ENID, Okla. — By Rick Nelson
The replacement heifer represents the productive future for the cow-calf herd, and her early development and reproductive performance is the best indicator of how she will perform later in life.
So, it is extremely important the heifer is given every chance at a productive life. Often the greatest limiting factor to successful heifer development is attainment of puberty. Heifers that reach puberty later will likely calve later in the season and may not rebreed for the second calf in time to catch up with the rest of the cowherd.
Thankfully, many of the factors that affect attainment of puberty can be managed with a good nutrition program and proper selection.
A good starting point in determining the feeding strategy for your replacement heifer program is determining what their expected mature size will be. This can be accomplished by looking at the mature cowherd (if heifers are retained from your own herd) or by asking the seller how large the heifer’s dam is. After an expected mature size is determined, target weights for breeding and calving can be calculated.
A good rule of thumb is that heifers should be approximately 65 percent of their mature weight at breeding. From there, one can determine what gains we should target during the development period. For example, a heifer with an expected mature weight of 1,200 pounds should weigh approximately 780 pounds at breeding. If she is weaned at 6 months of age weighing 500 pounds and breeding is planned at 14 months of age, she needs to gain 420 pounds over a 240 day period. This gives a targeted average daily gain (ADG) of 1.75 pounds per day.
While it is important for heifers to reach targeted weights during the development phase, the timing and rate of gain can be altered to match forage or feed availability during that time. Although feeding to enhance weight gain at a consistent rate is most common in a heifer development program, it is possible forage quality and availability might be greatest at the beginning of the development period.
If this is the case, heifers can be managed to reach higher gains early, reaching the target weight sooner in the growing period. Feed costs then can be saved later in the development period as heifers merely need to be fed to maintain their body weight.
It is important heifers are not overfed during the development period and allowed to become too fleshy. Heifers with too much fat may not only have problems getting bred, but they also may accumulate fat in their mammary tissue. If fat is accumulated in the mammary tissue during development this may have a lifetime impact on the heifer’s milk production.
A good nutritional plan is a critical point that should be given a great deal of thought and thoroughly planned for any heifer development program. By designing a nutritional program to take full advantage of the forage available, a significant cost savings may be realized.
It is important to plan ahead and determine the nutritional needs of the heifers, quality of the forage available and of any supplement that may be needed. While it may seem like a challenging task and a great deal of work, planning ahead is a crucial step in developing replacement heifers and ensuring their reproductive success in the mature cowherd.
Nelson is Oklahoma Cooperative Extension Service ag educator for Garfield County.