Freeze-dried Lactobacillus spp. improved average daily liveweight gain and reduced methane intensity in growing lambs

Direct fed microbials (DFM) are natural and safe enteric methane mitigants for ruminant livestock systems. While previous studies have demonstrated the effect of Lactobacillus spp. on methane mitigation, challenges remain in effectively delivering DFM in extensive grazing systems. The objective of this experiment was to evaluate the effect of controlled feeding of a freeze-dried, DFM comprising Lactobacillus spp. (providing 1 × 10¹¹ CFU kg^-1 fresh grain) for 70 days to growing lambs on methane emissions and intensity, liveweight gain, and carcass characteristics.

The average daily liveweight gain (ADG) was 24% greater (P = 0.009) and the total body condition score change from the start to the end of the experiment was 28% greater (P = 0.019) for lambs supplemented with freeze-dried Lactobacillus spp. (FDL) compared to the control lambs (CON). Average methane production (g methane per day) tended to be lower (P = 0.095) and methane intensity (g methane g^-1 ADG) was 30% lower (P = 0.008) in FDL lambs compared to CON lambs. While carcass characteristics were not statistically different, the FDL lambs showed a tendency (P = 0.088) for a greater hot standard carcass weight.

This experiment showed that FDL supplementation to growing lambs on a hay-based diet improved liveweight gain and lowered methane intensity over a 70-day feeding period. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.