Associations between antimicrobial use and the prevalence of antimicrobial resistance in fecal Escherichia coli from feedlot cattle in western Canada

A randomized, controlled, blinded clinical trial was performed at a research feedlot in western Canada. Auction-market-derived steers (n = 288) were randomly assigned to 1 of 3 treatments: 1) no antimicrobials on arrival; 2) oxytetracycline in the starter ration for 14 d; and 3) long-acting oxytetracycline subcutaneously on day 0. Minimal inhibitory concentrations of 7 antimicrobials were determined for 3 generic fecal E. coli isolates per animal on arrival and throughout the feeding period. There was a low prevalence of antimicrobial resistance in generic E. coli isolates from calves on arrival. There were increased proportions of cattle with resistant E. coli isolates early in the feeding period among calves in groups 2 and 3. Individual animal treatments were not associated with increased proportions of cattle with resistant E. coli isolates preslaughter. There was no difference in the proportion of animals with E. coli isolates resistant to tetracycline between the treatment groups preslaughter. However, there were significantly more animals with tetracycline resistant isolates of E. coli preslaughter than at arrival.     

Mycotoxins and mycoflora in animal feedstuffs in western Canada.

Feed samples associated with 51 cases of suspected or potential mycotoxicoses of farm animals in western Canada were examined during a three year study. Ochratoxin A was detected in four cases, T-2 toxin and diacetoxyscirpenol in one, and sterigmatocystin in one. Samples examined for microflora associated with production of these mycotoxins contained Penicillium spp., Aspergillus ochraceus, Fusarium spp. and fungi of the Aspergillus glaucus group. Samples were analyzed for T-2 toxin and diacetoxyscirpenol only if Fusarium spp. were present. The first known incidence of suspected sterigmatocystin poisoning of poultry through feed ingestion has been encountered.     

Rabies diagnosis in western Canada, 1985-1989

The results of laboratory examination of 20460 specimens for the diagnosis of rabies by the standard fluorescent antibody and mouse inoculation tests over a five year period are presented. Specimens were received from British Columbia, Alberta, Saskatchewan, Manitoba, and the Yukon and Northwest Territories. Of those examined, 9.96% were positive. The main reservoirs of rabies were skunks, bats, and foxes. During this observation period a rabies epizootic occurred in skunks in Saskatchewan. When both tests were performed, the fluorescent antibody test was found to agree with the mouse inoculation test in over 99% of cases.     

Ochratoxin A in blood from slaughter pigs in western Canada.

Twelve hundred blood samples were obtained in 1986 from pigs slaughtered in western Canada. The samples were assayed for ochratoxin as it is a potential contaminant in the food system. Blood ochratoxin concentration is a good indicator of tissue concentrations, particularly those in the liver and kidney. High performance liquid chromatography analysis of serum for ochratoxin demonstrated that 3.6 and 4.2% of the blood samples collected in February and March (n = 194) and May, June and July (n = 1006), respectively, had ochratoxin concentrations that exceeded 20 ng/mL. Overall the percent of samples that had concentrations of greater than 10, 20, 50, 100 and 200 ng/mL serum were 11.3, 4.1, 1.25, 0.42 and 0.08%, respectively. Samples that had ochratoxin concentrations that were greater than 20 ng/mL of serum were confirmed using two independent methods: liquid chromatography-mass spectrometry analysis and methyl ester derivatization followed by high performance liquid chromatography analysis.     

Seroepidemiology of undifferentiated fever in feedlot calves in western Canada.

The relationships between 4 bacterial and 3 viral antibody titers and morbidity (undifferentiated fever (UF)) and mortality were investigated in recently weaned beef calves. Blood samples from 100 animals that required treatment for UF (Cases) and 100 healthy control animals (Controls) were obtained: upon arrival at the feedlot (Arrival), at the time of selection as a Case or Control (Selection), and at approximately 33 d of the feeding period (Convalescent). Seroconversion to Pasteurella haemolytica antileukotoxin was associated with an increased risk of UF (OR = 2.83); however, seroconversion to bovine herpesvirus-1 G-IV glycoprotein was associated with a decreased risk of UF (OR = 0.43). Higher Arrival bovine viral diarrhea virus antibody titer was associated with a decreased risk of UF (OR = 0.83). Increases in Mycoplasma alkalescens antibody titer after Arrival were associated with an increased risk of UF (OR = 1.10). Higher Arrival Haemophilus somnus antibody titer and increases in Haemophilus somnus antibody titer after Arrival were both associated with a decreased risk of UF (OR = 0.76 and OR = 0.78). The odds of overall mortality (OR = 5.09) and hemophilosis mortality (OR = 11.31) in Cases were significantly (P < 0.05) higher than in the Controls. Higher Arrival bovine herpesvirus-1 antibody titer was associated with an increased risk of mortality (OR = 1.30). Protective immunity to Pasteurella haemolytica antileukotoxin, Haemophilus somnus, bovine herpesvirus-1 G-IV glycoprotein, bovine viral diarrhea virus, and Mycoplasma spp. may be necessary to reduce the occurrence of UF. Animals with UF are at an increased risk of overall and hemophilosis mortality.     

