.710(P <0.01)) between the high-grade meat weight of carcass and gender and waist flesh respectively, extremely significantly or significantly correlation between the back part meat weight and carcass weight, waist thick meat, marbling(r2 =0.241(P<0.01) r2=0.500(P <0.05), r2 =0.642(P <0.05));and strong correlation between high quality meat weight and marbling(r2=0.467(P < 0.05)), that is, the above all parts of meat weight can reflect the meat performance of the carcass.Study shows that the model which established by using of 7 indicators on carcass meat performance,which consist of gender, body weight, muscle thickness, back fat thickness, loin eye area, live weight and marbling.the regression equation: High-grade meat weight Y=51.039 + 0.104 ×castration coefficient + 0.195 × carcass weight- 0.279 × waist flesh- 0.076 × eye muscle area- 0.104 × weight; Back part meat weight Y=45.028- 0.869 ×castration coefficient + 0.425 × carcass weight- 0.24 × 0.141 × eye muscle area and weight; High quality meat weight Y= 66.05 + 0.592 × carcass weight- 0.385 × eye muscle area- 0.213 × weight), can provide reference basis for formulating the carcass meat quantity standard of Xinjiang Brown Cattle.