Effect of exogenous bovine somatotropin on sodium, potassium and chloride contents of milk in lactating crossbred cows *

Abstract

The effect of bovine somatotropin (bST) administration on mineral contents of milk was studied in 24 crossbred cows. The animals were given placebo injections of sterile normal saline and from groups Tâ‚‚ , T₃ and Tâ‚„ were given 250 mg, 350 mg and 500 mg sometribove zinc divided into Tâ‚, Tâ‚‚, T₃ and Tâ‚„ groups. The cows from group Tâ‚ were suspension in sustained release preparation respectively at every 14 days interval for 10 cycles. The bST-treated cows had higher milk sodium than that of control cows. The values in group T₃ were significantly (P < 0.01) higher than Tâ‚, Tâ‚‚, and Tâ‚„ groups. The bST treated cows had higher potassium concentration, however, the difference was statistically nonsignificant. There was no difference in milk chloride concentration in the 4 groups studied.