the present invention relates generally to a method for the treatment and / or prophylaxis of conditions arising from or otherwise associated with aberrations in hormone signalling . the present invention further provides an animal model useful for screening for agents capable of agonizing or antagonizing hormone signalling . more particularly , the present invention contemplates a method for the treatment and / or prophylaxis of conditions arising from or otherwise associated with aberrations in growth hormone signalling . the present invention further comprises a genetically modified animal . more particularly , the animals are genetically modified such that they have altered growth hormone signalling . the genetically modified animals of the present invention range from laboratory animals useful inter alia for animal models for studying hormone regulation and for the development of therapeutic protocols predicated , in part , on modulating hormone signalling to livestock animals . the latter may be manipulated for improved food production .