Recent research at Colorado State University indicates beef from carcasses with modest marbling (equivalent to average choice) provides consumers with an 82 percent probability of a positive sensory experience (Figure 1), which is greater than the probability of a positive sensory experience associated with small marbling (equivalent to low choice; 62 percent).
Most importantly, the probability is maximized at 99 percent in steaks from carcasses with slightly abundant marbling (equivalent to low prime).
Thus, to ensure that consumers have a positive eating experience, the industry must supply highly marbled beef carcasses. Unfortunately, the U.S. beef industry continues to struggle with this, as evidenced by limited industry-wide progress toward increased marbling deposition.
This can be seen in National Beef Quality Audit (NBQA) data from the two most recent audits. According to the 2011 NBQA, industry experts estimated the “ideal” consist of beef carcasses was 69 percent choice and prime, based on demand indicated by retailers, restaurateurs and food service companies (Figure 2).
However, in that same audit, only 61 percent of carcasses actually graded choice and prime – an 8-percentage-point shortfall. Progress during the six-year period leading up to 2011 had been limited, based on the fact that the percent of carcasses grading choice and prime increased only 6.5 percent (just 3.7 percentage points) from 57.3 to 61 percent from 2005 to 2011.
There are opportunities for the beef industry to provide a greater supply of highly marbled beef.
Marbling deposition is moderately to highly heritable, which can enable marbling improvement due to genetic selection alone. However, the remaining variation in marbling (a bit more than half of total variation) is due to the environment, including how cattle are managed.
Recent research suggests that deposition of marbling can be influenced much earlier in a beef animal’s life than previously believed, indicating an opportunity for changes to be made via management.
According to researchers at Washington State University, cells in beef cattle that eventually become fat or muscle tissue originate during embryonic development as “progenitor” cells (i.e., they are forebears of future body cells).
Promotion of one or the other of these early cell lines results in either enhanced muscle growth or fat cell formation, including marbling deposition. Influencing progenitor cells via nutrition or management early in development (versus later) is more effective due to the declining number of these cells as an animal gets older.
Creation of fat cells begins in an embryo during mid-gestation and continues into the newborn stage. This is followed by the start of subcutaneous, intermuscular (seam) and intramuscular (marbling) fat cell creation, which continues through pre-weaning (for both subcutaneous and intermuscular) and as late as 250 days old (for intramuscular).
Intramuscular fat cell creation can be influenced via dietary or management intervention during a “marbling window,” which is the time frame from pre-weaning through about 250 days old in which fat deposition processes may be altered.
Based on this biological phenomenon and published research data, there are clear opportunities to increase marbling in cattle by focusing on specific management practices in calves – particularly prior to arrival at a feedyard – that promote intramuscular fat deposition.
Cow-calf producers should consider these possible areas of influence when seeking to increase the marbling potential of their calves:
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Early weaning: Weaning calves early can increase marbling deposition but doesn’t necessarily enhance eating quality and has not been shown to affect cattle that are heat-adapted, grade a low-percent choice or are harvested at a backfat thickness similar to normal weaned cattle.
Since early weaned cattle have accelerated fat synthesis early in life (including increased backfat deposition), they are more physiologically advanced than normal weaned calves at harvest.
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Late weaning: Although data are limited, there is no evidence of decreased marbling deposition resulting from calves weaned late (i.e., 300 days old).
However, the earlier cattle can be placed on feed (as early or normal weaned calves versus yearlings), the greater their marbling potential.
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Creep feeding: Providing creep feed to calves weaned at a normal age (e.g., 205 days) can increase marbling deposition, but results are not consistent.
Similarly, the effect of creep feed source (i.e., fiber- versus starch-based) on marbling is not convincing.
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High-energy post-weaning diet: Among early weaned calves, a high-energy post-weaning diet can increase fat deposition (both subcutaneous and intramuscular) versus forage- or limit-feeding.
But, neither feed source (i.e., fiber- versus starch-based) nor rumen degradability of protein appear to matter. It should be noted that due to accelerated backfat deposition, differences will not be observed if cattle are harvested at a constant backfat thickness since calves early weaned onto grain will not have an opportunity to express their marbling potential.
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Trace minerals: Several trace minerals clearly influence marbling deposition during the feedyard phase (e.g., copper and zinc), but their dietary effect around the time of weaning has not been thoroughly studied. Further research is needed in this area.
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Weaning method: The method used to wean (i.e., abrupt removal, two-stage with nose flaps, fenceline, etc.) influences a calf’s level of stress at the time of weaning, based predominantly on differences in short-term performance and behavior during the immediate post-weaning period. However, larger long-term differences in performance have not been shown, and carcass traits have not been studied; further research is needed.
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Post-weaning health: Rate of post-weaning sickness influences marbling deposition, particularly treatment for bovine respiratory disease in high-risk cattle. However, morbidity rate in low-risk cattle does not appear to influence marbling deposition.
Parasite burden at feedyard arrival can alter intramuscular fat deposition, and de-worming protocols have been shown to influence carcass quality. Regardless, limited data specific to the effects of morbidity during the immediate post-weaning period are available.
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Castration: It is widely accepted that castration of male calves improves marbling deposition and end-product palatability. However, in higher-marbling breeds of cattle (e.g., Angus, Holstein) early castration at lighter weights improves marbling, tenderness and palatability.
Additionally, there is a benefit to end-product quality if castration at heavy weights can be avoided.
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Implants: Administration of growth-promoting implants at branding or weaning does not hinder marbling deposition, but administering two or more implants to a steer during his lifetime will.
Among early weaned calves, implants don’t appear to affect marbling if given at weaning. However, implants given to heavy calves early in the growing period can negatively impact marbling versus delaying the implant when days on feed is constant.
In conclusion, producers should consider strategies around weaning to improve marbling. These include weaning early via a low-stress method, feeding a high concentrate diet after early weaning, castrating at lighter weights, ensuring copper and zinc requirements are met, minimizing sickness in high-risk cattle and reducing parasite load.
Further, producers should place cattle on feed at a younger age, not implant heavy calves and realize that creep feeding has not consistently been shown to improve marbling.
While the industry’s focus has been on genetics and feedyard management to maximize carcass marbling, cow-calf operators should realize that they have a substantial influence on marbling via the management of their calves around the time of weaning. 
Editor’s note: The complete white paper (Effects of the 60-d Window Around the Time of Weaning on Subsequent Quality Grade and Eating Quality of Beef,) from which this summary was generated, can be accessed via clicking the link above.
References omitted due to space but are available upon request. Click here to email an editor.
- Jason Ahola
- Assistant Professor – Beef Production Systems
- Colorado State University
