Hodnett D W, Jorgensen N A, Deluca H F
College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706.
J Dairy Sci. 1992 Feb;75(2):485-91. doi: 10.3168/jds.S0022-0302(92)77785-6.
The effectiveness of a combination of 1 alpha-hydroxyvitamin D3 and 25-hydroxyvitamin D3 for reducing incidence of parturient paresis in aged Holstein cows was tested. Intramuscular injection of .5 mg of 1 alpha-hydroxyvitamin D3 plus 4 mg of 25-hydroxyvitamin D3 increased plasma 1,25-dihydroxyvitamin D concentrations through parturition. Treatment with 1 alpha-hydroxyvitamin D3 plus 25-hydroxyvitamin D3 raised prepartum serum Ca approximately 2 mg/dl and prepartum serum P approximately 4 to 5 mg/dl higher than untreated controls. Both treated and control cows had approximately a 2-mg/dl decrease in serum Ca following parturition. The prepartum diet of alfalfa silage and hay was supplemented with a grain mixture supplying 100 g of Ca/d from ground limestone. Under these dietary conditions, incidence of parturient paresis was reduced from 33 to 8%. In a separate experiment, treatment with 1 alpha-hydroxyvitamin D3 plus 25-hydroxyvitamin D3 did not reduce incidence of parturient paresis when cows consumed mixed diets of different feed-stuff composition. Further experiments are required to determine specifically the factor or factors responsible for the difference in response to active vitamin D compound administration between the two experiments. Prepartum dietary Ca intake may be one such factor.
对1α-羟基维生素D3和25-羟基维生素D3联合使用降低老龄荷斯坦奶牛生产瘫痪发病率的效果进行了测试。肌肉注射0.5毫克1α-羟基维生素D3加4毫克25-羟基维生素D3可使分娩期间血浆1,25-二羟基维生素D浓度升高。用1α-羟基维生素D3加25-羟基维生素D3治疗使产前血清钙比未治疗的对照组大约高2毫克/分升，产前血清磷比未治疗的对照组大约高4至5毫克/分升。分娩后，治疗组和对照组奶牛的血清钙均下降了约2毫克/分升。产前日粮为苜蓿青贮料和干草，并补充了由石灰石粉提供100克钙/天的谷物混合物。在这些日粮条件下，生产瘫痪的发病率从33%降至8%。在另一项实验中，当奶牛食用不同饲料组成的混合日粮时，用1α-羟基维生素D3加25-羟基维生素D3治疗并未降低生产瘫痪的发病率。需要进一步的实验来具体确定导致这两项实验中对活性维生素D化合物给药反应差异的一个或多个因素。产前日粮钙摄入量可能是这样一个因素。
