PMC3905159_01
PMC3905159_02
Incidence of congenital cataracts by year of birth with a confidence interval of 95% (represented by error bars).
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F2
The oldest affected animal was born in 2002 and the incidence varied over time (Figure  2).
Family tree (dam line only). The red dots represent animals with cataracts, the green dots represent animals with no ocular abnormalities and the black dots represent the animals not examined (not in the herd). Data for sires was not available. Animals with cataracts are spread evenly across the diagram, suggesting there is no hereditary component.
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PMC3905159_02_2046-0481-67-2-3.jpg
F3
Examination of the cow line where animals had been examined shows an even spread of cataracts across the herd (Figure  3).