Herencia de la pigmentación ocular en el rodeo Hereford de la Estación Experimental Mario A. Cassinoni

Ocular pigmentation in cattle is related to the presence of melanin pigment in the periocular region. It has photoprotective properties, which is why it has been of interest. The relationship between the degree of ocular pigmentation and the incidence of diseases has been studied. In turn, this characteristic is heritable so, through genetic selection, the degree of pigmentation can be increased, thus reducing the incidence of diseases. The present work, carried out in May 2023, consists of a characterization of the ocular pigmentation of the Hereford breeding herd of the Mario A. Cassinoni Experimental Station, Faculty of Agronomy, University of the Republic. A total of 51 calves born in 2022 and 51 breeding cows were sampled using the scale proposed by the Uruguayan Hereford Breeders Society: from 0 to 100%, with 25% intervals. The calf population had an overall average eye pigmentation, both eyes, of 90%, while that of the dams was 77%. Insemination was performed with 100% pigmented bulls, in order to achieve rapid genetic progress in favor of pigmentation.  Eighty-two percent of the calves sampled had 100% average pigmentation of both eyes, while 61% of the cows had 100% eye pigmentation. The relationship between average eye pigmentation of parents and offspring was studied through a second degree polynomial function: y= -0.0297 x2+6.1369 x - 215, 98, adjusted with an r2 of 0.9534. That is to say that for every 25% increase in the ocular pigmentation of the parents, the offspring increase by 6.13%, stagnating at values close to 80-90%.