Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691.
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691.
J Dairy Sci. 2017 Jul;100(7):5368-5377. doi: 10.3168/jds.2016-12096. Epub 2017 Apr 27.
Eighteen multiparous cows were used in a split-plot replicated Latin square with two 28-d periods to evaluate the effects of source of supplemental Cu, Zn, and Mn (sulfates or hydroxy) on apparent absorption of minerals when fed in either a forage- or by-product-based diet. The by-product diets were formulated to have greater concentrations of NDF and lesser concentrations of starch, and specific ingredients were chosen because they were good sources of soluble fiber and β-glucans, which bind trace minerals in nonruminants. We hypothesized that hydroxy trace minerals would interact less with digesta and have greater apparent absorption compared with sulfate minerals, and the difference in apparent absorption would be greater for the by-product diet compared with the forage-based diet. During the 56-d experiment, cows remained on the same fiber treatment but source of supplemental trace mineral was different for each 28-d period; thus, all cows were exposed to both mineral treatments. During each period cows were fed no supplemental Cu, Zn, or Mn for 16 d, followed by 12 d of feeding supplemental minerals from either sulfate or hydroxy sources. Supplemental minerals for each of the mineral sources fed provided approximately 10, 35, and 32 mg/kg of supplemental Cu, Zn, and Mn, respectively, for both fiber treatments. Total Cu, Zn, and Mn dietary concentrations, respectively, were approximately 19, 65, and 70 mg/kg for the forage diets and 21, 85, and 79 for the by-product diets. Treatment had no effect on dry matter intake (24.2 kg/d) or milk production (34.9 kg/d). Cows consuming the by-product diets had greater Zn (1,863 vs. 1,453 mg/d) and Mn (1,790 vs. 1,588 mg/d) intake compared with cows fed forage diets, but apparent Zn absorption was similar between treatments. Manganese apparent absorption was greater for the by-product diets compared with the forage diets (16 vs. 11%). A fiber by mineral interaction was observed for Cu apparent absorption, as cows fed hydroxy minerals with forage diets had greater apparent absorption compared with cows fed sulfate minerals; however, the opposite was observed with the by-product diets. Source of supplemental trace minerals and type of fiber in diets affected availability of Cu and Mn and should be considered in ration formulation.
十八头经产奶牛被用于一项两部分重复拉丁方设计，其中两个 28 天周期用于评估补充铜、锌和锰（硫酸盐或羟基盐）的来源对饲粮为粗饲料或副产品时矿物质表观吸收率的影响。副产品饲粮的配方具有更高的 NDF 浓度和更低的淀粉浓度，并且选择特定的成分是因为它们是可溶性纤维和 β-葡聚糖的良好来源，在非反刍动物中，这些物质可以结合痕量矿物质。我们假设羟基痕量矿物质与消化物的相互作用较小，与硫酸盐矿物质相比，其表观吸收率更高，并且与粗饲料饲粮相比，副产品饲粮的表观吸收率差异更大。在 56 天的实验中，奶牛一直处于相同的纤维处理，但每 28 天周期补充微量元素的来源不同；因此，所有奶牛都接受了两种矿物质处理。在每个周期中，奶牛连续 16 天不补充铜、锌或锰，然后连续 12 天分别补充来自硫酸盐或羟基源的补充矿物质。对于两种纤维处理，每种矿物质源提供的补充矿物质分别提供约 10、35 和 32 mg/kg 的补充铜、锌和锰。对于粗饲料饲粮，总铜、锌和锰的饲粮浓度分别约为 19、65 和 70 mg/kg，对于副产品饲粮，分别为 21、85 和 79 mg/kg。处理对干物质采食量（24.2 kg/d）或产奶量（34.9 kg/d）没有影响。与饲喂粗饲料饲粮的奶牛相比，饲喂副产品饲粮的奶牛的锌（1863 对 1453 mg/d）和锰（1790 对 1588 mg/d）摄入量更高，但处理间的锌表观吸收率相似。与粗饲料饲粮相比，副产品饲粮的锰表观吸收率更高（16 对 11%）。观察到铜表观吸收率存在纤维与矿物质的互作，因为饲喂含羟基矿物质的粗饲料饲粮的奶牛的铜表观吸收率高于饲喂硫酸盐矿物质的奶牛；然而，在副产品饲粮中观察到相反的情况。补充微量元素的来源和饲粮中的纤维类型影响铜和锰的有效性，在日粮配方中应加以考虑。
