Photosensitisation and other summer skin conditions cause significant welfare problems in cattle with access to photosensitising plants or experiencing liver disease.
Photosensitisation causes severe welfare suffering: the skin lesions on pale or white areas resemble extreme sunburn and are intensely painful and pruritic. Cattle with photosensitisation show obvious distress, seek shade aggressively, rub affected areas, and may refuse to graze during daylight hours. Secondary photosensitisation indicates underlying liver disease that itself impairs welfare. The welfare emergency of photosensitisation requires immediate removal of affected animals from sunlight and identification and removal of the photosensitising source. Skin healing takes weeks and requires ongoing welfare monitoring. The condition is largely preventable through good pasture management that avoids accumulation of photosensitising plants.