The Effects of Anthelmintic Treatments on the Development of Gastrointestinal Parasitism in Calves

Fortnightly treatment of susceptible calves with 1-tetramisole during the first two months of continuous exposure to pastures residually heavily-infected with Ostertagia ostertagi, Cooperia oncophora and Nematodirus helvetianus did not prevent the development of clinical parasitic gastroenteritis, although the infections were not as severe as in nontreated calves. Development of resistance in treated calves was manifested by significantly smaller numbers of Cooperia eggs in utero (which were reflected by reduced fecal egg counts) and by significantly smaller Nematodirus worm burdens than in susceptible calves that commenced grazing coincident with cessation of treatment. The findings also indicated that resistance to Nematodirus helvetianus was slower in developing in treated than in nontreated infected calves.     

The Development, Clinical Signs and Economic Losses of Gastrointestinal Parasitism in Feeder Cattle on Irrigated and Non-irrigated Dikeland and Upland Pastures

Investigations were carried out over three grazing seasons with parasitized and treated (control) steers on irrigated and non-irrigated upland and dikeland pastures. The stocking rate in each paddock was adjusted by either adding or removing animals so as to maintain as uniform a sward and rate of grazing as possible. Animals were weighed on and off the pastures and fortnightly during the grazing seasons.

During the first grazing season clinically normal steers shedding low numbers of gastrointestinal worm eggs contaminated the parasite-free pastures sufficiently to give rise to large residual pasture infections and clinical parasitic gastroenteritis in grazing stock during the second grazing season. Worm burdens of 100,000 to 200,000 Ostertagia ostertagi and Cooperia oncophora were established in several steers showing marked clinical signs. In spite of treatments with high dosages of thiabendazole in attempts to keep worm burdens at a minimum, there was a slow but gradual buildup of pasture infections in the paddocks grazed by the control steers over the three year period.

During the second and third grazing seasons there were significant differences in the daily rate of gain between the parasitized and control animals on both upland and dikeland pastures. The parasitized groups of steers had daily rates of gain ranging from 0.29 to 0.80 pounds less than their comparable control groups.

Under Maritime conditions, irrigation did not have a consistent effect on weight gains and development of parasitism.

     

Fusion of Ossification Centres in the Cat

Abstract— —Thirty-seven kittens from eleven litters have been radiographed and eight others have been completely dissected to provide a record of the times of fusion of the epiphyses of the limb bones. The observations are recorded with reference to individual bones and then to the limbs at approximately monthly intervals. Attention is drawn to the variable presence of the sesamoid bone in the medial head of the gastrocnemius muscle. A comment is made in the discussion on the sequence of fusion of the ossification centres.
Résumé— —Trente sept chatons provenant de II protées ont été radiographiés et huit autres ont été complètement disséqués afin d'établir un rapport sur les moments d'apparition de la soudure des épiphyses des os des membres. Les observations sont notées pour les os pris individuellement et ensuite pour les membres à des intervalles de un mois environ. L'attention est attirée sur la présence inconstante de l'os sésamoide dans la partie moyenne de l'extrêrmité du muscle gastrocnémien. Dans la discussion il est fait un commentaire sur la séquence de la soudure des centres d'ossification.
Zusammenfassung— —37 junge Katzen aus elf Würfen wurden radiographisch untersucht und acht andere vollständig seziert, um Unterlagen über die Zeitpunkte der Verschmelzung der Epiphysen der Extremitätenknochen zu erhalten. Die Beobachtungen wurden in Beziehung zu einzelnen Knochen und dann in Beziehung zu den Extremitäten mit ungefähr monatlichen Abständen gebracht. Die Aufmerksamkeit wird auf die wechselnde Anwesenheit des Sesambeins im medialen Ende des Gastrocnemicus gelenkt. In der Besprechung der Verschmelzungsreihenfolge der Ossifikationszentren wird dies kommentiert.     

Status of trichinosis in bears in the Atlantic provinces of Canada 1971--1976.

During 1971 to 1976 inclusive, 73 black bears, Ursus americanus and one polar bear, Thalarctos maritimus, originating in the Atlantic Provinces of Canada were examined for the presence of trichinosis. The polar bear was infected but all of the black bears were negative.     

Rabies Symposium—III. Aspects of Rabies in Man

Abstract— The author reviews rabies in man. Reference is made to sources of infection, the course of the disease in man, prophylactic vaccination, post-infection prophylaxis and possible complications.
Résumé— –L'auteur examine la question de la rage chez l'homme: sources d'infection, évolution de la maladie, vaccination prophylactique, prophylaxie après contage et complications possibles.
Zusammenfassung— Der Verfasser bespricht das Auftreten von Tollwut bei Menschen. Er weist auf die Infektionsquellen hin, beschreibt den Verlauf der Krankheit bei Menschen, vorbeugende Impfungen, Vorbeugungsmassnahmen nach einer Infektion und mögliche Komplikationen.