Tune into fetal programming

We’ve all heard the phrase “You are what you eat” – but research in the human health and bovine world is increasingly indicating that what mama eats has a great influence not only on her, but her progeny as well.

This area of research is called fetal programming – which refers to maternal events during the development of the fetus. Fetal programming has its roots in human health studies, where the inaugural study documented that offspring born to undernourished women in Nazi-occupied Holland during World War II delivered apparently normal, healthy babies. But later on in adulthood, these children developed hypertension, diabetes and other diseases at much higher rates than the remainder of the population. 

Researchers have continued to document that children who had inadequate nutrition as a fetus developed lifetime health problems, and that an increased risk for these health conditions is passed on to future generations.

Based on those findings, for the past decade animal scientists have been ramping up their fetal programming research efforts to discover how maternal insults to the cow during gestation impact offspring later in life. They are learning these impacts can be due to hormonal and environmental stresses as well as nutrition – and they can affect future calf health, growth and carcass performance, and reproduction.

Each Trimester Important

Lee Dickerson, with Land O’Lakes Purina, explains that researchers are learning that environmental factors like inadequate fetal nutrition can cause an organism’s genes to express themselves differently – negatively – even though the genes themselves don’t change. In research terms, this is called epigenetics. And Dickerson says, “These changes last permanently through the life of the animal and can be passed on to future generations.”

Thus, animal scientists are beginning to suggest cow-calf producers should strive to ensure that cows are receiving consistent nutrition in early, mid- and late gestation. “Each trimester appears to be critical,” says Dickerson. 

Traditionally, industry has tended to focus on cow nutrition during the last trimester, when over 75% of fetal growth occurs; but Dickerson points out that the first two-thirds of pregnancy is when the placenta develops, organs differentiate and grow and muscle cell growth and proliferation occurs.

To further make his point about the importance of cow nutrition during pregnancy, Dickerson says, “All the muscle cells that calf will ever have develop as a fetus – not after the calf is born.”

Research by Kim Vonnahme, a beef cattle reproductive physiologist, is shedding even more light on the important role of fetal programming. From her research, Vonnahme reports that while maternal nutrient delivery during pregnancy has been shown to program the growth and development of the fetus, both during pregnancy and later into adult life, it appears that maternal nutrition also programs the development of the placenta. She adds that not only is neonatal health compromised, but subsequent health may be programmed, as offspring from undernourished dams have been shown to exhibit poor growth and productivity, and also to develop significant diseases later in life. 

Vonnahme emphasizes that researchers are learning that it is during the early phase of fetal development that maximal placental growth, differentiation and vascularization occurs, as well as fetal organogenesis (development of internal organs), all of which are critical events for normal fetal development.

University of Nebraska beef reproductive physiologist Rick Funston has also reported convincing fetal programming results. Data was collected on three consecutive calf crops that grazed winter range and received supplementation prior to calving season. That was compared to data from calves born to cows that grazed winter range but received no supplement. The researchers also looked at data from cows wintered on cornstalks with and without supplementation.

The findings suggested that adding no supplemental protein can result in a higher incidence of sickness among calves and lower weaning weights. The calves are likely to have lighter finished weights too, and less potential for achieving a Choice quality grade or better. 

Funston’s research also shows how cow nutrition during gestation can affect heifer replacements’ fertility. Supplemented cows produced daughters that exhibited higher pregnancy rates and delivered their first calves earlier in the calving season.

In a nutshell, Dickerson puts it this way for cattlemen, “The gestational nutrition of your herd this year imprints the lifetime genetic potential and performance of subsequent generations.”

So, remember your cows – and their calves – truly are what they eat.

Fetal programming re-search as it applies to beef cattle is being carried out by private industry and at land-grant universities a-cross the county.