Factors affecting incidence of cancer eye
Breed
The disease occurs in cattle that have areas of unpigmented skin or conjunctiva. Breeds such as Hereford, Poll Hereford and white-faced Friesian are most susceptible, with Hereford crosses being less susceptible than purebreds. Cancer eye is rare in breeds with fully pigmented skin, such as Angus and Santa Gertrudis.
Strain and sire
Susceptibility to the disease varies with strain and sire. The heritability of cancer eye has been estimated as moderate at 0.4.
Pigmentation
Cattle with unpigmented skin around the eyes are more susceptible to cancer eye. Cancers usually start on unpigmented skin, but can then spread to pigmented areas. Eyelid pigment is present at birth and is easily assessed. Eyeball pigment usually takes more than 5 years to develop fully. Pigmentation of the eyelids and pigmentation of the eyeball are highly heritable and appear to be genetically related.
Conformation
It is likely that protruding eyeballs are more susceptible than ‘hooded’ eyes, which are more protected from sunlight.
Age
Older cattle are more prone to cancer eye. The disease is uncommon in cows under 5 years of age. Males and females are equally susceptible, but the cancer is seen less frequently in males because steers are sent for slaughter at an early age, and bulls tend to be culled at an earlier age than cows.
Nutrition
It has been reported that a high level of nutrition and growth rate increases the risk of cancer eye developing.
Anecdotal evidence suggests that iodine deficiency may be associated with an increased risk of cancer eye.
Cancer eye is more common during and after droughts due to longer hours spent grazing in the sun, more sunlight, dust and flies, and because stress lowers immunity.
Pregnancy
Cancer eye often seems to develop or progress more rapidly in the latter half of pregnancy. This may be due to increased stress or the immunosuppression associated with pregnancy.
It may simply be that farmers become more aware of a cancer eye when faced with the decision of whether it is humane to keep an affected cow long enough to calve and raise the calf.
Virus
Papillomavirus has sometimes been isolated from animals with cancer eye, but advanced virological techniques have so far failed to reveal any definite association between papillomavirus and the development of these tumours.
Ultraviolet solar radiation
Increased ultraviolet
(UV) radiation is thought to predispose cattle to cancer eye. Therefore cattle living at low latitudes and high altitudes may be at greater risk, because latitude, altitude and daily hours of sunlight all contribute to the amount of UV radiation.
http://www.dpi.nsw.gov.au/agriculture/livestock/health/specific/cattle/cancer-eye-in-cattle(Läs mer på länken)
Här är bilder på olika typ av ögoncancer (utöver de på länken och som ser lite lika ut det som syns på din kalv):
Early stage of cancer eye on the third eyelid of a cow. (
http://www.vet.k-state.edu/depts/VHC/agpract/articles/Bovine_Cancer_Eye.pdf)
("Bovine ocular squamous cell carcinoma is more commonly referred to in the cattle
industry as “cancer eye”. Squamous cell carcinoma is by far the most common tumor
afflicting the bovine eye, as well as the most frequently diagnosed cancerous tumor in the
bovine. The malignant tendencies of this disease make early recognition critical. This
disease is of extreme economic importance to the cattle producer as it accounts for nearly
12% of carcass condemnation."
(
http://www.nadis.org.uk/bulletins/lymphatic-and-other-tumours-in-cattle.aspx)
Relatively early cancer eye in an ox - it is the white structure at the junction between the sclera and cornea
http://www.uwyo.edu/vetsci/courses/patb_4110/4-8/class_notes.htmOm det är cancer så kommer det växa och sprida sig. Det som det kan blandas ihop med är pinkeye.
Skillnaderna kan du läsa om här:
http://www.facs.sk.ca/welfare_bovine_cf_cancereye.htmKontakta veterinär...
