Carr Sarah, Jia Yang, Crites Benjamin, Hamilton Charles, Burris Walter, Edwards J Lannett, Matthews James, Bridges Phillip J
Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, USA.
Department of Animal Science, University of Tennessee, Institute of Agriculture, AgResearch, Knoxville, TN 37996, USA.
Animals (Basel). 2020 Jun 3;10(6):967. doi: 10.3390/ani10060967.
Soils with marginal to deficient levels of selenium (Se) are widespread in the northwest, northeast, and southeast US. Supplementation to the diet of forage-grazing beef cattle with a vitamin-mineral mix containing additional Se is recommended in these geographic regions. We have reported that the form of supplemental Se provided to Angus-cross beef cows can affect circulating levels of progesterone (P4) on day 6 of the estrous cycle, a time when increased P4 is known to promote fertility. The objectives of this study were to (1) confirm and expand upon our initial report that the form of Se provided to cows affects early luteal-phase concentrations of systemic P4, (2) determine the effects of the form of Se on concentrations of P4 during gestation, and (3) determine the effects of the form of Se on concentrations of prolactin (PRL) during lactation. Throughout this study, Angus-cross beef cows had ad libitum access to a vitamin-mineral mix containing 35 ppm of Se in either an inorganic form (ISe) or a 1:1 mix of inorganic and organic forms (MIX). We observed a MIX-induced increase ( = 0.006) in systemic concentrations of P4 on day 7 but not on days 4 or 10 of the estrous cycle, consistent with our earlier report. We observed a MIX-induced increase ( = 0.02) in the systemic concentration of P4 at months 1, 3, 5, and 7 of gestation, and a MIX-induced decrease ( < 0.05) in systemic concentrations of PRL at months 5 and 6 of lactation. In summary, the form of Se provided to cows can be manipulated to affect the early luteal phase and gestational concentrations of P4, and postpartum concentrations of PRL.
美国西北部、东北部和东南部广泛分布着硒（Se）含量处于临界至缺乏水平的土壤。在这些地理区域，建议给放牧的肉牛日粮中添加含额外硒的维生素 - 矿物质混合物。我们曾报道，给安格斯杂交肉牛母牛提供的补充硒形式会影响发情周期第6天孕酮（P4）的循环水平，已知此时P4水平升高可促进生育能力。本研究的目的是：（1）证实并扩展我们最初的报告，即给母牛提供的硒形式会影响黄体早期全身P4的浓度；（2）确定硒形式对妊娠期P4浓度的影响；（3）确定硒形式对泌乳期催乳素（PRL）浓度的影响。在整个研究过程中，安格斯杂交肉牛母牛可随意获取含35 ppm硒的维生素 - 矿物质混合物，硒的形式为无机形式（ISe）或无机与有机形式1:1的混合物（MIX）。我们观察到，在发情周期第7天，MIX使全身P4浓度升高（ = 0.006），但在第4天或第10天未出现此情况，这与我们早期的报告一致。我们观察到，在妊娠第1、3、5和7个月，MIX使全身P4浓度升高（ = 0.02），在泌乳第5和6个月，MIX使全身PRL浓度降低（ < 0.05）。总之，给母牛提供的硒形式可被调控，以影响黄体早期和妊娠期的P4浓度以及产后PRL浓度。
