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Calf management to consumer acceptance, Part 2

The following research highlights are provided by Harlan Ritchie, Steven Rust and Daniel Buskirk, all of whom are beef cattle specialists at Michigan State University, East Lansing, as part of their Winter 2004 Beef Cattle Research Update. The following are reviews of research projects recently reported at scientific meetings or in scientific publications.

Delaying initial implant improved quality grade
University of Nebraska (NU) evaluated how delaying the initial feedlot implant would influence performance and carcass traits in steer calves implanted twice during the finishing period. One hundred crossbred steer calves, averaging 476 lb., were used in the study. One-half were implanted with Synovex S® after a 14-day acclimation period. The remainder were implanted with Synovex S 30 days after the 14-day acclimation period. All calves were reimplanted 112 days later with Synovex Choice® and harvested after another 100 days.
Average daily gain (ADG; 3.74 lb.), final weight (1,269 lb.), hot carcass weight (799 lb.), fat thickness (0.48 in.), ribeye area [12.79 square inch (sq. in.)] and yield grade (YG; 3.2) were not affected by implant regimen. However, the delayed-implant steers had significantly higher marbling scores (570 vs. 527), and a higher percentage graded Choice (92% vs. 68%). The authors concluded that delaying the administration of Synovex S until 30 days on feed can improve marbling score and quality grade without compromising feedlot performance.
(Funston et al. 2004. Nebraska Beef Cattle Report MP 80-A)

Using a reduced dose for initial implant for heifers
NU workers conducted a 177-day finishing trial to compare the effects of a new reduced-dose implant vs. a traditional higher-dose implant on performance and carcass characteristics when given to heifers as an initial implant. A total of 1,081 heifers, averaging 614 lb., were allotted to two treatments: 1) Revalor®-IH [8 milligrams (mg) estradiol, 80 mg trenbolone acetate (TBA)]; and 2) Synovex-H (20 mg estradiol benzoate, 200 mg testosterone propionate). All heifers were reimplanted with Revalor-200 (20 mg estradiol, 200 mg TBA) as a terminal implant 81 days prior to harvest. Heifers were fed an average of 177 days.
Dry-matter intake (DMI) was similar between treatments. Revalor-IH-implanted heifers tended to gain faster (3.65 lb. vs. 3.57 lb. per day) and had significantly improved feed conversions (5.26 vs. 5.39 feed:gain). There were no statistically significant differences between treatments in fat thickness, ribeye area, yield grade or percent of total carcasses grading Choice.
However, heifers implanted with Revalor-IH had improved marbling scores and significantly more carcasses grading in the upper two-thirds of Choice (23.6% vs. 14.9%). A simulated economic analysis using a value-based pricing grid showed that Revalor-IH-implanted heifers returned $14.22 per head more than Synovex-H-implanted heifers. This difference was due to the higher percent of the upper two-thirds Choice carcasses and 9-lb. greater carcass weight for the heifers implanted with Revalor-IH. The authors concluded that an initial reduced-dose implant appears equal or better in feedlot performance to traditional higher-dose implants and improves marbling, percent of carcasses grading upper two-thirds Choice, and net return when heifers are sold on a value-based grid marketing system.
(Farran et al. 2004. Nebraska Beef Cattle Report MP 80-A)

Rating consumer acceptability of strip loin steaks
Colorado State University (CSU) scientists studied the effects of changes in marbling score, Warner-Bratzler Shear Force (WBSF) and consumer sensory panel ratings on overall consumer acceptability of strip loin steaks (n=550). A total of 489 consumers evaluated the steaks for tenderness, juiciness and flavor on a nine-point scale (1=like extremely; 9=dislike extremely).
The probability of acceptance by consumers was high (85% or more) when average sensory rating for tenderness, juiciness or flavor was 3 or lower. Conversely, probability of acceptance was low (10% or less) when these ratings were 5 or higher. As sensory ratings decreased from 3 to 5, probability of acceptance declined very rapidly, from 90% to 10%, in a linear fashion. This suggests that small changes in consumer ratings for these traits can have dramatic effects on overall acceptability.
The study indicated acceptance increases approximately 10% for each full marbling score increase from Slight to Slightly Abundant.
The probability of consumer acceptability was S-shaped for WBSF, with a steep decline in acceptance as WBSF values increased from 6.6 lb. to 12.1 lb. Changes within the highest and lowest portions of the range in values had very little effect on probability of acceptance.
(Platter et al. 2003. J. Anim. Sci. 81:2741)

Calf-fed steers graded higher, were more palatable
Research has shown variable results when calf-feds and yearlings are compared for quality grade and measures of meat palatability. However, very few studies have made this comparison using contemporaries from the same herd. NU scientists used British-Continental steers to make this comparison in a two-year study where herdmates were assigned at weaning time to be finished as either calves or yearlings.
Calf-feds were placed directly in a finishing yard for 6 to 7 mo. and were 13 to 14 mo. old when harvested. Yearlings were backgrounded on various growing systems (drylot, cornstalks and pasture) and then finished for 3 mo. They were 19 to 20 mo. old when harvested. Both groups were fed to be harvested at a constant fat thickness end point of 0.5 in.
Yearlings had significantly heavier carcasses (828 lb. vs. 696 lb.) and greater ribeye areas (12.6 sq. in. vs. 11.3 sq. in.). There were no significant differences in fat thickness or yield grade. Calf-feds had significantly more marbling and a higher percentage of Choice carcasses than yearlings. Steaks from calves were significantly more tender as measured by shear force after 7, 14 and 21 days of aging. They were also scored higher by a sensory panel for tenderness, juiciness, flavor and overall acceptability after 7 and 14 days of aging.
Based on the shear force data, the probability of a tough steak from calf-feds was only 1.9%, 0.7% and 0.02% after 7, 14 and 21 days of aging, respectively. Yearlings showed a much higher probability of being tough: 29.2%, 11.9% and 4.0% after 7, 14 and 21 days of age, respectively.
(Brewer et al. 2004. Nebraska Beef Cattle Report MP 80-A)

Consumer trends
The following is a current list of food industry trends based upon Kiplinger analysts (The Kiplinger Agriculture Letter, Vol. 74, No. 21).
•Foods low in carbohydrates are in. More consumers are on diets low in carbs and high in protein and vegetables because of increasing concern about weight and obesity.
• Demand for pasta, bread and rice is declining.
• Some companies are offering low-carb protein bars, breads and ice cream.
• Light, low-fat and no-fat foods are coming back after a few years of declining sales.
• Sales of organic foods continue to grow at an annual rate of more than 20%. Snacks are growing faster than other types of organic foods.
•Retail food prices will increase as the U.S. economy recovers. The U.S. Consumer Price Index for all foods is expected to rise up to 3% in 2004.
• Percentage of income spent on meals consumed at home is expected to increase by 2%; those eaten at restaurants, 2.5%.

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