Management : Cow & Calf

Cattle

Researchers Trace Health of Cow Fetus, Newborn to Proper Pregnant Cow Nutrition

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Step by step, Kimberly Vonnahme is assembling the remaining puzzle pieces needed to fully understand the effects of maternal nutrition on the long-term outcomes of newborn calves.

Vonnahme, who earned a doctorate in reproductive physiology, and an entire team of researchers are putting another large piece of the puzzle in place. An associate professor and co-director of North Dakota State University’s Center for Nutrition and Pregnancy, Vonnahme collaborated with Rick Funston of the University of Nebraska in a 2006-08 study of 170 newborn calves grazed on Nebraska’s Gudmundsen Sand Hills.
 
Supplemental nutrition during pregnancy 
The study revealed striking differences in newborn calves whose dams either received or were denied supplemental nutrition at critical points throughout gestation. Funston, an associate professor of beef cattle reproduction physiology, also holds a doctorate in reproductive biology. In the Journal of Animal Science (Oct. 9, 2009), Funston confirmed that the team’s study has gone where no other research has ventured before. Previous work has proven the importance of proper nutrition during the last trimester. But their paper (“Effects of maternal nutrition on conceptus growth offspring performance: Implications for beef cattle production”) indicates proper pregnant cow nutrition throughout gestation doesn’t just affect fetal development — it can actually program how the fetus will develop long-term.
 
Timing of supplement delivery 
“Timing (of supplemental nutrients) is critical throughout gestation,” Vonnahme said. “It doesn’t matter if you have the best genetics in the world if the fetus doesn’t get an opportunity to grow and develop properly. What and how you feed mom both directly and indirectly influences her calf’s growth and development.” Vonnahme, who grew up on a grain and livestock farm in Iowa, said data reveal the fetus benefits if the dam is given nutritional supplements during early gestation, as well as during the last two months of gestation and following birth. Unfortunately, she said, producers may not think about adequate nutrition during the first half of the gestation period, concentrating instead on the last trimester when 75 percent of fetal development occurs.
 
Placenta drives early-gestation growth
Vonnahme said that data point to the essential role early gestation plays in placental development. Further study is needed to clarify exactly how the complex process works, but she said the development of the placenta’s vascular bed during early gestation is imperative to the growth of the “very tiny” fetus. And, placental development definitely affects fetal growth during gestation, as well as the calf’s postnatal future if it survives gestation.
 
Quality nutrition in late gestation is vital
Similarly, quality nutrition and supplements in late gestation likely affect the development of organs and tissues. That’s especially critical if grass or forage lacks vital nutrients. Numerous postnatal complications, including weak calves, slow postnatal growth, susceptibility to respiratory or other health problems — even death — can surface if the fetus fails to receive needed nutrients.
 
Benefits of supplementation 
On the flip side of the coin, data indicate that high-quality feed, supplemented at ”critical points” during gestation, trigger postnatal benefits such as higher birth weight, faster weight gains, diminished susceptibility to health challenges, earlier sexual maturity and higher-quality meat at harvest.
 
In a recent review article, Funston and Vonnahme reported that when cows were given a protein supplement during the last trimester of pregnancy, the offspring from the supplemented cows had these advantages:
  • Heifer calves reached puberty five days earlier than calves in the control group.
  • Seventy-seven percent were born within the first 21 days of the calving season, compared to 49 percent of calves from dams that were denied nutrient supplements.
  • Heifer calves born to dams receiving protein supplements had a 93 percent pregnancy rate compared to 80 percent among heifers born from dams without the supplement.
  • Heifers from supplemented dams had a higher percentage of unassisted births — 78 percent vs. 64 percent assisted — and resulting reduced labor costs. 
Higher-quality colostrum
In addition, the research revealed that well-nourished dams produced higher-quality colostrum, as evidenced by higher IgG levels. Those higher IgG levels translate into better immunity for calf health to protect against health challenges.
 
“The literature is still evolving,” Vonnahme said. “But vulnerable periods occur in the womb at different times for different issues where nutrition is critical. Timing is everything, but future work should enable us to more precisely narrow the window.”

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