日粮钙水平对哺乳期云南半细毛羊养分消化率的影响

Effects of Dietary Calcium Level on Nutrient Digestibility of Yunnan Semi-Fine Wool Sheep during Lactation

为研究日粮钙水平对营养物质消化率的影响,本试验选用25只云南半细毛羊哺乳母羊,分为5组,分别饲喂钙水平为0.35%、0.42%、0.61%、0.75%和0.96%的试验日粮。哺乳期共90 d,每30 d进行1次消化试验。结果表明:0.35%钙组的干物质(DM)采食量最低;哺乳中期,0.35%钙组的DM消化率高于0.75%钙组(P<0.05);0.35%和0.42%钙组的粗蛋白质(CP)消化率较低;哺乳中期和后期0.96%钙组的粗灰分消化率均高于0.35%、0.42%和0.75%钙组(P<0.05);哺乳中、后期0.35%钙组的钙消化率最高(P<0.05);哺乳中、后期,0.42%和0.35%钙组的磷消化率较低;哺乳后期0.61%钙组的中性洗涤纤维消化率低于0.42%和0.96%钙组(P<0.05);哺乳中期0.75%钙组的酸性洗涤纤维消化率最低,而在哺乳后期0.61%钙组最低;哺乳前期0.75%钙组的粗脂肪(EE)消化率高于0.42%钙组(P<0.05)。综上,日粮钙水平下降到0.35%时DM采食量显著下降;在哺乳前期日粮钙水平对除CP和EE外的养分消化率没有显著影响;在哺乳中后期,低钙日粮组(0.35%钙)的钙消化率最高,之后随日粮钙水平的提高先下降后保持稳定,其余养分消化率未见明显规律。

Twenty-five lactating Yunnan semi-fine wool ewes were used to study the effects of dietary calcium(Ca)levels on nutrient digestibility.Lactating ewes were divided into 5 groups and fed experimental diets with Ca levels of 0.35%,0.42%,0.61%,0.75%,and 0.96%,respectively.The experiment lasted for 90 days after lambing,and a digestion test is conducted every 30 days.The results showed that the dry matter intake(DMI)of the 0.35%Ca group was the lowest during lactation.In the middle of lactation,the dry matter(DM)digestibility of the 0.35%Ca group was significantly higher than that of 0.75%Ca group(P<0.05).The 0.35%and 0.42%Ca groups had lower crude protein(CP)digestibility.In the middle and late lactation period,the ash digestibility of 0.96%Ca group was significantly higher than the 0.35%,0.42%and 0.75%Ca groups(P<0.05).In the middle and late lactation period,the Ca digestibility of the 0.35%Ca group was the highest(P<0.05).In the middle and late lactation period,the phosphorus digestibility of 0.42%and 0.35%Ca groups were lower than that of other groups’.In the late lactation period,the neutral detergent fiber digestibility of the 0.61%Ca group was significantly lower than that of 0.42%and 0.96%Ca groups(P<0.05).In the middle lactation period,the acid detergent fiber(ADF)digestibility of the 0.75%Ca group was the lowest.In the late lactation period,the ADF digestibility of the 0.61%Ca group was the lowest.In the early lactation period,the ether extract(EE)digestibility of the 0.75%Ca group was significantly higher than that of 0.42%Ca group(P<0.05).In conclusion,the DMI decreased significantly when the dietary Ca level dropped to 0.35%.Dietary Ca levels had no significant effects on nutrient digestibility except CP and EE digestibility in the early lactation period.In the middle and late lactation period,the 0.35%Ca group had the highest Ca digestibility,and with the increase of dietary Ca level,the Ca digestibility decreased firstly and then remained stable;the digestibility of other nutrients showed no obvious regularity.