放牧与圈养模式对南江黄羊生长发育及胴体品质的影响

Growth Performance and Carcass Characteristics of Nanjiang Yellow Goats Raised by Fenced-in Feeding vs. Free-range Grazing

为探讨放牧与圈养对南江黄羊生长发育及胴体品质的影响,选择4月龄南江黄羊48只,分别设放牧组、圈养1组、圈养2组,相应采用传统放牧加补饲混合精料、圈养饲喂粗料加补饲混合精料、圈养饲喂全价颗粒料等3种养殖模式,试验期180d,10月龄屠宰。结果表明,圈养2组6~10月龄体重、胸围、4~10月龄总增重和平均月增重均极显著高于放牧组和圈养1组(P<0.01),而放牧组与圈养1组两者间差异均不显著(P>0.05)。试验各组的胴体重、GR值、净肉重和屠宰率的差异均不显著(P>0.05),圈养2组净肉率、肉骨比值均显著高于圈养1组(P<0.05)。圈养2组肌肉pH值小于放牧组,色差值a大于放牧组,两组间差异均显著(P<0.05)。试验各组的肌肉含水率、粗蛋白、粗脂肪、粗灰分、色差值L与b,差异均不显著(P>0.05)。圈养2组肌肉总氨基酸含量,以及其中的天冬氨酸、苏氨酸、丝氨酸、谷氨酸、蛋氨酸、亮氨酸、酪氨酸、苯丙氨酸和赖氨酸含量均显著高于放牧组(P<0.05)。圈养2组每只羊月均毛利比放牧组、圈养1组分别高9.6元、6.3元。

The growth performances and carcass characteristics of Nanjiang yellow goats raised by fenced-in feeding and free-range grazing were compared. Forty-eight 4-month-old goats were randomly divided into 3 groups, In a fenced-in setting, Group 1 was fed with silage and roughages, and Group 2 comprehensive nutrient pellets; whereas, Group 3 was allowed to graze freely on an open farm and supplemented with silage. The feeding lasted 180 days before the goats were slaughtered for carcass evaluation. The live body weight and chest girth of the goats aged 6- tol0-month-old, as well as the total and average monthly weight gains of the goats aged 4- to 10-month-old, in Group 2 were found to be higher than those in either Group 1 or Group 3 （P〈0. 01）, with no significant difference between the latter two groups （P〉0. 05）. No significant differences on the carcass weight, GR value, meat weights, and slaughter yield were observed among the 3 groups （P〉0.05）. However, the meat percentage of the goats in Group 2 was significantly higher than that of Group 1 at P〉0. 01; and, the meat/bone ratio, significantly higher at P^0. 05. The pH of the meat samples from Group 2 was significantly lower than that of Group 3 （P〉0. 01）; and, the color value, a, significantly greater than that of Group 3 （P 〈0. 05）. The contents of moisture, crude protein, crude fat, crude ash, and color values, L and b, of the meats among the 3 groups were not significantly different （P〉0. 05）. The meat of the goats in Group 2 contained significantly more total amino acids （P〉0.01）, as well as, aspartic acid, threonine, serine, glutamic acid, methionine, leucine, tyrosine, phenylalanine and lysine than Group 3 （P〈0.05）. Insofar as average monthly gross profit was concerned, Group 2 was 6.3 yuan more than Group 1, and 9.6 yuan higher than Group 3.