青干草颗粒度对绵羊日粮养分后肠道消化的影响

Influence of particle size of hay on nutrient digestion in hindgut of sheep

为探讨粗饲料颗粒度对反刍动物饲粮养分在后肠道及全消化道消化的影响,本试验将饲粮中的粗料青干草进行整草、长铡草(4～6cm,长草)、短铡草(1～3cm,短草)和粉碎(0.5cm,粉草)4种颗粒度的机械加工后进行定量饲喂(4×4拉丁方试验)。结果表明:1)青干草不同颗粒度饲粮在后肠道消化量占总消化量的比率为干物质28.50%～32.64%、粗蛋白14.63%～19.76%、中性洗涤纤维24.31%～28.00%、酸性洗涤纤维21.76%～25.08%;粉草饲粮中的干物质、粗蛋白、中性洗涤纤维的后肠道消化量占总消化量的比率均显著(P<0.05)高于其他3种饲粮,酸性洗涤纤维的比率则极显著(P<0.01)高于其他饲粮;2)4种饲粮的干物质、粗蛋白和酸性洗涤纤维全消化道表观消化率未发生明显改变,粉草饲粮的中性洗涤纤维全消化道表观消化率则明显(P<0.05)降低。由此可见,粗饲料颗粒度过小,降低饲粮养分在瘤胃和小肠的消化,饲粮养分在后肠道的消化增加。

Four 4-month-old wethers fitted with ileal cannulas were fed a constant concentrate and a hay in baled （BH）, long chopped （4-6 cm, LCH）, short chopped （1～3 cm, SCH） and fine ground （0.5 cm, FGH） form in a 4×4 Latin square design to evaluate the effects of forage particle size on nutrient digestion in the hindgut and total tract of sheep. Averaged nutrients digestion in the hindgut as a percentage of total tract digestion were as following； DM from 28.50%to 32.64%, CP from 14.63% to 19.76%, NDF from 24.3[% to 28.00%, and ADF from 21.76% to 25.08% for the diets containing different particle size of hay. DM, CP, and NDF digestion in the the hindgut as a percentage of total tract digestion of the diet containing FGH was significantly higher （P〈 0.05） than that of other diets and that of ADF of this diet was significantly higher （P〈0.01） than that of other diets. Digestion of DM, OM, CP and ADF in total tract were unaffected by diets, but digestion of NDF in total tract was significantly lower （P〈0.05） in FGH-diet. Forage with much small particle size could decrease nutrient digestion in the rumen and the small intestine and increase nutrient digestion in the hindgut of sheep.