Hove K, Kristiansen T
J Dairy Sci. 1982 Oct;65(10):1934-40. doi: 10.3168/jds.S0022-0302(82)82441-7.
Norwegian Red cows 4 yr or older were fed a high calcium diet the last 2 to 4 wk before calving to increase the severity of hypocalcemia at parturition. An oral dose of pellets of fat-encapsulated 1,25-dihydroxyvitamin D3 (500 micrograms) was given to 15 cows and placebo pellets to 12 cows. Treated cows were grouped according to time of treatment, 1) 4 cows treated within 24 h of calving, 2) 8 cows treated 1 to 3 days before, and 3) 3 cows treated 4 to 5 days before calving. Minerals in blood plasma were measured from day -10 to day +10 (calving: day 0). Average calcium concentration of cows treated 1 to 3 days before calving decreased from 2.6 to 2.4 and of placebo treated from 2.5 to 1.8 mmol/liter from day -1 to day +1. Treatment with 1,25-dihydroxyvitamin D3 at other times did not protect against hypocalcemia. Average concentrations of 1,25-dihydroxyvitamin D in plasma were 200 to 250 pg/ml on days -2 and -1 in 5 cows treated on days -3 and -2. Similar concentrations were reached by placebo cows 1 to 2 days after parturition. A single oral dose of 500 micrograms 1,25-dihydroxyvitamin D3 given 1 to 3 days before parturition can prevent hypocalcemia at calving. Difficulties in judging actual time for parturition led to optimal treatment of only 8 of 15 cows.
对4岁及以上的挪威红牛，在产犊前最后2至4周饲喂高钙日粮，以加重分娩时低钙血症的严重程度。给15头奶牛口服一剂脂肪包裹的1,25 - 二羟基维生素D3颗粒（500微克），给12头奶牛口服安慰剂颗粒。根据治疗时间对治疗的奶牛进行分组：1）4头在产犊后24小时内接受治疗；2）8头在产犊前1至3天接受治疗；3）3头在产犊前4至5天接受治疗。在第 - 10天至第 + 10天（产犊日为第0天）测定血浆中的矿物质。从第 - 1天到第 + 1天，产犊前1至3天接受治疗的奶牛平均钙浓度从2.6降至2.4，接受安慰剂治疗的奶牛从2.5降至1.8毫摩尔/升。在其他时间用1,25 - 二羟基维生素D3治疗不能预防低钙血症。在第 - 3天和第 - 2天接受治疗的5头奶牛中，第 - 2天和第 - 1天血浆中1,25 - 二羟基维生素D的平均浓度为200至250皮克/毫升。产后1至2天，安慰剂组奶牛也达到了类似浓度。在分娩前1至3天口服一剂500微克的1,25 - 二羟基维生素D3可预防产犊时的低钙血症。判断实际分娩时间的困难导致15头奶牛中只有8头得到了最佳治疗。
