The influence of trace mineral source on reproductive performance in recipient multiparous beef cows
Date
2022
Authors
Thomas, Tyler, author
Engle, Terry, advisor
Hess, Ann, committee member
Coleman, Stephen, committee member
Journal Title
Journal ISSN
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Abstract
An experiment was conducted to determine the effects of copper (Cu), cobalt (Co), manganese (Mn), selenium (Se), and zinc (Zn) source on the reproductive parameters of multiparous beef cows. Fifty cow-calf pairs were divided into ten groups (n=5 cow-calf pairs per group) and balanced across groups for animal source, cow weight, calf age, calf sex, and breed type. Each group was randomly assigned to one of the following treatments: 1) Organic trace minerals: 75 mg of Cu/d from Cu proteinate, 8 mg of Co/d from Co proteinate, 105 mg of Mn/d from Mn proteinate, 3 mg of Se/d from Sel-Plex, and 220 mg of Zn/d from Zn proteinate; and 2) Inorganic trace minerals (at two times the NASEM (2016) requirements): 255 mg of Cu/d from CuSO4∙5H20, 2.6 mg of Co/d from CoCO3, 1018 mg of Mn/d from MnSO4, 3 mg Se/d from Na2SeO4, and 763 mg of Zn from ZnSO4∙5H2O. Animals were fed a corn silage – corn stalk-based diet that met or exceeded the NASEM (2016) requirements for gestating beef cows with the exception of Cu, Co, Mn, Se, and Zn. Cows were individually supplemented with their appropriate treatments daily for 89 days, five days after the initiation of estrus synchronization (day 0). Estrus synchronization was achieved through implantation of a progesterone controlled internal drug release (CIDR; Zoetis; impregnated with 1.38 g progesterone) device and 2ml of gonadotropin-releasing hormone (GnRH; Factrel from Zoetis) administered intramuscularly. After seven days, the CIDR was removed, 2 ml lutalyse (HighCon from Zoetis) was administered intramuscularly, and an Estrotect patch was applied for estrus detection. After two additional days, recipient cows were given a second dose (2ml) of GnRH. Eight additional days later, all recipient cows that were synchronized were palpated, and those with a viable corpus luteum (CL) received an embryo as well as a CIDR. The CIDR was removed 15 days later and an Estrotect patch was applied. Expression of estrus was evaluated for the following four days of the experiment. Cows that did not express estrus, and cows that did not maintain a pregnancy from the first embryo, underwent the same estrus synchronization protocol a subsequent time. A licensed veterinarian made pregnancy diagnoses on August 18th, September 12th, and October 8th using an ultrasound, recording each cow as either pregnant or open. Blood samples were collected via jugular venipuncture from each animal on days 0, 16, 43, 68, and 94 of the experiment and analyzed for progesterone, luteinizing hormone, anti-mullerian hormone, follicle-stimulating hormone, and estradiol. However, as animals in this study varied by pregnancy status and days pregnant, mineral status and hormone status were evaluated by time points (TP) defined as TP0: prior to embryo transfer; TP1: day of embryo transfer; TP2: 28-33 days post embryo transfer; TP3: 58-60 days post embryo transfer; and TP4: 84 days post to embryo transfer. There was a treatment by time effect for plasma Cu concentrations (P < .03), with Cu concentrations of the inorganic treatment decreasing (0.89 to 0.76 mg Cu/L) and those of the organic treatment increasing (1.01 to 1.19 mg Cu/L) as the experiment progressed. There were no other significant time or treatment by time effects for plasma trace mineral concentrations. Cows receiving organic trace minerals had greater plasma Se and Cu (P < .0001) concentrations when compared to cows receiving the inorganic trace mineral. Plasma cobalt, manganese, and zinc concentrations were similar between the two treatments (P > 0.1). Pregnancy rates of the inorganic and organic treatments were similar at the conclusion of the trial (66.6% and 62.5%, respectively). Treatment outcomes were also similar (P > 0.10) for embryo transfer attempts, calf birth weights, and days pregnant. There were no treatment or treatment by time interactions for serum progesterone, luteinizing hormone, anti-mullerian hormone, follicle-stimulating hormone, or estradiol concentrations (P > 0.10). The differences in circulating trace elements between treatments did not appear to impact the hormone concentrations or reproductive outcomes in this trial. Further research is needed to further understand the impact of mineral source on reproductive outcomes.
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Subject
embryo transfer
mineral status
cattle
reproductive performance
mineral source