Publications

q fever in canada.	a canada-wide survey of q fever was begun in 1958 in co-operation with public health and veterinary laboratories to determine the presence and prevalence of the disease so that medical practitioners might be alerted to the potential dangers existing. serologic evidence obtained indicated that the q fever rickettsia now exists in cattle in all provinces of canada except new brunswick, nova scotia, and prince edward island. isolations of the rickettsia were obtained from bovine milk samples from o ...	1964	14175873
infectious bovine rhinotracheitis--clinical, pathological, and virological aspects.		1966	4287716
serum transaminase activity in calves affected by nutritional muscular dystrophy in northern ontario.		1967	6068867
serodiagnosis in q fever with special emphasis on the radioisotope precipitation test.		1968	5691056
rabies today--man and animals.		1969	5812488
case report. a mastitis problem in a dairy herd.		1969	5815591
a note on selenium contents of two leguminous forage species collected in ontario and the possible incidence on selenium-responsive diseases.		1969	5816710
epidemiological investigations on dictyocaulus viviparus (bloch, 1782) infection in cattle.		1970	4275423
correlation of bedrock type with the geography of leptospirosis.	leptospirosis occurs enzootically over most of southern ontario. leptospira pomona is the serotype most commonly found in outbreaks. antibodies to l. pomona occur frequently in the sera of deer in wilderness areas. the geographic location of leptospirosis presents a pattern which closely parallels the distribution of paleozoic bedrock. by contrast, l. pomona infection is absent from areas underlain by precambrian bedrock. comparisons of water chemistry, soil type, habitat, and host and pathogen ...	1970	4246001
trypanosomes in cattle in southern ontario.	trypanosomes were found in the blood of 155 out of 274 holstein cows of various ages from southern ontario. the incidence varied from about 8% in one herd to about 85% in another herd. two species of trypanosomes were found in cattle in the guelph area. one was trypanosoma theileri. the other was a much smaller trypanosome which morphologically resembles t. uniforme of the salivaria. this is the first report of such a trypanosome in cattle in north america. epimastigotes from blood agar slants o ...	1970	4246837
case report. dermatophilus skin infection in nine-day-old calves.		1970	5463902
infectious thromboembolic meningoencephalitis in ontario feedlot cattle.		1970	5464268
the isolation of trypanosomes from cattle in ontario.	a method for the recovery by blood culture of a t. theilieri-like flagellate from cattle is described. in ontario, 54% of 156 cows in 15 herds were found to have parasitemia.	1971	4254891
isolation of listeria monocytogenes from brain specimens of domestic animals in ontario.		1971	5005795
left abomasal displacement: an epidemiological study.		1972	5016928
bovine tuberculosis in humans in ontario. the epidemiologic features of 31 active cases occurring between 1964 and 1970.		1972	4627829
parasitisms in domesticated animals in ontario. i. ontario veterinary college records 1965-70.		1973	4688875
gastrointestinal parasites in cattle in ontario.		1973	4699612
disease trends in domestic animals and poultry in ontario 1971-72.		1973	4711498
a survey of calves treated for calf diarrhea at the ontario veterinary college 1966-1971.		1973	4769615
an outbreak of cysticercosis in feedlot cattle.		1974	4857011
drug resistance among pathogenic bacteria from animals in ontario.	prevalence of antimicrobial drug resistance among over 3000 clinical isolates of animal pathogens in ontario during 1971-72 has been studied. a high number of multiple resistance patterns is prevalent among members of enterobacteriaceae, especially escherichia coli and salmonella typhimurium. the most common resistance pattern among bovine strains was against not less than six drugs in common use. among different animal species the bovine population was found to be the source of a high percentag ...	1974	4277443
the veterinary requirements of the animal industry in ten years time.		1974	4434316
ddt and dieldrin in watersheds draining the tobacco belt of southern ontario.		1974	4462708
abomasal nematodes in cattle in ontario.	during 1970, 93 abomasa from cattle in ontario were examined, and from 63 of these abomasa nematode species of the genera ostertagia, haemonchus and/or trichostrongylus axei were recovered. the abomasa were from cattle six months to two years of age and were collected either from the postmortem room at the ontario veterinary college or from two abattoirs near guelph. the numbers of worms per abomasum were estimated and their genera were identified from a one-twentieth volume of the washings and ...	1974	4272952
