【摘要】 本试验旨在研究青稞替代玉米对育肥牦牛生产性能、屠宰性能、养分表观消化率及肉品质的影响。采用2×3交叉设计,以日粮类型(玉米、60%青稞+40%玉米)和不同精粗比(30∶70、40∶60和50∶50)为两因素,选取36头年龄4周岁左右、体重为(144±21.0)kg的麦洼公牦牛,随机分为6组,每组6个重复,每个重复1头牛。预饲期15d,正试期180d。结果表明:1)日粮类型及精粗比对牦牛生产性能无显著影响(P>0.05)。2)青稞-玉米组的净肉率显著高于玉米组(P<0.05),但屠宰率和眼肌面积无显著差异(P>0.05);精粗比对屠宰性能无显著影响(P>0.05);日粮类型和精粗比二因素对眼肌面积的互作影响显著(P<0.05),以青稞-玉米(40∶60)组效果最优。3)日粮类型对养分表观消化率无显著影响(P>0.05);与30∶70相比,40∶60和50∶50极显著提高了有机物(OM)和总能(GE)的表观消化率(P<0.01)、显著提高了粗蛋白(CP)的表观消化率(P<0.05);日粮类型和精粗比二因素对GE、OM和粗脂肪(EE)的表观消化率有显著的互作影响(P<0.05),以玉米(40∶60)组效果最佳。4)青稞-玉米组和玉米组背最长肌亮度值(L*)、红度值(a*)、pH值均无显著差异(P>0.05),但青稞-玉米组的黄度值(b*)和滴水损失显著低于玉米组(P<0.05)、蒸煮损失极显著低于玉米组(P<0.01);随着精粗比的升高,蒸煮损失有逐渐降低的趋势(P=0.075)。5)日粮类型对背最长肌的嫩度无显著影响(P>0.05);随着精粗比的升高,剪切力逐渐减小(P>0.05),肌纤维直径有减小的趋势(P=0.059),肌纤维密度显著增加(P<0.05),肌纤维面积显著减小(P<0.05)。综上所述,以青稞替代日粮中60%的玉米能够提高育肥牦牛的屠宰性能,改善牦牛肉的品质;日粮精粗比为40∶60时饲喂效果最佳。更多还原

【Abstract】 This study was conducted to investigate the effects of partial substitution of corn concentrate by highland barley in a yak fattening system.The experiment comprised a factorial combination of two levels of diet type(100%corn;60%highland barley+40%corn)and three different concentrate∶forage ratios(CFR,30∶70,40∶60,50∶50).Healthy Maiwa male yaks[n=36;4years of age;(144±21.0)kg body weight]were randomly divided into 6groups,of 6animals.Hence,the individual animals in each group were taken as experimental replicates.There was a pre-experimental period of 15 days,followed by a trial period of 180 days.Data collected included:production performance,slaughter performance,apparent digestibility of nutrients,muscle physical and chemical indexes,muscle tenderness and fiber characteristics of the yaks.It was found that:1)Diet type and concentrate∶forage ratio had no significant effect on production performance(P>0.05).2)The net meat percentage of the 60%-40% barley-corn group was significantly higher than that of the 100% corn group(P<0.05),but no significant differences between the two diet-type groups in dressing percentage and eye muscle area were observed(P>0.05).CFR had no significant effect on slaughter performance(P>0.05).There were significant interaction effects between the dietary types and concentrate∶forage ratios on the eye muscle area(P<0.05),and the best group was 60%-40% barley-corn with 40∶60CFR.3)Diet type had no significant impact on apparent digestibility of nutrients.However,compared with the 30∶70CFR,the apparent digestibilities of organic matter(OM),gross energy(GE)and crude protein(CP)were significantly improved in the 40∶60and 50∶50CFR groups(P=0.002,0.003 and 0.018,respectively).Significant interactions were observed between diet type and CFR,for the apparent digestibility of gross energy(GE),organic matter(OM),and ether extract(EE)(P<0.05),with the best group being 100%corn with 40∶60CFR.4)No significant difference was found between diet types for lightness value(L*),redness value(a*)and pH in the longissimus dorsi muscle(P>0.05),but the yellowness value(b*),drip loss and cooking loss of the60%-40% barley-corn group were significantly lower than those of the 100% corn group(P=0.044,0.048 and 0.003,respectively).With increasing CFR,cooking loss decreased(P=0.075).5)Diet type had no significant effect on muscle tenderness(P>0.05).However,with increased CFR,shear force was decreased(P>0.05),muscle fiber diameter was decreased(P=0.059),muscle fiber density was significantly increased(P<0.05),and muscle fiber area was significantly decreased(P<0.05).In conclusion,a 60% substitution of highland barley in a corn concentrate diet in a yak fattening system,improved the slaughter performance,and meat quality.Considering all the data,the optimal dietary concentrate∶forage ratio for yaks in this study was 40∶60.更多还原