Establishment of the algorithm for body mass index and its correlation with reproductive performance of Holstein in Southern China
The aim of this study was to research the optimal algorithm of body mass index(BMI)and its correlation with reproductive performance of Holstein in Southern China.In this study,the body size and body weight of heifers(n=330)were measured and six candidate BMI algorithms were set up based on body length(BL),body straight length(BSL),body height(BH)and body weight(BW),following referenced BMI construction principle and formula of hu-man.By analyzing the correlation between different BMI algorithms and body size and BW,and comparing the correlation between different body condition methods evaluation and the mating times and the first gestational age of heifers,the best algorithm of BMI was chosen to establish the optimal interval of BMI for the first-mated cows.The results showed that the formula BMI=BW/BH2 was strongly correlated with BW,but independent of body size.In addition,the formula was highly significantly correlated with the mating times and the first gestational age,which was the best algorithm to evaluate the reproductive performance for heifers.When BMI＞275.50 kg·m-2,the estrus conception rate increased rapidly.Mean-while,the levels of alanine aminotransferase,alkaline phosphatase,total cholesterol and high-density lipoprotein in serum of high-BMI cows(BMI＞275.50 kg·m-2)were significantly higher than those in low-BMI cows(BMI＜275.50 kg·m-2).When the BMI was between 275.50 and 341.10 kg·m-2,the probability of successful pregnancy after insemination was high-er,suggesting that this interval was the optimal interval of BMI for insemination of heifers.
dairy cowsbody mass indexmating timesthe first gestational ageestrus conception rate
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