Feeding Management Systems for Wintering Replacement Heifers

Wintering replacement heifers under conditions common to the Northern Great Plains can result in lowered reproductive performance if nutritional levels are inadequate. While it is known that heifers bred to calve at three years of age have less calving and rebreeding problems, economics of modem beef cattle production demand that heifers be bred to calve at two years of age. Timing becomes a very important factor because heifers must cycle and conceive at 15 months or earlier if they are expected to calve as two year olds. Attaining a high percentage of pregnancies by 15 months or sooner hinges directly upon the onset of the first ovulatory estrus in heifers, which has been shown to be quite variable. Numerous studies with heifers have shown that the interaction between heifer breed type and variations in winter energy level during the growing period can significantly alter the age at which heifers reach puberty