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      (Co)variances for reproduction, egg weight and chick weight in ostriches

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          Abstract

          The study investigated genetic parameters for egg and chick production recorded over an 8-month breeding season, as well as average egg and chick weight for pair-bred ostrich females. Estimates of h² were moderate for reproduction traits and very high for average egg and chick weight, where all traits were expressed as a trait of the dam. Genetic and phenotypic correlations were positive in sign for all trait combinations. Selection for an increased reproduction rate would thus not lead to an unwanted (downwards) correlated response in average egg or chick weight. Averaged annual breeding values for egg and chick production in breeding females increased at 1.4 and 2.3% per year, respectively. These results indicate that the genetic improvement of ostriches is feasible, provided that obstacles hampering it are overcome.

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          ASREML: Reference Manual

          A.R. Gilmour, B.R. Cullis, S.J. Welham … (1999)
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            Repeatability and phenotypic correlations for body weight and reproduction in commercial ostrich breeding pairs.

            S. J. Van Schalkwyk, S Cloete, J A de Kock (1996)
            1. Reproduction is an important aspect of ostrich farming, where income is mainly derived from hides and meat. No estimates of repeatability or phenotypic correlations for reproduction and body weight are currently 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 yearly 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 repeatability estimations, as the pairing off of the same male:female combinations repeatedly resulted in the confounding of these effects. 3. Phenotypic correlations of male body weight with egg production performance (-0.20) and female body weight with hatchability percentage (-0.16) were negative. Correlations of egg production performance with infertility (-0.20) and hatchability (0.23) percentages were favourable. 4. The repeatability of annual adult body weight was 0.68 +/- 0.05 in male ostriches and 0.61 +/- 0.05 in females. 5. Ostrich reproduction traits were extremely variable. An appreciable portion of this variation could be attributed to the repeatable nature of breeding pair performance from year to year. All the reproduction traits analysed were moderately repeatable, ranging from 0.38 +/- 0.07 (hatchability percentage) to 0.51 +/- 0.06 (percentage of embryonic deaths). Egg production performance during the first breeding season of 17 breeding pairs for which data were available predicted subsequent performance satisfactorily, suggesting that selection decisions can be made at quite an early age.
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              Factors affecting reproduction in farmed ostriches

              K.L BUNTER, S.W.P. Cloete, S.J. VAN SCHALKWYK … (2001)
              Article 0 comments Cited 3 times – based on 0 reviews     Review now
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                Author and article information

                Journal
                Journal ID (publisher-id): sajas
                Title: South African Journal of Animal Science
                Abbreviated Title: S. Afr. j. anim. sci.
                Publisher: The South African Society for Animal Science (SASAS) (Pretoria, Gauteng, South Africa )
                ISSN (Print): 0375-1589
                ISSN (Electronic): 2221-4062
                Publication date (Print and electronic): 2004
                Volume: 34
                Issue: 2
                Pages: 17-19
                Affiliations
                [03] Oudtshoorn orgnameKlein Karoo Agricultural Development Centre South Africa
                [01] Elsenburg orgnameElsenburg Agricultural Centre South Africa
                [02] Armidale orgnameUniversity of New England orgdiv1Animal Genetics and Breeding Unit Australia
                Article
                Publisher ID: S0375-15892004000200003 Publisher ID: S0375-1589(04)03400200003
                SO-VID: 949c12b7-320b-41da-8a1e-e9d8da00dd65
                License:

                This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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                Page count
                Figures: 0, Tables: 0, Equations: 0, References: 10, Pages: 3
                Product

                SciELO South Africa

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                Subject: Articles

                Keywords: heritability,genetic correlations,egg production,chick production,Breeding values
                Data availability:
                Keywords: heritability, genetic correlations, egg production, chick production, Breeding values

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