Night and day photographic recording of drinking habits of individual cows

Abstract

Water intake of cows at a water trough is measured by a water-meter. Every half-gallon rotation of the water-meter completes an electrical circuit which switches on an ultra-violet tube for 1 sec. The tube, in turn, switches on a movie camera which takes one photograph. The time at which each photograph is taken is plotted on an event recorder. The cows are identified by plates with matt black numbers painted on a blue fluorescent background