Parameter estimates for reproductive output and product quality traits of ostrich females within breeding seasons

Abstract

Data involving monthly records of egg production (EP), chick production (CP), hatchability (H), mean egg weight (MEW) and mean day-old chick weight (MCW) were analysed using REML procedures. All traits were treated as hen traits. Egg production of young birds increased to reach a peak of approximately 4 to 5 eggs per month relatively late in the breeding season (September to December). Older hens reached a higher peak of 6 to 9 eggs per month earlier in the breeding season (August to September). There was a secondary peak in older birds from November to December. All birds except 2-year olds exhibited evidence of a slump of production during October. Chick production, MEW, MCW and H followed similar trends. The random effects of direct additive genetic, permanent environment (PE), temporary environment (TEunique hen-year combinations) and service sire (SS) were estimated from the data. Heritability estimates of the direct additive genetic effect (h 2 a ) of the hen were 0.04 for EP, 0.05 for CP, 0.44 for MEW, 0.67 for MCW and 0.02 for H. The estimates of permanent environment (c 2 pe ) as a ratio of phenotypic variance for the four traits (MCW did not exhibit a significant c 2 pe effect) were 0.08, 0.08, 0.09 and 0.11, respectively. The effect of service sire as a ratio (c 2 ss ) was significant but relatively low for all traits, ranging from 0.04 for MEW and MCW to 0.06 for CP. Monthly EP and CP were highly correlated at all levels, ranging from 0.74 for the TE correlation to unity (1.00) for the genetic correlation. Egg production was favourably correlated with H at a genetic level (0.98). The genetic correlations of EP and CP with MEW and MCW were variable and in some cases antagonistic as is often found in poultry. The genetic correlations of H with MEW and MCW were positive (0.52 and 0.47, respectively). As expected, the genetic correlation of MEW and MCW was very high at 0.94. The results indicate that selection for improved reproduction (reproductive output and product quality traits) in ostriches is possible. Selection is unlikely to be complicated by unfavourable correlations with H, MEW and MCW. ________________________________________________________________________________

The influence of diet composition on egg and chick traits in captive Greater Rhea females

“…Most nutritional studies in ratites have been conducted in ostriches (reviewed by Angel, 1996;Ullrey and Allen, 1996;Aganga et al, 2003;Cooper et al, 2005), because it was the first and is currently the most commonly farmed ratite species (Gillespie and Schupp, 1998;Cloete et al, 2004;Ipek and Sahan, 2004;Lambrechts, 2004;Fair et al, 2005;Cloete et al, 2006). Thereafter, when rhea farming started to grow as an agricultural venture, the need for information about nutrient requirements was met by direct extrapolation from that available for ostriches (Angel, 1996;Carbajo Garcia et al, 1997;Aganga et al, 2003).…”

Red-necked ostrich (struthio camelus camelus) egg production, external characteristics and hatchability

“…Female ostriches during the first season started laying eggs late by one month compared to elder breeders, thereby produced less eggs. Fair et al (2005) showed that 2-year old hens (just mature) started slowly, increased egg production steadily up to five months into the breeding season but produced least eggs. This was attributed to the lack of sexual maturity and experience.…”