Evaluation of alternative selection objectives and schemes for optimisation of village goat improvement programs

Abstract

This study evaluated alternative breeding objectives and schemes for crossbred goats in a village/ community breeding program. A single-tier breeding structure was assumed in the optimisation of this breeding program. Considered were two selection schemes; within-group (WG) and across-groups (AG), and three alternative selection objectives; ALT I- defined based on relative weights (RWs) derived from producers’ preferences, ALT II- based on economic values (EVs) without risk and ALT III- based on risk-rated EVs, at different intensities of buck selection (proportion of bucks selected, P = 0.02 and 0.04) and selection criteria (mass and BLUP). The genetic gains (ΔG) in the breeding-objective traits, aggregate responses (RH), total economic response (TER) and the rate of inbreeding (ΔF) per generation varied depending on the scenarios ALT I, II and III, P and the selection criteria. A selection index considering ALT III (Risk-rated EVs) in derivation of ΔG for individual traits, RH and TER, and ΔF would be appropriate and optimal in both WG and AG selection schemes. However, these responses were higher in the AG scheme compared to the WG selection scheme, and the ΔF more favourable with increase in the number of groups co-operating. Responses under mass selection were also comparable to BLUP with the same rate of inbreeding, restricted to an acceptable level of 0.01. These imply that an AG selection scheme under mass selection would be optimal and logical for implementation in the smallholder low-input goat production systems. However, a minimum of 14 co-operating farmer groups would be required to produce considerable levels of responses and at acceptable levels of inbreeding.