Effect of complexed trace minerals on cumulus-oocyte complex recovery and in vitro embryo production in beef cattle1,2

Abstract

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.

Impacts of Bovine Trace Mineral Supplementation on Maternal and Offspring Production and Health

“…Similarly, dietary trace mineral supplementation had no effect on the number of ova/embryos recovered from beef heifers, or the number of corpus lutea on the ovaries, indicating trace mineral supplementation likely does not impact ovulation [ 8 ]. While follicular activity may not be impacted by trace minerals, the oocyte appears to be susceptible to maternal dietary supplementation, as supplementation prior to ovum pick-up (OPU) increased the number of cumulous-oocyte complexes (COC) collected and increased oocyte maturation rates during in vitro culture [ 9 ].…”

Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: postweaning responses of offspring reared as replacement heifers or feeder cattle

“…Previous research demonstrated that supplementing organic complexed trace minerals improved reproductive performance in dairy cattle, such as decreased interval to first estrus and increased pregnancy rates ( Uchida et al, 2001 ; Griffiths et al, 2007 ). In beef cows, supplementing organic complexed Co, Cu, Mn, and Zn resulted in greater number of culturable oocytes and transferable embryos from in vitro fertilization compared with cohorts receiving sulfate sources ( Dantas et al, 2019 ). These latter results may help explaining the hastened puberty attainment of heifers from AAC cows in this experiment.…”

Supplementing Trace Minerals to Beef Cows during Gestation to Enhance Productive and Health Responses of the Offspring

“…Organic trace mineral supplementation to dairy cows significantly increased milk production, milk fat yield, and milk protein yield compared to inorganic trace mineral supplemented cohorts [ 44 ]. Previous research has demonstrated supplemented organic complexed trace minerals improved reproductive performance in cattle, decreasing interval to first estrus and increasing pregnancy rates [ 45 , 46 ], as well as resulting in improved in vitro embryo production efficiency [ 47 ]. A meta-analysis by Rabiee et al [ 48 ] reported that lactating dairy cows supplemented with organic-complexed trace minerals have greater milk yield, fewer days open, and require fewer services per conception compared with inorganic supplemented cohorts.…”

“…The role of trace mineral source on reproductive performance is complex, especially given the plethora of processes each element participates in, and the essentiality of each in all aspects of development [ 32 ]. Previous research demonstrated lactating beef cows supplemented with organic Co, Cu, Mn, and Zn yielded a greater number of culturable oocytes and transferable embryos compared with cohorts receiving sulfate sources of the same elements [ 47 ]. Primordial germs cells within the developing ovary actively utilize machinery and enzymes against reactive oxygen species (ROS) to maintain cell integrity [ 96 ], and increased antioxidant enzyme activity and decreased ROS production during germ cell development results with trace mineral supplementation [ 97 , 98 ].…”