And, “No study has revealed any differences in the nutritional profile of animal products derived from GE-fed animals.” The authors noted that regulations on production and marketing of genetically engineered (GE) food vary across countries and concluded “there is an urgent need for international harmonization of both regulatory frameworks for GE crops and governance of advanced breeding techniques to prevent widespread disruptions in international trade of livestock feedstuffs in the future.”

Effect of prior management on finishing performance, carcass characteristics and economics
A group of 141 spring-born steers that were weaned in November and then wintered to gain less than 1 pound per day was divided into three groups in early May:

• Group 1 was placed directly into a finishing program.
• Group 2 was grazed on crested wheatgrass until mid-June, then moved to native range, and then was placed into a finishing program in early November.
• Group 3 was grazed on crested wheatgrass until mid-June, then moved to native range until late August, then grazed a mixture of field peas and barley followed by unharvested corn, and were then placed into a finishing program in early November.

In the comparisons discussed below, any differences or lack of differences were statistically significant.

During the six-month grazing periods, the steers in Group 3 gained more weight and were fatter at the start of finishing than those in Group 2. There was no difference in cost of gain for the grazing phase.

In the finishing program, the steers in Group 1 were fed longer, had lower ADG, were younger and lighter at slaughter, gained less efficiently and had lighter carcass weight than either of the groups that grazed throughout the summer and fall before entering the finishing program.

For the two groups that grazed through the summer and fall, those that had access to annual pasture and unharvested corn were heavier when placed on feed, required fewer days on feed to reach finish endpoints and were younger at slaughter. However, final weight, ADG, feed efficiency, carcass weight, yield grade and marbling were not different for the two groups.

Based on taste panel evaluations, tenderness, juiciness and flavor were not different among any of the three groups. Overall net returns were greater for Group 3 compared to the other two groups; net returns were $39 per head higher than Group 2 and $328 per head higher than the steers that were placed directly on feed in the spring. Returns for the group that was placed directly on feed were notably lower primarily because of lighter carcass weight and, to a lesser extent, higher expense. (Note: Financial returns can vary considerably depending on costs and revenue, so these returns should be viewed accordingly.)

What do quality grades mean to consumers?
A survey was conducted of over 1000 consumers to assess perceptions of select, choice and prime.

Respondents were asked to:

1. Rank the three grades on leanness
2. Rank the three on juiciness
3. Match pictures of ribeyes showing the grades with grade names, or match prices of $4 per pound, $8 per pound or $12 per pound with grade names

Only 14 percent ranked leanness correctly, and 57 percent said prime was leanest, but 55 percent still ranked prime highest on juiciness. Only 14 percent correctly matched pictures with grade name, an outcome, as the authors stated, “that is worse than would have occurred by purely random chance.”

Also, 55 percent of the respondents associated prime grade with the lowest price category of $4 per pound. (Note: It appears that consumers tended to associate “prime” with anything desirable to them.) When results were evaluated based on some characteristics of the respondents, the more highly educated and those with greater preference for steak were more likely to correctly match the names, pictures and price categories.

The authors suggested three possible actions:

• Drop the current USDA grading system and use private or third-party systems.
• Increase education on the relationship between marbling and taste.
• Provide descriptions beyond grade name, such as “USDA prime – higher fat, most juicy”, “USDA choice – juicy” and “USDA select – less fat, less juicy.”

However, the authors indicated there are limitations with any of these suggestions that may reduce applicability and not markedly increase consumer knowledge. (Note: While USDA grades may not be well understood by many consumers, they are important for trade purposes within the beef production chain.)

Comparison of Angus, Brahman and Romosinuano for maternal traits
Rominsuano is a Criollo-type, non-Bos indicus breed originally developed in Colombia. They have been suggested as a source of tropically adapted genetics with carcass quality attributes better than straight Bos indicus cattle. In this study, Angus, Brahman and Romosinuano were used to produce the three straightbreds and all six possible crosses. Over the six-year study, 1442 cow records and 1254 calf records were available for analysis.

