Grazing vs. Dry Lot to Develop Replacement Heifers

Cow-calf production systems that rely heavily on harvested and purchased feeds have less potential to be profitable. At the Antelope Range and Livestock Research Station in northwest South Dakota research evaluated the effectiveness of developing replacement heifers grazing forages through the winter on reproductive performance and costs associated with developing heifers.

Developing heifers on range is not a common practice in South Dakota due to the perception that adequate reproduction cannot be maintained in such a system. Data from the Antelope station showed that bred two and three-year-old cows could be managed on range with no hay during late gestation by feeding dried corn-gluten feed, a source of protein and fiber based energy. It is hypothesized that a similar management system could be used to develop heifers. Therefore, a study was conducted at the Antelope Research Station that compared two heifer development systems: 1) September weaned heifers grazing winter range with either dried distiller grains with soluble (DDGS) or 2) Heifers weaned in November and fed a conventional supplement and harvested forages in a dry lot.

Interesting results from the research project included:

  • Range developed early weaned heifers were able to overcome their lighter initial weights by gaining 0.33 lbs/day more than the dry lot heifers during the experiment.
  • Range heifers had a greater average daily gain during the month of March, April and May than the dry lot heifers.
  • Due to the greater than expected gain in the spring, the range-developed heifers tended to be heavier than the dry lot heifers (859 lbs and 830 lbs, respectively) at the end of the feeding period (May) however both groups reached their target breeding weights.
  • Dry lot heifers lost 3.5 lbs/day the first week they were turned out to green grass while the range heifers gained 1.9 lbs/day. This could be attributed to the fact that range heifers have experience foraging therefore have better grazing skills.
  • There was no difference in synchronized conception or overall pregnancy rates.
  • Cost per day will vary depending on your feed costs – however, during this study using DDGS on range was cheaper than in the dry lot.

Other research at SDSU Extension proves that heifers need to be on a positive plane of nutrition post-breeding to achieve reproductive success. As noted in this study, dry lot heifers turned out to grass lost over 3.5 pounds per day the first week. If this loss in average daily occurred post breeding, a 10% decrease in conception rates could result.

At the Antelope Research Station, heifers that grazed standing forages through the winter did not experience a negative average daily gain because they had better grazing skills than the dry lot heifers when turned out to green grass in the spring.

As a cow/calf producer consider looking out the side the box and developing replacement heifers on cover crops, standing/windrowed forages, bale grazing, crop residue, and dormant winter range instead of harvested forages to decrease developmental cost while achieving reproductive success.

Remember a balanced ration is still required. Contact a SDSU Extension Cow Calf Field Specialist to help develop a ration.