In this paper we describe a novel solution for delay sensitive one-to-many content distribution in P2P networks based on cooperative m-ary trees. Our scheme maximizes the overall throughput while minimizing endto-end delay by exploiting the full upload capacities of the participating peers and their proximity relationship. Our delivery scheme is based on cooperation between the source, the content-requesting peers and the helper peers. In our solution, the source splits the content into several blocks and feeds them into multiple m-ary trees rooted at the source. Every peer contributes its upload capacity by being a forwarding peer in at least one of the m-ary trees. Our performance evaluation shows that our proposal achieves similar throughput as the best known solution in the literature (Mutualcast) while at the same time reducing content delivery delay.