Smallholder dairy intensification in the Kenya highlands is characterised by a shift from free- to semi-zero- or zero-grazing management in response to inter-generational division of landholdings, keeping of smaller herds of dairy breeds, dependency on external feed resources and poor reproductive performance. As other sources of breeding stock are limited, the changes in herd structure and demographic rates in smallholder herds raise concerns as to whether these herds can produce sufficient replacement stock needed to sustain the continuing intensification. A deterministic model was developed to assess the potential for smallholder herds to be self-sustaining and to generate surplus replacement stock for aspiring dairy farmers as management continues to shift from free- to zero-grazing. The base situation reflected the actual proportion of free, semi-zero- and zero-grazing farms and the size, structure and demographic rates of the herds in representative low-, medium- and high- intensive farming systems in the Kenya highlands.

Model estimates at the base situation showed that the replacement stock available in all the three systems were sufficient for maintaining the breeding population with a surplus remaining for aspiring farmers adopting/or shifting from free- to semi-zero- or zero-grazing. However, the number of replacement stock available decreased with the reduction in farms practising free-grazing, because semi-zero- and zero-grazing farms are unable to produce their own replacement stock. A 4% annual decrease in the proportion of free-grazing farms resulted in insufficient replacement stock to maintain the existing herds in high- but not in low- and medium- intensive systems. In free-grazing farms, reducing the rate of cow mortalities and the proportion of replacement stock sold during the rearing period were the most promising interventions to sufficiently produce the needed replacement stock. Prospects for the continued intensification of smallholder dairying in the Kenya highlands thus depend upon the proportion of free-grazing farms maintained within the farming systems. A rational policy would be to promote intensification of smallholder dairying within a stratified dairy sub-sector.