As beef producers you can’t control all aspects of the future that are critical for your continued success in the beef industry; new government regulations, cattle feeder prices, corn prices are such examples.
One variable you can control, however, is the future genetic composition and productivity of your cowherd.
How do I have so much power in deciding the future you may ask? Here is the secret; the future productivity of your cowherd is dependent upon proper replacement heifer selection and development. Therefore, implementing proper selection criteria, developmental strategies, nutritional management, and breeding programs for replacement beef heifers are essential to maintain efficient and profitable for years to come.
From a short-term standpoint, retaining and developing a replacement heifer also represents a considerable investment, so it better be done right. Below are a few considerations for replacement heifer selection and management.
Heifer selection: The thought process for selection of replacement heifers does not begin at weaning or at birth; it begins when sires are selected in the previous breeding season. At this time, you should consider using a sire that possesses the genetic attributes that coincide with the production strategies and marketing plan of your operation.
Expected Progeny Differences (EPDs) should be used to assist you in selecting bulls to sire your replacement heifers. When using EPDs to assist with sire selection it is advisable to follow these recommendations:
1) Traits of economic importance should be prioritized and based on management practices and marketing plans of the specific herd;
2) The traits selected and level of the traits should be matched to the nutritional resources available and the environment. For example, selecting a sire with high milk EPD may not be a prudent choice if the nutritional resources are not available for that heifer to achieve this level of milk production; and
3) Strive toward optimization rather than maximization. In other words, don’t select a sire base only on him excelling in one trait (i.e. marbling) but rather select a better-rounded sire that has above average numbers for multiple traits of importance.
Lastly, don’t forget the value of the crossbred female. Crossbreeding offers two distinct advantages, 1) Heterosis (hybrid vigor), which is the superiority in performance of the crossbred animal compared to the average of the purebred parents, and 2) Combining strengths of the various breeds that make up the cross. It has been demonstrated that crossbred females are more productive, have more calves and producer more pounds of calf over their productive lifetime, and yield an economic advantage for commercial cattle producers.
Once the sires are selected, cows conceive, and calves hit the ground, additional selection criteria exist.
First and foremost, avoid freemartins. A freemartin is a heifer calf that was a twin to a bull calf. Greater than 90 percent of the time, the female in a male-female twin scenario will be infertile.
Select replacement heifers that are born during the first part of the calving season. These heifer calves will be the oldest and heaviest at weaning and thus, easier and less costly to feed to reach set body weight targets and have a greater chance of reaching puberty prior to the start of the breeding season.
At weaning, select the heifers that have the heaviest actual weaning weights. Again, these heifers will likely be the oldest. In addition, it has been demonstrated that pre-weaning growth rate has a greater impact on age at puberty attainment than post-weaning growth rate.
Lastly, select 10 to 15 percent more heifer than actually needed. Remember not all heifers selected will become pregnant nor will all heifers that look good at weaning look good at the start of the breeding season.
Post-weaning management: There are 5 simple goals when developing a replacement heifer. Heifers should: 1) reach puberty by 13 months of age, 2) conceive by 15 months of age, 3) calve at two years of age, 4) calve with minimal assistance, and 5) rebreed as a first calf heifer.
To ensure that all of these goals are met, proper post-weaning management of heifers is required. For post-weaning nutritional management, I recommend feeding to a target weight of 65 percent of the estimated mature body weight at the start of the breeding season and 85 percent at calving. Thus, if your average mature cow weight is 1300 lb., heifers should weigh 845 lbs. at the start of the breeding season. If heifers are 65 percent of the mature body weight at the start of the breeding season, the majority of them should have reached puberty and had multiple estrous cycles.
Because in most production scenarios there is a range of weaning weights, it is often advisable to split heifers into multiple groups so that nutritional delivery can be better targeted to growth needs. If you don’t split groups you run the risk of over-feeding the heavier heifers and getting them too fat (and wasting feed) or under-feeding the light heifers and failing to meet their needs.
Heifers should begin the breeding season two to three weeks prior to the rest of the cowherd. We all know that first-calf heifers are the hardest females to get rebred. Breeding the virgin heifers earlier than the mature cows allows extra time once heifers calve for them to reinitiate estrous cycles and get pregnant during the subsequent breeding season
I strongly encourage the use of estrous synchronization and artificial insemination (AI) in replacement beef heifers.
Although I could write another article on the importance of this, a two major advantages of using estrous synchronization and AI include the ability to stimulate prepubertal heifers to initiate having estrous cycles and thus allowing them to conceive earlier in the breeding season and the ability to use proven calving ease AI sires.
Take home message: The future of your cowherd is dependent upon decisions you make today. To ensure long-term success and productivity in the beef industry it is critical that you properly select and manage your replacement heifers.
Visit the University of Minnesota Beef Team website at www.extension.umn.edu/beef for more information on this and other beef-related topics.