Newcastle disease in wild water birds in western Canada, 1990

This report describes the investigation of mortality of double-crested cormorants (Phalacrocorax auritus), white pelicans (Pelecanus erythrorhynchos), and gulls (Larus spp.) in Alberta, Saskatchewan, and Manitoba during late summer 1990. Techniques used varied among areas, but virological and histopathological examination of birds was done in each area. The major clinical sign in cormorants was inability to fly, often with unilateral wing or leg paralysis. Focal nonsuppurative inflammation was present in the brain and spinal cord of cormorants and pelicans. Newcastle disease virus (NDV) was isolated from cormorants, a pelican, and a ring-billed gull (Larus delawarensls) from Saskatchewan. Cormorants from Alberta were positive for NDV in an immunofluorescent test. Most of the viruses were classed as velogenic and all had a similar monoclonal antibody profile to viruses from the 1970 to 1974 panzootic. Approximately half of cormorant, pelican, and gull eggs collected from affected colonies in the spring of 1991 had antibody to NDV. Antibody was also present in cormorant eggs from the Great Lakes. No unusual mortality was detected at any colony in 1991. Fledgling cormorants and gulls from colonies where mortality occurred in 1990 did not have antibody to NDV in June-July 1991. The overall extent of mortality among water birds and the source of the virus were not determined.     

Acute pit gas (hydrogen sulfide) poisoning in confinement cattle.

Rapid deaths in confinement cattle caused by exposure to hydrogen sulfide (H2S) gas from manure pits has not been reported in the USA. In 1997, 158 cattle in 2 confinement pens were exposed to H2S gas as the manure in the pits under a slatted floor was agitated prior to pumping. Approximately 35 of the cattle were lying on the floor when the upper agitator was turned on. Within 5 minutes, many these cattle were down on their sides and paddling. Of these, 26 died within a few minutes. The survivors were treated and sent to slaughter. Cattle that did not show immediate signs of toxicosis remained clinically unaffected. Two steers that were near death were brought to the Purdue Animal Disease Diagnostic Laboratory for clinical evaluation, euthanasia, and necropsy. They were recumbent and unresponsive to visual and auditory stimuli. Necropsy examination yielded no significant gross lesions. No evidence of viral or bacterial infection was found. Ocular fluid nitrate concentrations were within normal limits, and no lead was detected in either animal. Microscopic examination revealed lesions consistent with H2S-induced central nervous system anoxia. Histologically, sections of brain demonstrated massive, diffuse cerebral cortical laminar necrosis and edema. Portions of the outer lamina contained hypereosinophilic and shrunken neurons. The subcortical white matter was vacuolated in some areas. The history, clinical signs, and histologic lesion of cerebral laminar necrosis led to a diagnosis of H2S toxicosis in these cattle.     

Mycotoxins in fungal contaminated samples of animal feed from western Canada, 1982-1994.

Feed samples from 94 cases involving fungal contamination and suspected mycotoxicosis of farm animals in western Canada were examined during 1982-1994 to assess the incidence of mycotoxins. Samples were analyzed for aflatoxins, ochratoxin A, citrinin, sterigmatocystin, and the fungal estrogen zearalenone. Samples infected with Fusarium fungi were additionally assayed for nivalenol, deoxynivalenol, fusarenone-x, 15-acetyl-deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin. Mycotoxins were found in 21 feed samples from 17 cases (18% of the reported cases), generally at levels far below those needed to induce symptoms under laboratory conditions. HT-2 toxin and other type-A trichothecenes were detected in 5 samples, deoxynivalenol and other type-B trichothecenes in 13, ochratoxin A in 5, and citrinin in 2. In 9 cases, symptoms observed in the animals were consistent with the known effects of the mycotoxin(s) found in the particular feed samples.     

Identification of breeding objectives for Begait goat in western Tigray,North Ethiopia

Tropical Animal Health and Production - A sound breeding objective is the basis for genetic improvement in overall economic merit of farm animals. Begait goat is one of the identified breeds in...     

