Optimum crossbreeding systems for goats in low-input livestock production system in Kenya

• We model three crossbreeding systems and synthetic breed development for local goats.
• Desirable traits of local goats are required to form crossbreds for tropical areas.
• Three-breed composite is the crossbreeding system of choice in most dry environments.

The aim of the current simulation study was to maximize the amount (kg) of high value meat arising from surplus males and females per kilogram of the goat population and, maximize weight gains to turnoff age. Subsequently, the study aimed to decrease turnoff age, maximization of reproduction rates and minimization of the mature weight of does in the low-input livestock production system in Kenya. Three crossbreeding systems and a synthetic breed development were evaluated, namely; (a) straight breeding system that utilized pure Small East African goat (SEAG) where parental lines were maintained to generate the desired terminal crosses, (b) three-breed crossbreeding system that utilized SEAG as pure breed, Galla goat (GG) as the first cross sire breed, and Improved Boer goat (IBG) as the terminal sire, (c) two-breed rotational crossbreeding system where the SEAG and IBG were purebreds, and (d) synthetic breed development system utilizing SEAG × IBG. The HotCross crossbreeding simulation software was used to assess the predicted performance of the different goat breed crosses under conditions of agro ecological zones (AEZ) V and VI. A model was developed to compare these crossbreeding systems, and showed the optimum numbers required in each stage of a cross to maximize production. In the AEZ V, it was found that the three-breed terminal system gave 18.2 kg (76%) improvement over straightbreds per doe mated per year. The multi-breed composite realized 20.4 kg (86%) improvement over pure SEAG. In the AEZ VI, it was found that the three-breed terminal system gave 10 kg (64%) improvement over straightbreds per doe mated per year. The multi-breed composite realized 14.6 kg (94%) improvement straightbreds per doe mated per year. The two-breed rotation was worse than the multi-breed composite in both environments. This implies that in low-input livestock production system, a multi-breed composite may be the crossbreeding system of choice, so long as supportive infrastructure is put in place.