不同纤维组成和粒度的TMR对哺乳期犊牛生长性能和屠宰性能的影响

Effects of TMRs with Different Fiber Composition and Particle Size on Growth Performance and Carcass Traits of Suckling Calves

试验旨在研究日粮营养水平相同的条件下,以燕麦草粉(SO)、燕麦长草(LO)和大豆皮粉(SS)为主要中性洗涤纤维(NDF)来源的全混合日粮(TMR)对哺乳期荷斯坦犊牛生长性能、消化代谢、血清抗氧化指标、屠宰性能和肉品质的影响。试验选取45头新生荷斯坦犊牛,按照体重和日龄相近的原则分为3组,每组15头(公犊牛9头,母犊牛6头),7日龄起分别饲喂以SO、LO和SS为主要NDF来源的TMR,63日龄断奶,试验期56 d。每天记录犊牛的TMR采食量,并计算干物质采食量(DMI)。于7、63日龄晨饲前称量体重,在26~28日龄及54~56日龄采集粪便样品进行消化试验,14、63日龄空腹颈静脉采集血清测定抗氧化指标,64日龄时进行屠宰。结果表明:(1)试验全期(7~63日龄)各组犊牛体重、平均日增重、TDMI无显著差异(P>0.05),与LO组相比,SS组饲料转化比有降低的趋势(P=0.080)。(2)纤维来源和粒度对哺乳期犊牛干物质、粗蛋白质、粗脂肪表观消化率无显著影响(P>0.05),但与LO组相比,SS组粗纤维消化率有升高的趋势(0.05≤P<0.10)。(3)14日龄,LO组血清总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性显著高于SO组,丙二醛(MDA)浓度显著降低(P<0.05);63日龄,LO组GSH-Px活性显著低于SO组,MDA浓度显著升高(P<0.05),SS组和SO组血清抗氧化性能无显著差异(P>0.05)。(4)各试验组犊牛屠宰性能无显著差异(P>0.05),但与SO组相比,LO组肝脏指数有下降的趋势(P=0.051)。(5)纤维来源和粒度对犊牛肉品质无显著影响(P>0.05)。综上所述,短粒度TMR可提高犊牛对纤维的消化率,显著增加机体的抗氧化能力。大豆皮粉作为哺乳期犊牛TMR的主要NDF来源有更高的饲料转化率和纤维消化率。

This study evaluated the effects of total mixed rations(TMR) with oat hay powder(SO),oat hay(LO) and soybean hull powder(SS) as the main source of neutral detergent fiber(NDF) under the same nutrient level on growth performance,nutrient digestibility,serum antioxidant indices,carcass traits of Holstein suckling calves.45 neonatal Holstein calves were randomly divided into 3 groups.The calves(n=15 per group;9 for male and 6 for female) were fed a diet with SO or LO or SS,respectively,from 7 days of age,and were weaned at 63 days of age.The feeding trial was conducted for a period of 56 days.The feed intake was recorded every day,and the calves were weighed before morning feeding at 7 and 63 days of age.Blood samples were collected at 14 and 63 days of age,and fecal samples were collected during 26 to 28 days of age and 54 to 56 days of age for determing nutrient digestibilities.The calves were slaughtered at 64 days of age,and various organs and longissimus muscle samples were collected for analysis.The results showed that:①there were no significant differences in body weight,average daily gain,and DMI of calves among the groups throughout the whole feeding trial(P>0.05),and the feed conversion ratio(feed intake/body weight gain) in SS group showed a trend to be lower compared to that in LO group(P=0.080).②Fiber source and particle size did not affect the apparent digestibilities of dry matter,crude protein and ether extract in calves(P>0.05),however the crude fiber digestibility of SS group showed the trend to be higher than that of LO group(0.050.05).④There was no difference in carcass traits among three groups(P>0.05).Liver index of LO group showed the trend to be lower than that of SO group(P=0.051).⑤Fiber source and particle size did not affect the meat quality of suckling calves(P>0.05).In conclusion,the TMR with short particle size improved the fiber digestibility and antioxidant capacity of calves.The soybean hull powder as a main source of NDF in TMR has the effect of higher feed conversion ratio and fiber digestibility to suckling calves.