home → articles → Feed & Nutrition | Email to a Friend

Cattle Body Condition Research Calls For Maintaining a 5-6 Score

published: March 2nd 2011
source: Farm and Ranch Guide

Research suggests that feeding cows a ration that maintains a body condition score of five or six throughout gestation will help produce healthy calves.

Calves from cows that were not too fat or too thin throughout gestation - also appear to gain better than those calves from cows that were too fat or too thin.
 

Taking that one step further is Amy Radunz, beef cattle Extension specialist at the University of Wisconsin, Madison.

Radunz, a native of Hutchinson, Minn., focuses much of her work on the production of high quality meat.

In looking for desirable meat characteristics, Radunz is studying fetal or developmental programming in beef cattle.

"Researchers are discovering cow nutrition during gestation affects fetal growth and development of the calf, which can have long-term impacts on the calf's productivity," Radunz said, speaking to producers at the University of Minnesota Cow/Calf Days. "How we manage that cow from the day the calf is conceived - are there factors that are impacting and have economic implications for the industry? Before the calf hits the ground, we may be setting the stage and setting up their lifetime performance at that time."

Beef researchers are finding that maternal nutrition during gestation affects the calf's body composition, insulin sensitivity and growth rate - all of which have implications for production efficiency and meat quality. Maternal nutrition, environment and stressors during gestation can affect economically important traits such as growth rate, health and carcass composition, she said.

"If we want to focus on maximizing genetic potential in the feedlot in carcass traits, if we just focus on the feedlot, we're not going to answer all of those questions," Radunz said. "We need to look back further."

The fetal and postnatal periods are critical to the finishing cattle's marbling and fat disposition.

The highest energy requirement for a cow is the stage between calving and breeding. The later portion of gestation, when the fetus is growing, calls for the next highest energy requirement.

"When you look at production systems, particularly in this winter period, when her energy requirements are high, we're dealing with very different environmental conditions," she said. "This is where I see a lot of variability in how we manage our cows - in terms of feedstuffs and management."

Variability in feeding of and care for gestating cows can have a profound impact on the ultimate finishing animals, as well as future breeding stock.

Radunz reported on research from the University of Nebraska that supports the theory that late gestation is important for marbling development.

Steers calved from cows grazing native rangeland - with and without protein supplement - were followed from birth to harvest. The native range did not meet the protein requirements of the cows during late gestation. Calves born to cows supplemented with protein had carcasses with higher marbling scores, with a greater percentage of carcasses grading USDA Choice, and 60 pounds heavier hot carcass weights than those calves born to cows not supplemented with protein.

"We'd like less external fat and more marbling," she said. "Could we affect where the fat is deposited and how much fat is deposited depending on a developmental program? Potentially we could."

In another study conducted at The Ohio State University, cows were fed hay, corn or dried distillers grains with solubles (DDGS).

The cows consumed a similar amount of energy during late gestation, but the energy sources changed how nutrients were partitioned to the fetus.

Calves born to cows fed hay had lighter birth weights than calves born to cows fed DDGS or corn. Differences in birth weights, however, did not result in changes in the number of cow/calf pairs that had calving problems.

At weaning, the calves born to cows fed corn and DDGS were 21 to 16 pounds heavier, respectively , than calves from cows fed hay.

"No differences were observed in average daily gain, dry matter intake or feed efficiency, but calves from cows fed hay required more days on feed to reach a similar fat thickness as calves from cows fed corn or DDGS," said Radunz.

As a sidebar, she noted that calves born to cows fed corn during gestation had the least marbling and a lower percentage of carcasses grading in the upper two-thirds USDA Choice grade, compared to calves born to cows fed DDGS or hay.

"These results suggest that amount of marbling in the carcass may not only be determined by genetics, postnatal nutrition, and postnatal management, but also could be determined by what the cow is fed during gestation," she said.

In closing, Radunz pointed out that nutrition in early, mid and late gestation all affect the development of the calf. Nutrient restriction early in gestation can result in larger birth weights. Nutrient restriction late in gestation can result in lower birth weights.

"Producers should pay close attention to their cow nutrition programs - not solely because they impact the cow's performance, but they could also impact their calf's productivity and profitability," she said. "We know if we have nutrient restriction early or late, we have negative consequences. If we just keep the cow at a five or a six body condition score, that's the most solid recommendation I can give at this point.

"If you have poorly conditioned cows or first time heifers, separate them out and feed them a little more. If you can maintain a good body condition score, they are not going to require as much feed later on," she continued. "There are periods when it's easier to get a cow up to the five or six body condition score."