An American Hereford Association update is available for Heifer Calving Rate (HCR) EPDs. This EPD is reported in percentage units for daughters calving rate, where a higher value is more favorable. Whole Herd TPR has fueled the availability of this genetic selection tool for ultimate use in characterizing Hereford calving rate genetics for the membership and beef cattle industry.
The HCR EPDs are produced from an animal model genetic evaluation for 307,415 animals encompassing a six-generation pedigree. Heifer calving records were analyzed as a categorical trait in which over 106,000 records were used in the binary analysis as calved and not calved, based on recorded calf birth date. The contemporary groups were defined as herd, first-calf heifer yearling contemporary group, calf birth year and season. A restriction of age at first calving between 600-800 days was used as part of edits along with checks for contemporary group variation. Heifer calving rate for the dataset was 73%, under the criterion that the heifers calved by 800 days of age. The heritability for heifer calving rate is .15, which is consistent with the magnitude of estimates for lowly heritable reproductive traits, but still allows for genetic progress.
The following example depicts a comparison between two sires for their HCR EPDs to describe genetic differences in future daughter calving rate. Note that a higher value is associated with favorable genetic potential for calving rate in daughters. As with other EPDs, the difference between individuals is the best approach to using the HCR EPDs. With the economic impact of reproductive rate in beef cattle operations, the appeal of HCR EPDs is always top of mind. In the future these EPDs will provide the opportunity to include genetic evaluation results associated with reproduction to directly enhance the benefits of existing AHA selection indexes.
Six percent more daughters of Sire A are expected to calve as heifers, compared with Sire B’s daughters.
Prototype Evaluation Results
The HCR EPD listing provided in the following download contains sires with a minimum of 20 daughters in the prototype genetic evaluation. The average EPD for these sires is +2.8% with a range between -10.7 and +11.9%
Feed intake records from American Hereford Association research projects and breeder data collection have been analyzed in a genetic evaluation to predict Dry Matter Intake (DMI) EPDs. Reported in pounds of feed consumed per day, this EPD characterizes genetics for intake, with a lower numeric value being associated with less feed consumed on a dry matter basis.
The DMI EPDs are generated from a multi-trait animal model genetic evaluation for 17,717 animals. Traits represented in addition to edited 3,835 individual standardized feed intake records include contemporary weaning and yearling growth measures. Weaning weights are included for weaning contemporaries to the intake calves to account for selection bias. Feed intake heritability is .40, indicating that genetic selection for this trait can be effective.
The following example depicts a comparison between two sires for their DMI EPDs. Note that a lower value is associated with genetic potential for less intake in future progeny. As with other EPDs, the difference between individuals is the best approach in understanding the DMI EPDs. In this example, the progeny of Sire A are expected to consume 0.75 pounds less feed per day compared with Sire B’s progeny. This assumes that all progeny are exposed to the same postweaning feeding management and environment. Care should be taken in the interpretation and application of DMI EPDs, with the best approach being the future use of these genetic values in AHA selection indexes.
Progeny of Sire A, on the average, are expected to consume .75 lb less feed per day compared with Sire B’s progeny
Prototype Evaluation Results
The DMI EPD listing provided in the following download contains sires with a minimum of five intake progeny in the prototype genetic evaluation. The average EPD for these sires was +0.19 lb/d with a range between -2.17 and +1.76 lb/d. Future value of the DMI EPD will be most beneficial when the EPDs are incorporated into the AHA selection indexes.