Calcium and phophorus percent clearance ratios related to mineral nutrition in growing nelore (zebu) cattle

Abstract

Calcium, phosphorus and creatinine were measured in serum and urine samples taken from 80 growing Zebu cattle (Nelore), 8 to 24 months old, in order to calculate the percent clearance ratios of calcium and phosphorus, and verify the influences of mineral nutrition manegement and sex. The animals were raised under natural range conditions and divided in 4 groups (n-20) according to sex and mineral supplementary diet (sufficient or insufficient) to evaluate differences considering these two factors. The results were analysed through ANOVA. The serum levels of calcium and phosphorus were all within normal values. The average calcium percent clearance ratios were as follows: 0,65±0,69% (healthy males), 1,45±0,91% (healthy females), 1,53+1,80% (deficient males) and 2,06+1,59% (deficient females), with higher values in heifers. Phosphorus percent clearance ratios showed 0,38±0,56%> (males) and 0,43±0,38% (females) in healthy animals, and 1,58±1,82% (males) and 0,95±0,48%> (females) in the deficient ones, without differences related to sex. The animals in poor mineral nutrition management exhibited elevated calcium and phosphorus percent clearance ratios, as a possible reflex of the dietary related calcium and phosphorus metabolic imbalances.