The increasing use of functional foods as a non-invasive way to modulate and optimise human immune system function is now beginning to transfer into the production animal and companion animal areas as owners search for alternative ways of maintaining and improving animal health. To date, dietary supplementation trials, primarily carried out in humans and mice have demonstrated the ability of a wide variety of bioactive ingredients such as probiotics and specific ratios of omega-3 and omega-6 fatty acids, to modulate a range of immune functions. However, little data exists for other animal species such as the cat or dog and in particular the working dog. Working dogs are a vital component of the farming sector in New Zealand (NZ), however, many animals are subjected to inadequate nutrition that may compromise their short term performance and exercise recovery, and long term usefulness to the farmer (Jerram, 2005). In this study we assessed the potential benefits of dietary supplementation with a canola oil-based dietary supplement (canola is a rapeseed variant), formulated at Massey University, and manufactured in NZ, to enhance a number of immune parameters in the working dog.