The present invention provides transgenic, non-human animals that include a transgene that encodes a fatty acid desaturase, e.g., stearoyl-CoA desaturase, and methods for producing such animals. The invention further provides an expression cassette that includes a coding region for a desaturase such as stearoyl-CoA desaturase, operably linked to a heterologous, tissue-specific animal cell promoter. The invention further provides methods of producing a food product, such as milk, meat, or eggs, using a subject transgenic non-human animal, as well as food products harvested from a subject transgenic non-human animal.