Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/1998
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Calves are born with low conc of vit A. Therefore, calves often are supplemented with high levels of vit A early in life as an attempt to improve vit A status. Little is known of effects of high supplementation of neonatal calves with vit A on immune parameters and vit E conc in plasma. Therefore, 53 Holstein bull calves were used to determine effects of supplementation with vit A and vit E on leukocyte populations, weight gain, plasma vit A and E conc, serum protein, and scouring. Calves were assigned to 1 of 8 treatments at birth using a factorial design. Vit A was supplemented at either 0, 1700, 34000, or 68000 IU/d and vit E was supplemented at 100 IU/d of either d-alpha-tocopherol or d-alpha-tocopheryl ate. Calves were fed reconstituted milk replacer at 10% of body wt daily. Amounts fed were adjusted weekly according to weight gain or loss. Calves remained on trial for 28 d. Results indicate no effect of treatment on proportions of monocytes, CD3+, CD4+ and CD8+ T-cells, null cells or MHC Class II molecules. As calves aged, T-cells and B-cells increased over time. B-cells were higher in calves receiving d-alpha-tocop vs. d-alpha-tocopheryl acetate. Serum protein was also higher in calves receiving d-alpha-tocopherol. By 3 wk of age, calves receiving no supplemental vit A had greater gains compared to calves receiving 68000 IU/d. By 4 wk of age, calves receiving no supplemental vit A had greater gains compared to calves receiving 34000 IU/d and 68000 IU/d. No differences were detected in scour scores among treatments. Supplementation of calves with vit A had no effect on vit A conc in plasma. Calves supplemented with vit A had decreased vit E conc in plasma compared to calves not receiving additional vit A.