Animal welfare provision by dairy farmers has implications that go well beyond the individual dairy farm. In this study, we assess dairy farmers' willingness to pay to support a policy aimed at improving calf welfare and link this to altruism. We conceptualise the farmer's decision into private reasons, and motivations to improve animal welfare on their own farm or eliminate bad practices elsewhere. Our data comes from a survey with over 400 Irish dairy farmers that included an experimental component. Specifically, we used a contingent valuation referendum method to elicit farmers' willingness to pay. We measured altruism with a financially incentivised social value orientation scale. Our findings indicate that most farmers are supportive of a policy scheme to improve animal welfare, and altruism is positively associated with higher willingness to pay. Specifically, our findings suggest that altruists are willing to pay €429 per annum, while individualistically minded farmers are willing to pay €220 per annum to support the new initiative. Our findings have important policy implications as we show that the majority of farmers are willing to financially support the implementation of a policy that can help to prevent public bads.