Effect of Suckling Management and Ewe Concentrate Level on Methane-Related Carbon Footprint of Lamb Meat in Sardinian Dairy Sheep Farming

SIMPLE SUMMARY: Suckling lamb meat is the secondary product of the Mediterranean traditional dairy sheep industry. Similar to the main production, i.e., milk, lamb meat contributes to the emission of greenhouse gases (GHG), whose main portion is represented by enteric methane produced by the lamb dams. Such an emission, although limited in quantitative terms, should be mitigated by appropriate feeding or compensation techniques. Among all the sources of variation of meat lamb emissions, sex of the lamb and type of lambing (single or twins) showed the largest effect. ABSTRACT: The aim of this study was to estimate the methane-linked carbon footprint (CF) of the suckling lamb meat of Mediterranean dairy sheep. Ninety-six Sarda dairy ewes, divided into four groups of 24 animals each, were assigned to 2 × 2 factorial design. The experiment included the suckling lamb feeding system: traditional (TS), in which lambs followed their mothers on pasture during grazing time, vs. separated (SS), in which lambs remained indoors, separated from their mothers during the grazing time. Each group was divided into high (HS) and low (LS) supplemented ewes (600 g/d vs. 200 g/d of concentrate). The estimated CH(4) emission of the ewes, calculated per kg of body weight (BW) gain of the lamb during the suckling period, was then converted to CO(2)eq with multiplying factor of 25. The TS lambs showed lower methane-linked emissions than SS ones (p < 0.05). The sex of lambs affected their methane-linked CF, with males having lower (p < 0.05) values than females. Twins displayed much lower methane-linked CF than singles (4.56 vs. 7.30 kg of CO(2)eq per kg of BW gained), whereas the level of supplementation did not affect greenhouse gases (GHG) emission. Interaction displayed lower and not-different GHG emissions for both indoor- and outdoor-reared twins. In conclusion, the methane-linked CF of the suckling lamb meat can be reduced by maintaining the traditional lamb rearing system and by improving flock prolificacy.