The Effect Of Concentrate Protein Levels On Reproductive Performance Of Bucks In Xinong Saanen Dairy Goats

The present study was designed to study the impactof15% and 20% of the two crude proteinlevels of concentrateon feed intake, body weight, reproductive performance, plasma biochemical parameters and reproductive hormone concentrations of bucks in with different ageXinong Saanen dairy goats.Select8 adulthealthXinong Saanen bucks,which are2.5-year-old, a good semen quality, body weight is(91.06±4.59)kg, in accordance with the quality of semen will be dividedrandomly into the Adult bucks-Low protein diets(Feeding 15% crude protein level of concentrate;AL;n=4)and the Adult bucks-High protein diets(Feeding 20% crude protein level of concentrate;AH;n=4);select 10 health reserve Xinong Saanen dairy goat bucks,which are1.5-year-old,and body weight is(67.55±2.93)kg, according to their weight and genetic pedigree dividedrandomly into the Young bucks-Low protein diets(Feeding 15% crude protein level of concentrate;YL;n=5) and theYoung bucks-High protein diets(Feeding 20% crude protein level of concentrate;YH;n=5).In feeding conditions of separate forage to concentrate feed,test period of 48 weeks, divided into 12 stages. By statistic analysisfeed intake, weight changes, and testing semen quality, testicular circumference,ejaculation time,blood biochemical parameters, reproductive hormonesof bucks on every stage.The results of this study indicate that:(1)Improving protein levels of concentrate were significantly increased buck crude protein intake(P<0.05), the Adult bucks-High protein diets(AH)are more 33.11g/d than the Adult bucks-Low protein diets(AL), and heYoung bucks-High protein diets(YH)are more 27.14g/d than Young bucks-Low protein diets(YL).but protein levels of concentrate did not significantly affect buck weight, dry matter intake, forage-to-concentrate ratio(P>0.05). In the summer,body weight, dry matter intake, protein intake were lower, but forage ratio increased.(2)The protein level of concentrate did not significant impact ejaculate volume, semen pH, density, effective sperm count, sperm acrosome integrity of fresh, live equilibrium rate, survival rate after thawing, thawed plasma membrane integrity rate, fresh sperm viability and fresh sperm membrane integrity of bucks sperm(P>0.05), only the thawed buck sperm acrosome integrity rate of theYoung bucks-High protein diets(YH) was significantly higher than the Young bucks-Low protein diets(YL)(P<0.05).Seasonal changes significantly affect semen quality of bucks(P <0.05).(3)The age of the bucks significantly impact on ejaculate volume, semen pH, fresh sperm viability and fresh sperm membrane integrity, as follows: volume of ejaculate and the semen pH of Adult bucks-High protein diets(AH)are significantly higher than theYoung bucks-High protein diets(YH)(P<0.05);however, fresh semen motility and sperm membrane integrity of theYoung bucks-High protein diets(YH) are significantly higher than the Adult bucks-High protein diets(AH)(P<0.05),but no significant differencebetween with two low-protein groups(AL and YL)(P>0.05).(4)Raising the protein levels of concentrate can increase testicular circumference of bucks, the effect on testicular circumference of adult bucks reached a significant level(P <0.05). Seasonal changes significantly affect testicular circumferenceof bucks(P <0.05).(5)Improving protein levels of concentrate did not significantly reduce the time of ejaculation of bucks and improve pregnancy rate of estrous ewes after insemination(P> 0.05).But the insemination effect of semen of 1.5-year-old bucks is better than 2.5-year-old bucks.(6)Protein Levels of concentrate did not significant impact on plasma total protein, triglycerides, plasma cholesterol, plasma testosterone levels of bucks(P>0.05), plasma triglyceride concentrations ofadult bucks below the young bucks, but total plasma protein is higher than the young bucks, the results suggest the efficiency of fat utilization, synthesis and deposition of protein of adult bucksare greater than theyoung bucks, Seasonal changes significantly affect the Rams blood biochemical parameters and testosterone levels(P <0.05).To sum up, improving concentrate protein levels did not significantly improve semen quality and reproductive performance of bucks, therefore, concentrate crude protein level of 15% has been guaranteed to meet the nutritional needs of bucks.