It’s a long-standing debate regarding human behavior. Are criminals genetically hard-wired for crime and violence? Or is their misbehavior the result of inattentive parents and a poor home environment?
The same debate relates to cattle and beef quality. When a tender, juicy steak lands on a consumer’s plate, is it the result of good breeding or good management? Likewise, when a dry, tough cut of beef spoils a consumer’s eating experience, who is to blame?
Increasingly the evidence shows the need for both. Genes play an important role, and some cattle lack the genetic potential to produce top-quality beef regardless of management. But when the genetic potential is there, good management at every production stage is critical for protecting that potential and producing beef that meets consumer expectations.
Quality beyond the needle
Since the early days of BQA, a fundamental principle has been to avoid physical damage or defects such as injection-site lesions, bruising or residues. Those goals remain as high priorities, but as science provides evidence of how more subtle management factors can affect beef quality, producers have opportunities to not only prevent defects but to improve beef marbling, tenderness, and the overall consistency and quality of beef.
For years, conventional wisdom held that cattle deposited marbling only late in life, and that besides genetics, an extended finishing period on a high-energy ration was the primary factor in producing marbled beef.
While it remains true that grain-finishing plays a role in marbling, the process actually begins much earlier, and management of calves on pasture can affect, for better or worse, the animal’s ability to deposit marbling during the finishing period. Many cattle in a feed pen could be pre-destined for the Select grade, not because of their genetics but because they were sick, malnourished or severely stressed at some earlier stage of production.
VetLife technical services specialist Pete Anderson, PhD, has evaluated non-genetic factors that affect quality grade in finished cattle, based on data collected through VetLife’s Benchmark Performance Program and a review of research. Anderson groups these factors in four categories:
Placement factors or demographics;
Pre-feedyard nutrition, health and management;
Feedyard nutrition, health and management; and
Among the placement factors Anderson cites, some are unavoidable, while producer decisions could affect some others. Heifers, for example, tend to produce more Choice carcasses, on average, than steers — 54 percent compared with 42.8 percent in VetLife’s database, representing over 20 million cattle over the past few years. They also produce more Yield Grade 4 and 5 carcasses, but that could be a result of producers feeding them to fatter endpoints.
Seasonal differences also can influence grades. Part of this effect, Anderson says, probably relates to the natural tendency for animals to deposit more fat as day length becomes shorter in the fall and more lean muscle as day length becomes longer in spring. Also, he says, most cattle harvested in low-grading months probably spent time on lush forage prior to placement. Scientists theorize that high levels of vitamin A and vitamin D could inhibit marbling. In any case, these seasonal effects are unlikely to change, as the U.S. beef industry depends on year-round placements and slaughter.
Weight and age at time of placement on feed, factors over which producers have some control, also correlate with quality grade. In VetLife’s database, 46.2 percent of cattle placed on feed, weighing between 500 and 599 pounds, graded Choice or better, while 42.1 percent of those weighing 800 to 899 pounds at placement made similar grades. Grading percentages drop even more for cattle placed at 900 pounds or more.
These data come with somewhat of a catch though. Anderson notes that producers have reasons for feeding some cattle as calves and others as yearlings, so the grading differences might reflect, in part, cattle types or seasonal differences rather than a cause-and-effect relationship between weights and grades.
He also notes that placement weights do not directly indicate the age of cattle at placement, but the data suggest that younger cattle will grade better than older cattle fed to the same endpoints. This could become a beef-quality challenge as higher corn prices encourage later placements and shorter feeding periods.
Health and nutrition
One of the strongest statistical relationships in the Benchmark database, Anderson says, is a negative correlation between either death loss or medicine use and percentage Choice. Groups of cattle that have high morbidity and mortality invariably grade poorly relative to the rest of the population.
Research has demonstrated this relationship, as has anecdotal observation in feedyards. Many cattle feeders participating in the Benchmark program, Anderson says, assess the health risk of cattle entering their yards. They designate groups as high, low or moderate risk, based on weaning and vaccination histories, transit times and other factors. Tracking these cattle through slaughter over several years, they have found that among those placed at 500 pounds, 44 percent of “high-risk” calves graded Choice or better, compared with 52 percent of “low-risk” calves. The data show a similar trend for cattle placed at 600 pounds, with 38.7 percent of “high-risk” and 44.6 percent of ‘low-risk” calves grading Choice or better.
