Ounces of breeding preparation: Pounds of cure at weaning
Even as calving season and bull sale season continue, now is the time to begin preparing for breeding season. The best way to ensure as many females are cycling at the beginning of breeding season as possible, is to monitor body condition score now.
According to Dr. Jason Ahola, a professor of animal science at Colorado State University, the No. 1 factor that influences lifetime productivity for females in a cowherd is whether they get pregnant early in the breeding season as a yearling heifer. Ensuring that females are going into breeding season on a level nutritional plane rather than a decreasing plane of nutrition where they are potentially going down in body condition score (BCS). The general rule, he said, is cows ought to calve at a BCS of five and first calf heifers at a BCS of six to enter breeding at the proper score. If they didn’t calve at those scores, it is important to get them into proper body condition prior to breeding, something that takes time or a high-energy diet, which can be less than ideal when 75 to 90 pounds of gain separate score levels and time is of the essence.
Now through breeding is the time also for trace mineral supplementation. Trace minerals in a salt block, he said, are inadequate in levels of zinc, selenium, copper and manganese. Lick tubs or loose mineral mixes can ensure mineral intake if enough loose mineral or tubs are available for the number of cows based on the label. Overconsumption can be remedied by moving tubs or mineral feeders away from water sources or the addition of salt. Once green grass arrives, protein supplements become less important than minerals.
Ensuring that heifers are large enough and cycling at the beginning of the breeding season, ideally at least on their second cycle, can predict a heifer’s breeding future. Research evidence shows that heifers that breed late in the breeding season leave the herd more quickly, emphasizing the importance of adequately preparing them to breed successfully early in the breeding season.
Heifers should reach puberty in time to cycle twice prior to breeding, affected by weight, age and body condition. Selecting older, larger heifers can create a domino effect of breeding early in the season, calving early, recovering, and rebreeding early in the season once again.
While it may not be feasible on all operations, Ahola said it is beneficial to calve heifers a couple of weeks earlier than the cowherd to allow additional time to spend calving them and additional time to catch up and rebreed the following year. With heifers, he said there are more advantages to utilizing AI including selection of a true calving ease bull and the ability to easily identify heifers that breed late to cull as they are more likely to cost more over the time they remain in the herd.
Cattle producers likely know the date to turn out bulls or the date to begin synchronizing females to AI to result in a well-timed calving season. Planning for pre-breeding vaccinations, Ahola said, should also be on the calendar. There is evidence, he said, that if pre-breeding vaccinations and bull turn out dates collide, it can reduce pregnancy rates unless a killed vaccine is utilized. With modified live vaccines being superior, Ahola said scheduling vaccinations 30 days prior to breeding can mean higher pregnancy rates.
Ahola’s research suggests that whether a producer is synchronizing to AI or using bulls for natural service, the price per pregnancy is about equal assuming the producer is paying at or near the national average for a herd sire of $3,500 to $4,000.
With the price of a bull about the same as the labor and supplies necessary for AI, the advantage may lie in a higher number of early pregnancies, the ability to use higher growth bulls with better calving ease, easily implemented cross breeding, and higher quality replacement heifers as a result of AI. Now is the time, he said, to contact local semen company representatives if some additional guidance or information is needed.
If natural service or clean up bulls are utilized, Ahola said a breeding soundness exam for every bull, every year is worthwhile. It isn’t unusual for an older, sterile bull to fight off younger bulls, preventing a large percentage of females from settling, a major financial loss that can be prevented through a soundness exam.
This time of year is a good time to evaluate the soundness and structure of the bull battery and to take advantage of decent weigh bull and cull cow prices, using the proceeds to invest in a replacement. The nationwide average, he said, is 25 cows per bull, with erring on the side of more bulls. Ensuring an operation has adequate bull power now is easier than replacing bulls during breeding season. ❖
— Gabel is an assistant editor and reporter for The Fence Post. She can be reached at firstname.lastname@example.org or (970) 768-0024.
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