Alltech recently completed its 30th annual symposium, titled “What if,” with a focus on the future of agriculture and livestock production. During the symposium, Alex Evans, PhD, a reproductive physiologist from University College, Dublin, Ireland, discussed the critical issue of fertility in cattle, saying poor fertility is the largest issue facing beef-cattle producers.
Evans and his colleagues have studied the role of maternal nutrition and fetal development, and specifically how ovaries develop in the female fetus. Human studies, he says, have shown these relationships and his research has revealed similar effects in cattle. In a report titled “Maternal Undernutrition in Cows Impairs Ovarian and Cardiovascular Systems in Their Offspring,” published in the journal Biology of Reproduction, the researchers note that severe prenatal undernutrition is usually associated with low birth weights in offspring and disorders including hypertension, obesity, and diabetes. Little was known, however, about the effects of poor maternal nutrition on the cardiovascular, metabolic or reproductive systems.
The researchers used the bovine model, which has a gestational length and birth rate similar to humans. In their study, offspring from nutritionally restricted dams, during the first trimester, were born with identical birth weights and had similar post-natal growth rates (to 95 weeks of age), puberty, glucose metabolism, and responses to stress compared to offspring from control mothers.
However, they also found an increase in maternal testosterone concentrations during dietary restriction, and the nutritionally restricted cows had offspring with a diminished ovarian reserve, enlarged aorta, and increased arterial blood pressure compared with controls. The study linked maternal malnutrition and enhanced maternal androgen production with a diminished ovarian reserve as well as potential suboptimal fertility, enlarged aortic trunk size, and enhanced blood pressure. The researchers concluded that relatively mild transient reductions in maternal nutrition during the first trimester of pregnancy, even those that do not affect gross development, should be avoided to ensure healthy development of reproductive and cardiovascular systems in offspring.
In a video recorded during the conference, Evans says livestock producers in the future will need to produce more meat and milk using less inputs and with less environmental impact. He believes those goals are achievable through better genetics, nutrition, animal husbandry and disease management. The work will require an interdisciplinary approach, he says, with scientists from several disciplines working together toward common goals.
See the video and access more summaries from the conference at Alltech.com/symposium.