Effects Of Different Technical Measures On Milk Performance Of Holstein Cows In Summer

This studies tested some different ways to slow down heat stress of Holstein cow in summer periods and to improve their milk performance by supplementation of NaHCO₃ and mini-nutritious compound and adoption of physical colling in cowhouse.The three experiments were carried out respectively. In the first experiment, we studied the effects of NaHCO₃ supplementation in ration on cow milk performance. By cross design, 16 Holstein-Friesian cows were divided into group A and group B. The experiment was divided into two periods. 150g NaHCO₃ was added into the ration of each cow in the treatment group every day. The results indicated, compared with the control, that daily mean milk yield increased by 17.4% and 20.1 % (P<0.01); the fat content increased by 14.5 % and 6.93% (P<0.05) .In the second experiment, 20 healthy and midstage lactation Holstein-Friesian cows were randomly divided into two groups, one treatment and one control ,and mini-nutritious compound was added in ration of the treatment groups in order to compare differences of the performance between previous and posterior a half month of the treatment. The results indicated, that the daily mean milk yield of the treatment decreased by 0.35 kg(P>0.05 ). The daily mean milk yield of the control decreased by 2.71kg(P<0.01). Compared with posterior month of the treatment and the control, the fat content of the treatment increased by 12.6% and 8.3% respectively (P<0.05) .In the third experiment, physical cooling measure was adopted to study the influence of the temperature in cowshed on performance. 10 cows were randomly divided into two groups. For lowering temperature in the experimental group,electric fans and water-pouring instruments were installed in cowshed. The results indicated, compared with the control, the temperature decreased by10%,12% and 9.2% respectively. The humidity decreased by 1.9%, the daily mean milk yield of the treatment increased by 6.18% (P<0.05) . The fat content of the treatment decreased by 3.7%,that of the control decreased by 2.6% (P>0.05) .The results suggested that based on traditional ways, adopting different nutritive measures and physical measures could improve cow milk performance in summer.