日粮钙水平对云南半细毛羊乳成分的影响

Effect of dietary calcium on milk composition of Yunnan semi-fine-wool sheep

为研究日粮钙水平对云南半细毛羊乳成分的影响,试验选用50只云南半细毛羊妊娠后期的母羊,母羊预产期前14 d随机分为5个组(每组10只羊),分别饲喂钙水平为0.35%、0.42%、0.61%、0.75%和0.96%的试验日粮。母羊产羔后进入正试期(90 d),每30 d为1个阶段,分别为泌乳前期、中期和后期。每个阶段中间5 d,从每组选择5只母羊测定产奶量和乳成分。结果表明:(1)泌乳期各组的产奶量、羊乳的磷、能量、脂肪、蛋白、总固体、非脂乳固体含量均无显著差异(P>0.05)。(2)乳钙含量随日粮钙水平的提高而提高,并且在泌乳前期和后期0.35%钙水平组的乳钙含量显著低于0.61%、0.75%和0.96%钙水平组(P<0.05)。(3)泌乳中期0.61%、0.75%和0.96%钙水平组的乳糖显著高于0.35%钙水平组,分别提高3.32%(P<0.05)、3.69%(P<0.05)和4.43%(P<0.01)。泌乳后期0.35%钙水平组乳糖含量最低,较0.42%、0.61%、0.75%和0.96%钙水平组分别低4.55%(P<0.05)、8%(P<0.01)、8%(P<0.01)和8.70%(P<0.01)。综上,日粮钙水平影响乳钙含量且两者成正比;在泌乳中期和后期,当日粮钙水平提高到0.61%和0.42%后可提高乳糖含量。

This experiment was conducted to study the effect of dietary calcium(Ca)on milk composition of Yunnan semi-fine-wool sheep.Fifty Yunnan semi-fine-wool sheep in late pregnancy were used to carry out this experiment.The ewes were randomly divided into 5 groups with 10 replicates per group 14 days before the due date of delivery.The Ca levels for diets of 5 groups were 0.35%,0.42%,0.61%,0.75%and 0.96%,respectively.The experiment lasted for 90 days from lambing and every 30 days was a stage,which consisted of early lactation,mid-lactation and late lactation.In the middle 5 days of each stage,5 ewes were selected from each group to determine milk yield and milk composition.The results showed that:(1)There was no significant difference in milk yield,milk phosphorus,energy,fat,protein,total solids and solids-non-fat among all groups during lactation(P>0.05).(2)Milk Ca increased with the dietary Ca level increasing,and the milk Ca of 0.35%Ca group in early and late lactation was significantly lower than that of 0.61%,0.75%and 0.96%groups(P<0.05).(3)The lactose of 0.61%,0.75%and 0.96%groups was 3.32%(P<0.05),3.69%(P<0.05)and 4.43%(P<0.01)higher than that of 0.35%group during mid-lactation.Compared with 0.42%,0.61%,0.75%and 0.96%groups,the lactose of 0.35%Ca group were reduced by 4.55%(P<0.05),8%(P<0.01),8%(P<0.01)and 8.70%(P<0.01)during late lactation.These results indicated that dietary Ca affected milk Ca content,and the two were directly proportional.The lactose could be increased when dietary Ca was increased to 0.61%or 0.42%in middle or late lactation period.