| Leizhou goat is one of the best local goat breeds in Guangdong province,which has the characteristics of good meat quality,small odor and strong local adaptability.However,due to the lack of scientific breeding for a long time,the goat are small in size,slow in growth and low in fertility,which affects the economic benefits.The Chuanzhong black goat and the Nubian black goat are the most famous breeds of meat goats in China.They are large in size,fast in growth,high in fertility,and strong in lactation.Therefore,this study intends to take these three mutton goat breeds as the material,determine the offspring production performance of different hybrid combinations,and finally select the hybrid combination scheme suitable for Leizhou goats,so as to provide a research basis for breed improvement and goat breeding development in Guangdong.This test is divided into two parts,the first part on Leizhou goats mating varieties as control group,at the same time design Nubian black goats ♂× Leizhou goats ♀,Chuanzhong black goats ♂× Leizhou goats ♀,Leizhou goats ♂× Nubian black goats ♀,Leizhou goats ♂× Chuanzhong black goats ♀ four hybrid combinations,each hybrid combinations to choose 3 rams and 30 body condition similar to natural mating ewes.After birth,20 male lambs of each hybrid combination were randomly selected for feeding experiment.All male lambs were weaned at 2 months of age and castrated 1 week after weaning.From the age of 3 months to the age of 6 months.During feeding,the initial birth weight of the lamb was measured,and body size(body height,body length,chest circumference)and body weight were measured every month from the age of 3 months,so as to compare the growth performance differences of the offspring of different hybrid combinations.At the end of the feeding experiment at the age of 6 months,the offspring of each hybrid combination were randomly selected to slaughter 3 lambs,and the slaughter performance,meat quality and serum physiological and biochemical indicators of the offspring of different hybrid combinations were compared.In the second part of the experiment,the growth performance of the offspring of different hybrid combinations was investigated and measured.The source of the mutton goat raised by the farmer is the goat farm where the first part of this experiment is carried out.The breeds of mutton goat raised include the offspring of the Leizhou goat variety,the "Nulei" hybrid combination and the "Chuanlei" hybrid combination.In this study,472 meat goat(248 goat from Leizhou,106 offspring of "Nulei" and 118 offspring of "Chuanlei")raised by the farmer were tracked and measured for one year.The measurement items included the age from 0 months to 8 months,the body weight and body length(body height,chest circumference and body length)of each month.At the same time,the offspring of each hybrid combination were randomly selected to carry out slaughter experiment on three 6-month-old lambs,and the slaughter performance,meat quality and serum physiological and biochemical indicators were detected.The main results of this study are as follows:1.In terms of growth performance,the weight of "Nulei" and "Chuanlei" eunuchs at three months and six months were significantly higher than that of Leizhou eunuchs(P<0.05).The body height and oblique length of "Nulei" and "Chuanlei" eunuchs were significantly higher than those of Leizhou eunuchs at three,four,five and six months(P<0.05),and the chest circumference of "Nulei" and "Chuanlei" eunuchs were significantly higher than those of Leizhou eunuchs at three and four months(P<0.05).2.In terms of slaughter performance,the slaughter rate,total and semi-clean chamber rates of "Nulei" and "Chuanlei" goat were significantly higher than those of "Leizhou" goat(P<0.05).The slaughter rate and semi-clean chamber rate of "Nulei" goat were significantly higher than that of "Leizhou and " Chuanlei "" goat(P<0.05).3.In terms of meat quality,the flesh color of "Nulei" and "Chuanlei" castrated muscle was significantly darker than that of Leizhou castrated muscle(P<0.05).The acidity of the muscle of the "Chuanlei" goat was significantly lower than that of the "Leizhou" and "Nulei" goat(P<0.05),which may be less prone to deterioration.The shear force of the longest dorsal muscle of "Nulei" castrated goat was significantly higher than that of "Chuanlei" castrated goat(P<0.05),while the shear force of the longest dorsal muscle of "Chuanlei" castrated goat was significantly higher than that of "Leizhou castrated" castrated goat(P<0.05)."Chuanlei" wether muscle basic amino acid and essential amino acid content is significantly higher than "Nulei" wether and Leizhou wether(P<0.05),while in terms of influence the amino acids of fragrance,Leizhou wether significantly(P<0.05),the highest content of wether "Nulei" and the "Chuanlei" wether in significantly higher content of amino acids in kind is different(P<0.05).4.The body and liver nutrient metabolism levels and immunity of "Nulei" goat were significantly higher than those of "Chuanlei" goat and Leizhou goat under the standard feeding conditions of blood biochemical indexes(P<0.05).The "Chuanlei" goat may have lower body fat and a stronger liver.Nulei goat was significantly better than "Chuanlei" goat and Leizhou goat in disease immunity(P<0.05).5.The comprehensive results showed that the growth performance and slaughter performance of "Nulei" goat were better,and the metabolic ability and immune ability were significantly improved."Chuan lei" goat muscle taste better,muscle essential amino acid content increased significantly.At the same time,the breeding effect investigation of the breeding households showed that the hybrid advantage of leizhou goat and its hybrid generation could not be well reflected compared with the breeding conditions in the test field,so it was necessary to optimize the production management mode when hybridizing the local goat varieties in southern China. |
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