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Nutritional Considerations for the Late-Pregnancy and Lactating Heifer

Cattle | Pro Earth Animal Health

First-calf heifers pose a greater set of challenges than the adult cow. Supporting the health and continued growth of these animals while they’re pregnant and lactating is of utmost importance to ensure that they will be profitable additions to your herd not just with their first calf but in the years to come.

First-calf heifers that are not in optimum condition during their third trimester and following birth can experience nutritional deficits that may affect their performance for the rest of their lives. The nutritional needs of these animals is unique, as the heifer herself is still growing and developing.

The importance of BCS in heifers

The body condition score (BCS) is a simple, inexpensive, and accurate means of determining whether a cow is properly utilizing feed and has enough fat, muscle, and energy stores. In the United States and Canada, the BCS scale runs from 1 through 5 (or 1 through 9), with one being an animal that is in very poor condition and five (or 9) being obese. The BCS of a cow going into the third trimester will help determine how well she and the calf will fair in the coming months. A BCS of 4 – 5 (5 – 6) is optimal for a cow entering the third trimester.

Heifers that have a marginal or even low BCS will require a much higher level of supplementation than those animals that enter their third trimester in ideal body condition. Even then, complications such as a stillbirth, inadequate cleaning or the inability to breed back are possible.

The importance of maintaining proper rumen pH in first-calf heifers

Rumen pH is important for all cattle, but especially for first-calf heifers. The stresses placed on their bodies as their calf grows and then, after birth, nurses, requires that they are able to optimally utilize their feed. An unbalanced rumen pH can not only lead to acidosis after calving, but it can affect the heifer long-term, too. If a heifer develops acidosis, cleaning can be interrupted, leading to difficulty breeding back, infections, or even sterility.

Calves of heifers that are acidotic also have a higher likelihood of developing scours due to poor-quality colostrum and acidic milk.

Vital nutrients for late-pregnancy and post-partum heifers

First-calf heifers have unique dietary needs that cannot be met by feeding the normal rations that mature cows receive. The pregnant heifer will experience greater draws on her reserves in the third trimester than she has during the first part of her pregnancy. In addition to providing nourishment to her growing calf, she also must be receiving enough sustenance to continue her own growth and maturation.

Post-partum heifers require at least 30% more energy than mature cows. This is due to the strains lactation places on her body while she’s also utilizing a good deal of that for her own growth.

There are a number of nutrients that must be available in adequate amounts to support the proper growth of a fetus while also nourishing the cow. These needs will continue to increase until birth, making it imperative that those requirements are met.


Protein is a vital building block for every system of a growing heifer and calf. To maintain proper muscle and support organs, heifers must also be receiving enough protein without the calf’s increasing needs drawing on her own requirements and reserves.

Protein can be found in forages such as alfalfa or formulated feeds such as lick tubs or cubes. Forage in some areas may provide adequate protein but it is always a good idea to have testing done to make sure that nutrient levels are optimal and to identify any gaps so they can be supplemented.


Carbohydrates provide the energy necessary for daily activity; they are also required for the proper function of organs and body systems. In addition, they help maintain essential fat reserves that keep a cow in a positive energy balance.

Most high-quality forages will provide decent levels of energy. If, however, the forage quality has declined over the winter or there simply isn’t enough available, supplementation is likely needed. This can be provided through the addition of tubs, distillers grains, cubes, or other energy sources.


Certain vitamins are an important part of the development of a healthy fetus. Vitamins A and E, particularly, should be available in sufficient quantities. Vitamin A is needed by both the mother and her calf – if her colostrum is rich in Vitamin A, the calf’s likelihood of developing scours decreases. For the mother, successful post-partum expulsion of the placenta has been linked to an adequate intake of Vitamin A.

Cows require Vitamin E to improve Vitamin A absorption, in addition to minerals such as selenium. White muscle disease in calves is usually due to the mother having a Vitamin E deficiency during her pregnancy, and as such, not absorbing necessary levels of selenium.

Both Vitamins A and E can be found in forages; lush green pastures and hay. Aging hay and forage will likely have lower-than-ideal levels of these vitamins, so supplementation with alfalfa meal or even loose vitamin/mineral supplements might be needed for the pregnant heifer to receive the quantities she needs.


Determining which minerals should be supplemented in pregnant and post-partum heifers depends on a wide variety of factors. Trace mineral levels are often dictated by the soil in which feed and forage were grown. By default, however, pregnant animals will require an increase in their calcium and magnesium intake to support the continued development of their own bones, in addition to fetal bone growth and preparation for lactation.

Regional mineral formulas are an excellent way to provide your pregnant and lactating heifers with the minerals they need. Both block and loose mineral forms work well and will allow animals to self-regulate and consume as much as they need.

The nutritional support a heifer receives in the final months of her pregnancy and then through lactation will invariably influence the health of both mother and calf. Colostrum quality from a nutrient-deficient heifer will not provide the support the calf will need, making it doubly important to pay special attention to third-trimester nutrition.

Adequate high-quality feed, water, and supplementation (as needed) will be the key factors in a successful calving season for both mothers and babies.

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