【摘要】 用6只安装瘤胃瘘管的8月龄小尾寒羊公羊(平均体重29.98±3.53kg),采用对比试验设计,研究了精料补饲水平(150g/d,250g/d,350g/d,450g/d)对玉米秸自由采食量、料重比、N平衡、日粮营养物质消化率和绵羊日增重的影响。结果表明,秸秆自由采食量随精料补饲水平的增加而提高(P<0.01),但350g/d和450g/d补饲水平的差异不显著(P>0.05)。精料补饲量为150g/d时绵羊的日增重为负值,日粮营养水平不能满足维持需要。250g/d精料补饲水平下,精料和日粮的料重比均显著大于350g/d和450g/d两种精料补饲水平(P<0.05),而350g/d与450g/d精料补饲水平间的差异不显著(P>0.05)。单位日增重的精料消耗量以350g/d精料补饲水平组的表观值最低,日粮消耗量以450g/d最低。日粮DM、OM、CP、NDF、ADF消化率在150g/d、250g/d、350g/d精料补饲水平下随精料喂量的提高而显著提高,精料喂量由350g/d增加到450g/d后显著下降。食入N、粪N均随精料补饲量的增加而增加,尿N量在250g/d精料补饲水平下最低(P<0.01),尿N/可消化N在350g/d精料补饲水平下最低(P<0.01)。更多还原

【Abstract】 Six 8-month-old Han Little Tail sheep (average LBW 29.98±3.53 kg) fitted with permanent rumen fistulae were used to study the influence of concentrate supplementation level on feed intake, feed conversion rates, nitrogen balance and nutrients digestibility of diets. The diets were dry corn stalk based and 150, 250, 350 or 450 g/d mixed concentrate were supplemented per sheep when dry corn stalk was supplied in an ad libitum manner. The results indicated that daily corn stalk intake increased with the increase of concentrate level (P<0.01) till it reached 350 g/d, while the difference between 350 g/d and 450 g/d group was insignificant (P>0.05). When 150 g/d concentrate was supplemented for each sheep, the sheep could not ingest enough nutrients for maintenance and the average daily gain is negative. The feed conversion ratio both as concentrate: daily gain or as diet: daily gain when 250 g/d concentrate was supplemented was lower than when 350 g/d or 450 g/d concentrate was supplemented (P<0.05). The highest feed conversion ratio for concentrate was met when 350 g/d concentrate was supplemented, while for diets it was met when 450 g/d concentrate was supplemented, though the difference between these two groups was insignificant (P<0.05). The degradabilities of DM, OM, CP, NDF and ADF increased with concentrate supplementation level till reached 350 g/d, they had a significant decrease when it increased from 350 g/d to 450 g/d. Both nitrogen intake and nitrogen excreted from feces increased with concentrate supplementation level. Urea nitrogen excretion was lowest when 250 g/d concentrate was supplemented (P<0.01) and urea nitrogen excretion/nitrogen digested ratio was lowest when 350 g/d concentrate was supplemented (P<0.01).更多还原