Page 21 - MWC 02-04-2021s

The Midwest Cattleman · February 4, 2021 · P21
their productive life span. “This group of heifers to retrospec- puberty status of a
is partly because she weans that tively determine which heifers group of heifers is im-
additional calf and because she are reaching puberty at younger portant to know.
breeds early each year. Her calf ages, and which are conceiving “Some may be ready
is older and heavier at weaning,” early in the breeding season. We to go into an AI proto-
explained Thomas. are also collecting a DNA sample col. Others may not be
“With this research, we’re and will look at the genomic as- quite ready to breed, so
by Heather Smith Thomas for the Red Angus Magazine trying to develop precise ways sociations with those two pieces we could kick them out
of identifying heifers based on of the puzzle,” said Thomas. to pasture, give them
their genetic merits for repro- “The phenotypes we’re talking more time to develop,
ductive traits. If I want heifers about in terms of fertility are not and turn a bull out
pregnant as early as possible in only valuable for genetic predic- with them. Some may
their first breeding, they must tion, but also help us manage a be too far behind with One to two months before breeding, a veterinarian
reach puberty before the start of group of heifers for best economic will examine each heifer, collect pelvic measurement
that breeding season. I could use benefit,” Decker explained. “The continued on page 22 and assign a reproductive tract score based on her
puberty status.
protocols to help them, but even
those protocols function best
when most of the group has al-
ready attained puberty. We also
need heifers with the fertility po-
tential to conceive with as few of
services as possible, so they be-
come pregnant as early as possi-
ble,” he said.
Current methods of trying to
make genetic progress in repro-
ductive performance are limit-
ed. “The heifer pregnancy EPD
is calculated as a yes or no: did
she become pregnant after she
was exposed? That’s better than
nothing, but not as good as we
think we can do. We’re now col-
lecting pre-breeding and preg-
nancy information on a large