Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 7/25/2000
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Effects of dietary vitamin A (VA) and E (VE) on retinol (ROH), retinyl palmitate (RP), and VE concentrations in plasma, liver and blood leukocytes from neonatal calves were evaluated. Male, Holstein calves entered a 4-wk trial at less than/equal to 9 d of age and immediately after being transported for 34 h. They were fed milk replacer with 2000 (NRC level), 4000, or 34,000 IU VA/d and either 20 or 100 IU of VE/d. Plasma ROH levels decreased with time in all groups. By wk 4, plasma ROH was lower in calves fed less than/equal to 4000 IU/d than in calves fed 34,000 IU VA/d. Plasma RP remained low in less than/equal to 4000 IU VA/d groups, but increased markedly in the 34,000 IU VA/d group. By wk 4, liver VA (ROH+RP) was lower in less than/equal to 4000 IU VA/d groups than in the 34,000 IU VA/d group (33 ug/g). Plasma, liver and leukocyte VA were unaffected by dietary VE. In the 20 IU VE/d group, plasma and liver VE remained low and were unaffected by dietary VA. Plasma VE was affected (P less than 0.01) by dietary VA in the 100 VE/d groups. By wk 4, plasma VE in the 2000 IU VA + 100 IU VE/d (2569 ng/ml)and 4000 IU VA + 100 IU VE/d groups (2180 ng/ml) exceeded concentrations in the 34,000 IU VA + 100 IU VE/d group (1681 ng/ml). Liver VE concentrations were higher in calves fed 2000 (8242 ug/g) or 4000 IU VA/d (7736 ug/g) than in calves fed 34,000 IU VA/d (4392 ug/g). By wk 4, ROH and VE concentrations in leukocytes from the 34,000 IU VA/d group exceeded concentrations in leukocytes from less than/equal to 4000 IU VA/d groups. These results suggest that neonatal calves require more than 4000 IU VA and greater than/equal to 100 IU VE/d to ensure vitamin adequacy. Although dietary VA altered VE status, this effect was not associated with changes in health or growth.