Will Your Beef Cattle Heifers be Ready for AI Breeding?
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Douglas Landblom
DREC Beef Cattle and Integrated Systems Specialist
Dickinson Research Extension Center
Office: 701-456-1109; Mobil: 701-690-8245
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Reproduction is unquestionably the single most important criterion in the beef cattle enterprise, because profitability begins with new birth, which is the initiator of new wealth. It is from the tireless efforts of cow calf producers that new wealth is generated and it is from this new wealth that the entire beef cattle industry feeds.
Replacement heifers are literally the backbone of any beef cattle operation’s future performance, efficiency, and profitability. Therefore, selecting and breeding heifers to elite sires with known performance and efficiency traits is of utmost importance to the progressive cattleman. Because reproduction is the most profitable single management tool, heifers that calve early at the start of the calving season produce more pounds of beef and demonstrate greater herd longevity and lifetime productivity compared to their later calving counterparts. Accessing the merits of elite sires artificially with known genomic enhanced genetic potential is the most rapid and efficient way to enhance genetic merit of replacement heifer offspring.
Without question, artificial insemination is labor intensive, which is why less than 10% of breeding age females in the U.S. beef cattle herd are bred artificially? Nonetheless, cattlemen who know the value of the enhanced genomic merit available through AI devote the labor and focused time required to breed heifers artificially by appointment. And when TAI pregnancy rates approaching 60.0% or greater are attained, breeding cost per pregnant female is reasonably priced, because bull semen cost per unit has not increased appreciably over time compared to the average herd bull cost per pregnant female, which ebbs and flows with the cattle cycle.
A voluntary survey of cattle ranchers that synchronize replacement heifers for AI was initiated with the 2021 breeding season for the purpose of establishing trends and identifying areas where future research efforts can be expended. Without exception, environmental insult from drought, blizzards, brutally long winter cold spells, and nutrition play a heavy role in heifer response and pregnancy rate. Drought during the 2021 breeding season and back-to-back April 2022 blizzards effected pregnancy rates. Looking ahead into 2023, the recent harsh winter of 2022-2023 in all likelihood will have a negative effect on pregnancy rates unless nutritional protein/energy supplementation is provided to ensure heifers are in a positive gaining condition beginning 30-days before and 30-days after AI has been completed. Supplementation will be especially important this spring, because most heifers are 70 to 80 pounds lighter than normal following the recent harsh winter.
Looking at year-over-year change between heifer synchronization results from 2021 and 2022, costs increased for feed, vaccine, semen, and veterinary services, while pasture grazing system heifer pregnancy rates declined 17.0% due to stress resulting from the back-to-back April 2022 blizzards. Thus, for the upcoming 2023 synchronized heifer breeding season, cattlemen planning to synchronize estrus for appointment timed-AI breeding are advised to begin increasing the dietary protein/energy content of their drylot TMR diets or if their breeding program is based on grazing improved grasses, they are encouraged to initiate nutrient dense protein/energy pasture supplementation to ensure heifers are in a gaining condition at the time of insemination. This is especially true for grazing heifers, because early spring grass has 75 to 80% water content that makes it difficult for heifers to consume a sufficient amount of dry matter to meet nutrient requirements for body maintenance and gain. The target weight for most 13–15-month-old heifers is between 800-850 pounds; therefore, supplemental nutrition needs to be initiated soon to meet the desired target weight for appointment breeding. Fortunately, North Dakota is a state and region where a wide variety of feeds and co-products can be found to meet the necessary nutrient requirements for developing replacement heifers.
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