Effect of organic zinc, manganese, copper, and selenium chelates on colostrum production and reproductive and lameness indices in adequately supplemented Holstein cows.

The current study aimed to investigate if different sources of supplemental zinc (Zn), manganese (Mn), copper (Cu), and selenium (Se) fed to dry and lactating dairy cows affect reproductive performance, lameness status, and colostrum production. The experiment was carried out on 60 multiparous non-lactating Holstein cows in a commercial dairy herd. The cows received randomly mineral mixtures in three treatment groups containing inorganic, 25% organic-75% inorganic, or 50% organic-50% inorganic forms of Zn, Mn, Cu, and Se starting from approximately 3 weeks prior to calving up to 90 days postpartum. Supplements were included in rations and fed twice a day. Reproductive parameters including days to first service, days to first estrus, service per conception, and conception rate were investigated. After parturition, colostrum production, composition, and immunoglobulin G(1) concentration were determined. Lameness, as an indicator of trace minerals deficiency, was evaluated in a five-score scale. The source of mineral supplement only numerically improved the assessed parameters excluding colostrum fat, protein, and ash percent. The organic form of supplements did not significantly affect reproductive performance, lameness score, or colostrum production.