Synchronization of oestrus with prostaglandins

Luteolytic doses of the Tham salt of PGF₂ or one of its synthetic analogues cause premature regression of, the corpus luteum between the 5th and the 16th day of the oestrous cycle, inducing, 2 to 4 days after the injection, endcrine changes similar to a normal lultolysis and oestrus. After insemination at the time of this oestrus or at predefined times 72 to 96 hours after the injection, fertility is similar to that in controls. The paractical use of prostaglandins for the synchronization of oestrus in a herd of randomly cyclic animals takes account of the fact that only animals between the 5th and the 16th day respond to an injection. Various techniques are proposed, notably a double injection with an interval of 10–12 days.

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Kurzfassung Luteolytische Dosen eines Tham'schen Salzes von PGF₂, oder einer dessen synthetischen Analogen bringen vorzeitige Regressionen des corporis lutei zwischen dem 5ten und dem 16ten Tage hervor. Als Folge dieser Regressionen entwickeln sich innerhalb 2 bis 4 Tage nach der Einspritzung endokrine Veränderungen, die der normalen Luteolyse und Brunst ähnlich sind. Nach einer Besamung zur Zeit dieser Brunst oder zu vorherbestimmten Zeiten und zwar 72 und 92 Stunden nach der Einspritzung wird die gleiche Frunchtbarkeit wie in unbehandelten Kontrollen beobachtet. Nur ein Teil einer zyklischen Herde reagiert auf Prostaglandin, und es werden daher verschiedene Methoden der Viehwirtschaftsführung zur Überwindung dieses Problems erörtert, wie auch den Gebrauch einer Doppeleinspritzung von Prostaglandin mit einem 10 bis 12 tägigen Abstand zwischen den Behandlungen.

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Resume Les doses lutéolytiques de sel Tham de PGF₂ ou d'un de ses analogues synthetiques causent une reégression prématurée du corps jaunne entre le 5ème et le 16ème jour du cycle provoquant, 2 à 4 jours après l'injections, des changements endocriniens semblales à une lutéolyse normale et à un oestrus. Après l'insémination au moment de cet oestrus ou à des temps prédéfinis de 72 à 96 heures après l'injection, la fertilité est semblable à celle des animaux témoins non traités. L'utilisation pratique des prostaß-landinesd pour la synchronisation des chaleurs dans un troupoeau de femelles cyclées tient compte du fait que seules les femelles entre le 5ème et 16ème jour du cycle répondent à une injection. Différentes techniques sont proposées, notamment la double injection à 10–12 jours d'intervalle.

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Riassunto Le dosi luteolitiche del sale Them PGF₂ o di uno dei suoi analoghi sintetioi causano una regressione prematura del corpo giallo tra il 5^o ed il 16^o giorno del ciclo provooando, dopo un periodo che va dai 2 ai 4 giorni dall'iniezione, dei cambiamenti endocrini simili ad una luteolisi normale o ad un estro. Dopo l'inseminazine, nel momento di questo estro oppure in tempi predeterminati, in un periodo compreso tra 72 e 96 ore dopo l'iniezione, la fertilità è simile a quella jdegli animali di controllo non trattati. L'utilizzazione poratioa della prostaglandine per la sincronizzazione dei oalori in una mandria di femmine cicliche dimostra che le femmine rispondono all'iniezione soltanto tra il 5^o ed 16^o giorno del ciclo. Si propongono diverse techniche, in poarticolasre la doppia iniezione ad un intervallo di 10–12 giorni.

     

Intussusception following renal transplantation in dogs (author's transl)]

In a consecutive and non-selected study of 54 kidney transplanted dogs, 12 cases of intussusception of the small intestine developed in 8 dogs. The patogenesis is still unknown. It has been postulated that the time of the operation (4--7 hours) and the segmental termination of the post-operative atony in the intestine are essential factors in this fatal complication. The last 16 dogs in this material were peroperatively treated with antikolinergics (Mestinon NFN), which was continued until normal function of the intestine. In these dogs there were no evidence of intussusception. The value of this profylaxis is open to discussion and it is essential to solve the problem of intussusception through a "blind" and controlled trial.     

