Date of this Version
Agricultural Research Service, U.S. Department of Agriculture (April 1975).
The cattle Germ Plasm Evaluation Program at the U.S. Meat Animal Research Center is designed to characterize different biological types, as represented by different breeds, for the full spectrum of economic traits relating to growth, feed efficiency, reproduction, maternal ability and carcass and meat traits. The basic objective of this program is to develop an understanding relating to optimizing such biological factors as cow size, milk level, etc., in different feed environments and production situations.
The program was started with the 1969 breeding season. The first cycle (Cycle I, Phase 2)* involved breeding Hereford and Angus cows (Phase 1) by artificial insemination (AI) to Hereford, Angus, Jersey, South Devon, Limousin, Simmental and Charolais bulls (table 1, appendix). The three calf crops (1970, 1971 and 1972) by these sire breeds were born in March, April and early May. Reports on birth and weaning traits of all calves and on postweaning growth, feed efficiency and carcass and meat traits of the steers (ARS-NC-13, March, 1974) are available by request. All female progeny were retained for evaluation of reproduction and maternal traits.
The second cycle (Cycle II) started with the 1972 breeding season and includes two calf crops (1973 and 1974). Brown Swiss and Red Poll female populations were added to the Hereford and Angus cow herds used in Cycle I. The Hereford and Angus females were bred by AI to Hereford, Angus, Brown Swiss, Red Poll, Maine Anjou, Gelbvieh and Chianina bulls; the Red Poll and Brown Swiss females were bred by AI to Hereford, Angus, Red Poll and Brown Swiss bulls (table 2, appendix). Performance data being collected is similar to that obtained for the first cycle.
This report provides summarized data from the Cycle I, Phase 2 cows for puberty and conception as yearlings plus calving, rebreeding and weaning information as 2-year-olds (cows born in 1970-71-72), 3-year-olds (cows born in 1970-71) and 4-year-olds (cows born in 1970). Birth and preweaning data are presented for the calves (Cycle I, Phase 3) out of Cycle I, Phase 2, 2-year-old cows and sired by Hereford, Angus, Brahman, Devon and Holstein bulls (table 3, appendix). Data are included on calving difficulty and preweaning growth for the 1973-74, Cycle II, Phase 2 calf crops. Information is included on the 1973, Cycle II, Phase 2 calf crop for postweaning growth, puberty and conception as yearlings of the heifers and postweaning growth, feed efficiency and carcass and meat traits of the steers.