Body condition scores of cows among biggest factor in pregnancy success.
Statistics indicate reproductive losses cost the U.S. beef and dairy industries $1 billion annually
Statistics indicate reproductive losses cost the U.S. beef and dairy industries $1 billion annually – making it an important issue for cow-calf producers.
The challenge is optimizing reproduction while keeping costs down, and beef producers have to do that across very diverse environments, explains John Hall, Extension beef specialist at Virginia Poly Technical Institute.
Here are a few management strategies targeted at improving reproductive efficiencies in beef cattle.
Focus on first calf heifers. Virginia’s Hall emphasizes that first calf heifers do need some extra attention.
The rule of thumb has been to have heifers at 65% of their mature weight by breeding. But some recent Nebraska research shows that developing them to 55% of their weight showed no difference in pregnancy rates.
Hall suggests this may be a viable strategy when working with larger frame continental breeds, but he cautioned that the research showed that heifers at a target weight of 53% had fewer females cycling at the start of the breeding season, and those in the 55% range needed more calving assistance – especially among the British breeds.
Regarding the pattern of gain among heifers, Hall says the research doesn’t show any differences so long as heifers are at the appropriate target weight at breeding. Thus, he says to add the weight when it is “most economical.”
Hall also suggests that first calf heifers need to calve at a body condition score of 6 or 7. He says this will better help them rebreed as a two-year old.
Hall says monitoring body condition score (BCS) among the entire herd is an important management tool to help boost rebreeding success, with the goal being mature cows at a BCS of 5 at calving. “It is best to have cows calve in good body condition because you can’t make up enough ground between calving and breeding – as that is when the cow’s nutritional requirements are among the highest due to lactation.” He adds that thin cows equate delayed breeding.
Other tips from Hall:
- 1. He says early weaning is probably “the most powerful tool we have to increase pregnancy rates in first calf heifers.” Research indicates it can boost rates by 15-38%, but it needs to be done 60-90 days post-partum for the most benefit. Early weaning due to drought at 120-150 days post-partum has no impact on pregnancy rates, he reports.
- 2. Regarding dystocia among heifers, Hall says the research shows that those assisted early have higher rebreeding rates than those left to struggle. Thus, he says, “Go ahead a help those first calf heifers.”
- 3. Bull exposure, be it through fenceline contact or gomer bulls, can help jump start heifers coming into into heat by about 2 weeks earlier than they normally would, so it is worth considering.
- 4. And, he says Vitamin A is an important tool to help maintain reproductive efficiency when cows are on dormant range.