Brahman-sired male calves were significantly heavier at birth compared to Angus- or Romosinuano-sired male calves. Also, as has been shown in other research, Brahman-sired male calves were markedly heavier (by 12.8 pounds) at birth than Brahman-sired female calves; across the other sire groups, male calves averaged only 2.2 pounds heavier than females.

Romosinuano-sired calves gained significantly less to weaning. Weaning weight per cow exposed was not significantly different across the three straightbred groups.

Combining reciprocal crosses, weaning weight per cow exposed was:

• Angus-Romosinuano: 440 pounds
• Brahman-Romosinuano: 449 pounds
• Angus-Brahman: 488 pounds

Heterosis for weaning weight per cow exposed for the three reciprocal crosses was:

• Angus-Romosinuano: 70 pounds
• Brahman-Romosinuano: 81 pounds
• Angus-Brahman: 130 pounds

The authors concluded “most aspects of Romosinuano crossbred maternal performance were acceptable, but maternal performance of Brahman-Angus cows excelled.”

Effect on follicle age on pregnancy
Reports in lactating dairy cows have indicated that age of the follicle is a significant source of variation in fertility, but this had not been evaluated in beef cattle. Angus-Hereford postpartum cows (171 of which had calved once and 130 more than once) were synchronized with the five-day CO-Synch plus CIDR program. Prostaglandin (PGF2α) was administered either five and a half days (producing “young” follicles) or nine and a half days (producing “mature” follicles) after administration of estradiol.

Interval to estrus was significantly shorter with mature follicles and follicle age at A.I. was significantly greater. However, follicle size and pregnancy rate did not differ between the two groups. The authors concluded “these data suggest that age of the ovulatory follicle is not a major contributor to variation in fertility among beef cows.”

Effect of supplementation level on subsequent performance and profitability
Six studies were evaluated to assess effects of differing post-weaning supplement levels for calves grazing corn residues in the winter. Over the winter, the groups of calves were supplemented to achieve low ADG (LO, 2 pounds per day distillers grains, 0.57 ADG) or high ADG (HI, 5 pounds per day distillers grain, 1.41 ADG) while grazing corn stalks. After the winter period, all calves grazed cool- and warm-season grass pastures in the spring and summer when they were placed into a common finishing program.

During the spring and summer grazing period, the calves from the LO winter supplement/gain group gained more rapidly (1.39 pounds per day) than the calves on the HI (1.06 pounds per day) wintering program. All of these differences were statistically significant.

During the finishing period, the calves from the LO wintering program gained more slowly (4 pounds per day) than the calves from the HI wintering group (4.18 pounds per day). These differences were statistically significant. Feed consumption and feed efficiency were not significantly different for the LO or HI groups during the finishing period. However, the steers from the LO group were significantly lighter (1230 pounds) at slaughter than those from the HI group (1311 pounds).

Valuing both corn and distillers grains at two different prices, the steers from the HI group averaged $55.54 higher profit than those from the LO group. In this study, corn would have to be over $11.70 per bushel for the HI level of winter supplementation to not be more profitable than the LO supplementation level.

Lean beef – Are there limits?
The industry has been stressing leanness at least since the first Beef Quality Audit in 1991, when excess fat was identified as a major problem. Some experts are saying we’ve gone about as far as we can, or will, in reducing fat in beef. In a recent report from the Beef Board, it was noted that there are currently some 40 beef cuts that meet the USDA definition of lean, and more are appearing. In 1994, just seven cuts met the USDA specifications for lean. And, since most beef cuts are closely trimmed these days, there is not much difference in total fat content of select and prime retail cuts.

Note: Some wonder why feeders continue to produce finished cattle with excess outside fat that is then trimmed by the packer. For one reason, external and internal fat, including marbling, tend to be positively related. For another, carcass price bonuses for higher marbling/quality grade generally more than offset any discounts for excess fat (higher numerical yield grade). And as long as cattle keep gaining efficiently, the value of greater carcass weight generally more than offsets penalties for excess fat. Unless all that changes, we’ll probably continue to “over fatten” cattle.  

Stephen Hammack, Ph.D., is a professor and extension beef cattle specialist emeritus at Texas A&M University. This originally appeared in the Beef Cattle Browsing newsletter.

References omitted but available upon request. Email editor@progressivecattleman.com.