木薯渣不同补饲方式对西本杂牛增重的组合效应研究

The Study on Associative Effects of Feeding Regimes of Cassva Residues on the Growth Performance in Cross-bred Cattle

为探讨木薯渣(CR)不同补饲方式对西本杂牛增重的组合效应,选用平均体重155.8kg的西本杂公牛12头,随机分成4个处理,每个处理3头。处理Ⅰ为仅喂混合粗饲料(75%稻草+25%苜蓿)但不补饲CR的对照组,处理Ⅱ、处理Ш与处理Ⅳ为在饲喂混合粗饲料基础上以不同方式按每千克代谢体重30g给每头西本杂牛补给CR的试验组。处理Ⅱ在给牛投给混合粗饲料前3h一次性补饲CR,处理Ш在投给混合粗饲料后2h一次性补饲CR,处理Ⅳ将处理Ш的CR分3次等量补饲。试验结果为:平均日采食混合粗饲料量(ADRI)自高到低的排序为处理Ⅳ(3425.2)>处理Ⅲ(3247.5)>处理Ⅱ(3020.6)>处理Ⅰ(2974.7),括弧中的数字为ADRI,单位为g/d。西本杂牛稻草与苜蓿干草混合粗饲料补饲木薯渣(CR)的替代率(SR)均为负值,表明补饲CR可以提高混合粗饲料(75%稻草+25%苜蓿)的采食量,在采食量上表现为正组合效应,但SR不能定量地描述这种组合效应。各组平均日增重(ADG)自高到低的排序与ADRI相同,但处理Ⅳ(344)与处理Ⅲ(326)差异不显著(P>0.05),其余组间差异显著(P<0.05),括弧中的数字为ADG,单位为g/d。每千克增重所消耗日粮干物质量自高到低的排序为处理Ⅱ(16.63)>处理Ⅰ(14.03)>处理Ⅲ(14.01)>处理Ⅳ(13.79),处理Ⅱ显著高于另3个处理,其余3个处理之间差异不显著(P>0.05);这表明处理Ⅳ的日粮干物质转化效率最好,其次为处理Ⅲ,最差为处理Ⅱ。本研究表明,CR作为能量添补饲料,用于西本杂牛补饲时,可以通过改变补饲方式与增加饲喂次数这样的饲养措施来激发饲料间的正组合效应,从而提高动物的生产性能。

This experiment was carried out to evaluate the associative effect of feeding regimes of mixed roughages（75% rice straw＋25% alfalfa hay）supplemented with cassva residues（CR）on growth performance in cross-bred cattle.12 young Simon dahl cross-bred bull cattle（Simon dahl x ＂Yellow＂ breed）with an average weight of 155.8kg were randomly allocated into 4 dietary treatments.The cattle of treatmentⅠ were fed a basal diet of mixed roughages ad libitum.The CR was fed to cattle of treatment Ⅱ 3 hours before the mixed were randomly allocated into 4 dietary treatments.The cattle of treatmentⅠwere fed mixed roughages offered.In treatment Ш,CR was fed 2 hours after the mixed roughages.As for treatment Ⅳ,CR fed split-feeding three times a day,simulating a steady energy release that matched the slow N release from the alfalfa hay（AH）.The ADRI for the 4 reatments ranked by the following order：treatment Ⅳ（3425.2）treatment Ⅲ（3247.5） treatmentⅡ（3020.6）treatmentⅠ（2974.7）,the figures in parentheses were ADRI,g/d.The substitution rates（SR）for basal mixed roughages（BMR）with CR were negative and this indicated that supplemented CR could improve the dry matter intake（DMI）of BMR,i.e the positive associative effects（AE）were observed.However,SR couldn＇t describe the special AE of feeding regimes as usually did.As for the order of average daily gain（ADG）,ranked from greatest to least,is the same as that of ADRI.There were no significant differences between treatment Ⅳ（344）and treatment Ⅲ（326）（P0.05）,but the significant differences were existed among the other treatments（P0.05）,the figures in parentheses were ADG,g/d.The consumed DM per daily gain（ADMI/ADG） anked from greatest to least in the following order：treatmentⅡ（16.63） treatmentⅠ（14.03）treatment Ⅲ（14.01）treatment Ⅳ（13.79）,the value of treatmentⅡis significantly higher than that of other 3 treatments（P 0.05）.This indicated that the feed conversion efficiency of treatment Ⅳ is the best and that of treatmentⅡ is the worst.It was concluded that the positive associative effects on improving the growth performance could be achieved by developing the feeding regimes and increasing the feeding frequency to manipulate the rate of rumen degradability of CR comparable to that of AH for proper synchronization of energy and protein utilization when CR was used as energetic supplemental feed of cross-bred cattle.