overwintering of bovine gastrointestinal nematodes in southwestern ontario.	several steers, reared in isolation until approximately six months of age, were placed on a small isolated enclosed pasture from late spring to late fall of 1970, 1971 and 1972. the pasture was left vacant and unused during the winters and early springs. the pasture had been used in previous years by cattle, and in the late spring of 1970 was grazed by cattle know to be passing gastrointestinal nematode eggs in their feces. the steers were slaughtered periodically, and the prevalence of nematode ...	1974	4272963
an immunoprecipitin study of the incidence of influenza a antibodies in animal sera in the ottawa area.	a survey of over 600 'normal' sera from 14 animal species by immunoprecipitin tests in cellulose acetate using viron antigens revealed a high incidence of precipitating activity against a broad range of influenza a virus strains, particularly a2hhong kong/1/68 and /pr8. however, serum treatments trypsin-heat-periodate, naio4, v. cholerae receptor-destroying enzyme (rde), or kaolin eliminated most precipitating activity, which suggests that it was due to "non-specific" inhibitors of influenze vir ...	1975	167931
dynamite poisoning in hereford crossbreds in southeastern ontario.		1975	805655
ddt in watershed draining the tobacco belt of southern ontario.		1975	1063713
azathioprine in rheumatoid arthritis: a long-term follow-up study.	in 1973 we reported the beneficial effects of azathioprine in a double blind, cross-over study in 17 patients with classic rheumatoid arthritis. during subsequent follow-up over a mean period of 40 months, 4 patients had discontinued therapy because of poor therapeutic response and 1 because of nausea. eleven of the 12 patients still taking azathioprine had maintained their initial beneficial response or showed further improvement. adverse side effects during the follow-up period were minor. the ...	1975	1090297
a survey of vertebral abscesses in domestic animals in ontario.		1975	1131789
the recovery of mycoplasmas from the genital tracts of bulls in artificial breeding units in ontarïo.	one hundred and thirty-two penial-preputial swabbings, 140 raw and 42 processed semen samples were cultured for mycoplasmas. mycoplasma or acholeplasma were recovered from 87, 32 and one respectively, while ureaplasmas were recovered from 46, 34 and six respectively.	1975	1175080
brucellosis in ontario: a case control study.	data from cattle herds infected with brucellosis and from control (noninfected) herds were collected and analyzed using case control techniques. it appeared that herds located close to other infected herds and those herds whose owners made frequent purchases of cattle had an increased risk of acquiring brucellosis, particularly those who made purchases from other herds or from cattle dealers. infected herds had a lower level of vaccination than noninfected herds. however, the percentage vaccinat ...	1976	826309
bovine mastitis in ontario due to mycoplasma agalactiae subsp. bovis.	bovine mastitis caused by mycoplasma agalactiae subsp. bovis was first diagnosed in 16 of 55 cows in an ontario herd in feburary 1972. a total of 182 of 598 (30.4%) cows from 33 of 64 (51.5%) farms in widely separated areas of the province were culturally positive. herd incidence varied from 15 to 40% with one closed herd having an incidence of 61%. four herds were investigated culturally and serologically by the growth inhibition test for 15 months. in the acute phase the organism was present i ...	1976	1000385
insecticide and nutrient transport in water, related to agricultural land use of a stream basin in ontario, canada.	transport by stream water of insecticides and nutrients in big creek, norfolk county, ontario, canada, was examined by combining concentrations of substrates with flow data. big creek has its headwaters in dairy cattle country, its central basin area is mainly devoted to tobacco growing, and its lower reaches contain mixed farming, corn and vegetables, etc., before it flows into lake erie. three sampling sites were chosen to represent these 3 different land uses. generally concentrations of subs ...	1976	1015861
the gross and histopathologic lesions of maignant catarrhal fever in three captive sika deer (cervus nippon) in southern ontario.	the gross and histopathologic lesions of three captive sika deer (cervus nippon) with malignant catarrhal fever are described. lesions included those of the head and eye form and the more commonly described peracute form. one deer had been exposed to a wildebeeste (connochaetes gnou) and the other two to domestic sheep.	1977	557117