Anderson stresses three key points relating to the impact health and nutrition through an animal’s life can have on beef quality.
Marbling deposition is a lifetime event, not just the late stage of the feedyard phase.
Marbling is separate from subcutaneous fat. They are different tissues with different regulatory pathways.
Any nutritional insult, at any time in the life of the animal, will reduce marbling.
“Many nutritional insults are deliberate,” Anderson notes. Feedyards and order buyers traditionally have preferred thinner cattle so they can capitalize on efficient compensatory gains in the feedyard.
Market signals might need to change to encourage better, more consistent nutrition at the cow-calf level, which could potentially improve quality grades. Increasingly, premium-beef programs work back through the production chain, offering incentives for nutrition and health. By eliminating pricing discounts for moderately fleshy cattle, these programs might be able to improve beef quality.
Rapid growth in ethanol production and corresponding increases in corn prices and availability of distillers’ co-products have led to concerns over how co-product feeds might affect beef quality.
The nutritional profile of distillers’ grains can vary from plant to plant, as can inclusion rates in feedyard rations and interactions with other feed ingredients and grain-processing methods. Any
of these factors could cause some variation in how the co-products affect cattle performance and beef quality.
Anderson notes that researchers at Kansas State University reviewed 21 studies involving 106 co-product treatment groups and concluded that the effect of co-products on marbling largely depends on inclusion rates and feeding endpoints.
At low yield grade endpoints — either low-energy diet or lean cattle — co-products reduce marbling at any inclusion level.
At an endpoint of Yield Grade 3, co-products have no effect on marbling at up to 20 percent inclusion rate.
At high yield grade endpoints involving high days on feed, early maturing cattle or heifers, co-products increase marbling at low to intermediate inclusion rates.
On behalf of NCBA and funded through the Beef Checkoff, a group of Colorado State University animal scientists led by Darrell Tatum, PhD, issued a report last year titled “Pre-Harvest Cattle Management Practices for Enhancing Beef Tenderness.” This year, the same group produced a follow-up report focused specifically on heifers.
The documents summarize scientific evidence indicating that a coordinated approach using genetic selection and management through the production chain can enhance beef tenderness and consumer satisfaction.
The reports note that aggressive implanting programs during the finishing period can reduce beef tenderness in steers or heifers, but many common programs do not. Feeders targeting premium markets can capture much of the performance enhancement of implants with little effect on beef quality by selecting less aggressive implant strategies.
In research cited in the heifer report, scientists found no significant difference in tenderness between heifers that received one implant or no implants. Even two successive finishing implants, using less-potent products, did not significantly affect shear-force measurements. Re-implant programs using the more potent implants, however, did have a negative effect on beef tenderness.
Researchers found similar results regarding the effect of heifer implants on carcass quality grades, with the most aggressive implant programs producing fewer Choice carcasses while milder implants had minimal impact.
On average, heifers tend to produce less tender beef than steers, and one reason, the researchers note, is that heifers can be more excitable than steers and react differently to stress. Their temperament can pose a threat to beef quality, especially during the period leading up to slaughter. Scientists and packers have long known that pre-harvest stress can cause elevated muscle pH in cattle. Large increases in muscle pH cause “dark cutters,” which packers discount severely, but even moderate increases in pH can result in tougher beef that does not respond well to aging.
The report also notes that stressed cattle produce tougher beef even if muscle pH remains in the normal range. CSU researchers conducted a study in which they monitored behavior and blood lactate levels as stress indicators, as groups of cattle were transported to a packing plant. Cattle with the calmest behavior had the lowest blood lactate levels and produced the most tender beef. Cattle with the most agitated behavior after transport had the highest lactate levels and produced less tender beef.
These results demonstrate the need for calm, gentle handling during the pre-slaughter stage, including loading, transport and unloading, for all cattle, and especially heifers.
But good handling and stress reduction do not begin with finished cattle. Veterinarians and animal-handling specialists such as CSU’s Temple Grandin have long said that a calf’s early experiences with humans, horses, processing facilities and stock trailers will influence how it responds to handling and transport at later production stages. An animal that has been handled poorly, or not handled at all, is more likely to experience stress prior to slaughter, even if handling during that stage is appropriate.
So as with health and nutrition, beef quality assurance requires participation and cooperation from every sector. Cow-calf producers, by using calm, gentle handling practices, can prepare them for later events and protect beef quality.