Effects of intramuscular injections of folic acid, vitamin B12, or both, on lactational performance and energy status of multiparous dairy cows
Effects of intramuscular injections of folic acid, vitamin B12, or both, on lactational performance and energy status of multiparous dairy cows
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DOI：
10.3168/jds.2016-12381
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发表时间：
2017-05-01
影响因子：
3.5
通讯作者：
Girard, C. L.
中科院分区：
文献类型：
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作者：
Duplessis, M.;Lapierre, H.;Girard, C. L.
本试验的目的是了解从预产期前3周至产后7周每周肌肉注射叶酸和维生素B-12补充剂（单独或联合）时能量分配的变化。将24头Yucultiparous奶牛按照先前305天的泌乳产量分配到6个区组，每组4头奶牛，以2 x 2析因排列方式分配到0或320 mg叶酸和0或10 mg维生素B-12。叶酸补充剂可增加血浆叶酸浓度，且联合补充剂的增加幅度更大。维生素B-12补充剂增加了维生素B-12的血浆浓度。尽管产后能量平衡在治疗中相似，但接受叶酸补充剂的奶牛的产后身体状况评分高于未接受叶酸补充剂的奶牛。接受叶酸补充剂的奶牛的产奶量比没有补充叶酸的奶牛更早达到平台期。脂肪和蛋白质，以及总固体浓度和产量，不受治疗。产后血浆葡萄糖和胰岛素浓度较高，产后血浆非酯化脂肪酸浓度较低的奶牛，每周接受叶酸补充剂相比，奶牛没有。等离子体甲基丙二酸的浓度较低，不受处理的影响，表明维生素B-12的供应不受限制，即使是未补充的奶牛。产后血浆中半胱氨酸，组氨酸，桩，酪氨酸浓度增加，而血浆中甘氨酸浓度下降，叶酸补充剂。在本研究中，补充叶酸改变了能量分配在泌乳早期的牛奶总固体产量和产后能量平衡，较低的血浆非酯化脂肪酸浓度和身体状况评分的损失，以及较高的血糖和胰岛素浓度的奶牛接受叶酸补充剂相比，奶牛没有。
The purpose of this experiment was to gain understanding on changes in energy partitioning when folic acid and vitamin B-12, supplements, alone or combined, were given by weekly intramuscular injections from 3 wk before the expected calving date until 7 wk postpartum. Twenty-four Yucultiparous cows were assigned to 6 blocks of 4 cows each according to previous 305-d lactation yield to either 0 or 320 mg of folic acid and 0 or 10 rag of vitamin B-12 in a 2 x 2 factorial arrangement. Plasma concentration of folates was increased by folic acid supplement, and this increase was greater with the combined supplement. Vitamin B-12 supplement increased plasma concentration of vitamin B-12. Even though postpartum energy balance was similar among treatments, postpartum body condition score was higher for cows receiving folic acid supplement compared with cows that did not. Milk yield of cows receiving folic acid supplement reached a plateau earlier than for cows that did not. Fat and protein, as well as total solid concentrations and yields, were unaffected by treatments. Postpartum plasma concentrations of glucose and insulin were higher and postpartum plasma concentration of nonesterified fatty acids was lower for cows that received weekly folic acid supplement compared with cows that did not. Plasma. concentration of methylmalonic acid was low and unaffected by treatments, suggesting that vitamin B-12 supply was not limiting, even for unsupplemented cows. Postpartum plasma concentrations of Cys, His, Pile, and Tyr were increased, whereas plasma concentration of Gly was decreased, by folic acid supplement. In the present study, supplementary folic acid altered energy partitioning in early lactation as suggested by similar milk total solid yield and postpartum energy balance, lower plasma nonesterified fatty acid concentration and body condition score losses, and higher plasma glucose and insulin concentrations for cows receiving folic acid supplement compared with cows that did not.