Study Of Zinc Hydroxy-Methionine On Dairy Cows

The aims of this study was to evaluate the effect of Zinc hydroxymethionine on milk yield and milk quality and to find out the optimal application dose on dairy cows. The mechanism of Zinc hydroxymethionine in increasing milk yield and improving milk quality was discussed.Sixty clinically healthy lactating Holstein ,which had the adjacent milk yields> parturition date and production times, was divided into 4 groups(each group had 15 cows), randomly. One was used as the control group and the remains were used as treatment groups. The control and three treatment groups were added CK 25CK 500 and 750mg/kg Zinc hydroxymethionine in basic dietary, respectively. The milk samples were collected in the 0, 15 and 35th day after using Zinc hydroxymethionine and the milk components and milk somatic cell counts were examined. In clinical treatment period, the daily milk yields were noted.The effect of Zinc hydroxymethionine on milk yields. The treatment groups(250> 500 and 750mg/kg) were 0.77 , 1.27 and 0.69 kilograms bigger than the control group, and the increasing milk ratios were 3.4, 5.8 and 3.2%, respectively. The 250 and 750mg/kg groups were significantly different compared with the control group, while the 500mg/kg group were severely different compared with the control group. All the treatment groups had no significant difference compared each other. The control group, which had the biggest drop on milk yield compared with its yield at the start of this experiment, had dropped 2.6kg/day.cow, with drop ratioll.7%; while the experiment groups(250, 500 and 750mg/kg) had dropped 2.07 9.3%, 1.14 5.2% and 1.47 kg/day.cow 6.8%, respectively.The effect of Zinc hydroxymethionine on milk quality. Relative milk fat ratio: On 15th day after adding zinc hydroxymethionine , the treatment groups(250, 500 and 750mg/kg) were 0.13, 0.30 and 0.15%, respectively; on 35th day, the treatment groups(250, 500 and 750mg/kg) were 0.11, 0.13 and 0.25%. Relative milk protein ratio: On 15th day after adding zinc hydroxymethionine, the treatment groups(250, 500 and 750mg/kg) were 0.12, 0.20 and 0.24%, respectively; on 35th day, the treatment groups(250> 500 and 750mg/kg) were 0.05, 0.13 and 0.16%. Relative milk lactose ratio: On 15th day after adding zinc hydroxymethionine, the treatment groups(250,500 and 750mg/kg) were -0.01 , 0.02and -0.01 %, respectively; on 35th day, the treatment groups(250, 500 and 750mg/kg) were -0.12 0.02 -0.01 %,. Relative milk total solid ratio: On 15th day after adding zinc hydroxymethionine, the treatment groups(250, 500 and 750mg/kg) were 0.36, 0.59 and 0.33 %, respectively; on 35th day, the treatment groups(250, 500 and 750mg/kg) were 0.23 , 0.29 and 0.46 % . Relative milk solid not fat ratio: On 15th day after appending zinc hydroxymethionine, the treatment groups(250, 500 and 750mg/kg) were 0.34, 0.28 and 0.32%, respectively; on 35th day, the treatment groups(250, 500 and 750mg/kg) were0.28, 0.21 and 0.22%.The effect of Zinc hydroxymethionine on milk somatic cell counts. On 15' day after adding zinc hydroxymethionine , the number of milk somatic cell of the groups(0, 250, 500 and 750mg/kg) were 1.3, 5.6, 14.3 and 2.1% lower than those of the 0th day, respectively. On 35th day after adding zinc hydroxymethionine , the milk somatic cell numbers(0, 250, 500 and 750mg/kg) were 1.3, 1.4, 7.9 and 2.1 % lower than those of the 0th day, respectively.The results indicate that: zinc hydroxymethionine can significantly increase the milk yield, improve the milk quality and reduce the milk somatic cell counts.