Date Time Science finds simple way to make lamb leaner Scientists based at Rothamsted and the University of Bristol Veterinary School have found a clear link between the weight of lambs early in their life and meat quality – which is good news for consumers, farmers, and the environment. Currently, 35 per cent of lambs going to market have meat that is considered too fatty, but this new study, published in the journal Animal, shows that it’s the lambs which are heaviest at the point of weaning – when they switch from their mother’s milk to grazing – that go on to produce the leanest, most sought-after meat at market.