谷草与苜蓿的不同配比对绵羊日粮组合效应的影响

为了探讨不同精粗比下谷草与苜蓿配比对绵羊日粮组合效应的影响，本试验以谷草与苜蓿为粗饲料，采用体外产气法测定精粗比为40：60时，谷草：苜蓿为60：0、50：10、40：20、30：30、20：40、10：50及0：60，精粗比为30：70时，谷草：苜蓿为70：0、60：10、50：20、40：30、30：40、20：50、10：60及0：70的15组日粮及谷草、苜蓿和精料补充料分别培养2、4、6、9、12、24、36、48、72、96 h的产气量（GP），并通过24 h产气量（GP_{24 h}）及其加权估算值计算出各日粮的组合效应值（AE）。结果表明：①精粗比为40：60时，比较各组GP_{24 h}，50：10组极显著大于10：50组（P<0.01）；40：20、60：10组显著大于10：50组（P<0.05）；各组AE值均为正值，但组间无显著差异（P>0.05）；50：10的GP_{24 h}、b、a+b均为最大，其AE最优。②精粗比为30：70时，比较各组GP_{24 h}，50：20、60：10、70：0组显著大于0：70组（P<0.05），40：30、20：50组有大于0：70组的趋势（P=0.063，P=0.064）；各组AE值无显著差异（P>0.05）；40：30组的GP_{24 h}、b、a+b均较大，其AE最优，其次是20：50、10：60组。综合以上结果，谷草与苜蓿配比为50：10（精粗比为40：60）和40：30、20：50、10：60（精粗比为30：70）时，可以获得较高的AE。

Effect of Different Alfalfa and Rice Straw Proportion on Associative Effects of Sheep's Diets

This experiment was conducted to investigate the effects of the proportion of alfalfa and rice straw on associative effects (AE) of diets in vitro. Rice straw:alfalfa were 60:0, 50:10, 40:20, 30:30, 20:40,10:50,0:60 when concentrate-roughage ratio (C:R) was 40:60, and rice straw:alfalfa were 70:0, 60:10,50:20, 40:30,30:40,20:50,10:60,0:70 when C:R was 30:70. Gas production (GP) was recorded at 2, 4, 6, 9, 12, 24, 36, 48, 72 and 96 h. The AE was defined as the difference between the observed in vitro GP_{24 h} and the predicted value from individual feed fermented alone. The results showed as follows:① GP_{24 h} of the group 50:10 was extremely significantly greater than the group 10:50 (P<0.01), and GP_{24 h} of the groups 40:20 and 60:0 were significantly greater than the groups 10:50 (P<0.05) when C:R was 40:60. The AE of all groups were positive and there were no significant difference among them (P>0.05). When C:R was 40:60, the GP_{24 h},b,a+b of group 50:10 were the greatest and it's AE was the best.②GP_{24 h} of the groups 60:10, 70:0 and 50:20 were significantly greater than the group of 0:70 (P<0.05) and groups 40:30 and 20:50 were greater than the group 0:70 (P=0.063, P=0.064) when C:R was 30:70. The AE of all groups had no significant difference (P>0.05). When C:R was 30:70, the GP_{24 h},b,a+b of group 40:30 was the greatest and it's AE was the best, followed by the groups 20:50 and 10:60. It is concluded that the AE of the groups of 50:10 (C:R was 40:60), 40:30, 20:50 and 10:60 (C:R was 30:70) were greater.