Effects of Dietary Chromium Supplementation During Late Lactation on Productive Performance, Milk Composition, and Immune and Antioxidant Responses in Dairy Cows

The study evaluated whether organic chromium supplementation in the diets of Jersey cows in the final third of lactation has positive effects on productive performance and milk quality, as well as markers of metabolism, hematology, immunological, and oxidative response. We used 22 cows in a 56-day study, divided into two groups: control (n = 11) and chromium treatment at 10 mg/kg of dry matter per day (n = 11). We evaluated these animals' productive performance markers (milk production, feed intake, and lactation persistence), milk quality (composition and somatic cell counts), and blood biomarkers to assess animal health. Chromium concentration at the beginning of the experiment was within normal limits for the animal category (221 to 246 nM). The cows' consumption of organic chromium increased its bioavailability in the body, with higher concentration in the serum (<i>p</i> = 0.01) and milk (<i>p</i> = 0.013) of Jersey cows compared to the control cows. Supplementing cows with chromium resulted in higher fat-corrected milk production (<i>p</i> = 0.05), longer lactation persistence (<i>p</i> = 0.05), and feed efficiency (<i>p</i> = 0.02) compared to the control group. There was a lower SCC (<i>p</i> = 0.01) on days 28, 42, and 56, as well as a higher percentage of fat in the milk of supplemented cows on days 28 and 42 compared to that of the control group (<i>p</i> = 0.01). As a treatment effect (<i>p</i> ≤ 0.05), we found cows supplemented with chromium had a higher concentration of insulin, immunoglobulin G, and creatine kinase activity dismutase compared to control animals. Considering the treatment × day interaction (<i>p</i> ≤ 0.05), we observed greater activity of the creatine kinase enzymes (days 14, 28, and 56), as well as lower cholinesterase activity (days 42 and 56) compared to those of the control. The concentration of globulins (<i>p</i> = 0.05) and immunoglobulin G (<i>p</i> = 0.01) on day 56 was higher in cows that consumed chromium. Higher superoxide dismutase activity on days 42 and 56 (<i>p</i> = 0.04) was observed in the blood of cows supplemented with organic chromium compared to that of the control. Therefore, we conclude that the addition of organic chromium was beneficial to maintaining lactation persistence and increasing fat-corrected milk production.