Nutrition, Feeding, and Calves: the Effects of Accelerated Growth Rates and Estrogen Implants in Prepubertal Holstein Heifers on Growth, Feed Efficiency, and blood Parameters

摘要

sixty-eight Holstein heifers were used to determine the effects of accelerated growth rates by increased nutrient intake and estrogen implants on feed effi- ciency, structural growth, and blood parameters in heifers between 19 and 39 wk of age. At the beginning of the treatment period, the heifers were assigned to one of four treatment groups by using a randomized complete block design in a 2 × 2 factorial arrange- ment. The treatments were standard growth rate (700 g/d), accelerated growth rate (1000 g/d), stan- dard growth rate with an estradiol implant, and ac- celerated growth rate with an estradiol implant.