Maternal injectable mineral during early gestation impacts placental function and calf performance

Abstract

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.