Kitten Within the first 2 days after birth, kittens acquire passive immunity from their mother’s milk. Milk within the first few days of parturition is called colostrum, and contains high concentrations of immunoglobulins. These include immunoglobulin A and immunoglobulin G which cross the intestinal barrier of the neonate. The immunoglobulins and growth factors found in the colostrum begin to establish and strengthen the weak immune system of the offspring. Kittens are able to chew solid food around 5–6 weeks after birth, and it is recommended that 30% of their diet should consist of solid food at this time. The kitten remains
Colostrum lysozyme, lactoperoxidase, complement, and proline-rich polypeptides (PRP). A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well, including interleukins, tumor necrosis factor, chemokines, and others. Colostrum also contains a number of growth factors, such as insulin-like growth factors I (IGF-1), and II, transforming growth factors alpha, beta 1 and beta 2, fibroblast growth factors, epidermal growth factor, granulocyte-macrophage-stimulating growth factor, platelet-derived growth factor, vascular endothelial growth factor, and colony-stimulating factor-1. Notably in humans a lack of colostrum production is linked to a mutation in the ABCC11 gene that occurs