Why You Should Get with the (Fetal) Program

Fetal programming, also known as “developmental programming,” has been a hot topic for a number of years now. When we consider fetal programming from a nutritional perspective, we think of the lasting impacts gestational maternal nutrition has on calves. Often times, farmers and ranchers will say, “If you take care of your cows, they will take care of you,” and this certainly rings true.

Fetal programming occurs throughout gestation. Beginning early on during the first one-third of pregnancy, the placenta is developing in order to provide nutrients to reach the fetus from the dam’s supply. Also during early pregnancy, the organs are developing as cells are dividing, essential for proper organ maturation and function once the calf is born. During this time of year for our spring-calving herds, we are nearing the time of late gestation, an important time to evaluate your nutrition program.

Although the dam’s nutrient requirements are greatest during the first trimester, mainly due to lactation to provide for the calf at side, the second time point in the cycle of the cow when nutrient requirements are high is during the last trimester. During this time of gestation, nearly 70 percent of fetal growth occurs and in order to properly grow at that exponential rate, the cow needs to be consuming additional nutrients to provide her calf in utero as it leads to enhanced performance and profitability down the road.


A common measure of proper fetal development is through fetal growth which is measured through birth weight. Reduced birth weight as a result of cow nutrient restriction may indicate that the calf did not reach its genetic potential. Calves born smaller in size as a result of cow nutrient restriction during gestation can reflect less mature organs. This then may have an effect on the reduced ability to store heat or regulate body temperature, which for a spring-calving herd in many parts of the US is vitally important for survival. Less mature organs may also impact offspring health (Meyer et al., 2007, Corah et al., 1975) and a reduction in future growth and performance (Funston et al., 2008, Stalker et al., 2006, Martin et al., 2007).

Whether or not the birth weight is impacted by maternal nutrient restriction has been debatable in literature with a number of studies indicating no change in birth weight and others indicating altered birth weights. The variation in results may be dependent on many factors including nutrient intake, environment, cow age, breed, selection traits, etc.

When measuring weaning weights of calves born to supplemented or non-supplemented cows during late gestation, many studies have resulted in heavier calves weaned from cows that are supplemented versus their counterparts (Stalker et al., 2006, Funston et al., 2008, Larson et al., 2009). This trend continues to hold true through heifer pre-breeding weights and at pregnancy diagnosis. Heifers born to cows supplemented during late gestation have been shown to weigh 28 pounds more prior to breeding that heifers born to cows not meeting their nutrient requirements (Martin et al., 2007).

Reproductive performance may also be impacted by poor fetal programming during late gestation. Reproductive organ development for both females and males during gestation can have negative consequences down the road due to less nutrients available during development. Heifers born to cows supplemented during gestation have been shown to have greater pregnancy rates throughout the breeding season where in one study, 77% of heifers born to supplemented cows calved during the first 21 days of the calving season compared to only 49% of heifers that were born to cows not supplemented (Martin et al., 2007). These results indicate the change in reproductive performance that may be imprinted on heifers in utero.

On the feedlot side, less calves were treated while in the feedlot when they were born to cows supplemented during gestation (Larson et al., 2009). The majority of illness and death loss in the feedlot segment is from bovine respiratory diseases (BRD). It is possible that the dam’s nutrient restriction during gestation could increase the risk of respiratory diseases later in life, potentially from improper organ development, in this case affecting proper lung development and function.

In addition to health, calves born to cows that were supplemented during pregnancy had improved quality grades with a greater percentage grading choice and upper 2/3 choice. For many producers, this improvement would play a role in the profitability and value of those calves.

Nutrient restriction to the cow during this phase has been researched and reported to have negative impacts on organ maturation, fetal growth and productivity later in her calf’s life. Restricting the cow is restricting the calf’s genetic potential. Genetic selection occurs when making mating decisions, but you can program the calf during gestation to help your genetics be more profitable by providing ideal growing conditions. You have worked too hard for many generations in your herd to take a step back in calf performance potential just because your cows are not provided with the necessary nutrients during gestation.

In order for the calf to develop properly and to maximize its genetic potential, make sure gestating cows don’t run short of critical nutrients like macro and trace minerals, vitamins and protein. These nutrients will generally need to be delivered to the cow in ways beyond simple pasture forages. An easy way to ensure that these nutrients are provided to them is through a self-fed supplement.

A simple way to provide supplementation

We need to keep in mind that this can be a stressful time of year not only for us through harvest, but also for our animals with less quality forages available and more drought conditions moving through some parts of the country. Consider what your cows are consuming and whether they might benefit from supplementation, starting now through calving. CRYSTALYX® Brand Supplements are a simple solution to making sure cows are not only consuming the nutrients they need for themselves, but also for the calves in utero.  

Let’s face it — the fall is a busy time for us all. Whether time is spent getting things done around the farm or ranch or with harvest season in full swing, you may not be giving as much attention to your cows out on pasture as you need to be. Your cows can’t take any time off during late gestation. Put out a self-fed supplement and it will be available to cows around the clock. Minimize time and labor and give yourself peace of mind. Your cows will essentially be taking care of themselves so they can raise a better-performing, more profitable calf to ultimately take care of you.



Fowden, A. L., D. A. Giussani, and A. J. Forhead. 2006. Intrauterine programming of physiological systems: causes and consequences. Physiology (Bethesda) 21: 29-37.

Martin, J. L., K. A. Vonnahme, D. C. Adams, G. P. Lardy, and R. N. Funston. 2007. Effects of dam nutrition on growth and reproductive performance of heifer calves. J. Anim. Sci. 85: 841-847.

Corah, L., T. Dunn, and C. Kaltenbach. 1975. Influence of prepartum nutrition on the reproductive performance of beef females and the performance of their progeny. J. Anim. Sci. 41: 819-824.

Funston, R. N., J. L. Martin, D. Adams, and D. Larson. 2010b. Winter grazing system and supplementation of beef cows during late gestation influence heifer progeny. J. Anim. Sci. 88: 4094-4101.

Stalker, L. A., D. C. Adams, T. J. Klopfenstein, D. M. Feuz, and R. N. Funston. 2006. Effects of pre- and postpartum nutrition on reproduction in spring calving cows and calf feedlot performance. J. Anim. Sci. 84: 2582-2589.

Martin, J. L., K. A. Vonnahme, D. C. Adams, G. P. Lardy, and R. N. Funston. 2007. Effects of dam nutrition on growth and reproductive performance of heifer calves. J. Anim. Sci. 85: 841-847.

Larson, D. M., J. L. Martin, D. C. Adams, and R. N. Funston. 2009. Winter grazing system and supplementation during late gestation influence performance of beef cows and steer progeny. J. Anim. Sci. 87: 1147-1155.