NR 49. The effect of mineral supplementation on mineral status, productive and reproductive performance in a grazing herd

Abstract

In order to evaluate the effect of mineral supplementation on mineral status productive and reproductive performance, a herd of crossbred criollo x cebu animals grazing in natural savannas was divided at random into two groups with similar age and body conditions and subjected to the following treatments: Treatment 1 (T1) with only common salt (NaCl) and treatment 2 (T2) with a complete mineral supplement. A health program was also applied to both treatments. After 437 days of evaluation T1 had an average salt intake of 19.8 g./hd/day whereas T2 had a consumption of 53.9 g./hd/day of mineral supplement. Mineral supplementation showed effects and some differences were found (P < .05) in serum mineral concentrations and also in bone mineral profiles (P<0.01). Weight gains were 107 g./hd/day higher in T2 (P<.05) when compared to T1 with weight losses of -20 g./hd/day during the dry season. Cows, heifers and young bulls were heavier during the dry season (P<.05). Pregnancies of T2 were higher in cows and heifers the year round. There was also a decline in the calving-conception interval and abortions in T2 (P<.05). These results proved that mineral supplementation yields better results in body mineral balance, production and reproductive performance.