Bred Heifer Mythology
Most cow-calf producers believe three myths associated with the development of heifers into cows. I will discuss them briefly in this article.
- Myth #1. Limit the amount of feed given to heifers prior to calving so the calves will be small and calving difficulties will be less. The facts are that by limiting feed to bred heifers we weaken them; therefore, they have less stamina to get through the calving process and we actually increase calving difficulty. Less feed also causes them to be in poor body condition after calving.
- Myth #2. A heifer's first calf will be an inferior calf and lack weaning weight. This is positively wrong. I have summarized the weaning weights of calves produced by our raised cow herd at The Noble Research Institute's Pasture Demonstration Farm since 1991. There is naturally some year to year variation (Figure 1), but on the average during this eight-year period, calves from first calf heifers weighed slightly more than calves produced by older cows. How can this be? One reason is that the heifer's breeding season is one month earlier than the cow herd's breeding season; so, calves are older at weaning time. Also, if we are doing a good job of selection, heifers are genetically superior to older cows. The fact remains, through proper management and the selection of bulls with low birth-weights and good growth, calves from first-calf heifers are acceptable.
- Myth #3. First-calf heifers are a problem to rebreed. When handled properly, first-calf heifers will rebreed well. We manage our heifers to grow out well between weaning and breeding. They will weigh approximately 75% of their mature weight at first breeding and 85-90% of their mature weight at first calving (when they are 22-23 months old).
The largest impact in this type of management is that heifers are so poor that we lessen the likelihood that they will breed back on time, if at all. Bred heifers should be maintained in at least a Body Condition Score (BCS) of five. BCS sixes and sevens are probably better. If you historically have to pull a lot of calves, there is probably something wrong with your genetic selections and your heifer development program (or lack thereof).
These heifers are in excellent condition at calving time (BCS sixes and sevens). They are fed good quality hay and an adequate-to-surplus amount of protein. We normally have ryegrass or small grain pasture to put these heifers on after they calve. Yes, this is expensive; however, it doesn't compare to the cost of an open 2.5 year old female. If it costs you $100/head in additional feed to insure that you get heifers bred back for their second calf, you will be ahead to incur the cost rather than have her open. It should be mentioned that first-calf heifers are not kept separate from the cow herd until they wean their first calf. In this program, they are placed with mature cows just prior to the time for them to rebreed for their second calf.
Figure 2 shows our "breedbacks" on first-calf heifers versus older cows from 1991 through 1998. You can see that once again, the myth about first-calf heifers is false. The poor breed back for cows in 1991 is because a bull went bad. The bull was fertility checked before "turnout" but went bad during the breeding season. This brings up the point that we should monitor when cows come in heat and see if a large number are not being settled. If we delete the 1991 data, pregnancy rates of our first calf heifers still exceeded those of our mature cows over the last seven years.
If you need help with your heifer selection, bull selection, or management practices, feel free to contact me. A good source for bulls is the Oklahoma Beef Incorporated (OBI) sale near Stillwater on April 12. You may obtain a catalog by calling Dr. Sally Dolezal at (405) 744-6060 and requesting one. Good luck.