Vagnoni David B, Davidson Michayla, Rubio Livia, Oetzel Garrett R, Comets Emmanuelle
Department of Animal Science, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA.
Animals (Basel). 2021 Nov 2;11(11):3131. doi: 10.3390/ani11113131.
Postpartum hypocalcemia is a problem in dairy cows. Both the Jersey vs. Holstein breed and increasing parity are known risk factors. Our objectives were: (1) to evaluate a simple approach to provide dietary acidogenic salts suitable for application on small dairies and (2) to evaluate the combined effects of degree of acidification and oral Ca supplementation along with breed and parity group on periparturient Ca status of Holstein and Jersey cows. Cows were moved weekly from the far-off dry pen at 260 days pregnant to the close-up pen, where all cows received the acidogenic diets. The diet was offered as a total mixed ration and CaCl, and our source of acidogenic salts was top-dressed in liquid form and mixed in by hand. Thirty-six cows were blocked by parity group (parity = 2 vs. parity ≥ 3) and breed (Holstein vs. Jersey) and assigned to one of two treatments (no intervention or postpartum oral Ca bolus supplementation) in an alternating fashion, based on expected date of parturition. Urinary acidification appeared complete within 3-4 days. Increased urinary Ca excretion was >93% of maximum from 7-21 days before falling to <5% of maximum by 28 days. Serum Ca concentrations 12-24 h postpartum were lower for Jerseys vs. Holsteins and for parity ≥ 3 vs. parity = 2 cows. Serum Ca over 6-48 h postpartum decreased and increased, respectively, with oral Ca supplementation for parity = 2 and parity ≥ 3 cows. Decreased prepartum urinary Ca excretion and increased colostrum yield appear to be independent risk factors of hypocalcemia for parity ≥ 3 Jerseys.
产后低钙血症是奶牛面临的一个问题。已知泽西牛与荷斯坦牛品种以及胎次增加都是风险因素。我们的目标是：（1）评估一种简单的方法来提供适合在小型奶牛场应用的日粮产酸盐，以及（2）评估酸化程度和口服钙补充剂与品种和胎次组对荷斯坦牛和泽西牛围产期钙状态的综合影响。奶牛在怀孕260天时每周从远处的干奶牛舍转移到待产牛舍，所有奶牛在那里都接受产酸日粮。日粮以全混合日粮的形式提供，氯化钙作为我们的产酸盐来源以液体形式进行表层施肥并手工混合。36头奶牛按胎次组（胎次 = 2 与胎次≥3）和品种（荷斯坦牛与泽西牛）进行分组，并根据预计分娩日期交替分配到两种处理之一（无干预或产后口服钙丸补充）。尿液酸化在3 - 4天内似乎完成。尿钙排泄增加在产前7 - 21天达到最大值的>93%，到28天时降至最大值的<5%。产后12 - 24小时，泽西牛的血清钙浓度低于荷斯坦牛，胎次≥3的奶牛低于胎次 = 2的奶牛。产后6 - 48小时，对于胎次 = 2和胎次≥3的奶牛，口服钙补充剂分别使血清钙降低和升高。产前尿钙排泄减少和初乳产量增加似乎是胎次≥3的泽西牛发生低钙血症的独立风险因素。
