Effects of recombinant bovine somatotropin(γBST) on mineral composition of milk were investigated in Twenty-five multiparous Holstein dairy cows. Recombinant BST was administered by two different routes; intramusculary(12.5㎎ and 25㎎/day) and subcutaneously (500㎎ and 750㎎) in sustained-release vehicle every 2 weeks beginning 4 week postpartum and continuing for 7 months.
Milks were collected 0,1, 2, 3, 5 and 7 months after beginning of treatments in control and rBST-administered groups.
Mineral composition, such as Ca, Pi, Na, K, Mg, Zn, Fe and Mn, in milk were not affected by the administration of γBST regardless of dose and dosage forms.
It is concluded from the observations of these experiments that the dose and dosage forms of γBST employed in this work might not affect milk mineral composition in dairy cows under the normal sanitary condition and adequate nutrient bulance.
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