title: Clinical effects of low dietary phosphorus concentrations in feed given to lactating dairy cows.
abstract: Thirty-four Holstein cows, pregnant with their second calf, were individually fed diets containing 3 concentrations of phosphorus (P): 24 cows for 12 months and 10 cows for 7.5 months of lactation. Cows were randomly allotted to the specific dietary groups 2 months before expected parturition. The 3 dietary concentrations of P were 0.24%, 0.32%, and 0.42% in diet. Cows given 0.24% P in diets produced significantly less milk than did cows in the other groups. Other clinical signs of P deficiency in the cows fed the diet with 0.24% P included loss of body weight, decreased feed consumption, and lower inorganic serum P concentration 2 to 10 weeks after parturition. There were no significant differences in the variables measured between cows given dietary P concentrations of 0.32% and 0.42%. There was no evidence of hemoglobinuria after parturition. Reproductive performance did not differ significantly, although the trend was in favor of the cows fed the diet with 0.24% P.
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004032:Diet; D005260:Female; D007774:Lactation / Q000187:drug effects / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism / Q000494:pharmacology*; D011247:Pregnancy
chemical_list: D010758:Phosphorus