Pituitary abscess in young calves associated with the use of a controlled suckling device.

Abstract

Figure 2. Affected calf with exophthalmos, palpebral paralysis, and ulcerative keratitis. Pituitary abscesses were observed in cattle in Rio Grande do Sul, southern Brazil. On 1 farm, 3 (1.2%) of 250 3month-old crossbred Devon calves were affected. On a second farm, 7 (1.5%) of 470 crossbred Aberdeen Angus 3 Nelore calves were affected. Sucking by all animals was controlled by use of a plastic nose device (Fig. 1) for 7 days. When the nose device was removed, some animals had extensive ulcerative lesions in the nostrils. Six to 7 days after removal of the device, the affected calves had nervous system signs characterized by dysphagia, ataxia, depression, dropped jaw, inability to close the mouth, drooling, and partial mandibular paralysis with difficulty in chewing and swallowing. There was unilateral prolapse of the ocular globe with palpebral paralysis and corneal opacity or hemorrhagic and ulcerative traumatic keratitis and conjunctivitis (Fig. 2). Ptosis of the tongue was also noted. Two animals from the first farm were euthanized 19 and 26 days, respectively, after the onset of clinical signs. The third animal recovered after treatment with a penicillin–streptomycin combination. On the second farm, 5 calves died and 2 survived after similar treatment with the same antibiotics. The surviving animals had moderate neck extension and paralysis. Two calves from the first farm and 1 calf from the second farm were necropsied. The brains were removed and fixed in buffered formalin. In all calves, the dura mater covering the pituitary area was thickened and yellowish and protruded into the cranial cavity, causing compression of cranial nerves. A solitary, well-encapsulated focal abscess above the basisphenoid bone occupied the sella turcica area in all calves. The abscesses were approximately 3 cm in diameter and were filled with a viscous yellow to green liquid or a caseous material and surrounded by a 1–3-mm-wide whitegray capsule. No lesions were observed in the cribriform plate or in the basilar pore of the frontal lobes. In 1 calf, abscesses 1–3 cm in diameter were found in the ventral and medial nasal sinuses. No lesions or signs of sepsis were seen in any other organs. Histologic examination of the grossly affected areas revealed pyogranulomatous inflammation and abscessation. Arcanobacterium pyogenes was isolated by aerobic culture on blood-agar medium. In these calves, mandibular paralysis suggested involvement of the trigeminal nerve, which is responsible for facial sensibility and chewing. Signs of ocular prolapse suggested involvement of the abducent nerve.9 Arcanobacterium pyogenes is the most common isolate in chronic suppurative lesions of the brain, but other bacteria,