Tips for Breeding Tricky Two-Year-Olds

Keeping cows in the herd long enough for them to pay for themselves, is often easier said than done especially when brining young cows into the herd each year to replace cull cows. This is because in order to get young females into the brood cow herd, we must first succeed at breeding them back after they have their first calf. Two-year old cows are the most difficult group to rebreed because they are still growing while raising their first calf, thus requiring extra groceries in order to meet nutrient demands and resume normal estrous cycles. It is also especially critical that she conceives at this age because to date she has yet to bring any income into the bank until her first calf is weaned and sold this fall. Depending on individual cost of production, cows must remain on average in the herd until they are at least 6 years of age and weaned 5 calves before they’ll start turning positive dollars at the bottom of the balance sheet.

Management Tips
Here are some tips for how can we get more of these tricky two-year olds’ pregnant:

• Let them graze the best quality pasture and/or supplement:
  By increasing the feed quality and/or supplementing them separately from mature cows, young cows will receive the extra necessary nutrients to meet their maintenance, growth and lactation requirements. In addition, extra nutrient intake allows young cows to devote some nutrients to reproduction, resume estrous cycles and hopefully rebreed within 82 days after calving in order to maintain a 365 day calving interval.
• Short-term or early weaning:
  With peak milk production coinciding with the start of the breeding season, short term weaning (48 hours prior to estrous synchronization or bull turn out) or early weaning (45 to 80 days old) can be utilized to induce estrus in postpartum cows. The event of decreased suckling triggers hormone changes and the replenishing of essential hormones necessary to resume cyclicity. With short-term or early weaning, it’s important to remember to supply the calves with high quality forage and protein supplements so performance is not significantly affected. Short-term and early weaning may not only help induce earlier resumption of estrus cycles, but also have shown to increase pregnancy rates in thin first-calf heifers (<5 BCS).
• Reproductive Technologies: CIDRs and Bull Exposure:
  External factors can also be used to induce estrus in young cows to help them rebreed earlier. One way involves the use of exogenous progesterone in a controlled internal drug release (CIDR). CIDRs are an effective way to boost resumption of estrous cycles in anestrus cows, young or old, and can be used in a variety of AI protocols as well as with natural service synchronization. Also, exposure to a sterile/gomer bull or androgenized cow are ways to begin natural circulation of reproductive hormones. This occurs due to the natural release of pheromones, which triggers reproductive hormone responses from the young cow to begin resuming estrous cycles.

Although two-year old females are some of the most difficult to manage in the herd, they also represent the new genetics of the operation and will likely deliver much desired value in the future. Visit with your team of experts for your operation to determine a way that works best for you to successfully rebreed and retain these quality young females into the brood cow herd.

Source: Taylor Grussing, South Dakota State University