Date of this Version
United States Department of Agriculture, Agriculture Research Service, July 1995.
Angus bulls (born 1982-1984) were used in Cycle IV and the remaining 16 bulls (born since 1988) were used for the first time in Cycle V.
Tuli. The Tuli, a Sanga type of cattle (non-humped), was developed relatively recently in a research program initiated in the 1940's using foundation cattle considered to be the most productive type selected from indigenous Tswana cattle in Zimbabwe. Australian scientists at CSIRO, Tropical Agricultural Research Station, Rockhampton, Queensland, and a consortium of private breeders in Australia imported frozen Tuli embryos from Zimbabwe into Australia in 1990. Semen from nine Tuli bulls was imported from Australia for use in the experiment.
Boran. Borans are a pure Zebu breed (Bos indicus, humped) that evolved in southern Ethiopia and are believed to have been developed for milk and meat production under stressful tropical conditions. They were imported into Australia from East Africa (Zambia). Semen from eight Boran bulls was imported from Australia for the experiment.
Brahman. Semen from a current broad sample of 21 Brahman (Grey and Red) bulls (born from 1984-1989, mean birth year 1987) was used to produce FI progeny. Semen was used from 26 bulls (born from 1964 to 1975, mean birth year 1969) sampled earlier in the program to facilitate pooling of data over cycles and estimate genetic trends.
Belgian Blue. Muscle hyperplasia (double muscling) has been favored for at least 40 years by Belgian Blue breeders in Belgium. Semen from 26 bulls is being used in the experiment.
Piedmontese. Piedmontese originates in the Piedmont region of northern Italy. Muscle hyperplasia has also been emphasized as a criterion of selection in this breed. Seventeen Piedmontese sires included in Cycle IV of the program were repeated to produce one calf crop (1992) in Cycle V.
Calves were produced in the spring of 1992- 1994. Each year a sample of about 80 male calves were left intact to evaluate growth and pubertal development of bulls. The remaining male calves were castrated within 24 hours of birth. Calves we~ creep fed whole oats from mid-July until weaning in early October.