Expert: Karin - 8/17/2011

Question
Where do cattle get pink eye.  I understand if one has it, it is contagious.  Can they go permanently blind.

Answer
Hi Nancy,

Pink eye can come from several forms and many different pathogens, such as dusty feed, blowing sand or dirt, plant pollens, wed seeds, virus infection, fly bites, tall grass scraping the eye as the animal grazes, or UV rays in sunlight combined with a face-fly population, but the most common infectious agent for this disease is from a bacterium called Moraxella bovis. Flies, beside face-flies including horn flies, house flies, stable flies can play a minor role to a pink eye outbreak, in physically carrying the pink eye bacterium from one animal to another, but face flies are the number one and worse culprits for spreading pink-eye infection in your herd. And yes, it is infectious: Once one or two animals have it, it'll spread like wildfire through the herd.

As far as blindness is concerned, this depends on how serious the disease is. Quite often I believe that if pink eye is not treated right away, or if the infection is so serious that pus and/or an ulcer builds up in the eye enough that the eyeball will rupture animals can and will go permanently blind. But rupture is rare, as is permanent blindness.  In most cases, once treated the infection will clear up.

But the thing is to make sure it is actually pink-eye and not something else. IBR (Infectious Bovine Rhinotracheitis) can cause the eyes to get inflamed and watering and develop lesions that look very similar to infectious pinkeye.  However these lesions start from the outside and go inward, whereas pink eye opacity starts from the center and works its way outwards.  IBR can also start anytime of the year, but pink eye is prevalent during fly-season (which is July to August, around this time of year), when the sunlight is most intense, grass is tall, and weather is dry.

I hope that answers your questions. :)

-Karin