Phosphorus Concentrations In Blood, Milk, Feces, Bone And Selected Fluids And Tissues Of Growing Heifers
Williams S. N., McDowell L. R., Warnick A. C., Wilkinson N. S. and Lawrence L. A. 1991: Phosphorus concentrations in blood, milk, feces, bone and selected fluids and tissues of growing heifers as affected by dietary phosphorus. Livestock Research for Rural Development. Volume 3, Article #18.
Effects of dietary P on concentrations of P in blood, milk, feces, bone, saliva, rumen fluid, various tissues and hair of growing Angus heifers were evaluated. The duration of the experiment ranged from 525 to 772 d depending on slaughter date of individual animals. Initially, 14 weaned Angus heifers were fed “ad libitum” a low-P diet (0.10% P, dry basis) for 270 d. Heifers were subse- quently allotted randomly into two groups (seven animals/group) and received either 0.12% P (low P) or 0.20% P (adequate P) (dry basis). The experimental period was 245 d of the treatment phase for non-pregnant and until 3 week postpartum for pregnant heifers.
Serum, plasma and whole blood P concentrations varied throughout the experiment but, generally, tended to reflect dietary P addition. For the majority of the sampling periods, both treatment groups were able to maintain accepted normal serum and plasma P concentrations. Liver, kidney, heart, muscle, rumen fluid, feces and hair P levels proved insensitive for distinguishing between treatment groups. Dietary P level had no effect on P or Ca content of milk. Saliva P concentration was related to treatment groups for both sampling periods. Rib bone P expressed as percent ash or milligram P/cm3 was greater (P<0.05) for animals receiving higher dietary P. Of the parameters studied, bone P concentration best reflected dietary P intake.