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Profitability hinges on getting her rebred

published: October 3rd 2008
by: Martha Hollida Garrett

The two-year-old first calf heifer that needs to rebreed may be one of your most valued females, but she can be one of the most costly and one that requires more management.
    According to Tom Geary with the USDA Ag Research Service, she is the most valuable and most expensive animal in the herd. She has not brought you a paycheck and yet you have invested a considerable amount of money in her up to this point. In fact, Geary uses the figure of $950 plus as the cost for developing a replacement female.
    If this female is going to be a brood cow and one that enhances your bottom line, then its critical that she raise a calf every year. Research proves that this is the time when she is most likely to come up open. Research also says if they get behind here, it is almost impossible to ever make up the difference in terms of pounds and in dollars produced in a cow/calf operation. In addition, the lost income has to be absorbed by the rest of the cows in the herd.
    Reproductive studies say that if she fails to rebreed at this point, she won’t actually pay for herself till after weaning her fourth calf.
    Dr. Dennis Herd, Texas A&M University extension beef cattle nutritionist emeritus, points out that culling her is expensive because of your investment in her, plus you have the loss of her calf  this year. This is why it’s in the best interest of the producer to spend a little extra effort and money to get her rebred.
    “At this point, she is trying to do three things. She is trying to maintain herself, produce milk and then reproduce. Rebreeding is her lowest priority,” says Dr. Herd. Only after she has produced milk and met her requirements, will she allott energy to the production of reproductive hormones.
    When the brain detects low energy levels, it shuts down the production of these hormones and she will not cycle until blood energy levels are high enough to meet all her requirements.
    Herd says most rebreeding problems are due to the body condition of the heifer at calving and adds that it is accurate to say she has been through the most stressful time of her life, weaning, breeding, fetal development and calving. In addition, a two year-old will lose her baby teeth and will not graze as efficiently.
    He also reminds producers that  two-year-old  and even three -year-old heifers are still growing themselves.
    Successful rebreeding starts before the first breeding period.
    A virgin heifer at approximately a month before breeding needs to be at about 65% of her mature weight. Producers are also strongly encouraged to breed heifers one cycle ahead of the older cows.  This allows them more time after calving for rebreeding.
    “A heifer should be at 85% of her mature weight at calving and ideally carrying a body condition score (BCS) of 6. Producers need to remember that she can look good before calving, but that calving decreases her weight beyond just the calf’s weight,” explains Dr. Herd.
    Joe Jones, manager of Briggs Ranch, headquartered in Victoria, Texas agrees that body condition and nutrition are the key factors.
    “You can try all the tricks you want, pulling calves off the cows for 72 hours, synchronizing, etc, but if you don’t have the nutrition in them that they need you are spinning your wheels,” says Jones.
    At Briggs, they weigh all their heifers prior to breeding the first time and their minimum weight for breeding is 750 lbs. Then during the pregnancy they keep molasses supplement out for the females as well as maintain quality forage. They sort the heifers off as they calve, so that they can be helped along from day one with that calf to increase the odds for rebreeding.
    Dale Bell, Bell Cattle Co., Gainesville, Texas agrees.
    “I think nutrition is first and foremost if you want to get these two-year-olds with a baby calf at side rebred. We make sure our heifers have the size needed when we breed the first time. Our fall calvers are usually put on some wheat pastures to push them along and we make sure those heifers that calve in January-March are supplemented until that grass is strong and they’re bred,” says Bell.
    Herd recommends supplementing heifers with 9-10% protein feed.
    Work at Ohio State University recommends rates of gain of 1.5-1.7 pounds/day to meet the needs of most heifers at breeding. If a two-year-old is to weigh 85 % of her mature weight then she has 280 days between breeding and calving to reach that target weight. A heifer should gain between 0.7 -1.0 lbs per day.
    Herd says that a lot of producers cut back too much or do not feed at all during the first pregnancy as they are afraid this will affect the calf’s birth weight.
    “Research does not back this up, in fact if you stunt or cause the heifer to be smaller, then her pelvic area is also smaller, which can lead to calving problems,” he explains.
    If a heifer calves at a BCS 3 or 4, it is almost impossible to feed her enough early in lactation to get her to increase her BCS and to produce milk while continuing to grow. Herd stresses that it is easier to add condition before calving than after.
     One research study quoted in the Angus Journal  says that improving BCS before calving from 3 up to 6 has been shown to raise rebreeding rates from 17% to 90% in first calf heifers,  But 6 is the recommended BCS, as no improvement is shown for higher scores.
    Producers are urged to separate the heifers from the older cows for sure, but if facilities are available, it is helpful to sort properly conditioned heifers from the poorly conditioned and feed appropriately.
    Another factor that is crucial to efficient rebreeding is dystocia,  according to published work by Glen Selk, professor of animal science at Oklahoma State University. Cattle that experience calving problems have a 16% lower pregnancy rate during the next breeding season.
    Heifers requiring assistance in early Stage 2 of calving return to estrus earlier in the post-calving period and have higher pregnancy rates than heifers receiving traditionally accepted obstetric assistance, he states.
    Young cows that are allowed to endure a prolonged labor (more than one hour) often deliver a weak calf and have a 20% lower rate of cycling at the start of the next breeding season. In addition, according to Selk, the rebreeding percentage is 17% lower than for counterparts that were given help during the first hour of labor.
    Data from a Kansas State University study showed that for every 10 days since calving (up to 70 days) the percentage of cows cycling before breeding season increases 7.5%.
    The numbers dictate that if a heifer calves late, she likely will calve late the rest of her life or miss one calf completely.
    Herd says that often people will try pulling calves off for a short period of time to get the heifer to cycle, but he offers early weaning as a consideration over that.
    “If the cows are really thin, you might want to go ahead and wean early, but chances are she is not going to catch up in time if she comes out of calving or into the rebreeding window too thin,” he emphasizes.
    Russell Trefny, Weimar, Texas, agrees.
    “Getting that first calf heifer rebred is one of the most difficult things I have to do in the management of our program. We have found that by weaning the calves early, we can get these heifers to cycle and breed back a lot faster. I put the calves on a pre-conditioning program and let the female focus on getting us a calf next year,” says Trefny, who produces a lot of Brangus influenced calves.
     Producers should make sure all heifers have been vaccinated appropriately  and might consider having their veterinarian perform a reproductive tract score in heifers 30-60 days before breeding. Also low birth weight bulls should be selected for those first calf heifers. Cowmen can also consider using a synchronization program to get more heifers bred in the first few days of the breeding season and breeding the heifers 14-21 days earlier than the cows. All of these steps can help to get the first calf heifer rebred.
    Jones sums it up this way, “It doesn’t matter how many tricks you have up your sleeve. You can pull calves off for 72 hours, synchronize all you want and etc., but if you don’t have the necessary nutrition for them to maintain, milk and rebreed, then you are wasting your time.”
    Again she’s the most valuable female at this stage, but you can take steps to make sure she is not the most costly.