This presentation on By-products was held for a training program out of Dhaka, at Natore district, involving 60 participants. A by-product is defined as the secondary product derived from a manufacturing process or chemical reaction. It is not the primary product or service being produced. In the context of production, a by-product is the 'output from a joint production process that is minor in quantity and/or net realizable value (NRV) when compared to the main products.