Peripartum Performance, Blood-biochemistry Index And Endocrine Factors Of Dairy Cows In Response To Prepartum Energy Intake

The studies on different energy supplied by forage during dry period of Dairy Cows on their dry matter intake (DMI) after calving, peripartum performance, blood-biochemistry, endocrine factors about energy metabolite and ingestion were developed. 30 fed Chinese Hostein cows being 5~8 years, 3~6 times of late pregnancy, clinical health, lactation product exceeding 5000Kg, were randomly allocated into three different energy level groups, Group of NRC standard energy (control group, G1)i Group of 120% NRC standard energy (G2) and Group of 80% NRC standard energy (G3).They were divided and dietary treatments were fed from 28d before expected calving date to calving. After parturition, all the cows were offered ad libitum according to the NRC standard energy to 56d when the studies completed. DMI, live weight, milk yields and its components.blood-biochemistry index and endocrine factors about energy metabolite and ingestion were measured during this period. The results indicate that: 1. The Group of 80% NRC standard energy (G4) cows increase DMI in postpartum, relieve negative energy balance (NEB) in Peripartum and improve condition of body; While The Group of 120% NRC standard energy (G2) cows decrease DMI in postpartum, increase negative energy balance (NEB) in Peripartum and worsen condition of body. 2. The G3 cows improve milk performance, 16% higher milk yields, two week sooner reaching milk flood tide and three week longer milk flood tide lasted, more protein and lipide contents in milk than GI ; While the Gil cows decrease milk performance, 15% lower milk yields than GI and cannot reaching milk flood tide.3.The G3 cows induce the time when NPY can be inspected to be ahead. At the first day after calving NPY can be inspected in blood of G3 cows and disappeared two weeks later, while it is at the 14th day after calving when NPY can be inspected in blood of G2 and GI cows and then disappear two weeks latter. 4. The G3 cows induce more concentration of leptin than the G2 and G1 cows; relieve the state NEB or/and energy lack after calving.