What is pinkeye?
Pinkeye is the common name for a corneal ulcer in cattle. The main cause of pinkeye is the bacteria Moraxella bovis, which is present in nasal and eye secretions of clinically infected and carrier animals. It can spread between animals via flies or through close contact. Pinkeye typically occurs in young stock from November through to March.
How does pinkeye occur?
Moraxella bovis has lots of little hairlike projections called pili which attach to the surface of the eye. It then produces toxins which erode the cornea and cause ulceration and severe inflammation. Initial damage to the eye, such as dust and UV light predisposes to disease. Trauma from grass seeds also increases the risk of pinkeye: some farmers report feeding out hay in round feeders increases pinkeye, likely due to the increased risk of eye abrasions when feeding this way.
Early signs of pinkeye are wateriness followed by cloudiness of the cornea in one or both eyes. With severe ulcers, the inflammation continues, and the eye will look yellow and red. Some animals will end up with a permanent white scar on their cornea and if the eye ruptures they may be left permanently blind. There can also be associated poor growth in affected animals.
How can I prevent pinkeye from occurring?
Vaccinating with Piliguard helps combat pinkeye over the summer months. It reduces the incidence and severity of pinkeye infections, thereby reducing production losses and treatment costs. To be effective, vaccination must occur at least 3–6 weeks prior to the onset of the pinkeye season i.e., now! We recommend vaccination of all calves (over 4 weeks of age) and replacement heifers. If it is a prolonged pinkeye season, then a booster dose may be administered 5 months following the initial vaccination.
Other management strategies should also be put in place to help reduce the risk of pinkeye:
- Control fly numbers with insecticides such as Easy-Dose or Arrest.
- Treat and isolate affected animals promptly.
- Minimise yarding to reduce the spread through close contact.
- If yarding is needed, avoid doing it in dusty or windy conditions.
- Reduce stocking rates and avoid grazing on long dry pastures
- Maintain nutrition to maximise calf and heifer immune function
How do I treat pinkeye?
If you see an animal with symptoms of pinkeye such as shut eyelids, wateriness, or a lesion on the eye surface, then it is recommended they are restrained and examined. Look for grass seeds using clean, gloved fingers to evert the eyelids (if a grass seed is found in numerous animals then management changes should be considered which may involve pasture, hay, and feeding methods).
- Use a topical eye antibiotic such as Cloxacillin or Opticlox Eye Ointment. These are formulated to help the antibiotic to remain at active levels at the eyes surface for 48 hours. To apply, evert the lower eyelid and place a line of ointment between the eye surface and the lower eyelid, about ¼ to ½ of a tube. Repeat in 48 hours if necessary. If only one eye is affected, treat the unaffected eye at the same time (but apply the antibiotic to it first!).
- Eye patches are beneficial, as they minimise the spread of the disease as well as providing some relief for affected animals as affected eyes are very sensitive to dust, flies, and sunlight.
- If a large proportion of animals are affected, then they can be treated using a long acting intramuscular or subcutaneous antibiotic which may be much easier from a management perspective.
If you have any questions regarding pinkeye, then please contact Farm Services 1300 838 700 for a chat with one of our veterinarians.
*Halloween is coming up. Make up a batch of these delicious Pinkeye Treats for the school lunchboxes
Blitz together 1 packet of Marie biscuits, a tin of sweetened condensed milk and the grated rind of a lemon. Roll into balls and cool in the fridge. Cut a packet of red glacé cherries into halves. Melt 225g of white cooking chocolate (but save a few bits unmelted for later). Dip eyeballs in the chocolate and top with halved cherry irises and currant pupils. Leave to set in fridge. Melt the last of the white chocolate, add red food colouring and mix. Draw on blood vessels with a toothpick. Bon appétit!