Santa Gertrudis Breeders International makes selecting for fertility easier
Historically, beef producers have found it difficult to select for reproductive traits. These traits are challenging to measure and tend to be less heritable when compared to growth and carcass traits. Over the years, there has been little agreement between cattlemen on how to measure reproductive efficiency in the beef herd. Is it age at first calving, interval between calves, days from first breeding to conception or pregnancy rate? Or is there some other indicator that best measures efficient reproduction? A more perplexing question is how does a producer make selection decisions that will result in improved cowherd reproductive traits? The answer—fertility Expected Progeny Differences. EPDs represent the beef industry’s most powerful source of information for selection and genetic improvement. EPDs are the best estimate of an animal’s genetic worth, and research has shown that small genetic improvement in cow herd fertility often has a positive impact on profitability.
Recently, the Santa Gertrudis Breeders International Performance Committee announced the release of two EPDs designed to measure reproductive traits—Heifer Pregnancy and Breed Back. The EPDs were developed using pedigree information, member breeding records, pregnancy-check results and calving data. These newly published tools are designed to assist in the identification of animals with desirable reproductive ability.
Research has shown that heifers that fail to breed the first year, and are held over, have an average lifetime calf crop of 55 percent, compared to 86 percent for herd mates that become pregnant the first year. SGBI’s Heifer Pregnancy EPD measures the probability that a heifer will get pregnant as a yearling. This EPD is reported in units of percentage; a higher EPD sire would be expected to have daughters with a greater probability, or chance, of becoming pregnant than a sire with a lower EPD.
Getting first-calf heifers rebred on a yearly calving schedule is one of the greatest challenges cow-calf producers face. Because the demands of lactation and growth can cause an extended interval from calving to first heat, the first-calf heifer is particularly difficult to rebreed after calving. SGBI’s Breed Back EPD measures the probability a 2-year-old will be pregnant given she was listed as pregnant as a yearling. Improvements in this area can greatly contribute to an operation’s bottom line in both immediate pregnancy rates and cow longevity since it has been proven that those cows that breed back quickly will stay in the herd longer. SGBI’s Breed Back EPDs are also reported in units of percentage; a higher EPD sire would be expected to have daughters with a greater probability, or chance, of becoming pregnant than a sire with a lower EPD.
Beef cattle breeding is about profit, and profitability starts with reproduction. SGBI’s Heifer Pregnancy and Breed Back EPDs validate that Santa Gertrudis Breeders International’s members are committed to identifying and breeding cattle that perform profitably in the most challenging environments. Santa Gertrudis are data driven and profit proven.