Effect Of Dietary Cation-anion Balance On Production Performance And Blood Biochemistry Indicators Of Diary Cows In The Condition Of Heatstress

In the condition of heat stress, dietary cation-anion balance had a significantly effects on production and health of dairy cow. They can directly affect the balance of acid and base, metabolism of mineral matter, the level of enzyme and hormone. By this way, they can improve health condition, feed intake and production of dairy cow.75 middle lactation(104.8±12 DMI) China Holstein cows come from Anding Pengfeng dairy farm of Beijing were used in this experiment. These cows were randomly divided into five groups by similar parity, milk yield and weight into five treatment groups, every group were adjusted the DCAB value by providing with different level cation-anion salt. Five group were groupⅠ,Ⅱ,Ⅲ,Ⅳand control group, the DCAB value of these group diets were 195.76, 186.68, 177.77, 166.94 and 239.12 mEq/kg DM. The experimental stage were lasted 67 days, 7 days for test period beforehand and 60 days for test period. We change the DCAB value to study the effect of different DCAB value on the performance and blood chemistry of dairy cattle on the condition of heat stress. The results indicated that in the condition of heat stress, different DCAB value diet can influence the performance and the milk quality. Compared with control group, the milk yield of groupⅠandⅡincreased 1.6% and 0.8%, but the milk yield of groupⅢandⅣdecreased 2.2% and 1.7%, but the difference is not significant (P>0.05). However, the milk fat rate, milk protein rate, lactose, total solids mass and somatic cell count were not significantly affected by change the DCAB value of the diets. Meanwhile, the concentration of nitric acid salt and nitrous acid salt in milk were not significantly affected by these diets(P>0.05). (2) The concentration of K, Ca, Na and Mg in the urine were not significantly affected by the different DCAB value diets (P > 0.05). However, the concentration of Cl- was increased with the decreased of DCAB value of the diets. Compared with the control group, groupⅠandⅡincreased 33.8% and 35.6%, have the significantly difference (P<0.05). GroupⅢandⅣincreased 95.4% and 76.9%, have the significantly difference (P<0.01), groupⅢandⅣcompared with groupⅠandⅡ, there have a significantly increased (P<0.05). The pH of urine was increased with the DCAB value increased, control group, groupⅠandⅡcompared with groupⅢandⅣ, there have a significantly increased (P<0.05). (3) Creatine phosphokinase in blood serum of dairy cows were significantly affected by the different DCAB value diets, the data of groupⅠandⅡcompared with control group, groupⅢandⅣwere decreased, the data were 17.64%, 12.41%, 7.88% and 15.43%, 10.05%, 5.4%, groupⅠandⅡcompared with groupⅢandⅣ, there have a significantly difference (P<0.05). Glutamic-pyruvic transaminase in blood serum of dairy cows were not significantly affected by these diets. In the condition of heat stress, hormone in blood serum were affected by different DCAB value diets, the concentration of T4 and T3 in blood serum were not significantly affected by the different DCAB(P>0.05). But COR in the blood serum of dairy cows were significantly affected by these diets, the data of groupⅠcompared with other group were significantly increased (P<0.05), the data of other group were not have significantly difference (P>0.05). (4) Blood glucose in serum were not significantly affected by different DCAB diets (P>0.05). The concentration of urea nitrogen in blood serum were significantly affected by DCAB, the concentration of urea nitrogen increased progressively with the increased of DCAB value. GroupⅠcompared with groupⅡincreased 18.67%, have a significantly difference (P<0.05), but there were not significantly different between other groups. The concentration of total protein, albumin, the ratio of albumin and globulin were not significantly affected by DCAB (P>0.05). (5) The concentration of Ca and Cl in blood serum of dairy cows were significantly affected by DCAB, the concentration of Ca was decreased with the increased of DCAB value. The concentration of Cl was increased with the decrease of DCAB value, but there have not significantly difference (P>0.05). Meanwhile, the concentration of Na in blood serum of groupⅠand control group were affected by DCAB, but there were not significantly difference (P>0.05).