tissue pathology and comparative microanatomy of onchocerca from a resident of ontario and other enzootic onchocerca species from canada and the u.s.a.	the microanatomy of one male and one female specimen of a zoonotic onchocera sp in a fibrous nodule excised from the wrist of an ontario resident, two bovine onchocerca from saskatchewan and manitoba, canada, and o. cervicalis from the ligamentum nuchae of a horse in georgia, u.s.a., were compared. in dimensions and cuticular morphology, the three canadian specimens of onchocera shared certain features and closely resembled both o. cervicalis and o. gutturosa. the number of cuticular striae in s ...	1977	596957
the prevalence of serum antibodies to toxoplasma gondii in ontario mammals.	the prevalence of seropositive reactions to toxoplasma gondii was studied in farm animals, companion animals, wild rodents and birds. of the animals tested, 17% of cattle, 65% of sheep, 45% of pigs, 9% of horses, 33% of dogs and 20% of cats were seropositive by the sabin-feldman dye test. in addition 11% of mice (mus musculus), 5% of deer mice (peromyscus), 3% of rats (rattus norvegicus) and less than 2% of sparrows (passer domestcus) were seropositive. all samples from short-tailed field mice ( ...	1978	667705
corynebacterium equi lymphadenitis in ontario cattle.		1979	466639
industrial fluoride pollution. chronic fluoride poisoning in cornwall island cattle.	an aluminum plant on the south bank of the st. lawrence river, southwest of cornwall island, ontario, canada, has emitted 0.816 metric tons of fluoride daily since 1973; considerably higher amounts were emitted from 1959 to 1973. the plant has been designated as the "major source of fluoride emissions impacting on cornwall island." chronic fluoride poisoning in cornwall island cattle was manifested clinically by stunted growth and dental fluorosis to a degree of severe interference with drinking ...	1979	467082
the rates and patterns of survivorship and disease in a university dairy herd.	the rates and patterns of disease occurrence and survivorship were determined over a six year period in a university operated dairy herd. of the ten diseases selected for study, clinical mastitis occurred most frequently with an incidence rate of 10.1% and displaced abomasum occurred least frequently with an incidence rate of 4.4%. the occurrence of all disease except those of the ovary was associated with the age of the cow. mastitis, pneumonia and cystic graafian follicles tended to reoccur in ...	1979	509376
approaches to immunization of infants and young children against gastroenteritis due to rotaviruses.	recent studies have shown that in developed countries rotaviruses are the single most important etiologic agents of acute gastroenteritis that requires hospitalization of infants and young children. although deaths from gastroenteritis are, in general, infrequent in the developed countries, an effective rotavirus vaccine would clearly be of benefit to reduce the heavy toll of morbidity from gastroenteritis due to rotavirus. in the developing countries the impact of diarrheal diseases is staggeri ...	1980	6251528
the first 10 years of the dialysis-transplantation program at the hospital for sick children, toronto. 1: predialysis and dialysis.	renal dialysis and transplantation have been used for many years for adults with kidney failure but only recently for children. in may 1967 a renal-dialysis-transplantation program was established at the hospital for sick children, toronto for patients aged 6 to 18 years living within 240 km of toronto. in 1973, children aged 1 to 5 years began to be accepted into the program, and by august 1977, 90 children (mean age 11 years) from all parts of canada had been admitted to the program. the creat ...	1980	6988064
twenty years of experience with dairy herd health in ontario.	this article expresses observations on planned herd health for dairy cattle, based on experience gained in the ambulatory clinic practice of the ontario veterinary college. the author and his colleagues, especially dr. r.a. curtis, have initiated and delivered a preventive medicine approach to veterinary practice in the teaching program and teaching practice for the past 20 years. in addition, herd health presentations have been made to veterinary associations in every province in canada and to ...	1980	7260827
factors associated with mortality in feedlot cattle: the bruce county beef cattle project.	the design of and the analysis of data from the bruch county beef cattle project, particularity the field study, are presented and discussed. a major value of the study may lie in its ability to relate laboratory findings to events in the field. the factor most strongly related to mortality was ration, with cattle on hay based rations having a much lower mortality on average than cattle on corn based rations. in general, management activities associated with growing cattle (as opposed to fatteni ...	1980	7397593
