Milk production is of fundamental and practical importance in all farm mammals. With dairy cattle in particular extensive study of milk secretion has resulted in raising the milking performance in all domestic breeds. This has mainly been achieved by the adoption of improved breeding and feeding practices.

Milk production is of fundamental and practical importance to the sheep industry. Reports indicate considerable differences in milking ability between ewes of different breeds as well as between ewes of the same breed.Milking capacity of ewes is dependent on both nutritional and hereditary factors, probably the nutritional factor being the more important. Under commercial farming conditions milk yield might affect not only the growth rates of ‘fat’ lambs and the quality of their carcases, but eventually also the constitution of the ewe lambs retained in the flocks for breeding purposes. It therefore appeared that milking ability of Romney ewes in New Zealand would be a matter worthy of investigation.