Fat Is The Critical Element In a Good Eating Grassfed Beef Animal

Grassfed beef would be more consistent if we can rely on a forage base that is finishing quality nearly all the time.

By Dr. Anibal Pordomingo

SANTA ROSA, Argentina: Finishing cattle on pasture with adequate marbling and consistency requires planning and skill.  Growing and finishing cattle on pasture is a race against time and the premium market we are targeting dictates many of the rules.   

A 100 percent grass protocol, from weaning to slaughter is a big production constraint. Likewise, marbling (grade), tenderness, flavor and color are all important consumer marketing factors expected in a premium-priced product. Of these attributes, meat tenderness is the most important.   

Research points out that harvesting at young ages (less than three years) correlates with tenderness of all cuts. The older the animal at processing, the greater the chances for undesirable colors and flavors. Tenderness can also worsen with age and nutritional stress. But, finishing (fattening) seems to be the single most relevant factor in an overall good eating experience.   

Increased fatness has been associated with water muscle integrity, water holding capacity, reduced weight loss, retained juiciness during aging and overall meat tenderness. Recent research from our group in Argentina suggests that rate of gain during the finishing period is more related to tenderness than the feeding system (feedlot vs pasture).  

 Length of the growing-finishing period, which starts when the calf is purchased or weaned until it is sold as a finished steer or heifer, should be kept as short as possible.  Periods of 12 to 15 months (from purchase as a stocker calf to sale) produce some of the best grassfed beef. Longer periods generally mean lower overall gains, periods of hardship and more than one summer or one winter in the program (higher costs per pound).   

But, having stated the relevance of age for tenderness, research has also shown that the age at harvest could be extended to 30 months without harming tenderness, as long as animals are well finished. 

Young animals, harvested lean, have little marbling and a thin layer of back fat. Little back fat leaves part of the carcass uncovered and unprotected from fast cooling (creates dark cutters), water loss, and moldy with development of undesirable flavors (gamey taste) during aging.  Aging will need to be restricted to reduce losses and odd flavors, but the tenderization effect of aging will be less effective.   

It would be better to grow the animals for an extra six months if needed and harvest them well finished (well fattened), than harvesting the animals young but extra lean and having to convince ourselves and the public that grass-fed has to be extra lean and tough.   

Research suggests that intramuscular fat increases almost linearly with age under a good nutrition regime. Subcutaneous and organ fat deposition follows an exponential increase with energy concentration of feed and age of the animal. We also know that older animals tend to lay on more fat relative to muscle than younger ones.   

But, we must know that muscle growth and fat deposition are not independent compartments. Calves lay fat in all compartments if the energy intake is high enough. This means that we can start the process of producing desirable meat from weaning and before if we have the adequate feed.   

In other words, our product would be more consistent if we can rely on a forage base which has finishing quality at nearly all times.  This, however, does not mean a 3-lb-per-day forage. We will find that steady gains of 1.8 lb/day can produce the beef we are looking for.   

A program could tolerate mild feed restrictions if time for compensation is allowed. We could produce good beef consistently with gains near 1.2 lb/day for the first half of the animal’s life as long as gains exceed 2.0 lb/day during the second half. However, a low gain period should not be pushed too far (too long) and gains should not drop below 1 lb/day.  

Compensatory growth helps in the finishing phase to reach a target weight, but marbling and overall fattening may be compromised.  Marbling fat in grassfed beef isa challenge that starts before birth.   

Genetics for marbling also correlate with early maturing, low to medium frame cattle (frame scores 3 to 4). Cross breeding is a tool to bring together a good set of beef attributes without having to drastically change the cow herd.  The simple terminal cross concept can be easily adapted to produce calves that do well on grass.   

Black or red baldy (Hereford x Angus) steers are the preferred animals in Argentina and Uruguay to finish on pasture.   

Likewise, lowframe Shorthorn x Angus is another interesting cross. Searching for the adequate biotype within breeds that fits our program is the key. But, before doing so, we need to plan a program that will consistently work within our resources and environmental constraints. Trial and error has to evolve into a reliable program.  

Producer experiences show that marbling early is easier if we start with a good nutritional management of the cow during the last half of gestation and during the first four months after calving.  

Well nursed calves have the opportunity to express their potential for marbling. Fat cell proliferation and development seems to be sensitive to nutrition until 10months of age in cattle. Therefore, we need to exert good management before and after weaning. Quality of grass is particularly crucial for early weaned calves. 

■  Anibal Pordomingo is a researcher and grassfed beef producer in the Argentine Pampas.