Small animal deworming protocols, client education, and veterinarian perception of zoonotic parasites in western Canada

Questionnaires were mailed to veterinarians in western Canada to determine dog and cat deworming protocols and the association between perceived zoonotic risk and perceived prevalence of endoparasites and deworming protocols. Of the responding veterinarians (545), 13% and 39% recommended deworming protocols consistent with established guidelines for puppies and kittens, respectively. Mixed animal practitioners and high-perceived prevalence of Toxocara cati were associated with increased appropriate kitten deworming (P < 0.01 and P = 0.04, respectively). High-perceived zoonotic concern of Toxocara canis was associated with increased appropriate puppy deworming (P = 0.01). Sixty-eight percent of veterinarians noted an established hospital deworming protocol, although only 78% followed the protocol. Forty-four percent of veterinarians stated they discussed with all clients the zoonotic risk of animal-derived endoparasites, whereas the remainder discussed it only under particular circumstances or not at all. Most small animal deworming protocols recommended in western Canada begin too late to inhibit endoparasite shedding. Increased educational efforts directed at veterinarians are warranted.     

Associations among age, scrotal circumference, and proportion of morphologically normal spermatozoa in young beef bulls during an initial breeding soundness examination.

OBJECTIVE: To evaluate age and scrotal circumference as predictors of semen quality in young beef bulls. DESIGN: Cohort study. ANIMALS: 1,173 beef bulls < 15 months old. PROCEDURE: During initial breeding soundness examination, variables for bulls producing > or = 70% morphologically normal spermatozoa were compared with those for bulls producing < 70% morphologically normal spermatozoa. Mean and 95% confidence interval for age and scrotal circumference were constructed to detect differences between groups of bulls over all observations and within the 5 most common breeds. For these 5 breeds, chi 2 analysis was used to evaluate differences in the proportion of bulls that had values less than the population mean for scrotal circumference, age, and percentage of morphologically normal spermatozoa. Multivariate regression was used to quantify variation in the proportion of morphologically normal spermatozoa that could be explained by age and scrotal circumference. RESULTS: Mean (+/- SD) age and scrotal circumference differed significantly for bulls that produced > or = 70% morphologically normal spermatozoa (12.7 +/- 1.1 months and 35.6 +/- 2.7 cm) and bulls that produced < 70% morphologically normal spermatozoa (12.1 +/- 1.2 months and 34.8 +/- 3.3 cm). The proportion of bulls younger than mean age at first examination and the proportion producing > or = 70% morphologically normal spermatozoa differed among breeds. Age and scrotal circumference explained only 11% of the variation in semen quality. CLINICAL IMPLICATIONS: Among young beef bulls, those that were older and had larger testes were more likely to produce > or = 70% morphologically normal spermatozoa. Age and scrotal circumference were not sufficient predictors of semen quality.     

Distribution of Streptococcus suis capsular types in Quebec and western Canada

Of a total of 561 isolates of Streptococcus suis recovered from various tissues of diseased pigs, 464 were from veterinary laboratories in Quebec and 97 were from western Canada, particularly Alberta (84). Almost 83% of all these isolates belonged to the 23 known S. suis capsular types. There was no marked difference between the two groups of isolates. Capsular type 2 was the most prevalent and represented 32% of all isolates. The other important capsular types were, in decreasing order, 3, 1/2, 8 and 4. Lungs, brain, and meninges were the source of the majority of isolates. More than 40% of all S. suis isolates were found in pure culture. The number of isolations of this microorganism was higher in piglets aged five to eight weeks than in any other age group.     

Associations between sperm abnormalities, breed, age, and scrotal circumference in beef bulls

The objectives of this study were to determine the associations of breed, age, and scrotal circumference (SC), and their interaction, on the prevalence of sperm abnormalities in beef bulls in Alberta, Canada, and the percentage of satisfactory potential breeders identified during breeding soundness examination solely due to normal sperm morphology. Eosin-nigrosin stained semen smears and evaluation reports of 1642 bull breeding soundness evaluations were procured from 6 veterinary clinics in Alberta. Sperm morphology was determined for at least 100 sperm per bull. The most common defects were detached head [4.86% ± 5.71%; mean ± standard deviation (s)], distal midpiece reflex (6.19% ± 9.13%), and bent tail (1.01% ± 1.54%). Although breed, age, and SC did not significantly affect the prevalence of head or midpiece defects, morphologically normal or abnormal sperm, tail defects were more prevalent in Angus and Hereford bulls compared with other breeds. Overall, solely on the basis of sperm morphology, 1363 (83.0%) bulls were classified as satisfactory potential breeders and the remainder 279 (17.0%) as unsatisfactory (> 30% abnormal sperm, > 20% defective heads, or both). Although not significantly different, the breed with the highest percentage of satisfactory potential breeders was Limousin (90.6%) and the lowest was Hereford (78.8%). That 17% of bulls subjected to breeding soundness evaluation were designated as unsatisfactory solely on the basis of sperm morphology highlights its importance.