Fetal programming impacts offspring quality
Rapid City, S.D. – Producing more pounds of high quality beef is the ultimate goal for most ranchers.
According to a South Dakota State University meat scientist, calves are the progeny of two factors – genetics and their environment. The environment can impact change in the genetic background of an animal depending upon different management styles.
“Our job as ranchers is to make sure the environment or the management we utilize maximizes the genetic potential that is there,” according to Amanda Blair. “We can’t gain more genetic potential after that animal hits the ground, but we can build that into the animal through years of genetic selection.”
Blair told producers during the Range Beef Cow Symposium in Rapid City, S.D. that there are techniques they can use to maximize that genetic potential.
“We use nutrition, extending time on feed, management and technology to maximize the potential that is there,” she explained.
Quality and grade
These techniques can be used successfully to improve the quality and yield grade.
“However, this doesn’t happen very often in the same animal. Only one in 4,000 carcasses is prime yield grade one,” she said.
“The carcass is made up of muscle, fat and bone,” Blair continued.
While quality grade is a measure of palatability, yield grade is the percentage of the carcass that ends up as closely trimmed retail cuts.
“Consumers care about the appearance of beef. They want to see beef that is a bright, cherry red color, with a nice white color to the fat,” she explained. “They have a particular interest in the lean to fat ratio. This varies among consumers. Some like more marbling; some like less.”
Consumers also look at the lean to bone ratio, palatability, taste and cost.
“A lot of these issues come down to muscle and fat,” Blair explained.
By using genetic selection tools, manipulating nutrition to maximize muscle growth potential and utilizing technology efficiently with implant strategies and the use of beta agonists, the U.S. can produce a high quality product.
Blair said researchers are in the beginning stages of looking at fetal programming and how it impacts the offspring.
“We are just beginning to understand the importance of the gestational environment in maximizing potential in the offspring from health and growth performance to meat characteristics,” Blair explained.
Fetal programming is based on the idea that the gestational environment is a permanent influence on post-natal metabolism and growth.
“Basically, it means offspring are programmed in utero to deal with the environment they will be born into,” she stated.
Research has shown that during the second trimester, secondary muscle fiber development and the initiation of fat development occurs.
“That is when the muscles that will ultimately become the carcass are developing,” the meat scientist said.
“What we have found is that if there are any limitations on muscle fiber or fat development during this point of gestation, we are not going to get that back. That is true for most all domestic livestock species,” she said. “Ultimately, it affects body composition.”
Blair shared the results of a research project looking at nutritional restriction of the pregnant cow during mid-gestation when muscle fiber and fat were developing in the calf.
Basically, the study showed calves from positive energy cows had more back fat, while calves produced from negative energy cows showed a yield grade improvement at slaughter. These calves deposited more of their fat as marbling or intramuscular fat and less as subcutaneous fat.
Blair said the energy status of the cow had no impact on the color of the meat of the offspring.
While Blair sees potential use of this research in the future application of nutrition, she doesn’t recommend that ranchers cut back their nutritional program for their cows during the second trimester. Obviously, there are several other factors that can impact the cows by restricting their nutrition during the second trimester, Blair said.