Induction of bovine polioencephalomalacia with a feeding system based on molasses and urea.

Polioencephalomalacia (PEM), a disease first described in the United States and related to intensive beef production, appeared in Cuba coincident with the use of a new, molasses-urea-based diet to fatten bulls. Because the only experimental means so far of reproducing PEM has been with amprolium, a structural analog of thiamin, the present study attempted to induce the disease using the molasses-urea-based diet. Six Holstein bulls (200-300 kg) were studied during consumption of three successive diets: 1) commercial molasses-urea-restricted forage diet of Cuban feedlots, 2) a period in which forage was gradually withdrawn and 3) a forage-free diet composed only of molasses, urea and fish meal. PEM was reproduced in this way. At ten-day intervals, blood concentrations of glucose, lactate, pyruvate and urea were measured, as well as when clinical signs of PEM appeared. The signs, clinical course and lesions of the experimentally induced disease were comparable to those of field cases. The biochemical results suggested a block in pyruvate oxidation as in PEM elsewhere in the world. No evidence existed of urea intoxication. In addition, brain and liver concentration of total thiamin from field cases and normal animals were found to be similar.     

Neutralizing activity in the gastrointestinal contents of piglets vaccinated with a live or formaldehyde-inactivated porcine enterovirus.

Neutralizing activity against porcine enterovirus strain T80 was demonstrated in the gastrointestinal contents of piglets given live T80 virus orally or parenterally, but little or no neutralizing activity was detected in the gastrointestinal contents of piglets given formaldehyde-inactivated virus by either route. The gastrointestinal neutralizing response was first detected 14 days after oral dosing, coincidentally with a fall in the titre and distribution of virus. The neutralizing response was highest at 23 days, and dropped markedly by 36 days, whereas no response was detected until 36 days in piglets which received live virus by the intramuscular route. Virus generally appeared earlier, was more widely distributed, and reached higher titres in the gastrointestinal tract of piglets which received live virus orally than in those which received the same preparation by the intramuscular route. The highest serum neutralizing response occurred in the piglets given live virus orally. The serum response in the piglets which received live virus intramuscularly appeared earlier and was biphasic. The serum response in the piglets receiving formaldehyde-inactivated virus appeared as early as the response to live virus given by the same route, but remained relatively low throughout the period of observation.     

Parasites of Dogs from Indian Settlements in Northwestern Canada: A Survey with Public Health Implications

A total of 959 faecal samples were obtained from dogs in 12 native communities in Northern Saskatchewan, Central and Northern Alberta and the Northwest Territories. All samples were examined using a flotation technique. Samples from an area of endemic human amoebic infections were also examined by a formol-ether sedimentation method. Eighteen necropsies were performed.

Entamoeba histolytica cysts were recovered from dog faeces at Loon Lake, Saskatchewan.

Toxocara canis had low incidence in Saskatchewan and Central Alberta, and appeared to be almost non-existent further North. Toxascaris leonina was found in all areas surveyed. Canine hookworm infections were plentiful in all areas, the highest incidence being recorded from Northern Alberta and Northwest Territories. Many Taenia (or Echinococcus) infections were found consistently in all areas. Only one infection with Dipylidium caninum was discovered.

Metorchis conjunctus infections were found to be common in the Saskatchewan reserves. Infections with Diphyllobothrium sp. were found in all communities with access to good fishing. One specimen of Dioctophyma renale was recovered at necropsy.

Infections with parasites of no known zoonotic importance such as Trichuris, Alaria and Isospora species were also recorded.

     

Use of Mailed Questionnaire Data in a Study of Swine Congenital Malformations

A study was designed to evaluate the representativeness and accuracy of data collected on swine birth defects by mailed questionnaire. The study was conducted in the three contiguous counties of Johnson, Lafayette and Pettis in west central Missouri. A personal interview survey and an examination of malformed pigs were used to validate mailed questionnaire data which estimated the frequency and distribution of malformations observed in pigs over a six month period. This period between April and September 1970 was defined as the study period. The results were compared to a previous six month period (April-September 1969), or baseline period, when only the mailed questionnaire was used. The frequency and distribution of the reported malformations by type did not differ significantly (at the p=0.05 level) between the study period (70.4% response) and the baseline period (31.3% response). Evaluation of this and additional data collected during the study suggested that the mailed questionnaire can be used effectively to estimate the frequency and distribution of swine malformations within a defined geographic area.