Tom Cartwright

Thomas Campbell Cartwright, born March 8, 1924, in York, South Carolina, graduated with honors in Animal Husbandry in 1948 from Clemson University. He received the M.S. degree in Genetics in 1949 and the Ph.D. degree in Animal Breeding in 1954 from Texas A&M College. He was Instructor of Genetics in 1949, Atomic Energy Commission Fellow from 1949 to 1951, and Associate Animal Husbandman and Geneticist at the Texas A&M Agricultural Research Center at McGregor from 1952 to 1958. He was appointed Professor, Animal Husbandry Department, Texas A&M College in 1958. He received the Association of Former Students Distinguished Achievement Award in Teaching at Texas A&M in 1962, was selected as a Fellow of the American Association for the Advancement of Science in 1965, and received the Animal Breeding Award from the American Society of Animal Science in 1973 and the International Agriculture Award from the American Society of Animal Science in 1983. He was recognized in 1987 with the title of Professor Emeritus of the Animal Science Department, Texas A&M University, and received the Distinguished Alumni Award from Clemson University in 1989.

His early research at the McGregor Center involved performance testing (growth and reproduction) and crossbreeding. The crossbreeding research had the original intent of developing two synthetic breeds (3/4 Hereford-1/4 Brahman and 3/4 Brahman-1/4 Hereford) adapted to different Texas conditions. Producing the F1 crosses needed to make the foundation crosses provided cattle that were well suited to the study of heat tolerance. The heat tolerance research was the topic of his Ph.D. dissertation, and was the first documentation of the levels of heterosis in the Hereford-Brahman F1. Continuation of this crossbreeding research led to the recognition that the net productivity of the F1 cross was clearly superior to the straightbreds. In an "editorial" written in a report to the cooperating breeders, Tom predicted that the future would see hybrid beef cattle in almost the same proportion as hybrids in hogs. This upset several breeders to the point of terminating their participation as cooperators. The development of the two Hereford-Brahman composite breeds was terminated in the early 1960s, but important crossbreeding research was continued.

The thrust of the early performance testing research was to objectively document the variability of performance within and between beef breeds. Tom's first assignment as an employee of Texas Agricultural Experiment Station (TAES) was to draft a journal article summarizing the results of gain tests that had been conducted at the TAES Substaion at Balmorhea, where a program of winter feeding of bull calves from cooperating breeders was carried out beginning in 1942. In this article, the heritability of rate of gain in young growing bulls was reported to be moderately high. Gain testing bulls from cooperating breeders was continued at McGregor and corroborated the heritability estimates from Balmorhea. The work done at Balmorhea and McGregor, reinforced by an earlier journal article from the USDA Station at Miles City, MT, set off the gain testing and selection race.

While gain testing was continued at McGregor, meaningful data were accumulated on the variability of the efficiency of production of the cow herd. Major effect was devoted to the study of growth curves in order to develop a better understanding of the relationships of growth to cow productivity. Systems analysis tools were used to develop mathematical models to study trait level impacts on system efficiency, elucidate such phenomena as complementarity, and to account for the trade offs associated with antagonisms between traits. The McGregor breeding research was redesigned starting in 1970 with the objective of gaining more basic information on how cattle grow and reproduce. The systems research was continued and expanded during the 1970s and 80s, and Tom became a world leader in the application of systems techniques to livestock breeding.