In vitro viability of cryopreserved equine embryos following different freezing protocols.

The main objective of this study was to evaluate two freezing protocols and the effect of agar embedding on survival of day 6.5 equine embryos. A total of 133 embryos were used, in one group (n = 51), embryos were first embedded in agar before the freezing protocol was started. A freezing protocol to -30 degrees C or -33 degrees C was used before plunging embryos into liquid nitrogen (LN2). The embryos were thawed in water at 37 degrees C, evaluated and placed in culture. After 24 h culture, the embryos were evaluated for their morphology and development. No differences were observed between embryos plunged at -30 degrees or at -33 degrees C in LN2. The analysis of the morphology and development after thawing showed that the diameter and developmental stage at freezing correlated with embryo survival. Morula and early blastocyst stages of development were associated with better quality after freezing and thawing and had a better potential to survive after in vitro culture (p < 0.05) compared to more advanced stages. The agar failed to protect embryos from zona pellucida damage, but a tendency to prevent rupture was observed in larger embedded embryos.     

Physiopathologie et thérapeutique de l'utérus en période puerpérale chez la vache laitière: revue

Accurate diagnosis and effective therapeutics of uterine pathologies in cattle represent some of the daily preoccupations for the veterinarians involved in herd health medicine. A rational approach requires a competence based on fundamental and clinical knowledge.

The physiological aspects of the uterine involution in cattle are reviewed with emphasis about the in utero bacteriological dynamic and the endocrinological evolution during this period. The pathogenesis of uterine pathologies is discussed following new research results and new knowledge on the mechanisms of uterine defense. The value and limitations of the clinical diagnosis is briefly reviewed. The therapeutics of uterine pathologies is debated in relation with the pathophysiology of the uterine involution and with the rational of the traditional and new concepts of the treatment of the postpartum uterine pathologies.

     

Prevalence of enteropathogenic Escherichia coli in naturally occurring cases of poult enteritis-mortality syndrome

Enteropathogenic Escherichia coli (EPEC) previously were identified in poult enteritis-mortality syndrome (PEMS)-affected turkeys and associated as a cause of this disease. In the present study, the prevalence of EPEC in PEMS-affected turkeys was examined retrospectively with archived tissues and intestinal contents collected from 12 PEMS-affected turkey flocks in 1998. Formalin-fixed intestinal tissues were examined by light and electron microscopy for attaching and effacing (AE) lesions characteristic of EPEC, and frozen (-75 C) intestinal contents were examined for presence of EPEC. Escherichia coli isolates were characterized on the basis of epithelial cell attachment, fluorescent actin staining (FAS) test, and presence of E. coli attaching/effacing (EAE), shigalike toxin (SLT) type I, SLT II, and bundle-forming pilus (BFP) genes by polymerase chain reaction procedures. EPEC isolates were examined for pathogenicity and ability to induce AE lesions in experimentally inoculated young turkeys. AE lesions were identified by light microscopy in Giemsa-stained intestines from 7 of 12 PEMS-affected turkey flocks. Lesions consisted of bacterial microcolonies attached to epithelial surfaces with epithelial degeneration at sites of attachment and inflammatory infiltration of the lamina propria. Electron microscopy confirmed the identity of AE lesions in six of seven flocks determined to have AE lesions by light microscopy. EPEC were identified in 4 of 12 flocks on the basis of the presence of EAE genes a nd absence of SLT I and SLT II genes; all isolates lacked BFP genes. EPEC isolates produced AE lesions and variable mortality in turkeys coinfected with turkey coronavirus. In total, EPEC were associated with 10 of 12 (83%) naturally occurring PEMS cases on the basis of identification of AE lesions and/or EPEC isolates. These findings provide additional evidence suggesting a possible role for EPEC in the pathogenesis of PEMS.     

Parvovirus-like particles associated with diarrhea in unweaned piglets.

Numerous parvovirus-like particles, 18 to 26 nm in diameter, were detected by electron microscopy in the intestinal contents of two to three week old piglets with mild to severe diarrhea, in six Quebec pig herds. Hemagglutination of guinea pig and African green monkey red blood cells was obtained with clarified intestinal contents. Two isolates were found to be antigenically related to porcine and canine parvoviruses, while another differed from the porcine parvovirus using the hemagglutination-inhibition test. Three isolates could be cultivated in cell cultures as demonstrated by the development of a cytopathic effect, hemagglutination activity, immunofluorescence and identification of the virions in the cell culture fluids by electron microscopy. The possibility of a primary etiological role for these parvoviruses in diarrhea of unweaned piglets is discussed.     

Inheritance of new genetic markers in lentil (Lens Miller)

Summary We report on the inheritance of 11 morphological markers and 17 isozymes in lentil (Lens culinaris). The monogenic inheritance of 11 morphological markers and 11 isozymes is confirmed. The inheritance of six isozymes (Aco-2, Enp, Est-3, Est-4, Lap-3, and Mdh-m) is reported for the first time in lentil. This brings the total number of described genes in lentil to 78. Cases of disturbed segregation were more frequent than expected by chance. It is suggested that disturbed segregation was in most cases caused by linkage with a piece of chromosome that showed preferential elimination in crosses between Lens culinaris ssp. odemensis and other subspecies. The prevalence of disturbed segregation in crosses with Lens culinaris ssp. odemensis could limit the usefulness of this subspecies in genetic and linkage studies.     

Laboratory study of cd and hg uptake by two freshwater molluscs in relation to concentration,age and exposure time

To assess the potential of two molluscs species as bioindicators of Cd and Hg pollution in aquatic ecosystems, a laboratory study was conducted on the short-lived gastropod Viviparus georgianus and the pelecypod Elliptio complanata. Using analysis of covariance (ANCOVA), we have evaluated the contribution of the aqueous trace metal concentration, the size of the molluscs and the exposure time to explain the Cd and Hg body concentration. Results show that all the parameters analyzed have a significant effect on Cd and Hg body variation in the gastropod except for the time of exposure and the interaction time of exposure-height of the individuals. The same results are observed for the pelecypod, except that the length of the individuals has not a significant influence on Cd and Hg variation. The major part of the variability of the body metal concentration seems to be explained by these three parameters: the water metal concentration, the interaction of water metal concentration with time of exposure and the interaction of water metal concentration with time of exposure and the size of the individuals.     

Changes in the susceptibility of Actinobacillus pleuropneumoniae to antimicrobial agents in Quebec (1981-1986)

An important reduction in the in vitro efficacy of spectinomycin and chloramphenicol was recorded between 1981 and 1986 against the causal agent of porcine pleuropneumonia Actinobacillus. Antimicrobial susceptibility tests were carried out by use of Kirby-Bauer disk diffusion technique on a total of 723 isolates of Actinobacillus pleuropneumoniae. Results did not agree with those of other reports in which a constant susceptibility to any of the antimicrobial agents tested was reported with serotype 2 isolates. The ability to acquire drug resistance may differ from one serotype to another.     

Ovarian teratoma and endometritis in a mare

An 8-year-old Arabian mare was admitted for a large ovarian anovulatory follicle. A clinical diagnosis of ovarian tumor and endometritis was established. Histological examinations revealed an ovarian teratoma and a grade II endometritis. Three months after unilateral ovariectomy, the mare was confirmed pregnant and eventually gave birth uneventfully.