Reproductive failure is consistently a top reason for culling beef cows from the herd.
Culling young females is very costly to commercial producers because a young female
hasn’t generated enough income to pay for the cost of developing that female. One way
to improve reproductive performance in the cowherd is through genetics. Although
reproductive traits tend to be lowly heritable, genetic improvement can be made
through selection.
Beef producers traditionally have selected for increased scrotal circumference to
improve female fertility. Scrotal circumference is an indicator trait and is positively
correlated to female reproductive performance. Faster genetic improvement could be
made by selecting for an easy-to-measure, economically relevant trait.
The American Hereford Association’s whole-herd reporting program has enabled the
collection of more difficult-to-measure phenotypes such as reproductive performance.
Producers enrolled in the program must report the reproductive status of all breeding-
age females on a yearly basis. This reporting system includes information such as if
a female was exposed for breeding and if she calved the following year. Traits like heifer
calving rate and the likelihood that daughters will calve as a heifer if they were retained
as replacements can be developed based on the data reported by Hereford breeders. Our
objective was to estimate the heritability of heifer calving rate, an economically relevant
trait.
