Department of Animal Science, University of Tennessee, Knoxville, TN.
Departamento de Produção Animal, Universidade Estadual Paulista - UNESP, Botucatu, SP, Brazil.
J Anim Sci. 2019 Apr 3;97(4):1478-1490. doi: 10.1093/jas/skz005.
The objective of this experiment was to evaluate the impact of complexed trace mineral supplementation on ovum pick-up (OPU) and in vitro embryo production in lactating beef cows. Thirty days prior to fixed-time artificial insemination (FTAI; day -30), 68 postpartum cows were stratified by BW, BCS, and parity before being randomly assigned to 10 pens of either a treatment (TRT; n = 5) or a control (CNT; n = 5) group. Each group received a weekly mineral supplement allotment of 1.16 kg × week-1 × cow-calf pair-1 for 14 wk. Cows assigned to the TRT group received a mineral supplement that contained amino acid complexes of zinc, copper, and manganese, as well as cobalt glucoheptonate (Availa Plus; Zinpro Corp., Eden Prairie, MN, USA), while cows assigned to the CNT group received a mineral supplement that was formulated to contain similar concentrations of these trace minerals from inorganic sources. All cows were submitted to a 7 d CO-Synch + CIDR protocol on day -10 and bred using FTAI on day 0. Pregnancy diagnosis was performed on day 28 and nonpregnant cows were removed. All pregnant cows were subjected to ovum pick-up (OPU) on day 52 and 67 of gestation. Cumulus-oocyte complexes (COCs) were evaluated and graded prior to in vitro fertilization (IVF). Analysis of variance was conducted to determine effects of treatment on response variables, and pen was considered the experimental unit. Supplement consumption did not differ (P = 0.48) between treatments (1.16 ± 0.12 vs. 1.07 ± 0.15 kg of DM × week-1 × cow-calf pair-1 for TRT and CNT, respectively). Total COC recovery was greater (P = 0.03) from TRT when compared with CNT cows (22.4 ± 2.0 vs. 16.4 ± 1.4 COCs × pen-1, respectively) and the number of COCs meeting maturation criteria was increased in TRT cows (P = 0.05) when compared with CNT cows (15.9 ± 1.6 vs. 11.8 ± 1.0 COCs × pen-1, respectively). Production of transferable embryos tended to be greater (P = 0.06) for TRT than CNT cows (4.7 ± 0.6 vs. 2.7 ± 0.7 embryos × pen-1, respectively). Furthermore, when expressed as a ratio, the number of recovered COCs meeting maturation criteria that were required to produce a transferable embryo tended to be lower for TRT than CNT cows (3.10 ± 0.93 vs. 7.02 ± 1.60; P = 0.06). In summary, complete replacement with complexed trace mineral improved COC recovery and in vitro embryo production when compared with inorganic forms of these trace minerals in beef cows.
本实验的目的是评估复合微量元素补充对泌乳奶牛卵母细胞采集（OPU）和体外胚胎生产的影响。在定时人工授精（FTAI；-30 天）前 30 天，根据体重、体况评分和胎次将 68 头产后奶牛进行分层，然后随机分配到 10 个处理（TRT；n=5）或对照（CNT；n=5）组的 10 个围栏中。每组每周接受 1.16 公斤×周-1×奶牛-小牛对-1 的矿物质补充剂分配，共 14 周。分配到 TRT 组的奶牛接受含有锌、铜和锰的氨基酸复合物以及钴葡庚糖酸盐（Availa Plus；Zinpro Corp.，Eden Prairie，MN，USA）的矿物质补充剂，而分配到 CNT 组的奶牛接受的矿物质补充剂是用无机来源的类似浓度的这些痕量矿物质配制的。所有奶牛在-10 天接受 7 天 CO-Synch + CIDR 方案，并在 0 天进行 FTAI 配种。在第 28 天进行妊娠诊断，淘汰非妊娠奶牛。所有妊娠奶牛在妊娠 52 和 67 天进行卵母细胞采集（OPU）。在体外受精（IVF）前评估和分级卵丘-卵母细胞复合物（COCs）。进行方差分析以确定处理对反应变量的影响，围栏被视为实验单位。补充剂的消耗量在处理之间没有差异（P=0.48）（TRT 和 CNT 分别为 1.16±0.12 和 1.07±0.15 公斤 DM×周-1×奶牛-小牛对-1）。与 CNT 奶牛相比，TRT 奶牛的总 COC 回收率更高（P=0.03）（分别为 22.4±2.0 和 16.4±1.4 COCs/围栏-1），并且 TRT 奶牛中符合成熟标准的 COC 数量增加（P=0.05）与 CNT 奶牛相比（分别为 15.9±1.6 和 11.8±1.0 COCs/围栏-1）。TRT 奶牛的可转移胚胎生产趋于更高（P=0.06）比 CNT 奶牛（分别为 4.7±0.6 和 2.7±0.7 个胚胎/围栏-1）。此外，当表示为比值时，TRT 奶牛产生可转移胚胎所需的符合成熟标准的回收 COC 的数量趋于低于 CNT 奶牛（3.10±0.93 与 7.02±1.60；P=0.06）。总之，与这些痕量矿物质的无机形式相比，用复合痕量矿物质完全替代可提高奶牛的 COC 回收率和体外胚胎生产。
