In vivo mechanical and in vitro electromagnetic side-effects of a ruminal transponder in cattle.

This work was undertaken to assess the long-term impacts of a ruminal transponder, used for electronic identification, on ruminal motility and on health and performance of cattle, as well as to study the electromagnetic effects on ruminal bacteria in vitro. A passive transponder (51.4 g, 67 x 17 mm) was delivered into the forestomachs of 8 calves, 32 bulls, 10 heifers, and 40 dairy cows. Final readability was 87.5% in calves, 96.9% in bulls, 90% in heifers, and 100% in cows at 481, 360, 650, and 601 d, respectively, after transponder administration. The transponder did not affect production or reproduction of cows over a 2-yr period, or performance of bulls, or mortality compared with control animals. Chewing movements per bolus were lower (P <0.01) in treated animals than in controls (49.6 vs. 52.2, 51.2 vs. 63.6, and 57.0 vs. 59.7 for bulls, heifers, and cows, respectively). Regurgitation frequency (number of boluses/10 min) tended to be greater in treated cattle: 12.4 vs. 11.3 (P = 0.07), 11.3 vs. 10.6, and 11.3 vs. 10.7 (P = 0.08) for bulls, heifers, and cows, respectively. Rumination patterns of calves fitted with transponders within the first weeks of life were similar to controls. During the experiment, 43 treated animals (8 calves, 29 bulls, and 6 cows) were slaughtered. Thirty transponders were localized in the reticulum (3 calves, 24 bulls, and 3 cows), 11 in the rumen (4 calves, 4 bulls, and 3 cows), and 2 were not recovered (1 calf and 1 bull). Within the calves, 57% of the boluses were found in the rumen. In 8 reticula (2 calves and 6 bulls) and 1 rumen (1 cow), an impression left by physical contact of the transponder was observed, although histological examination did not reveal specific lesions in the mucosa of the dystrophic areas. In strained, whole ruminal contents incubated in vitro, pH values were lower after 24 and 48 h (P <0.001) of continuous exposure to an electromagnetic field induced by the transponder-reading system. After 48 h of incubation, total bacterial numbers and NH3-N concentration were greater (P <0.001) in exposed flasks than in controls. These data indicate that the transponder may alter, via mechanical action, the reticuloruminal mucosa and rumination patterns. Furthermore, the transponder may increase, via its electromagnetic action, the growth rate and metabolic activity of ruminal bacteria.

Naturally occurring nephroblastomas in light meat broilers.

Twenty-seven cases of nephroblastoma were observed in 54 culled light meat broilers during a 1-year period. The tumours were generally unilateral and varied in size. Metastases were not observed. Histopathological studies showed epithelial and mesenchymal structures at different stages of development. Ultramicroscopy and immunohistochemistry findings revealed viral particles in intercellular spaces and in the lumen of the tubules not morphologically unlike avian leukosis/sarcoma viruses.

Enzootic intranasal tumour of goats in Italy.

An outbreak of enzootic intranasal tumour (EIT) in a goat herd in Central Italy is described. From October 1990 to September 1992 41 tumors were diagnosed in goats ranging in age from 6 months to 6 years and of both the Alpine and Saanen breeds. Clinically the affected goats showed nasal discharge, facial swelling, sneezing and snoring respiration and weight loss. Post-mortem examinations revealed uni- or bilateral tumours of the olfactory mucous membrane. The neoplasms were classified as low grade adenocarcinomas. Ultrastructurally, retrovirus-like particles were observed in 10/10 tumours examined. Epidemiological and ultrastructural findings strongly suggest a viral aetiology for intranasal enzootic adenocarcinoma in the goats examined.

Eosinophilia, granuloma formation, migratory behaviour of second stage larvae in murine Toxocara canis infection. Effect of the inoculum size.

Experimental infection of mice with Toxocara canis provides one of the best models for immunological and pathological studies of the visceral larva migrans syndrome. Blood eosinophilia, the migratory behaviour of second stage larvae and granuloma formation were studied in Swiss mice infected with Toxocara canis. Eosinophilia, spleen, liver and lung indexes were followed during a primary infection with different inoculum sizes (500 and 1500 eggs) while the migratory behaviour of larvae was studied in a primary infection with 1500 eggs over a period of 4 months. In mice infected with three challenges of 1500 eggs in order to elicit a strong inflammatory reaction in the tissues, a histopathological study was carried out. The results showed that eosinophilia, spleen and lung indexes (but not the liver index) were influenced by the parasite inoculum size. The migratory behaviour study showed that larval recovery was maximal three days post-infection, from the liver and lungs; the peak recovery from the skeletal muscles and brain being on days 15 and 30 post-infection, respectively. The histopathological study revealed the formation of granulomas in all the tissues examined (liver, lungs, kidneys, spleen, lymph nodes, myocardium etc.) but not in nervous tissue or in the retina of the eye. Granulomas in the lungs were larger than those found in the liver. The implications of these results are discussed considering host-parasite inter-relations.

[An electron microscopic study of liver cells in a case of chronic hepatitis HBsAg positive (author's transl)]. / Reperti al microscopio elettronico in un caso di epatite cronica HBsAg positivo.

Electron microscopic examination on liver tissues from one patient with chronic active hepatitis HBsAg positive is described. Spherical, virus-like particles of 220-230 A size were observed in the nucleus; in the cytoplasm only nonspecific changes were present.