Date of Award
Master of Science
Haley M. Jamison
Robert R. Shrode, Robert S. Dotson
The birth-to-weaning performance records of 1869 non-creep fed and 791 creep fed calves were utilized in this study. These data were collected from purebred and high grade commercial cow herds in the Tennessee Beef Cattle Improvement Program in the Cumberland Plateau area of Tennessee. The data were collected over a 3-year period (1964-66). Two traits of economic importance, viz., average daily gain from birth to weaning and type score at weaning, were used in these analyses. The objective of this study was to evaluate the effects of age of dam, sex of calf, season or month of birth and age of calf on average daily gain to weaning and type score at weaning of calves produced on the Cumberland Plateau in Tennessee.
The effects of age of dam on average daily gain from birth to weaning were highly significant (P<.01) for both non-creep and creep fed calves. A cow's individual performance was lowest at 2-, 3-, 4-, and 12-years of age for non-creep fed calves. Whereas, in the creep fed group, 2- and 3-year-old dams produced calves with the lowest average daily gains.
Age of dam had a small but significant effect on type score of non-creep fed calves. The maximum type score of a cow's calves were obtained when she was within the range of 3 to 8 years, and decreased as she became older. No significant differences among the type scores of creep fed calves were observed.
Sex of calf had a significant effect on average daily gain of "both non-creep and creep fed calves. Non-creep fed bull calves gained 0.17 pound more than heifers, and steers gained 0.04 pound less than bull calves. In the creep fed group, the estimates were 0.20, 0.15 and -.05 for bulls, steers and heifers, respectively.
Sex of calf influenced type score of non-creep fed calves. Bull calves graded significantly higher than steers and heifers. Whereas, there was no significant difference between steers and heifers.
Sex of calf had a significant influence on the creep fed calves. Bulls had a type score significantly higher than steers, and the type score of steers was significantly higher than heifers.
August-born calves were inferior in performance to calves born in other months. Generally, calves born in February, March, April, May, June and October appear to be desirable for the area sampled in these analyses.
Month of birth had no apparent effect on type score of creep fed calves. Non-creep fed calves born in January, February, March and August graded significantly lower than calves born in any other month. However, from these data it appears that some adjustment for month of birth is warranted.
Age of calf was one of the most important sources of variation in average daily gain and type score. The average daily gain of calves decreased in a linear manner; whereas, type score increased as the calf's age increased within the limits of these data.
Austin, Merrill D., "Factors influencing weaning performance of beef calves on the plateau area of Tennessee. " Master's Thesis, University of Tennessee, 1968.