Subject. A stud Hereford bull valued at 50 guineas, which had died during the night, without showing any symptoms of illness.
History. Before proceeding with a post mortem examination, many questions were asked, in order to obtain any useful information as to the past history of the animal, and the following facts were elicited: The bull had been introduced into the owner's herd on 15th November, 1946, coming from a stud in the Wellington district, and was then 18 months old. Since arriving on the property he had been depastured on sub-clover, rye and natural grasses. When the bull was led from the Blayney trucking yards to the property—a distance of about seven miles with two moderately steep hills—he showed some respiratory distress which was attributed to the train journey. Since then he had never been hurried or driven, and nothing similar was seen again. He had never been ill or drenched since his arrival on the property. The owner stated that the bull was always much quieter than one would expect from such an animal, but that he had never been "dopey."
Post Morten Examination. On examination, the carcase was seen to be that of a well-developed Hereford bull, in good condition. Rigor mortis was just passing from the forelegs, but was still present in the hind legs. The abdomen was not unduly distended with gas. There were no visible external lesions. A slight nasal discharge was apparent, consisting of clear fluid, slightly mucoid in consistency. The conjunctivae were intensely injected, oral and nasal mucous membranes were cyanotic, and the rectum was slightly everted, probably due to abdominal pressure. There were no signs of struggling having preceded death.
On opening the abdominal cavity, the rumen was punctured to permit the escape of gas, which had very little odour. The rumen was full of feed which had undergone very little fermentation. The other stomachs appeared normal except that the contents of the omasum seemed a little drier than normal. Liver and intestines appeared normal. The kidneys presented a mottled appearance and the cortex was dark and congested. The capsule of the spleen presented an uneven surface, there being foci of thickening throughout. On section there appeared to be a slight thickening of the interstitial tissue. All lymph glands appeared normal.
The thoracic cavity then was opened and was found to contain about 700 mls. of dirty brown fluid. Adhesions were present between both lungs and the chest walls. The pericardial sac was found to contain about 100 mls. of brown fluid. The heart was normal in size and consistency, but presented extensive sub-epicardial petechiae. On section, the valves were apparently normal, but there were extensive sub-endocardial petechiae. The myocardium did not appear to be involved.
Attention was then turned to the lungs. Both showed extensive consolidation over the upper portions, about one-third of each being involved. There was some emphysema along the ventral borders. On section, both red and grey hepatisation were seen, the latter predominating. Interstitial tissue showed both emphysema and some oedema. There was no gangrene present. The interesting feature was the presence, in the bronchi and bronchioles, of masses of fine chaff particles, greatly swollen by absorption of moisture, and forming casts of those tubes. These casts were surrounded by thin fibrous capsules, obviously a protective effort on the part of the body. The bronchial mucous membrane showed inflammatory changes and mucoid secretion was present in quantity. There was every indication that these foreign bodies had been present for some time. In view of these findings, a diagnosis of chronic foreign body pneumonia was made.
Discussion. The stud of origin of this bull is situated in an area which had been very dry during 1946, and it seems reasonable to assume that the bull had been hand-fed on chaff having a fairly high dust content; and during this feeding he had inhaled the particles found in the lungs. The history of the bull, after arrival in the Blayney area, would seem to preclude the trouble having occurred there, as would the fine capsule laid down around the casts, which would seem to denote a longer duration of the trouble. If this assumption is correct, the case presents a possible danger which might always accompany hand-feeding with undampened chaff, and it may explain also otherwise inexplicable deaths which have occurred during hand-feeding.
Specimens of lung, kidney, spleen and casts were submitted to Glenfield for examination, and, following this, the diagnosis already made was confirmed. No comment was offered regarding the postulated theory as to the cause of the condition.