Marbling is good but balance is best
December 28, 2013
As a young man, walking alongside his father at the livestock yards, Dustin Mohrhauser gave little thought to how his interests in beef and the beef industry might shape his future.
Now, the Hartford, S.D., native is completing his meat science doctorate and working as a South Dakota State University graduate research assistant. His days are dedicated to identifying key factors beef producers around the world might use to maximize quality beef production.
Mohrhauser's commitment to his career recently led the 2013 Colvin Fund selection committee of Certified Angus Beef, LLC (CAB) to present him with a $1,000 discretionary award for his committed pursuit of a meat science degree. The organization also commended him for his "outstanding scholastic achievement and exceptional leadership."
"Showing cattle and swine as a member of 4-H really piqued my interest in animal science," Mohrhauser says. "On our family farm, we raised both livestock and crops, but I always greatly enjoyed the livestock activities. My Dad worked at the Sioux Falls Stockyards, so I was around many cattle sales and saw cattle that came from a broad area."
“During gestation, there’s a tremendous draw of nutrients from the cow to the fetus and, thus, the nutritional status of the... fetal environment may alter muscle and fat development and, ultimately, offspring carcass characteristics,”
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Participating in 4-H judging team activities, which included livestock evaluation opportunities, deepened Mohrhauser's interest in animal science and beef quality.
"In my first years of college, I was active in meat judging," Mohrhauser says. "My advisor then was Duane Wulf. My experience with that judging team and what I learned from Dr. Wulf compelled me to further my meat science studies, leading me to work to complete a Ph.D. under Dr. Amanda Blair, while coaching a judging team and continuing to learn about beef quality."
Advances in DNA technology are giving beef producers an edge, but Mohrhauser says the basics of high-quality meat, grounded in marbling, have not changed.
"Marbling is what beef producers get paid for," Mohrhauser says.
Intramuscular fat, or marbling, is the intermingling or dispersion of fat within lean meat. Meat is graded through an evaluation of the amount and distribution of marbling in beef ribeye muscle at the cut surface after the carcass has been ribbed between the 12th and 13th ribs. The degree of marbling found is the primary factor in determining quality grade.
In grading beef, packers look for a composite of evaluation factors that affect meat tenderness, juiciness and flavor. Evaluation also includes carcass maturity, firmness, texture, color of lean meat and distribution of marbling within lean cuts.
Because high quality meat nets premiums for beef producers, Mohrhauser notes that a better understanding of how production practices affect meat quality can help producers improve their bottom line.
"If producers can follow their animals through carcass evaluation and see both how and why their meat is graded at a certain level, that will help them make sound economic choices about production," Mohrhauser says. "Carcass data helps beef producers better understand the quality of their genetics and the animals in their herd."
Mohrhauser's studies have helped him understand that improving muscle mass in relation to fat on an animal results in a higher cutability carcass but may also result in less marbling, or lower quality meat.
"If the animal is too fat, there's a lot of waste," Mohrhauser says. "Improving muscle mass in relation to external fat may result in increased cutability or carcass yield. But, increasing muscle mass may also result in decreased marbling within the ribeye. Carcass cutability and quality tends to be a very antagonistic relationship where improving one trait (quality or cutability) may be detrimental to the other trait. From a genetic standpoint, selecting sires and dams with the best genetics for both marbling and ribeye is a good start at trying to optimize both carcass quality and cutability. Having a thorough knowledge of how production practices affect the final outcome of that animal's quality is equally important."
Part of Mohrhauser's research has included evaluation of the impact of cow nutrition during gestation. His team's findings show that there are no options for nutritional shortcuts when it comes to pregnant cows.
"When thinking about how to improve beef quality and cutability, your first thoughts probably focus on the nutrition and management of the calf from birth through harvest or maybe even the mating selections determined for the breeding season," Mohrhauser says. "However, one factor that may have a major role in determining a calf's carcass quality and cutability is often overlooked – the nutrition of cows during gestation."
Mohrhauser's studies revealed that it's not uncommon for periods of inadequate nutrition to take place during the time a cow is pregnant, especially during drought cycles.
"During gestation, there's a tremendous draw of nutrients from the cow to the fetus and, thus, the nutritional status of the mother and the subsequent fetal environment may alter muscle and fat development and, ultimately, offspring carcass characteristics," Mohrhauser says. "It may be important to maintain cow condition with a suggested body condition score around 5 if possible."
Mohrhauser hasn't zeroed in on specific career goals yet. He recently completed a year-long term serving as the Midwest Region Director for the American Meat Science Association student membership and received an International Livestock Congress Travel Fellowship this past January. His primary research includes exploration of the impact of maternal nutrition on calf performance and carcass characteristics as well as the investigation of the mechanisms involved in improving meat tenderness through meat aging.
"I'm hoping to continue some of the purebred Limousin beef operation my wife has grown up with," Mohrhauser says. "Whether I end up in the meat industry or in a university atmosphere, I'll continue working to ensure that consumers enjoy the highest possible quality eating experience every time and enjoy their beef.
"It's important that the beef industry maintains its current advantage in the protein marketplace," Mohrhauser adds. "As researchers, we want to ensure consistent meat quality and make sure consumers have access to high-quality beef, whether that's steak or hamburger."