It is a generalized eye problem in ruminants that includes several pathologies and that generates great economic losses. The most important thing is the difficulty of treating the animals adequately, especially in extensive and bait farms due to management problems.
There are several particular therapeutic and preventive methods, adapted to cattle to minimize handling and achieve optimal cure rates.
Most common causes of conjunctivitis and keratoconjunctivitis
We will look at various types of conjunctivitis and keratoconjunctivitis and how they can significantly affect cattle, especially when it comes to calves.
- Moraxella bovis:
- Neisseria Catarrhalis
- Chlamydia species
- Mycoplasma species
- Specific keratitis:
- Thelazia species
- Secondary conjunctivitis
- Bovine viral diarrhea (BVD)
- Infectious bovine rhinotracheitis (IBR)
Produced by foreign bodies, such as spikes
I diagnose keraconjunctivitis
QIB, a problem that affects cattle
We want to emphasize Infectious Bovine Keratoconjunctivitis or QIB, since it greatly affects the biosecurity of our farms. Some of the most relevant data about this disease are:
- Bovidae of all ages are susceptible: but there is more incidence in young animals
- There is contagion by direct contact and flies
- Its appearance is in summer and autumn
- Variable virulence from one year to another.
- Grazing epizootic (epidemic characteristics)
- It can affect up to 80% of animals.
- Maximum peak of infection at 3-4 weeks after the outbreak
- Perpetuation by animals carrying the bacteria in the conjunctiva, nasal and vaginal cavity
How to identify conjunctivitis and keratoconjunctivitis?
When our cattle present any of these symptoms, it is important that we treat them as soon as possible, as on some occasions they can lead to the loss of the eye.
- Spasm of the eyelids, eyes closed, photophobia.
- Epiphora: watery tears and mucopurulent discharge.
- Conjunctival opacity and vascularization of the cornea.
- If you are in the recovery phase: diffuse opacity, cloudy eye, vision difficulties
- Chronic white scar. Residual scar in 2% of cases and perforation
- Eye with Uveitis
And, therefore, how do you know the diagnosis?
After doing bacterial cultures, with DIRECT IMMUNOFLUORESCENCE from tear secretion, we could speak of a differential diagnosis of Conjunctivitis due to foreign body trauma.
Transmission and risk factors of QIB
The QIB is more frequent in summer when flies, dust and grass abound. It can appear together with the presence of spikes, so we must pay special attention during those times of the year.
Furthermore, under experimental conditions transmission is rare in the absence of flies. Although it is important to know that flies like M. autumnalis remain infected for three days.
How long does QIB immunity last in cattle?
A lasting immunity is produced until the following season. Depending on the strain and infectious agent, a large number of pathogens related to QCIB (Bovine Infectious Conjunctivitis Kerato) have been isolated in Spain
We must bear in mind that, in reinfections, the clinical signs are minimal and there is an increase and duration of the degree of immunity. It also helps that the antibodies are contained in the tear and prevent the adhesion of the bacteria (fimbriae) to the cornea.
The problem is that there are no registered vaccines in Europe, apart from the antigenic diversity between Moraxella strains (common pathogen) and that there are many other bacterial infectious agents.
- subconjunctival infiltration
- Treatment for Infectious Bovine Keratoconjunctivitis
- Treatment can be topical, systemic, or subconjunctival.
- Topical treatment
Mórasela bovis, it is susceptible to most antibiotics. The problem is to achieve sufficient levels of antibiotic in tears and serum to achieve a complete cure, which will last between 7 -15 days.
Next, we show you the most frequently used antibiotics and their topical regimen, which is impractical in most diseases in cattle due to their handling in feedlots:
Oxytetracycline, gentamicin and a combination of neomycin-polymyxin B and bacitracin are effective but the application is 3 times / day for 3-7 days.
Benzathine cloxacillin in mineral oil requires less frequency of administration and two applications every 72 hours are effective. 250-375 mg / ml.
Porcine benzylpenicillin and delayed-acting dihydrostreptomycin effective for 72 hours.
The use of treatments Topical treatment in cattle as the only therapy is not very effective, or only in the initial stages of the disease.
It can be used alone or in combination with other treatments, it is necessary to explore the eye to rule out the presence of spikes or other foreign bodies, today we use long-lasting antibiotics with tear elimination registered for the treatment of infectious kerato conjunctivitis, such as Tulatomycin .
Therapy of choice, alone or combined with systemic treatment, for the majority of keratoconjunctivitis that affects cattle. Some of the characteristics that define this method are:
- Easy application.
- Longer effects than topicals
- Drug combination
- Single application effective in most cases.
- If done on time, cure rates are very high, close to 95%.
- It is essential to do a good previous examination of the eye, to rule out the presence of foreign bodies.
- Phases of subconjunctival infiltration
- Sedation and immobilization of the animal
- It depends on the management system: Drawer of cures or sleeve
- Local anesthesia: double anesthetic eye drops
- Inoculation of the drug:
- Volume less than 1 ml (0.5-1)
- 25G x 16mm needles.
We must emphasize that irritants should not be used, do it only with those that have been tested with delayed action. Also that it is performed only in the bulbar conjunctiva and that it is not very effective in the eyelid. In addition, we usually use antibiotics such as Tulathromycin alone or in combination with methylprepnisolone, with therapeutic effects greater than 10 days.