Performance and metabolic responses of Holstein calves to supplemental chromium in colostrum and milk.

Twenty-two newborn Holstein female calves (BW = 39.7 ± 0.40 kg) were used to investigate the effects of chromium-l-methionine (Cr-Met) supplementation of colostrum for 3d after birth and mature milk up to wk 8 on feed intake, growth performance, health status, and metabolic and endocrine traits. Calves were randomly assigned to 2 groups, each consisting of 11 animals: 1) control and 2) 0.03 mg of supplemental Cr/kg of BW(0.75). Body weight, height at withers, and hearth girth were measured weekly. Dry matter intake, rectal temperature, fecal score, and respiratory score were recorded daily. Blood samples were collected at 12, 24, and 72 h after birth, and then every week up to 8 wk. Chromium did not affect mean body weight, dry matter intake, and withers height, but it increased hearth girth and average daily gain, tended to increase final BW, and decreased feed conversion ratio. Respiration rate increased and fecal score decreased with Cr, and rectal temperature tended to decrease with Cr. No Cr × time interactions were observed for performance and health status results except for fecal score. Blood glucose, insulin, insulin-to-glucose ratio, insulin-like growth factor-I, total protein, and triiodothyronine were not affected, whereas blood β-hydroxybutyrate, nonesterified fatty acids, cholesterol, cortisol, and thyroxin were affected by Cr supplementation. Supplemental Cr-Met decreased blood β-hydroxybutyrate at 72 h and in wk 1, 3, 4, 5, and 6 and decreased blood nonesterified fatty acids at 12h and in wk 3, 4, and 5 after birth. Blood cholesterol decreased in all sampling times, except for 12h and wk 7. Chromium decreased blood cortisol at 24h and in wk 2, 4, and 8. In conclusion, the present results demonstrate the beneficial effects of colostrum and milk supplementation with Cr to improve the performance and metabolic status of newborn calves.