Summary and Implications
A total of 10,518 head of 4H project beef calves had both growth and carcass data collected on them from 1971 through 2005. Iowa’s 4H projects have beginning weights measured around January 1 and then all cattle are weighed at the county or state fair so ADGs can be calculated. In addition, many projects are terminated in conjunction with a carcass contest and standard carcass data collected. From the middle 1970s until 2005 live weights have increased by over 200 pounds with a corresponding 133 pound increase in hot carcass weight. During this same time period average daily gains have increased from 2.3 to 3.0 pounds daily. 4H project cattle trended leaner from the 1970s to the 1980s, but during the 1990s and into the new millennium have trended fatter. Rib eye area increased by about 1 square inch, however, due to an increase in carcass weight the rib eye area per hundred pounds of carcass weight has decreased. Quality grade from the 1970s decreased from over 70% Choice and higher down to 55%, but in the last decade has returned to over 75% Choice and better. Percent yield grade 1 and 2 increased to over 70% in the 1980s, however, with the emphasis on higher quality grade has decreased back to 55% yield grade 1 and 2s. 4H beef projects are placed in contests with a formula called retail value per day on feed. Factors found that significantly impact this placing were final weight, ADG, dressing percent, hot carcass weight, rib eye area, quality grade and carcass price as impacted by quality and yield grade.
Iowa State University
Busby, W. Darrell and Strohbehn, Daryl R.
"A Historical Summary of Iowa 4H Beef Carcass Data—1971–2005,"
Animal Industry Report:
AS 653, ASL R2193.
Available at: http://lib.dr.iastate.edu/ans_air/vol653/iss1/19