集约化高产奶牛低钙血症及其影响因素调查

Investigation on Hypocalcemia and Its Influence Factors in High-yield Dairy Cows of Intensive Farm

回顾性调查新疆昌吉地区某集约化规模化高产奶牛养殖场低钙血症的发病率及其影响因素。通过现场调查收集养殖场的兽医诊疗记录,统计奶牛低钙血症的全年发病率,计算胎次发病率,比较健康奶牛和低钙血症奶牛的泌乳量、输精次数、初配天数、运动量的差异性,对胎次发病率与前述因素进行相关性分析。结果显示,该养殖场2021年低钙血症的年发病率为9.94%;该病的全年发病率在秋季9月和10月最低,分别为5.52%和5.48%,冬季1月和2月最高,分别为17.70%和22.02%。低钙血症的发病率随着奶牛胎次的增加而升高。低钙血症组当前胎次的总泌乳量、泌乳天数、日平均泌乳量均极显著低于健康组(P<0.01);低钙血症组当前胎次的总运动量与日平均运动量均极显著低于健康组(P<0.01);低钙血症组的输精次数与初配天数极显著高于健康组(P<0.01)。当前胎次的总泌乳量、泌乳天数、日平均泌乳量、总运动量、日平均运动量均与低钙血症的胎次发病率呈极显著负相关。综上所述,低钙血症对高产奶牛的泌乳性能、运动量、配种都有负面影响。该养殖场低钙血症发病率较高,未来应重点关注产后泌乳量和运动量下降的高胎次奶牛,该群体患低钙血症的风险更高,同时也要做好冬季的饲养管理工作,减少养殖场的经济损失。

Retrospective investigation on the incidence rate of hypocalcemia(IRHC)and its influencing factors in an intensive large-scale high-yield dairy farm was conducted in Changji,Xinjiang.By means of the on-site collection of veterinary diagnosis and treatment records of the farm,the annual IRHC was surveyed.The incidence rate of hypocalcemia per parity(IRHCPP)was calculated.The lactation volume,the number of inseminations(NI),the days of first mating,the exercise amount between health and hypocalcemia cows were compared and the IRHCPP was analysed with aforementioned influencing factors.The results showed that the annual IRHC in the farm in 2021 was 9.94%,in which it was the lowest in September and October as 5.52%and 5.48%respectively,and the highest in January and February as 17.70%and 22.02%respectively.The IRHC increased with the increase of parities.The total milking yield(TMY),the lactation days(LD),and the daily average milking yield(DAMY)of current parity in the hypocalcemia group were significantly lower than those in the healthy group(P<0.01);The total exercise amount(TEA)and average daily exercise amount(ADEA)of the current parity in the hypocalcemia group were significantly lower than those in the healthy group(P<0.01);The hypocalcemia group was significantly higher than the healthy group in terms of the number of insemination times and initial mating days(P<0.01).The TMY,LD,DAMY,TEA,and ADEA of the current parity were negatively correlated with the IRHCPP significantly.In summary,hypocalcemia has a negative impact on the lactation performance,exercise amount,and mating of cows.The IRHC in this farm is high.It is suggested that the more attention should be paid on those milking cows of the higher parities with tendency of decreased milking yield,deceased exercise amount postpartum due to their higher risk of hypocalcemia.And also,the breeding management in winter should be strengthened to reduce the economic losses of the farm.