The hypothesis of the study was that feeding a relatively low amount of Se biofortified alfalfa hay during the dry period and early lactation would improve selenium status and glutathione peroxidase activity in dairy cows and their calves. Ten Jersey and 8 Holstein primiparous dairy cows were supplemented with Se biofortified (TRT; n = 9) or non-biofortified (CTR; n = 9) alfalfa hay at a rate of 1 kg/100 kg of BW mixed with the TMR from 40 d prior parturition to 2 weeks post-partum. Se concentration in whole blood, liver, milk, and colostrum, the transfer of Se to calves, and the glutathione peroxidase (GPx) activity were assessed. TRT had 2-fold larger (P < 0.05) Se in blood v. CTR that resulted in larger Se in liver and colostrum but not milk and larger GPx activity in plasma and erythrocytes but not in milk. Compared to CTR, calves from TRT had larger Se in blood but only a numerical (P = 0.09) larger GPx activity in plasma. A positive correlation was detected between Se in the blood and GPx activity in erythrocytes and plasma in cows. Our results demonstrated that feeding pregnant primiparous dairy cows with a relatively low amount of Se-biofortified alfalfa hay is an effective way to increase Se in the blood and liver, leading to greater antioxidant activity via GPx. The same treatment was effective in improving Se concentration in calves but had a modest effect on their GPx activity. Feeding Se biofortified hay increased Se concentration in colostrum but not in milk.

中文翻译：

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低量饲喂硒生物强化苜蓿干草可改善过渡奶牛及其小牛的硒状态和谷胱甘肽过氧化物酶活性

该研究的假设是，在干旱期和泌乳早期饲喂相对少量的硒生物强化苜蓿干草将改善奶牛及其小牛的硒状态和谷胱甘肽过氧化物酶活性。10 头泽西和 8 头荷斯坦初产奶牛补充了生物强化硒（TRT；n= 9) 或非生物强化 (CTR;n= 9) 从分娩前 40 天到产后 2 周，以 1 公斤/100 公斤 BW 的比例将苜蓿干草与 TMR 混合。评估了全血、肝脏、牛奶和初乳中的硒浓度、硒向小牛的转移以及谷胱甘肽过氧化物酶 (GPx) 的活性。TRT 有 2 倍大 (磷< 0.05) 血液中的硒五。CTR 导致肝脏和初乳中更大的硒，但不是牛奶，血浆和红细胞中更大的 GPx 活性，但不是牛奶。与 CTR 相比，TRT 的小牛血液中的硒含量较高，但只有一个数值 (磷= 0.09) 血浆中较大的 GPx 活性。血液中的硒与奶牛红细胞和血浆中的 GPx 活性呈正相关。我们的研究结果表明，用相对较少量的硒生物强化苜蓿干草喂养怀孕的初产奶牛是增加血液和肝脏中硒的有效方法，从而提高抗氧化活性通过GPx。相同的处理可有效提高小牛的硒浓度，但对它们的 GPx 活性影响不大。喂食硒生物强化的干草会增加初乳中的硒浓度，但不会增加牛奶中的硒浓度。