Host parasite relationships in Trypanosoma (duttonella) vivax with special reference to the influence of antigenic variation

A mouse model system was used to study various aspects of host and parasite relationships in Trypanosoma vivax infections. These included the phenomenon of antigenic variation, the variable parasite antigens responsible for this phenomenon, parasite-host adaption, host immune responses and the role of genes in the major histocompatibility complex in the control of infection. While the mouse model system has allowed investigation of these aspects of host parasite relationships, it is clear that the system is much more limited than those generally used in T. brucei spp and T. congolense infections. This is indicated by the discovery that not all VATs of T. vivax were equally infective for mice, though in some cases infectivity could be improved by bovine serum supplementation and/or immunosuppression of the mouse host. In the case of rats, infection was even restricted to a smaller number of the VATs studied. It was, however, possible to biochemically characterize the variable surface antigen carried by T. vivax and show its similarity to those carried by T. brucei and T. congolense. The H-2 complex was found not to influence acquired resistance of inbred strains. Cyclic transmissions of T. vivax infections to goats combined with chemotherapy were carried out in an attempt to induce protection to subsequent infection as has been shown in T. brucei and T. congolense infections. Such protection could, however, not be obtained, The failure of the metacyclic VATs to induce immunity, was perhaps due to rapid decrease in antibody titres to bloodstream VATs found after treatment and prior to rechallenge. The usefulness of the mouse model system in elucidating the mechanisms responsible for the non-H-2 linked differences in susceptibility to T. vivax infections should be further explored and its relevance to mechanisms of trypanotolerance in domestic ruminants defined.     

Effect of Tomanol on the pharmacokinetics and tissue distribution of penicillin G in dairy cows

Following concomitant intravenous administration of Tomanol and sodium penicillin G to six Dutch Friesian dairy cows a significant decrease in total body clearance of penicillin (34.7%) and a prolongation of the elimination half-life of penicillin (17.2%) was observed. Tomanol did not affect other pharmacokinetic parameters such as rate constants of drug transfer (k12/k21, alpha en beta), distribution volume of the central compartment (V1), and extrapolated serum drug levels. Intravenous or intramuscular administration of Tomanol had no effect on the tissue distribution of penicillin G, because neither a change in the ratios of muscle to serum and of kidney cortex to serum nor a change in an induced steady state level of low penicilline G serum concentrations was observed. From the data obtained it is concluded that concomitant Tomanol administration with penicillin induces an elevation of the serum penicillin concentration and prolongs the persistence of penicillin residues in carcass meat and organs.     

Induction of acquired cellular resistance in mice with viable and macrophage-processed Listeria monocytogenes

Intracutaneous immunization of mice with 10(5) or 10(6) viable listeria resulted in acquired cellular resistance (ACR) of short duration (7 days). The period during which viable Listeria monocytogenes had to be present in order to induce ACR was estimated by killing the listeria at different times after immunization by injecting the bactericidal antibiotic amoxycillin. The killing of listeria within 6 h after injection prevented the induction of A CR completely, between 6 and 12 h partially, while survival of listeria within animals for at least 18 h was required for the induction of complete protection. To determine whether multiplication of viable listeria was a prerequisite for the induction of ACR, the bacteriostatic antibiotic minocycline was injected for four days after immunization. Induction of ACR was only possible if the dose of viable listeria was large enough to permit a proportion of the listeria to escape bacteriostasis. Interaction of peritoneal macrophages of normal mice and viable listeria yielded a supernatant which induced specific ACR in normal recipient mice. No ACR could be induced with supernatant obtained from normal macrophages after digestion of killed listeria. A reduced level of ACR was obtained with supernatant collected after interaction of macrophages from immune mice and viable listeria. The immunogenic material present in the supernatant of normal macrophages after interaction with viable listeria is thermolabile, has a molecular weight of over 300,000, and is not affected by treatment with DNase, RNase, or trypsin.     

Combined Streptomycin-Isoniazid-Rifampin Therapy in the Treatment of Johne's Disease in a Goat

Johne's disease (paratuberculosis) is an insidious, invariably fatal, chronic disease of ruminants. An increasing role for the goat as a companion animal as well as its commercial use stimulated interest in attempting to treat Johne's disease in this species. The disease tends to differ both clinically and pathologically in goats compared to cattle because the former species often has less severe intestinal involvement. It was, therefore, speculated that response to therapy may differ between cattle and goats. In addition, the combination drug regime of isoniazid, rifampin and streptomycin, widely accepted for human mycobacterial infections, has not been previously employed for treatment of Mycobacterium paratuberculosis. The clinical course and pathological findings of a case of naturally occurring Johne's disease subsequent to a combined drug regime of isoniazid, rifampin and streptomycin is discussed.     

The relationship between plasma triglyceride concentrations and body fat content in male and female broilers—a basis for selection?

1. The relationship between plasma triglyceride concentrations and body fat content was examined in three groups of male and one of female broiler chickens fed ad libitum on a normal growing diet.

2. Phenotypic correlations between total plasma triglyceride concentration and fat content were + 0.50, + 0.37 and + 0.39 for the three groups of male broilers and +0.33 for the group of females. Triglyceride content of plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) showed similar correlations with fat content.

3. Selection of birds from a flock of 550 male broilers on the basis of high or low plasma VLDL plus LDL triglyceride concentrations produced groups with significant differences in body fat content but little difference in body weight.

4. The results suggest that measurements of plasma triglyceride concentration could be used as an indirect means of selecting for decreased body fat content in broiler breeding programmes.