Drivers and milk yield impacts of forage crop diversification in Napier grass-based smallholder dairy systems: evidence from Kenya.

Smallholder dairy systems in developing countries are constrained by feed scarcity, low feed quality, and low milk productivity. In Kenya, production mainly relies on Napier grass monocultures, which intensify these challenges. Forage crop diversification offers a pathway to improve feed availability and animal nutrition; however, empirical evidence on its drivers and productivity effects remains limited. The study addresses this gap by examining the drivers of forage crop diversification and its relationship with milk yield using data collected in 2024 from three regions in Kenya: Uasin Gishu, Nyandarua, and Kakamega. A double-hurdle model examined the determinants of decisions and the extent of forage crop diversification, and propensity score matching (PSM) estimated its effect on milk yield, with inverse probability-weighted regression adjustment (IPWRA) used as a robustness check. Results showed that herd size, livestock shed, extension services, and the use of artificial insemination influenced both the decisions and extent of forage crop diversification. Forage crop diversification was associated with higher dry-season milk yield, with PSM estimating a 26.8% increase (ATT = 0.929 L/cow/day, p = 0.003) and IPWRA estimating a 23.5% increase (ATT = 0.814 L/cow/day, p = 0.002). However, the wet season effect was smaller and not confirmed by the doubly robust IPWRA estimator. The findings highlight forage crop diversification as an important strategy for improving milk productivity during the dry season. Extension services should be strengthened to trigger and scale forage crop diversification. Complementary innovations, such as artificial insemination, should also be promoted to further accelerate forage crop diversification and productivity gains.