Comparison of cattle of a five-breed diallel: size, growth, condition and pubertal characters of second-generation heifers.

Monthly weights, heights and condition scores and measurements taken at the time of puberty were utilized to estimate effects of breed-type and heterosis on characters related to growth, size and puberty of second-generation heifers of a five-breed diallel involving Angus, Brahman, Hereford, Holstein and Jersey. One group of heifers was maintained on pasture with supplemental feed; two other groups were fed in individual pens starting at weaning and 1 yr of age, respectively. A model including main effects of breed-type, sire within breed-type, management, parity of dam and birth-season was used for analyzing all characters. Breed-type tested with sire within breed-type was significant for all characters except ADG from 360 to 450 d. Straightbred and crossbred means were larger for the second generation than for the first, presumably due to management and(or) year effects. Heterosis generally was positive and, when expressed as a percentage, decreased with age, which is in agreement with other research reports. Holsteins and Brahmans were largest for growth and size characters, whereas Jerseys were smallest. Jerseys were the youngest, lightest and shortest at puberty, whereas Brahmans were oldest, heaviest and tallest.