PHOTOPIGMENT BASIS FOR DICHROMATIC COLOR-VISION IN COWS, GOATS, AND SHEEP

Electroretinogram (ERG) flicker photometry was used to measure the spe ctral properties of cones in three common ungulates-cattle (Bos taurus ), goats (Capra hircus), and sheep (Ovis aries). Two cone mechanisms w ere identified in each species. The location of peak sensitivity of an S-cone mechanism varied from about 444 to 455 nm for the three specie s; analogous values for an M/L-cone were tightly clumped at about 552- 555 nm. Each of these three species has the requisite photopigment bas is for dichromatic color vision and they are, thus, similar to other u ngulates examined earlier.