Assement Of Different Types Of Rations And The Study Of Feeding Hyprofat To Dairy Cows

Two parts were discussed in this thesis. The first part studied the effects of the different ration structures on milk performance, apparent digestibility and nitrogen balance of dairy cows in mid-lactation. The second part studied the effects of two feeding methods and the feeding of Hyprofat on the physiological reactions, DMI, foraging behaviour and milk performance of dairy cows in the heat-stressed condition. In this trial, cows were offered a total mixed ration(TMR) or separate ingredients ration.Trial â…  . Appraisement of the feeding value of different types of diets on dairy cows.Sixteen healthy Holstein dairy cows in mid-lactation were chosed according to amatched pair design to study two kinds of roughage including curtal soybean straw(Group â…  ) and 50% whole-plant maize silage plus 50% ryegrass haylage (Group â…¡)on milk performance in a 130-day feeding trial;Three pairs of cows were allocated into a 3-day digestion and balanced trial by Total Collection of Urine and Feces Method to study the digestivity and nitrogen balance of the two kinds of diets. The results indicated: (1)The milk production(P<0.01), milk protein proportion (P<0.01). SNF proportion (P<0.01), and milk density(P<0.05) of Group I were significantly higher than Group â…¡; (2)The DMI and apparent digestibility of DM, CP, EE, ADF, Ca, P were 17.4kg/d, 58.0%, 54.3%, 51.7%, 66.1%, 14%, 18% and 21kg/d, 69.4%, 66.1%, 58.8%, 63.2%, 17%, 19% in group â…  and group â…¡ respectively; (3) DM and CP intake in group â…  were lower than that of NRC(2001) and the cows were in negative nitrogen balance. The results of this study suggested that soybean stem could be the source of the roughage in short period in the seasons which was...