Effect of Sodium Selenite and Hydroxy-Selenomethionine Supplementation in Hanwoo Cows on Reproductive Performance and...

Selenium is an essential trace mineral that is involved in several biological processes, including antioxidant defense, immune function, and reproductive efficiency. Therefore, this study aimed to investigate the effects of selenium supplementation in Hanwoo cows on maternal reproductive performance and physiological responses, as well as the early growth and metabolic profiles of the offspring. Hanwoo cows (n = 30) were assigned to control (no supplement), sodium selenite (SS; 0.3 ppm/head/day), and hydroxy-selenomethionine (OH-SeMet; 0.3 ppm/head/day) treatment groups. Maternal reproductive performance and calf growth were examined. Cows in the OH-SeMet group had a significantly shorter postpartum interval and 4.25-fold higher conception rates than those in the control and SS groups. Plasma selenium concentrations were significantly higher in the OH-SeMet group at 3 months postpartum, with improved antioxidant status. Calves from OH-SeMet-supplemented cows had greater birth weights and higher plasma selenium, total immunoglobulin, and ghrelin concentrations. In addition, ruminal microbiota analysis revealed an increased Firmicutes-to-Bacteroidetes ratio in cows supplemented with OH-SeMet. In conclusion, dietary organic selenium supplementation in Hanwoo cows improved maternal reproductive efficiency and antioxidant status and promoted early growth in their offspring.