Predicting the fertilising ability of avian semen: the development of an objective colourimetric method for assessing the metabolic activity of fowl spermatozoa.

1. A simple, objective colourimetric technique for estimating the capacity of fowl spermatozoa to reduce a tetrazolium dye is described. 2. The test is shown to give a quantitative measurement of the metabolic activity of spermatozoa, as judged by their rate of oxygen utilisation, and thus of the 'quality' of semen in poultry.