Results and Discussion
Effects of year are presented in Table 1. Steer initial weight was about 640 lb the first three years and 523 lb in 1999. These initial weights are not pay weights, but are the weights when they started on research trials after a 4-week receiving period. Final weight averaged 1255 lb in 1996 and was as high as 1332 lb in 1999. Average daily gains were quite good and show a trend upwards over time, topping off at 4.01 lb/day in 1999. Hot carcass weight reflects differences in final weight. Backfat was about 0.4 to 0.5 inches except in 1999 when cattle were fed to a higher final weight and averaged 0.62 inches of back fat. Over 80% of these cattle graded Choice except in 1998 when 65% of the cattle graded low choice or above. No explanation for these differences are readily apparent. Ribeye area averaged over 12 square inches and no pattern due to year was apparent. The USDA Yield grades averaged about three, except in 1999 when steers were heavier and fatter at the time of slaughter.
Effects of cattle source on performance are presented in Table 2. Calves from the Coshocton Branch were about 15 lb heavier than purchased calves initially and were about 80 lb heavier at slaughter. The Coshocton steers gained 0.4 lb/day faster than the purchased steers; gains of the Columbus steers were intermediate. The Columbus calves were 16 lb lighter than Coshocton calves initially and were 23 lb lighter at slaughter. Backfat was about 0.1 inches greater for Columbus calves than for the other two sources. Yield grade followed the same pattern. Ribeye area was greatest for the purchased calves, lowest for the Columbus calves, and intermediate for the Coshocton calves. It is evident from these data that genetics based on sires from the Ohio Bull test allow for the production of excellent feeder calves. These sires are generally only one generation from the top AI sires in the country. The Ohio Bull Test should be considered an excellent source of genetics for commercial beef producers in Ohio.
Effects of hide color on performance are presented in Table 3. Hide color did not affect gains, final weights, or hot carcass weights. Red and white hided cattle had 0.05 inches less backfat than black or smoke colored cattle. On the other hand, black and smoke colored cattle had the highest marbling scores, while reds were the lowest, and white hided cattle were intermediate. Red and white hided cattle had the largest ribeye area; blacks and smokes had the smallest ribeye area, and white cattle with a black nose were intermediate. Following the same trend, steers with red or white hides had the best yield grades, blacks and smokes had the poorest yield grades, and white cattle with black noses were intermediate.
Effect of health history on performance is presented in Table 4. We treated approximately 50% of these newly weaned calves over the four year period. The data set does not include "realizers" that never were deemed fit to be placed on a finishing experiment. Therefore, the data set includes only animals that responded to antibiotic therapy and recovered from their respiratory illness. Steers that were treated multiple times had lower initial weights than those never treated or only treated once. This reflects the initial set back in performance one would expect in calves struggling to recover from respiratory disease. No carcass characteristics were affected by health history except marbling score. There was a significant relationship between antibiotic treatment and marbling. This relationship is not a result of indirect effects on growth rate or subcutaneous fat accretion; these factors showed no relationship with health history. While the cause of this reduced marbling response is unknown, it is possible that the initial bout with illness upon arrival may have long lasting negative effects on intramuscular fat cells and any genetic predisposition for marbling.