an evaluation of screening programs for the detection of brucellosis in dairy herds.	data were collected from approximately 1000 dairy herds, initially blood tested for brucellosis in 1977, in each of southeastern and southwestern ontario. these data were used to evaluate three brucellosis screening programs, the area recertification program, the market cow program and the milk test program. the milk test program was the most efficient program at detecting brucellosis, 29.5% of the herds tested were classified as infected, but lacked the ability to detect a large proportion of " ...	1980	7397599
incidence rates of cystic follicles in holstein cows according to 15-day and 30-day intervals.	cystic ovarian follicles occurred in 198 out of 1599 (12.4%) ontario holstein lactations. these occurrences were grouped by date of diagnosis into 15-day and 30-day intervals after calving, and only open cows were considered. the incidence rates for the 15-day intervals form zero to 150 days of lactation varied form 0.2% to 3.5%; the highest rate was 31 to 45 days. the incidence rates for the 30-day intervals from zero to 210 days of lactation varied form 1.4% to 6.8%, depending on the method of ...	1981	7261593
factors associated with morbidity and mortality in feedlot calves: the bruce county beef project, year two.	the results of the second year of the project confirmed most of the major findings from the initial year. feeding cornsilage, particularly as the major roughage in the first month after arrival was associated with excess mortality. mixing of cattle from different sources and vaccinating against respiratory disease appeared to be the most important additional factors that increased mortality rates. delaying vaccination at least two days postarrival may have prevented the negative effects of vacci ...	1981	7260727
hypomagnesaemia in beef cows wintered in ontario.	a field experiment was undertaken in northern ontario in order to assess the magnesium status of beef cattle raised in the area. magnesium status was assessed using several criteria including blood and urine magnesium levels, and bone biopsy samples. eighteen groups each containing four pregnant shorthorn beef cows were used. each of the following three mineral feeds were offered to six groups throughout the experiment: a mineral feed without magnesium, a mineral feed containing 8% magnesium in ...	1981	7260729
occurrence of "haemophilus somnus" in bovine semen and in the prepuce of bulls and steers.	haemophilus somnus was isolated from 40 of 79 unprocessed bovine semen samples, 14 of 23 preputial washings of bulls and three of eight preputial washings of steers. the results indicate nonvenereal colonization of the male urogenital tract. it is suggested that dissemination of h. somnus from the urogenital tract may be of significance in the epizootiology of h. somnus associated diseases.	1982	7093816
evaluation of dairy bulls in ontario for calving ease of offspring.	the first sire evaluations for calving ease for bulls used in ontario were published in may, 1981. evaluations used calving records collected by ontario dairy herd improvement association from all supervised herds from may, 1980, to april, 1981. a total of 34,240 records including herd, breed, sire, and cow identification, date of calving, and information about cow size, parity, sex of calf, mortality, and dystocia score were collected. after editing, 28,947 records were available from 1,178 hol ...	1982	7153398
factors associated with mortality and treatment costs in feedlot calves: the bruce county beef project, years 1978, 1979, 1980.	three years of data on factors associated with death losses and health costs in ontario feedlot calves were analyzed. the results support the previously reported findings; however, significant differences in the third year (1980-81) of the study were noted. calf groups that were "mixed" after arrival in the feedlot or had a larger than average number of calves (means = 142) had increased death losses and health costs. calf groups whose ration was changed from dry hay to hay silage or corn silage ...	1982	7172100
somatic cell counts, mastitis and milk production in selected ontario dairy herds.	somatic cell counts were performed monthly on bulk tank milk samples for all producers in the ontario counties of hastings, lennox/addington and prince edward throughout 1978 and 1979. other data were obtained via a structured questionnaire and from the records of the ontario milk marketing board. many producers have not adopted practices that have been advocated for the integrated control of mastitis. for example, 43.3% of producers surveyed used single service paper towels, 63.3% regularly use ...	1982	7200385
