Evaluation of maternal bromoform supplementation in late gestation on blood parameters of cows and their progeny

Bromoform supplementation has been successful in reducing enteric methanogenesis in ruminants; however, the impacts on the health of these animals are still limited. The current study evaluates the impact of maternal bromoform supplementation on the health of late-gestation cows and their progeny. Pregnant Angus cows (n = 42) were allocated into a control or bromoform group (n = 21 cows per treatment). Bromoform extracted from Asparagopsis armata (7,372 mg/kg) was supplemented once daily. Blood samples were collected from cows before supplementation (baseline). Within 24 h of parturition, blood and colostrum samples were collected from each cow and blood from neonates. Colostrum brix was measured to indicate immunoglobulin content. All data was analysed using the MIXED procedure in SAS. Supplementation of cows with bromoform resulted in increased blood urea to creatinine ratio (P = 0.048), base excess (P = 0.049), total carbon dioxide (TCO₂; P = 0.048) and a decrease in blood glutamate dehydrogenase (GLDH; P = 0.031) compared to the control group. For cows in the bromoform group, a trend was observed for higher levels of partial pressure of carbon dioxide (pCO₂; P = 0.070) and bicarbonate (HCO₃^-; P = 0.052), and lower levels of partial pressure of oxygen (pO₂; P = 0.058) compared to the control group. Blood gamma-glutamyl transferase (GGT) was elevated in offspring of cows fed bromoform (P = 0.050). The lower blood pO₂ of pregnant cows fed bromoform and elevated blood GGT levels in offspring are not well understood and highlight the need for further investigation. Additionally, the low-dose bromoform supplementation affected various blood gas parameters of cows and calves, demonstrating the importance of monitoring these parameters when using different doses of halogenated compounds in livestock.