Effects of organic chromium and energy source on performance of Holstein dairy cows during the transition period

Thirty-two multiparous Holstein cows were used to investigate the effects of chromium-l-methionine (Cr-Met) supplementation and dietary energy source on performance and lactation during the Transition period. Cows were fed a total mixed ration consisting of two energy source from 28 d before anticipated calving through 28 d after calving. The Cr-Met was supplemented at dosages of 0 or 0.08 mg of Cr/kg of metabolic body weight. The study was designed as a randomized complete block design with 2 (Cr-Met levels) × 2 (energy sources) factorial arrangement. Fish oil Supplementation had no significant effect on prepartum dry matter intake (DMI) but decreased postpartum DMI. Supplemental Cr-Met increased prepartum and postpartum DMI. The effect of treatments on milk production was not significant. No differences were detected in milk composition except for fat percentage; in which cows were fed the fish oil had lower percentage of fat compared to others. Ammonia–N concentration was not affected by treatments. The molar proportion of acetate and butyrate were significantly decreased when fish oil was added to the diets.