https://en.wikipedia.org/wiki/John_LeKay

LeKay also stated that Hirst had got other ideas for his work from a “marked-up duplicate copy” of a Carolina Biological Supply Company catalogue, which he had given him. One example was Hirst's work Mother and Child, Divided – a cow and calf cut in half and placed in formaldehyde: "You have no idea how much he got from this catalogue. The Cow Divided is on page 647 – it is a model of a cow divided down the centre, like his piece."