In semi-arid tropical regions, production performances of cattle are mainly affected by seasonal variation in forage availability and quality. Especially in sub-Saharan African (SSA), forage can be so scarce during a long dry season that cattle may face severe feed shortages, leading to low production and live weight losses. In a first step, this PhD thesis investigated the effects of low feed intake and its interrelationship with diet quality on liquid and solid digesta passage through the gastrointestinal tract (GIT), diet digestibility, rumen microbial protein synthesis, enteric methane (CH4) formation and manure quality in Kenyan Boran cattle. In a second step, potential diet improvement with locally-available supplement feeds and its effect on the mentioned variables was investigated.