By Dan Larson, Great Plains Livestock Consulting, Inc.
As we move toward the spring breeding season, reflect on last fall’s preg check. If you found open cows or if the cows bred later than ideal, there are strategies to improve pregnancy rates without spending large sums of money. The most common barriers to improvement are nutrition and management.
In the current market environment, improving conception rates is exceptionally important. Calves born from cows bred earlier in the season net more value than those born later. Based on today’s calf prices, the added value for calves born in the fi rst versus the second and third cycles is $48 and $120, respectively. Simply moving from the third cycle to the
second cycle increases calf value by $72 per head. The advantage to heifer calves born in the fi rst cycle is carried through to their own reproductive success and progeny value.
Research from Texas A&M University shows heifers that calve in the fi rst cycle as 2-year-olds have a lifetime return on investment of 10% or more compared with those that initially calve in the second cycle. In essence, an 8- or 9-year-old cow that calves in the fi rst cycle each year profi ts the equivalent of one and a half to two extra calves in same period that
cow calves in the second cycle. So, if an operation can successfully shift the herd to calving in the fi rst cycle, it will lead to more profi tability in the fi rst year and likely each subsequent year.
Critical challenges. Nutrition is key to improving fi rst-service conception rates. Energy and protein are essential to breeding success. We often focus on protein requirements, but may overlook energy. Energy needs of a lactating beef cow at breeding time is infl uenced by age, milking ability and body condition score (BCS). A lactating beef cow in a BCS 6 requires 0.60 Mcal/lb. of net energy for maintenance, or about 17 lb of total digestible nutrients (TDN) per day. In order to properly use energy, protein needs must also be met.
Protein in a lactating beef cow should be approximately 10.5% to 11%. Many hay sources will meet both energy and protein requirements. However, when poor-quality hay or crop residues are used, supplemental sources of energy and protein such as corn co-products are excellent replacements. This year, many cows may be bred in confi nement or semi-confi nement settings until suffi cient pasture regrowth. Regardless of where breeding occurs, the transition from winter feeding to breeding nutrition needs to be well-planned.
Occasionally, cows moving from a drylot to spring pasture experience a reduction in nutrient quality, especially in a drought situation where grass is in short supply. Regardless of the
cause, a negative energy balance can halt cyclic activity, reducing early conception, especially fi rst service conception. Producers who balance a diet to closely match grass resources or supplementing poor quality pasture will improve early conception rates. Early spring pasture energy content may be as high as 0.80 Mcal/lb. with 18% crude protein.
Work with your nutritionist to develop a ration system to make the transition from winter feeding to spring pasture as smooth as possible. Doing so will avoid the nutritional shock that can accompany a dramatic ration change and the potential embryonic death.
DAN LARSON is a ruminant nutritionist at Great Plains Livestock Consulting, Inc. His experience in both cow–calf and feedlot cattle operations offers a unique perspective on the beef industry.
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