Breeding programmes for smallholder sheep farming systems: II. Optimization of cooperative village breeding schemes

A simulation study was conducted to optimize a cooperative village-based
sheep breeding scheme for Menz sheep of Ethiopia. Genetic gains and
profits were estimated under nine levels of farmers’ participation and
three scenarios of controlled breeding achieved in the breeding programme,
as well as under three cooperative flock sizes, ewe to ram mating
ratios and durations of ram use for breeding. Under fully controlled breeding,
that is, when there is no gene flow between participating (P) and
non-participating (NP) flocks, profits ranged from Birr 36.9 at 90% of participation
to Birr 21.3 at 10% of participation. However, genetic progress
was not affected adversely. When there was gene flow from the NP to P
flocks, profits declined from Birr 28.6 to Birr
3.7 as participation declined
from 90 to 10%. Under the two-way gene flow model (i.e. when P and NP
flocks are herded mixed in communal grazing areas), NP flocks benefited
from the genetic gain achieved in the P flocks, but the benefits declined
sharply when participation declined beyond 60%. Our results indicate
that a cooperative breeding group can be established with as low as 600
breeding ewes mated at a ratio of 45 ewes to one ram, and the rams being
used for breeding for a period of two years. This study showed that farmer
cooperation is crucial to effect genetic improvement under smallholder
low-input sheep farming systems.