Jolley: Talking With Dr. Kim Vonnahme About Fetal Health
10/28/2009 09:30AM
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I spent the better part of an hour talking with Dr. Vonnahme of North Dakota State University about fetal development and heifer health only to come back to what my mother kept telling me decades ago. “You are what you eat.” It seems to be a cross species truism.
A few years ago she collaborated with Dr. Rick Funston at the University of Lincoln and published a paper that summed up a 3-year experiment designed to evaluate the effects of maternal nutrition on growth and reproductive performance of heifer calves.
“As the fetus is developing, its reproductive system is developing, too. If it’s developing in a healthier environment, its reproductive performance later in life should be better.”
Backing up that statement, they found that supplementing feed with protein during late gestation resulted in heifers that were heavier at weaning and breeding, and had higher pregnancy rates.
The difference was significant, too. First service pregnancy rate was 77% for heifers from protein-supplemented dams but only 49% for heifers born to unsupplemented cows. Overall pregnancy rate was still significant - 93% versus 80%.
Vonnahme calls it developmental programming, where the nutritional environment that the calf experiences when it is in the uterus, will dictate its performance after birth. In other words, your cattle are what their mamas ate. Undernourishment, for instance, can lead to reduced birth weight, physiologic alterations such as glucose intolerance, skewed growth patterns and even alterations in carcass characteristics.
Dr. Vonnahme has learned that maternal stimuli during fetal development can have a direct impact on our growing livestock. She warned about the long term detrimental effects of maternal insults – lack of proper nutrition during pregnancy or external stresses.
Proper maternal nutrition impacts neonatal development, too. The mammary gland develops better and colostrum yield, the first defense against disease is improved. Vonnahme was involved in a recent study at NDSU where lambs were immediately separated from their dams, fed artificial colostrum to body weight, and levels of IgG were measured 24 hr later. Lambs born from restricted dams had increased IgG transfer compared to control fed dams. This may seem like a surprise, but Vonnahme believes that the fetal gastrointestinal system may be programmed in nutrient restricted animals to be more efficient in extracting nutrients, specifically large molecules like immunoglobulins. “If you were a fetus, and you weren’t receiving the nutrients you needed in the uterus, your body is adapting to the environment you think you will be born into. In order for me to survive outside, I better be efficient”.
Vonnahme talked about some recent findings, too. For instance the surprising discovery that both over- and under-nourishing first parity animals could have the same detrimental effect – lower birth weights.
The doctor said, “We know maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, but we need to know more about the effects of maternal nutrition on the health and productivity of their offspring.”
While studies remain underway at NDSU in both sheep and cattle research, Dr. Funston has further shown that cows grazing pasture fed a protein supplement can lead to steer calves that have more marbling and grade better.
“The more we learn about what the nutrient requirements are for both mom and the developing calf, the healthier, and more productive our livestock will be.”
Chuck Jolley is a free lance writer, based in Kansas City, who covers a wide range of ag industry topics for Cattlenetwork.com and Agnetwork.com.