REPEATABILITY AND PHENOTYPIC CORRELATIONS FOR BODY-WEIGHT AND REPRODUCTION IN COMMERCIAL OSTRICH BREEDING PAIRS

1. Reproduction is an important aspect of ostrich farming, where incom e is mainly derived from hides and meat. No estimates of repeatability or phenotypic correlations for reproduction and body weight are curre ntly available for commercial ostriches. 2. Means, standard deviations , repeatability coefficients and phenotypic correlations for and among reproductive traits and body weight were computed for the average yea rly production of 42 to 67 mixed age ostrich breeding pairs maintained on the Klein Karoo Agricultural Development Centre from 1990 to 1994. The among-breeding-pair variance component was used in the repeatabil ity estimations, as the pairing off of the same male:female combinatio ns repeatedly resulted in the confounding of these effects. 3. Phenoty pic correlations of male body weight with egg production performance ( -0.20) and female body weight with hatchability percentage (-0.16) wer e negative. Correlations of egg production performance with infertilit y (-0.20) and hatchability (0.23) percentages were favourable. 4. The repeatability of annual adult body weight was 0.68 +/- 0.05 in male os triches and 0.61 +/- 0.05 in females. 5. Ostrich reproduction traits w ere extremely variable. An appreciable portion of this variation could be attributed to the repeatable nature of breeding pair performance f rom year to year. All the reproduction traits analysed were moderately repeatable, ranging from 0.38 + 0.07 (hatchability percentage) to 0.5 1 +/- 0.06 (percentage of embryonic deaths). Egg production performanc e during the first breeding season of 17 breeding pairs for which data were available predicted subsequent performance satisfactorily, sugge sting that selection decisions can be made at quite an early age.