Effects of Dietary Calcium Level on Growth Performance and Calcium Digestion Metabolism of Growing Dairy Buffaloes
This experiment was conducted to determine the effects of dietary calcium level on the growth per-formance and calcium digestion metabolism of growing dairy buffaloes.Thirty-two healthy,similar-weighted buffaloes aged 11 months were randomly divided into four groups,each consisting of 8 animals.They were fed experimental diets with calcium levels of 0.49％,0.54％,0.59％and 0.64％,respectively,while other nutri-ent levels in the diets remained consistent.The feeding trial lasted for 52 days,including a 10-day pre-test peri-od and a 42-day formal test period.During the last 5 days of the formal test period,three buffaloes from each group were randomly selected for a 5-day digestion and metabolism trial.The results showed as follows:1)di-etary calcium level significantly affected the dry matter intake of growing dairy buffaloes(P＜0.05),but did not significantly affect the average daily gain and feed/gain ratio(P＞0.05).Among these,the group with a calcium level of 0.59％exhibited the highest average daily gain and dry matter intake.2)Dietary calcium level did not significantly affect the apparent digestibility of dry matter and crude protein of growing dairy buffaloes(P＞0.05).However,dietary calcium level had significant effects on the apparent digestibility of calcium and phosphorus(P＜0.05),with the 0.54％calcium level group showing the highest apparent digestibility of calci-um and phosphorus.3)Dietary calcium level had significant effects on the calcium intake,fecal calcium excre-tion,urine calcium excretion,total calcium excretion and the ratios of fecal calcium excretion to total calcium excretion,urine calcium excretion to calcium intake,urine calcium excretion to total calcium excretion of growing dairy buffaloes(P＜0.05).There was no significant difference in the ratio of fecal calcium excretion to calcium intake(P＞0.05).The linear regression equation of dietary calcium level(x)and calcium excretion(y)of growing dairy buffaloes was y=0.005 8x+0.176 6(R2=0.962 2),and the calcium maintenance re-quirement for growing dairy buffaloes was 1.753 7 g/(kg W0.75·d)according to the regression equation.In conclusion,considering the results of growth performance and calcium digestion metabolism of growing dairy buffaloes,the optimal dietary calcium level is 0.54％to 0.59％.[Chinese Journal of Animal Nutrition,2024,36(12):7809-7818]
万方数据
维普
