Submitted to: American Dairy Science Association Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 6/23/1997
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Recent trends in calf management have promoted increased supplementation of milk replacers with vitamin A. Physiological consequences of this practice, however, are poorly understood. Holstein calves were fed pooled colostrum within 2 h after birth and thereafter for 4 wk with a commercial milk replacer (without vitamins A and E) containing retinyl acetate (RA) at 0, 1700 (NRC requirement), 34000, or 68000 IU/d. Calves within each RA treatment were fed 100 IU/d of d-alpha-tocopherol (E-alcohol) or d-alpha-tocopherol acetate (E-acetate). Retinol, vitamin E, and beta-carotene (beta-c) concentrations in plasma taken at birth and twice weekly until the end of the study were determined by reverse-phase HPLC. Concentrations of beta-c were unaffected by RA or vitamin E treatments, and averaged 12 ng/ml across all treatments. Plasma retinol concentrations were positively correlated (r2 + .8719, P < .001) with the level of RA fed, ranging from a mean of 41 ng/ml in unsupplemented calves to 114 ng/ml in calves fed 68000 IU/d. The form of vitamin E fed (E-alcohol or E-acetate) did not influence (P > .05) retinol concentrations.