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Any sign of a sore eye in cattle, and farmers are quick to diagnose a case of pinkeye. This term is often incorrectly used, leading to incorrect treatment. There are a variety of eye conditions that can affect cattle, and as eye health is a delicate matter, it is important to get the correct diagnosis.
Recently, Offaly beef farmer James Ward learned the importance of a correct diagnosis as his herd was hit hard with eye disease. The problem began when one animal's eyes started weeping and became sore looking. This was followed rapidly by three more animals suffering from the same symptoms. James treated the infected bulls with a general antibiotic and sent them out to grass, as he thought that this would prevent further spread of the disease.
Rapid infection
It was too late - the infection had taken hold in the herd and within a few days a further 26 animals started to display symptoms. At first, the animal's eyes had a watery discharge, which quickly developed into thick white-yellow pus. The eyes of the cattle then started to swell and redden (this is due to the inflammation of the inner lining of the eye).
Diagnosis
Initially James had suspected pinkeye and was told by others that it was silage eye, both of which were incorrect. The local vet diagnosed it as conjunctivitis. The type, however, was not the common pinkeye (infectious bovine keratoconjunctivitis or IBK) - it was thought to be infectious bovine rhinotracheitis (IBR). The main distinguishing factor between the two forms of conjunctivitis is the presence of ulcers on the eye that is seen with pinkeye.
Although IBR is most commonly associated with nasal and upper respiratory issues, it can manifest itself in a number of ways. This can include the symptoms mentioned above as well as inflammation inside the nose, general dullness and a reduced appetite, all of which the animals did display on closer inspection.
"The vet said the sunny weather made it worse," James noted. Exposure to ultraviolet (UV) rays from the sun accelerates the incidence of eye conditions. This is why they are more prevalent in the summer.
Trying to catch 30 bulls with a cattle tongs and get a ointment into their eye isn't light work
The infected animals were treated with oxytetracycline (a long-acting intramuscular antibiotic), and received ointment into the eye. Topical treatment of the infection with mastitis tubes is an effective but labour-intensive practice, said James: "Trying to catch 30 bulls with a cattle tongs and get a ointment into their eye isn't light work."
The treatment regime was repeated again after 48 hours and it was successful, with only two animals needing a third treatment. "It cleared up quick enough, but it still came and went with a cost." Not only are there veterinary costs associated with the treatment of the cattle, but there is also the underlying cost of reduced growth rates.
Prevention
"It wasn't worth the risk in the end," James said as he reflected on his choice not to vaccinate for IBR this year. "I was so busy when I bought the animals in that it was just something I decided wasn't a priority." In other years, James had vaccinated against IBR and never had this issue.
IBR can have serious detrimental effects on infected animals and vaccination may be a cheaper option in the long run. According to Animal Health Ireland, over 70% of Irish farms have evidence of infection: it is a very real issue.
Eye Infection
There are three common causes of eye infection in cattle: pinkeye, silage eye and IBR. Pinkeye (IBK), which is caused by Moraxella bovis bacteria, is the most common form of conjunctivitis at this time of year, due to fly spread. As mentioned above, it is characterised by ulcers on the eye, but early signs include excessive tearing, squinting and blinking.
Silage eye (bovine iritis) is seen in animals fed silage or haylage and so is not as common during the summer months. Initial signs also include the eye watering but as the infection progresses the eye becomes a blue/white colour.
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