Pregnant women are expected to eat foods that will benefit the child as it begins to grow and develop inside the womb. The same concept goes for dairy cattle, too. At the recent Cornell Dairy Nutrition Conference held in Syracuse, N.Y., professor W.E. Brown highlighted ways in which dam nutrition has an influence on offspring.
Developmental implications can be seen as early as the periconception period but can also be altered at any point during gestation. Experiences such as reduced nutrient supply, heat stress, or intra-uterine growth retardation from pregnancies with multiple fetuses can all have negative effects on the calf.
Although it is difficult to study developmental programming in other species due to the difficulty of testing milk, dairy calves make the ideal model to collect data from since the calves are separated from the dam at birth. “The feeding of milk replacer to calves with similar housing allows for remarkable consistency of experimental design that is difficult to replicated in other species. Therefore, dairy calves are primed as the premier model for evaluating gestational developmental programming effects,” said the Cornell professor.
A dairy cow’s energy balance requirements differ depending on the stage of lactation. Typically during postpartum, dairy cows encounter a negative energy balance, which normally returns to neutral or positive around breeding time. The degree of energy balance can have long-term effects on the developing fetus. Brown said, “Cows that conceived during peak milk production and have strong persistency for milk production may be challenging their growing fetus to compete with nutrients with the mammary gland.”
Body condition score (BCS) at calving has also proven to have effects on calf development. Studies have shown that cows with a greater body condition score at calving experienced less of a negative energy balance throughout the gestation period. Dairy calf birth weight has proven to be roughly 4.4 pounds higher with each 0.5-unit boost in dam BCS at calving, although Brown noted this is not to be altogether expected.
Dairy diet additives such as rumen-protected choline and rumen-protected amino acids also provide the opportunity to help with fetus development. Choline has long been a topic of discussion as to whether it should be a required nutrient for transition dairy cows. The question is, what can it do for the calf? “In transition dairy cows, supplementation with rumen protected choline for 21 days prepartum increased birth weight in their Holstein heifer offspring and increased preweaning gain and feed efficiency in a sex and breed specific manner for Holstein and Holstein x Angus calves,” cited the professor. Studies using rumen-protected methionine supplementation has also shown positive effects on the calves. In fact, rumen-protected methionine supplementation given 21 to 28 days prepartum resulted in higher offspring birth weight, body weight through 9 weeks of age, withers and hip height, and average daily gains.
There are many factors that can influence offspring development. Looking at the use of dietary additives and achieving the correct energy balance in your herd can ultimately aid in the success of your calf-rearing program. “As this body of research grows, the future of the dairy industry may involve more deliberately setting up the calves for success through the use of dam nutritional management during gestation,” concluded the professor.
