Based on anecdotal evidence that shearing lambs boosts their growth rates, The New Zealand Merino Company (NZM) commissioned AgResearch to provide a review of the existing scientific literature.
Download the literature review Shearing of Lambs here.
The literature review found that, while there are many other reasons for shearing lambs (e.g. prevention of flystrike), there is no guaranteed positive effect on growth rates achieved by shearing.
The ability of lambs to grow faster depends on the availability of feed – while cool temperatures may stimulate feed intake (and therefore stimulate growth), lambs will not grow more quickly if insufficient feed is available. Further, both hot and cold temperatures can depress feed intake (and growth), so the availability of shade and shelter is also essential for good lamb growth rates.