Goff J P, Stabel J R
USDA, Agricultural Research Service, National Animal Disease Center, Ames, IA 50010.
J Dairy Sci. 1990 Nov;73(11):3195-9. doi: 10.3168/jds.S0022-0302(90)79010-8.
Retinol (vitamin A), alpha-tocopherol (vitamin E), and Zn are micronutrients essential for health and performance. We determined the effects of parturition, lactation, and periparturient Ca status on plasma retinol, alpha-tocopherol, and Zn in 18 Jersey cows during the 2 wk before and after parturition. Six cows developed clinical milk fever. Prepartum plasma concentrations of retinol, alpha-tocopherol, and Zn decreased progressively in all animals. A nadir was reached at 1 d postpartum when concentrations declined to 38, 47, and 67%, respectively, of prepartal baseline concentrations. Plasma Zn returned to baseline concentrations within 3 d of calving, and plasma alpha-tocopherol returned toward baseline about 10 d after calving. Plasma retinol remained below baseline concentrations throughout the first 2 wk of lactation. The decline in plasma Zn observed at calving was more severe in cows with milk fever (parturient paresis) than in cows without milk fever. The decrease in plasma retinol and alpha-tocopherol observed at parturition was similar in cows with or without milk fever. These data document an acute decline in plasma retinol, alpha-tocopherol, and Zn in the immediate periparturient period and indicate that the decline in plasma Zn is more severe in cows with milk fever.
视黄醇（维生素A）、α-生育酚（维生素E）和锌是维持健康和正常生理机能所必需的微量营养素。我们测定了分娩、泌乳以及围产期钙状况对18头泽西奶牛分娩前后2周血浆视黄醇、α-生育酚和锌水平的影响。其中6头奶牛出现了临床性产乳热。所有动物产前血浆视黄醇、α-生育酚和锌的浓度均逐渐下降。产后1天降至最低点，此时浓度分别降至产前基线浓度的38%、47%和67%。血浆锌在产犊后3天内恢复到基线浓度，血浆α-生育酚在产犊后约10天恢复至接近基线水平。在泌乳的前2周，血浆视黄醇浓度一直低于基线水平。产犊时观察到的血浆锌下降在患产乳热（生产瘫痪）的奶牛中比未患产乳热的奶牛更为严重。有无产乳热的奶牛在分娩时血浆视黄醇和α-生育酚的下降情况相似。这些数据表明围产期血浆视黄醇、α-生育酚和锌会急剧下降，并且表明患产乳热的奶牛血浆锌下降更为严重。
