Simple SummaryAnimal genetic resources are a vital component of our genetic, economic, and cultural heritage, playing a crucial role in the economy, food production, regional identity, and ecosystem services. Local breeds, including donkey breeds that have lost their primary function, are often existentially endangered and require reintegration into alternative economic utilization programs. Donkey meat and particularly donkey milk have attracted consumer interest due to their nutritional and functional value. This research focused on the production and quality indicators of donkey meat and milk, aiming to establish and optimize sustainable economic utilization programs for donkeys. This approach represents the most effective strategy for long-term in situ conservation programs of endangered local donkey breeds in their natural habitats. The research outcomes provide a solid basis for the development of similar programs for other local donkey breeds.AbstractThe problem of the erosion of animal genetic resources is evident in certain local donkey breeds, and their long-term sustainability can be achieved by economically repositioning them. To develop alternative and sustainable commercial programs, the meat and milk production characteristics of Istrian donkey and Littoral Dinaric donkey breeds were investigated. The meat production characteristics were examined in mature males, whose carcasses were dissected, and meat composition was determined using NIT spectrophotometry and gas chromatography. Milk yield and milk composition were determined in jennies in second or subsequent lactations by measuring milk volume and using infrared spectrometry and gas chromatography. Compared to the Littoral Dinaric donkey, the Istrian donkey has a higher carcass weight and dressing percentage (p< 0.001). The share of boneless meat in relation to live weight was 28.27% in the Istrian donkey and 26.18% in the Littoral Dinaric donkey. The absolute masses of primal cuts of meat in E, I, and II classes were significantly greater in Istrian donkeys than in Littoral Dinaric donkeys (p< 0.01), although the differences in the proportions of primal cuts were not significant. The breed did not have a significant impact on the color, pH, or meat composition. A significant influence of breed on milk yield, lactose, protein, and the fat content of milk was observed (p< 0.01). A significant influence of breed on the ratio of n-6/n-3 PUFA fatty acids in donkey milk was observed (p= 0.002). The values of the atherogenic and thrombogenic indexes were favorable, considering potential beneficial effects of donkey milk and meat on consumer health. The findings of this research suggest that local donkey breeds hold significant potential for meat and milk production, focusing on the uniqueness and quality of their products rather than the quantity of meat and milk they can produce.