乳牛体内维生素D_3代谢与骨软病的研究

STUDY ON VITAMIN D, METABOLISM ANDOSTEOMALAC1A IN DAIRY COWS

在北京郊区某农场，选择１０头健康乳牛作为对照组，几头具有骨营养不良的乳牛作为试验组，分别进行了饲料和血清钙、磷含量分析、血清ＡＫＰ活性及其同功酶、血清维生素Ｄ＿３及其活性代谢产物等项目的检测，尾椎Ｘ线检查及维生素Ｄ＿３治疗试验等。结论如下：①该场乳牛发生的骨营养不良为骨质软化症，维生素Ｄ＿３及其活性代谢产物缺乏是其主要病因；②血清２５－ＯＨ－Ｄ＿３和１，２５－（ＯＨ）＿２－Ｄ＿３是诊断乳牛维生素Ｄ营养状况和乳牛骨软病的敏感指标之一；③血清ＡＫＰ同功酶酶谱所显示的以骨ＡＫＰ酶带发生的特征性变化，可作为早期诊断乳牛骨软病的重要指标；④血清钙、无机磷、ＡＫＰ活性及尾椎Ｘ线检查，作为乳牛骨软病的早期诊断指标是不确实的，但对重症病例仍有较重要的诊断意义；⑤每周肌注１．８×１０ ６ＩＵ维生素Ｄ＿３，可作为临床乳牛骨软病治疗的推荐剂量。

Ten healthy cows as a control group and cows with osteomalacia as the experimentalgroup were selected out from a suburban farm of Beijing.Calciuni and Phosphorus inration and serum, activity of serutn alkaline phosphatase and its isoenzymes, serum vita-min D_3 and its active metabolites, X-ray examination of tail vertera and treatment ex-periment with vitamin D_3 were analysed.Tlie results showed as follow:1. The osteodystrophy in dairy cows was osteoinalacia on the farm mainly caused bydeficiency of vitamin D3 and its active metabolites.2.The concentrations of serum 25-hydroxycholecalciferol and 1,25-dihydroxychole-calciferol are sensitive indicators for diagnosis of osteomalacia and examination of nutri-tional level of vitamin D in dairy cows.3. The zymiogram that is the characteristic of serum AKP isoenzymes correspondingto change of the band of bone AKP isoenzyme is a sensitive indicator for early diagno-sis of osteomalacia.4.It is not reliable to use the concentrations of serum calcium,inorganic phospho-rus, activity of AKP and finding of tail vertera in X-ray as early parameters of osteo-malacia diagnosis except of serious cases.5. A suggested dose of vitamin D_3 for treatment of osteomalacia in dairy cows is1.8 × 10￣6 IU/per week for intramuscular injection.