Before a heifer can join the milking herd, there are four phases of life that she must successfully complete: (1) newborn; (2) milk fed and starter; (3) grower; and (4) breeding and development. The nutritional requirements for each phase of life are very distinct and play an essential part in setting the course for success. One area often overlooked is the nutrition requirements of the breeding and development phase.
"The breeding and development phase is a critical step in the path to becoming a member of the lactating herd, as a heifer must be bred and have a calf to fulfill this role," says Dr. Jamie Jarrett, dairy marketing nutritionist with Purina Animal Nutrition LLC. "As a result, reproduction, not nutrition is typically the focus during this phase. But, heifers have very specific nutritional requirements during this time that can be overlooked."
The demand for certain key nutrients increase as dairy replacement heifers reach puberty. Jarrett points out that this stage requires less energy than others, but the heifer still has needs for essential vitamins, minerals, protein and amino acids.
Many farms will feed this group of heifers the "refusals" from the lactating herd. "Feeding refusals may seem like an economical choice and the best use of this feedstuff, but a diet made of refusals is likely to be imprecise in nutrient profile and inconsistent," she says. Improper delivery of an ideal nutrient profile may create nutrient shortages in the diet which has the opportunity to reduce frame size, wither height and overall growth of the heifer.1
"A heifer diet of feed refusals may meet the needs of the dairy but leads to inconsistent nutrient offerings to heifers from day to day," says Jarrett.
Herds that put this age group of heifers on pasture are not immune to nutrient shortages in the diet either, because grazing diets – depending on the quality of the pasture – often are lower in crude protein, too.
The lack of crude protein in this group of animals also will be exacerbated this year by drought conditions of the previous year, says Jarrett. Forages grown in drought conditions will have altered nutrient profiles (i.e. protein, energy and fiber), and the protein-to -fiber ratio will be significantly decreased.
Stress can increase the need for these key nutrients, especially to maintain healthy immune function. Dairy heifers can become stressed as a result of moving from calf pens to heifer breeding pens or pastures, co-mingling with new animals or dietary changes typical of heifer feeding programs.
Low-protein heifer diets can be a common problem interfacing with growth rates and health challenges. If growth rates can be improved, cost per pound of gain may be positively affected if feed efficiency also is improved; immune system function will likely improve; cull rates and death loss may be reduced; breeding size is achieved early; heifers enter the productive, lactating herd early; and heifers produce more milk during their first lactation.2
In addition to these benefits, supplementing diets of prepubescent and breeding-age heifers with additional vitamins, minerals and crude protein can enhance a healthy reproductive system, supporting key reproductive cycling, fertility and embryo health.
Research shows that benefits of feeding organic trace minerals include improvements in growth, milk production, reproduction and somatic cell score.3 These trace minerals are essential for a wide variety of physiological processes regulating growth, production, reproduction and health.4
"The benefits to supplementing this group of heifers is there, but finding the additional time and labor to tend to heifer management often is a low priority," says Jarrett.
Jarrett says a solution to meet these additional nutritional needs is being adapted from the beef market. "Lick tubs are commonly used by beef producers to supplement the nutrition of cattle on pasture and the delivery venues of these products have already been proven successful within beef management protocols." These lick tubs are now being formulated to meet the needs of dairy heifers. The added upside, Jarrett says, is the minimal labor involved for the dairy producer.
The dense physical form of tub feeding helps prevent animals from too quickly consuming or wasting nutrient supplements, in addition to providing a convenient, weather- resistant means of offering these nutrients to heifers.
Researchers from Purdue University recently evaluated whether or not this feed delivery method would work in dairy heifer diets. During this trial, heifers were split into two different groups on pasture. Both groups were supplemented with a grain mix of 34% corn, 18% soy hulls and 48% of an 18% crude protein grower pellet at 1.25 percent of body weight. Both groups were fed to allow for gains of at least 1.8 pounds per day per heifer, regardless of treatment. The only difference between the two groups was that one received a lick tub and the other had no lick tub.5
At the end of the three-month trial, results showed that heifers that had access to the lick tub gained approximately 0.2 pounds per head per day more than heifers that did not have access to the lick tubs.
Research results indicate free-choice booster tubs can be an excellent way to provide needed nutrients with minimal waste and optimal benefit to the heifers.
For more information, contact Dr. Jamie Jarrett at (651) 375-5579 or email: JPJarrett@landolakes.com.
 Hopkins, Brinton A. and Whitlow, Lon W, North Carolina Cooperative Extension Service; Feeding Dairy Heifers from Weaning to Calving.
2 Feeding by-products to heifers: Are they really cheaper?; Corbett, Robert, DVM, PAS. 2012 Dairy Calf & Heifer Conference Proceedings.
3 Spears, J.W. 1996. Organic trace minerals in ruminant nutrition. Anim. Feed Sci. Tech. 58:151-163.
4 Gressley, Tanya F; University of Delaware. Zinc, Copper, Manganese and Selenium in Dairy Cattle Rations; Proceedings of the 7th Annual Mid-Atlantic Nutrition Conference; 2009.
5 Nennich, T., T. Dennis, H. Schmitz, and J. Tower. 2012. Supplementing young grazing dairy heifers with luck tubs – A case study. Purdue University AS-610-W.