Maternal injectable mineral during early gestation impacts placental function and calf performance
Ogg, Makayla Anne
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Limited research has evaluated the effects of maternal mineral supplementation during early gestation on placental function and progeny growth. For this study, Angus and SimAngus cows (n = 52) were bred via artificial insemination. At day (d) 60 of gestation, cows were assigned to one of two treatment groups; an injectable group (INJ, n = 26) receiving a single subcutaneous mineral injection and a control group (CON; n = 26). A subset of cows (CON n = 10; INJ n = 6) were selected for liver biopsy at d60 and 209 + or - 1 of gestation. At d139.5 + or - 0.5 and 209 + or - 1 of gestation, uterine artery measurements were collected using Color Doppler ultrasonography. Placentas, liver tissue, and blood samples were collected from the first 11 cows from the subset group that calved (n = 11; CON, n = 5; INJ, n = 6). Analysis revealed a TRT*d interaction at d139.5 + or - 0.5 for circulating Co concentrations which were greater in INJ (P = 0.05) compared to CON cows. Circulating Zn concentrations tended to be decreased at d209 + or - 1 (P = 0.06) in INJ cows compared to the CON cows. Circulating Cu tended to be increased (P-value = 0.09) and Mn was decreased (P = 0.04) in INJ cows throughout the study. A TRT*d interaction was observed at d139.5 + or - 0.5 for non-gravid uterine artery area, diameter, and circumference to be increased in the INJ cows (P = 0.004, 0.006, and 0.006, respectively). Additionally, pulsatility index of the gravid uterine artery tended to be increased (P = 0.09) in the INJ cows. Hepatic Fe concentrations were decreased in the INJ cows (P = 0.01) at d209 + or - 1. Blood and liver samples were collected from calves (CON n = 24; INJ n = 26). INJ calves had greater liver Se concentrations (P = 0.001), lower Fe concentrations (P=0.04), and tended to have increased liver concentrations of Zn (P = 0.09) and Mn (P = 0.08) compared to CON calves. Finally, INJ calves tended to have elevated levels of serum Se (P = 0.09) compared to CON calves. These results suggest that injectable mineral administration during early gestation altered placental function and calf performance.