Effects Of Biotin On Energy And Metabolizable Protein Balance And Production Performance Of Dairy Cows In Transition

The dairy cows experience the pregnancy, parturition, lactation, which improve metabolic demands. However the dry matter intake of dairy cow usually decreases due to diet conversion and hormone regulation. Energy intake can not meet the requirement, so the dairy cow is always in the state of negative energy balance(NEB), which may lead to periparturient disorders such as fatty liver and ketonsis. Many studies indicate that dietary biotin supplementation can improve cow hoof quality and milk production performance, but the effects of biotin on energy balance is limited. CPM-Dairy can accurately predict the diet nutrient composition, metabolizable energy efficiency, metabolizable protein efficiency and feed nutrient for maintenance, pregnancy, lactation and growth. The study first seeks to assess the nutrition intake of dairy cows in transition periods by CPM-Dairy and laboratory analysis,and to calculate net energy and metabolizable requirements, intake and balance with the actual dry mater intake, body weight, milk production and composition. Second, the study is conducted to explore the effect of dietary biotin supplementation on production performance and energy balance. The aim of our study is to provide reference and theoretical basis for practical production.Dietary actual nutrition intake assessment of dairy cows in transition period. We analyze the nutrition composition of ingredient of transition diet with CPM-Dairy and calculate net energy and metabolizable requirements, intake and balance with the actual dry mater intake, body weight, milk production and composition of ten dairy cows in transition period. The results showed that:the requirement of net energy and metabolizable protein was affected little during pre-calving, while it was great increased after calving.The actual intake of net energy and metabolizable protein from diet was relative to dry matter intake. Therefore,the balance of net energy and metabolizable protein was negative after calving and returned to the normal lever at 35 d and 28 d respectively.Effects of biotin on energy and metabolizable protein balance and production performance of dairy cows in transition period. 20 cows were selected and divided into 2groups(10 in each group) with the test method of pairing. The control group was only feed basal diet and the biotin treatment was added 30 mg/d biotin extra. Trial period from prenatal14 d to postpartum 35 d. The results showed that:(1) Biotin supplementation had no effect ondry mater intake(P > 0.05).(2) Biotin supplementation increased plasma glucose concentration at 14 d postpartum(P < 0.05).(3) Biotin supplementation had no effects on plasma urea nitrogen(P > 0.05).(4) Biotin supplementation had no effect on energy and metabolizable protein balance(P < 0.05).(5) Biotin supplementation increased milk yield(P< 0.05), but had no effect on milk fat percentage, milk protein percentage and milk glucose percentage(P > 0.05).(6) Biotin supplementation had no effect on hoof hardness and moisture content(P > 0.05).In conclusion, the balance of net energy and metabolizable protein are negative postpartum, and biotin supplementation can improve production performance of dairy cows in early lactation.