First calf heifers always require a little extra TLC for their first breeding season. One thing producers must consider before breeding is the age and size of their heifers.
While age is certainly an important factor, most research indicates that it is the size and weight of the heifer that is the biggest indicator of breeding readiness.
Experts agree that the traditional approach for heifer development has been to shoot for 65 percent of mature body weight at breeding time in order to maximize pregnancy rate.
Many areas of the country have abundant feed resources, so it’s easily possible to have heifers weighing 900 pounds, or more, at 14 to 15 months of age. If a heifer weighs 500 pounds at 200 days of age and the target is 800 pounds, we only need a gain of 300 pounds in 235 days, or 1.3 pounds per day.
In her book “Storey’s Guide to Raising Beef Cattle,” Heather Smith Thomas says it takes nine months of gestation to develop the calf after the heifer becomes pregnant, so “feed her properly so she can breed and conceive at 15 months of age. Then she’ll calve at about 24 months of age.”
It is not recommended for heifers to calve at under the age of 2 years, so producers must take age into consideration when choosing their breeding season for first calf heifers.
Once you have determined that your heifers are at the appropriate age and size for breeding, you’ll want to make sure you select the appropriate bull for their needs.
“Selecting bulls with low birth weight EPDs is most important when they are to be used on small cows or first-calf heifers. Since weights at all points in the lives of cattle are positively correlated, some sacrifices in growth may have to be made to stay within a workable range of calving ease or birth weight for a particular herd,” said Ronnie Silcox and Roger McGraw from the University of Georgia and North Carolina University in their article “Bull Selection Is Foundation For Profitable Herd.”
The age and size at which heifers reach puberty vary by breed, as well as sire selection within the breed.
Age and weight at puberty are moderately to highly heritable traits. This means that producers can use selection to improve these traits within a given herd. An easy method of selection for age at puberty in replacement heifers is to select daughters of bulls with large scrotal circumference. An interesting correlation, in general, bulls with larger scrotal circumferences have daughters that reach puberty earlier.
Virginia Cooperative Extension noted in an article that “crossbred heifers are younger at puberty than purebred heifers.”
Putting a little extra effort into your heifers for their first breeding season and ensuring they have reached the proper weight and age at puberty will benefit you and your herd down the road. Be sure to consult your veterinarian to come up with a proper nutritional program to get your heifers in the best shape and size possible.
