Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/23/2003
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Effects of feeding intensified diets to neonatal calves on growth performance and protein utilization have been described. However, effects of accelerated growth on other nutritional parameters, including vitamin utilization have not been described. The current study evaluated effects of age and plane of nutrition on the plasma concentrations of beta-carotene and vitamins D (25-hydroxyvitamin D3), A (retinol), and E (RRR-alpha-tocopherol) in milk replacer-fed calves. Twenty-two Holstein bull calves were fed a standard (0.57 kg/d of a 22% CP, 20% fat milk replacer, n=11) or an intensified (1.14 kg/d of a 28% CP, 20% fat milk replacer, n=11) diet from 1 through 8 wk of age. Texturized calf starter was fed ad libitum to calves fed the intensified diet, but limit-fed to calves on the standard diet to target an average daily weight gain of 0.36 kg. Average daily weight gain of the intensified calves (0.58 kg) was greater (P less than 0.05) than that of the standard calves (0.26 kg). For all calves, beta-carotene, retinol, and RRR-alpha-tocopherol concentrations in plasma decreased markedly (P less than 0.05) from wk 1 to wk 2 of the study. 25-Hydroxyvitamin D3 concentrations increased (P less than 0.05) from wk 1 to wk 2. Concentrations of 25-hydroxyvitamin D3 in calves fed the standard diet, however, decreased after wk 6, and were lower (P less than 0.05) than intensified calves by wk 8. Unlike calves on the standard diet, calves fed an intensified diet had decreased (P less than 0.05) concentrations of retinol and RRR-alpha-tocopherol by wk 8. These results suggest that feeding an intensified diet during the neonatal period may increase the demand for retinol and RRR-alpha-tocopherol. These demands are likely associated with increased growth. These age and dietary related changes in vitamin status may impact maturation of neonatal immune function, ultimately affecting the neonatal calf's susceptibility to infectious disease.