This experiment was conducted to investigate the effects of dietary phosphorus levels on lactation performance,phosphorus digestion and metabolism and blood indices of lactating buffaloes.Thirty-two healthy buffaloes with good body condition,similar parity,about 3 months of lactation and roughly equal milk output were randomly divided into 4 groups according to body weight with 8 buffaloes in each group and 1 buffalo in each replicate.The buffaloes in the four groups were fed diets with phosphorus levels of 0.30％,0.39％,0.48％and 0.57％,respectively,and the other nutrient levels were consistent.The experiment lasted for 35 days,including 14 days of pre-trial period and 21 days of trial period.In the last 5 days of the trial period,3 buffaloes in each group were randomly selected to perform digestion and metabolism tests by total feces and u-rine collection method.The results showed as follows:1)dietary phosphorus levels had no significant effects on the average daily milk yield,4％fat correction milk yield,milk protein rate,milk fat rate,milk non-fat milk solid rate,milk calcium content and milk phosphorus content of lactating buffaloes(P＞0.05),and the 4％fat correction milk yield in 0.39％phosphorus level group was the highest.2)Dietary phosphorus levels significantly affected the contents of intake phosphorus,fecal phosphorus,total phosphorus excretion and avail-able phosphorus of lactating buffaloes(P＜0.05),and the above indices were increased with the increase of di-etary phosphorus level;dietary phosphorus levels significantly affected the neutral detergent fiber(NDF)ap-parent digestibility,phosphorus apparent digestibility,fecal phosphorus to phosphorus intake ratio and milk phosphorus to phosphorus intake ratio of lactating buffaloes(P＜0.05),the NDF apparent digestibility in 0.48％phosphorus level group was significantly higher than that in the other 3 groups(P＜0.05),the phos-phorus apparent digestibility in 0.30％phosphorus level group was significantly lower than that in the other 3 groups(P＜0.05),the fecal phosphorus to phosphorus intake ratio in 0.39％phosphorus level group was sig-nificantly higher than that in the other 3 groups(P＜0.05),and the milk phosphorus to phosphorus intake ratio in 0.48％phosphorus level group was significantly lower than that in the other 3 groups(P＜0.05).3)Dietary phosphorus levels significantly affected the blood phosphorus content and serum alkaline phosphatase(ALP)activity of lactating buffaloes(P＜0.05),in which the blood phosphorus content was increased with the in-crease of dietary phosphorus level,and the serum ALP activity was decreased with the increase of dietary phos-phorus level.In conclusion,combining lactation performance,phosphorus digestion and metabolism,and blood indices,and considering phosphorus excretion and environmental pollution,the feeding effects on lacta-ting buffaloes in 0.39％phosphorus level group is better,and it is recommended that the dietary phosphorus level for lactating buffaloes should be 0.39％.[Chinese Journal of Animal Nutrition,2023,35(12):7892-7902]
dietary phosphorus levelslactating buffaloeslactation performancephosphorus digestion and metabolismblood indices
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