The aim was to establish a representative model of the bovine mammary gland in order to underpin applied research in mammary gland development and lactation. Cell culture insert methodology is currently being utilized in place of a three dimensional culture system, the shortcomings of which have been discussed elsewhere (McConochie et al., 2004). Cell culture insert methodology offers a promising alternative, with the potential to recreate in vitro a polarised epithelial layer. Previously it has been shown that on collagen I coated inserts, ABERMEC are able to synthesise and secrete mammary specific proteins in the apparent absence of the key mediators laminin and prolactin. It was hypothesised that undefined factors in serum were a possible cause for this phenomenon.