Resumo

TADA, O.; MUCHENJE, V.  e  DZAMA, K.. Effective population size and inbreeding rate of indigenous Nguni cattle under in situ conservation in the low-input communal production system. S. Afr. j. anim. sci. [online]. 2013, vol.43, n.2, pp.137-142. ISSN 2221-4062.

Nineteen rural Nguni cattle enterprises managed at communal and small-scale level were used in a study to determine population genetic parameters, level of Nguni genetic contribution, and risk status of community-based animal genetic resources. Chi-square tests were performed to ascertain the association between enterprise ownership and level of Nguni genetic contribution. Analysis of (co)variance was used to determine significant factors affecting breeding ratio, effective population size (N_e) and inbreeding rate per generation (∆F). About 75% of the animals in the pooled communities were pure Nguni, and the breed was classified as not at risk of extinction, while the individual enterprises were classified as being endangered-maintained without the exchange of germ plasm among them. There were no significant differences between communal enterprises (0.270 ± 0.0699) and small-scale (0.213 ± 0.0748) in the ratio of breeding males to breeding females. Pooled N_e was 348.14, whereas N_e was 19.5 ± 4.60 for communal enterprises and14.1 ± 5.03 for small-scale. It was concluded that enterprise ownership had no effect on small population genetic parameters in community-based in situ conservation programmes. It is recommended that policies be adopted to integrate enterprises, and increase herd sizes and Ne to preserve within-breed genetic diversity.

Palavras-chave : Breeding ratio; enterprise duration; herd size; in situ conservation.

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