Replacement heifers are a key element in any breeders herd improvement program, therefore maximizing their genetic potential and productivity is essential. A recent issue of Working Ranch, October 2009 contained two articles that should be read in conjunction—”Born to Breed” and “The Weaning Diet”. It is essential that the replacement heifer get off to the best start and the weaning diet is critical – “When heifers get a strong start, their longevity as a cow improves…” and I would add their productivity.

So what can we do in the weaning process and diet to maximize our heifers’ genetic potential and to meet the goal of 65% of mature weight at breeding and 85% of mature weight at first calving?

First, we are strong adherents of keeping the heifer on the cow for 6 months, letting nature do the best development possible. Even were we milking full-time we would do what we could to incorporate a suckler herd for our replacement and breeding stock heifers.

Second, at weaning time minimize the stressors on the heifer as much as possible. Some specifics. Practice a form of fence-line weaning until the “bawl” is out of your girls—a couple days. Vaccinate and de-horn either well prior to weaning or well after weaning—not within the first month. Don’t pile on! Provide a comfortable, well-bedded, clean area with access to shelter. Nothing worse than a dry dusty lot in summer or a wide open, unsheltered, wet, muddy pen in fall and winter for your future cows—respiratory maladies are just laying in wait to open up a big can of ‘set-back”.

Third, determine within your production model, how to keep the physiological growth and development of your heifers on an upward plane of movement, or at a minimum, a level plane for the next couple of months. You do not want to seem your heifers losing base body condition after weaning.

“Save your best hay for your calves” is not just an old saw—it is old wisdom. Your heifers should have access to all the best hay they will clean up without waste morning and evening. We strongly recommend the highest quality mixed grass/legume hay with a heavy percentage on the grass (75—80%). With this heavy percentage of grass, protein content in the 10—12% range is good.

At SMD we prefer the heavy grass content in our young stock hay. Our thinking being that we want the young heifers to be constantly expanding their stomach/rumen capacity. But it has to be high quality / “appetizing” hay. Utilizing a heavier grass hay we provide additional protein supplementation to meet the heifers needs and keep them moving upward on the developmental plane. A 50-50 mix of whole or rolled oats and a 13% sweet feed at about 1.5% of heifer weight, fed halves, morning and evening have worked well for us. This ration is used through the winter with our late fall weaning until first breeding.

There are multiple resources on the web to assist you design your own heifer development program or contact your local extension. Here are a couple of links to get that process started: Heifer Nutrition and Development Oregon State University and Replacement Heifer Development – Iowa Beef Center

These young girls are your herd’s future, keep them moving upward!