Erythrocyte delta-aminolevulinic acid dehydrase changes in the preruminant calf

Sixteen preruminant, male Holstein calves were tested for erythrocyte delta-aminolevulinic acid dehydrase activity, hemoglobin and erythrocyte count in blood samples taken weekly during the first 13 wk of life. delta-Aminolevulinic acid dehydrase showed a continual increase in activity beginning at wk 3 to a maximal activity at wk 9. Hemoglobin content was decreased by wk 5 and erythrocyte count was reduced by wk 6. delta-Aminolevulinic acid dehydrase enzyme activities increased with age corresponding to changes in hemoglobin and erythrocyte count during early postnatal development of the preruminant calf.