日粮中不同水平棉秆对育肥期绵羊瘤胃发酵参数和屠宰性能的影响

【目的】研究不同棉秆水平的日粮对育肥期绵羊瘤胃发酵参数和屠宰性能的影响。【方法】选取60只6月龄、体重为(43.08±5.93) kg的小尾寒羊,驱虫后依据体重进行单因素完全随机试验设计,随机分为6组,每组10只。以等能等氮原则配制试验日粮,其中CK1组不添加棉秆和棉籽粕,CK2组添加棉籽粕,20％组、30％组、40％组和50％组分别添加20%~50%的棉秆,试验期70 d。【结果】(1)瘤胃pH值CK1组比CK2组高6.25%,差异极显著(P<0.01);30%组和40%棉秆添加组分别比CK2组高5.48%和4.85%,差异显著(P<0.05)。(2)瘤胃NH₃-N浓度40%棉秆添加组分别比CK1组和CK2组低40.44%(P<0.01)和39.40%(P<0.05);30%组比CK1组低26.89%,差异显著(P<0.05)。(3)瘤胃乙酸、丙酸、丁酸和总挥发性脂肪酸的浓度各处理组间差异均不显著(P>0.05);乙酸/丙酸比例CK2组分别比20%组、30%组和40%棉秆添加组低34.58%、31.69%和35.69%,差异均极显著(P<0.01);异丁酸浓度CK1组分别比20%组、40%组和50%棉秆添加组高195.31%、243.64%和220.34%,差异均极显著(P<0.01),CK1组分别比CK2组和30%组高166.19%和182.09%,差异显著(P<0.05);异戊酸浓度CK1组分别比CK2组、20%组、40%组和50%棉秆添加组高116.45%、101.18%、151.47%和119.23%,差异均极显著(P<0.01),CK1组比30%组高71.00%,差异显著(P<0.05);戊酸浓度CK1组比40%棉秆添加组高178.05%,差异显著(P<0.05)。(4)日粮添加不同棉秆水平对绵羊活体重、胴体重、屠宰率、心脏和睾丸重均无显著影响(P>0.05);肝脏重20%组比40%棉秆添加组高28.37%,差异显著(P<0.05);脾脏重20%组均比CK2组、30%组、40%组和50%棉秆添加组高50.00%,差异显著(P<0.05);肺重40%棉秆添加组显著低于其它处理组(P<0.05);肾脏重CK2组比20%棉秆添加组低42.85%,差异极显著(P<0.01),CK2组分别比40%和50%棉秆添加组低22.22%和25.00%,差异均显著(P<0.05)。【结论】在育肥期绵羊日粮中添加棉花秸秆,以20%的添加量为宜。

Effects of Different Levels of Cotton Stalk on Rumen Fermentation Parameters and Slaughter Performance of Fattening Sheep

【Objective】 This paper is to study the effects of diets with different cotton stalk levels on rumen fermentation parameters and slaughter performance of sheep during fattening period. 【Method】60 small tail Han sheep 6 month old weighing(43.08±5.93) kg were selected and randomly divided into 6 groups with 10 sheep in each groups. The experimental diet was formulated according to the principle of the same energy and the same nitrogen, CK1 group was not added with cotton stalk and cottonseed meal, CK2 group was added cottonseed meal, 20%, 30%, 40% and 50% groups were added with 20%-50% cotton stalk, respectively. The experimental period was 70 days. 【Result】(1) Rumen pH value of CK1 group was 6.25% higher than CK2 group, the difference was very significant (P<0.01),30% and 40% cotton stalk addition groups were higher 5.48% and 4.85% than CK2 group respectively, the difference was significant (P<0.05). (2) Rumen NH3-N concentration of 40% cotton stalk addition group was 40.44% (P< 0.01) and 39.40% (P<0.05) lower than CK1 and CK2 groups respectively, and 30% group was 26.89% lower than CK1 group, the difference was significant (P<0.05). (3) The concentrations of acetic acid, propionic acid, butyric acid and total volatile fatty acids in rumen were not significantly different among the treatments (P>0.05). The acetic acid and propionic acid ratio of CK2 group was34.58%, 31.69% and 35.69% lower than those of 20%, 30% and 40% cotton stalk addition groups respectively (P<0.01). The concentration of isobutyric acid of CK1 group were 195.31%, 243.64% and 220.34% higher than those of 20%, 40% and 50% cotton stalk addition groups respectively (P< 0.01). CK1 group was 166.19% and 182.09% higher than that of CK2 and 30% group respectively (P<0.05). The isovaleric acid concentration of CK1 group was 116.45%, 101.18%, 151.47% and 119.23% higher than those of CK2, 20%, 40%and 50% cotton stalk addition groups respectively (P< 0.01). CK1 group was 71.00% higher than that of 30% group (P<0.05). The valeric acid concentration was 178.05% higher than 40% cotton stalk addition group (P<0.05). (4) Dietary cotton stalk supplementation had no significant effect on live weight, carcass weight, slaughter rate, heart and testicular weight of sheep (P>0.05). The liver weight 20% group was 28.37% higher than 40% cotton stalk addition group (P<0.05). The spleen weight 20% group was 50.00% higher than CK2 group, 30%, 40% and 50% cotton stalk addition groups respectively, the difference was significant (P<0.05). The lung weight of 40% cotton stalk group was significantly lower than that of other treatments (P<0.05). The kidney weight of CK2 group was 42.85% lower than that of 20% cotton stalk group (P<0.01).The CK2 group was 22.22% lower than that of 40% and 50% cotton stalk groups, the difference was significant (P<0.05). 【Conclusion】The results showed that 20% cotton straw was suitable for sheep diet during fattening period.