Raising strong, healthy cows isn’t just about the day-to-day feed and setting up future generations for success. Because calves rely on nutrients from their mother during fetal development, mineral intake during a cow’s pregnancy is one of the most important factors in achieving this goal. Known as ‘fetal programming,’ the idea is that a calf’s future health and productivity can be improved by providing its mother with the right nutrients.
What is fetal programming?
Fetal programming means the nutrients a cow receives while pregnant can impact her calf’s growth, immunity, and future milk production. If a pregnant cow has mineral deficiencies, her calf might face health issues, slower growth, and reduced productivity as an adult. Maintaining adequate mineral intake throughout gestation can help raise healthier cows that are better milk producers.
Minerals: in utero or in the milk
While calves will get many of these minerals in utero and store them in the liver for later use, certain minerals will largely come from the milk received shortly following birth. These minerals are also important to the health and future productivity of the calf. In female calves, the mammary gland forms in the first few days following birth. Her nutritional status at this time directly relates to the number of milk-producing cells that will form, which play a role in her productivity levels later in life. Without adequate nutrition in the very early part of her life, that animal will never reach its full potential.
Trace minerals such as copper, zinc, chromium, manganese, cobalt, and selenium are important in calves’ early lives; hence cows need to be fed a good-quality supplement covering all of these.
A 2020 research review by the University of Montana found that supplementing cows with minerals like cobalt, copper, manganese, and zinc before calving can boost the calves’ liver mineral stores, which supports their health. While these supplements don’t impact calf birth weight, they can help increase weaning weights, especially when chelated minerals are supplemented.
Trace minerals also play a role in immune health. For example, adding copper, manganese, and zinc to a cow’s diet before calving can improve the calf’s antioxidant levels, which helps protect against illness. However, some minerals, like manganese, are harder to boost through supplements.
Why is selenium so important?
Of these, selenium is one of the most important single-trace minerals. Selenium is only stored in the body for a short time, so levels in the blood and liver will cycle rapidly through the young calf following birth. Large amounts of selenium are used to drive the calf’s growth and early immune function. Supplementing the dam with good-quality selenium ensures the calf is supplied during gestation and that good levels of selenium will also be bound into milk protein, resulting in good supplementation of the calf in the weeks following birth.
By supplementing good-quality selenium to the whole herd, farmers who feed calves whole milk will not only be increasing the herd’s immunity and productivity, they’ll be boosting the level of this key mineral in their calf milk as well.
As with most trace elements, form matters. To ensure adequate levels in milk, selenium needs to be bound to a protein (selenomethionine), e.g., selenium yeast, or in a fully rumen-protected form, such as Smartsel. These are the only forms that have any significant effect on selenium levels in milk.
How to supplement during pregnancy
Each mineral supports different functions, so it’s important to talk to your ruminant nutritionist, vet, or Agvance consultant to ensure your cows receive the correct mineral balance based on herd health, pasture quality, and stage of lactation. They will guide you through the following:
- Testing soil and forage – Knowing mineral levels in your pasture helps you target any gaps.
- Choosing quality supplements—Ensure cows absorb these minerals by choosing reliable products. Bioavailability is crucial, and organic minerals have shown better results than inorganic.
- Adjusting diets as needed – Nutritional needs change during pregnancy, so monitor and adjust mineral levels at different stages.
Supplementing minerals throughout the gestation period and after birth isn’t just for short-term health – it’s an investment in your herd’s future. Correcting mineral deficiencies in pregnant cows helps calves stay healthy, boosts survival rates, and improves productivity across the herd. By taking a proactive approach to mineral management, we’ll achieve better results over time, improving animal health and production, and farm profitability.
SOURCES
- Impacts of Bovine Trace Mineral Supplementation on Maternal and Offspring Production and Health
- Understanding the critical role of mineral supplementation for the transitioning dairy cow
- Mineral balance for in-calf dairy cows
- Nutrition – Dairy NZ
- Fetal programming in lactating cows