Effects of Retinyl Palmitate and Cholecalciferol Added Recombinant BST formulation Treatment on Milk Production and Health in Dairy Cows

Retinyl palmitate와 cholecalciferol이 첨가된 재조합 BST 제제 투여가 젖소의 산유량과 건강에 미치는 영향

This study was performed to investigate the effects of recombinant BST formulation treatment on the milk yield, milk components, mastitis, and general cow health condition when the formulations of retinyl palmitate, cholecalciferol and rBST were administered after the peak period of milk production. The milk yields of treatment groups (Group I, II, III and IV) were increased from 21.5% to 29.0% than that of control group. There was significant difference in milk production between treatment group II, IV and control group (P<0.05). However, there was no significant difference in milk production between treatment group I, III and control group (P<0.05). And the addition of retinyl palmitate and cholecalciferol into rBST formulation did not increase the milk yield. The milk of treatment groups with sustained-release rBST did not show significant difference in milk components (milk fat, protein, lactose, and solid not fat). However, there were minor changes, primarily in fat content of milk, during the first few weeks of rBST administration. There was no incidence of clinical mastitis between rBST treatment groups and control group. Addition of high and medium concentration of retinyl palmitate and cholecalciferol into sustained-release rBST formulation was efficient in reduction of somatic cell count in milk. There was great energy deficit in all treatment groups compared with control group during the early study period. Thus, the body condition score of all treatment groups showed lower value than control group. No evidences of metabolic health problems, such as ketosis, milk fever, and downer cow were observed. Incidence of general lameness did not appear on all treatment groups during 140 days of this study.