Assessment and economic evaluation of sheep reproduction efficiency, challenges and mitigation strategies in Kajiado, Kenya. Effective reproduction of sheep and goats allow pastoralists to produce animals for food production, but also to ensure that they have new young animals each year to replace their old reproductive livestock (mothers). However, different diseases, climate change factors (such as drought) and other challenges can interfere with the capacity of sheep and goats to get pregnant or to deliver a healthy new-born animal. Such negative impacts can have important consequences to pastoralists, who may not have enough offspring to sell and therefore will not generate enough income to sustain their family or livelihood. In extreme cases, they will not be able to replace their reproductive females livestock (mothers), meaning that the size of their herd will decrease, diminishing pastoralists capacity to recover in the future and to survive. For this reason, it is essential to identify those factors that may have a negative or positive impact on reproduction of these animals and to estimate how much of an impact these may have. This can be done with indicators of reproduction performance (e.g. percentage of lambs born death or percentage of ewes lambing per year in a herd) that could provide information to measure changes in reproduction capacity. However, information on these indicators is not available for sheep and goat pastoralists in Kenya, representing a barrier to monitor their situation and to identify problems or successes. The study proposed here aims at generating the basic knowledge on the current level of the reproduction performance indicators for different sheep and goat herds, which could then be used as a reference to identify those pastoralists more at risk of losing their animals and those better performing. This will be done through scanning of the available literature, interview with key experts and interviews with pastoralists. We will test if climate change factors (such as large mobility of animals, poor access to water or fresh pastures or conflicts), socio-economic factors (such as gender of the pastoralist or number of dependents), type of advice channels to pastoralists, presence of infections or existing innovations have the capacity to influence the level of these reproduction indicators. We will also use this knowledge to conduct economic analysis to estimate the financial losses or gains due to changes in the capacity of reproduction of sheep or goats. In addition, we will test for six major diseases that affect sheep and goats' reproduction capacity, but that can also infect and cause illnesses in humans. The results of the study will therefore generate a baseline knowledge to indicate possible areas of interventions or research that could help pastoralists to improve the reproduction capacity of their sheep or goats. The project will represent a multi-disciplinary collaboration between researchers and students of the University of Nairobi, Kenya, and the Royal Veterinary College in the United Kingdom. The Newton Fund builds research and innovation partnerships with developing countries across the world to promote the economic development and social welfare of the partner countries.