antibody titers to pasteurella haemolytica a1 in ontario beef cattle.	indirect bacterial agglutination titers to pasteurella haemolytica a1 were determined in serum, thoracic, pericardial, or peritoneal fluid from cattle necropsied as part of the bruce county beef project in 1979-80 and 1980-81. antibody titers were also assayed in serum from 84 calves on entry to feedlots in the fall of 1979. titers on entry were low compared to antibody levels at necropsy. cattle which died with pneumonia, in particular those dying of fibrinous pneumonia (shipping fever), had lo ...	1982	6756619
antimicrobial use in feedlot calves: its association with culture rates and antimicrobial susceptibility.	data were collected on anti-microbial usage and health problems, in beef feedlot calves. although the association between them was not significant, many feedlot owners did not use recommended dosages or duration of treatment and this may have led to a reduced recovery rate.injectable tetracyclines were the most frequent antimicrobial for primary treatment of sick calves; whereas chloramphenicol was selected most frequently when the primary treatment appeared to be ineffective. treatment with ant ...	1983	6831306
an observational study of corynebacterium bovis in selected ontario dairy herds.	an observational study of corynebacterium bovis was conducted in 74 ontario dairy herds. the levels of infection with c. bovis were 19.9, 36.2 and 85.6% at the quarter, cow and herd level, respectively. teat disinfection was found to be the variable best able to distinguish between herds with a high or low c. bovis quarter infection rate. mean total milk somatic cell counts for 1103 quarters and 107 cows infected with only c. bovis ranged between 150,000 and 200,000/ml and were significantly hig ...	1983	6831308
factors influencing morbidity and mortality in feedlot calves in ontario.		1983	6612961
evaluation of cow reproduction in the pureline foundation phase of the canadian national dairy cattle breeding project.	five reproduction traits--number of inseminations per cow, days to first estrus, days open, calving interval, and culling rate for infertility--were studied on dairy cows from a long-term breeding project of the agriculture canada research branch. five experimental farms maintained either holstein line, ayrshire line, or both. traits were analyzed within each line by a model in which station, year, sire group (paternal parentage), and bull (cow's mate) were considered. variation these factors ca ...	1983	6682866
a mail survey of factors associated with morbidity and mortality in feedlot calves in southwestern ontario.	the design and results of a mail survey of a simple random sample of southwestern ontario feedlot owners are presented. the survey provided general data about management of feedlot calves and the association between a number of factors and disease and/or death rates. the number of calves purchased was related positively, in a linear manner, to mortality and morbidity rates. increased levels of morbidity and mortality were noted when the ration was changed to corn silage from dry-hay within the f ...	1983	6309344
a field trial, of preshipment vaccination, with intranasal infectious bovine rhinotracheitis-parainfluenza-3 vaccines.	a total of 849 calves, 278 controls, 335 vaccinated intranasally with ibr-pi3/ts and 236 vaccinated intranasally with ibr-pi3/ptc were studied in a field trial of preimmunization. all calves were vaccinated in saskatchewan at least three weeks prior to shipment to feedlots. four hundred and twenty six calves were not sold within eight weeks of vaccination; however, seven of these died within four weeks of vaccination. treatment rates varied from 1.0% to 5.2%. there was no significant effect of v ...	1983	6315194
susceptibility of goats and calves after experimental inoculation or contact exposure to a canadian strain of mycoplasma mycoides subsp. mycoides isolated from a goat.	transmissibility of mycoplasma mycoides subsp. mycoides infection from experimentally inoculated goats to other goats and calves was studied. eight goats and six calves were housed in an 18 m2 room. six of the goats were inoculated endobronchially with strain d44 isolated from a natural case of polyarthritis in ontario. these six goats died within a week of mycoplasma septicemia. the two contact goats or the six calves never showed signs of disease and m. mycoides subsp. mycoides was not recover ...	1983	6365296
listeria monocytogenes infections in canada.	since its first isolation by murray in 1926 listeria monocytogenes has become recognized as a significant pathogen occurring worldwide and involving a wide range of wild and domestic animals including man. the first confirmed human listeriosis case in canada was published by stoot in 1951. a later survey based on records maintained at the laboratory centre for disease control, ottawa showed 101 cases detected over a 21 year period in nine provinces. the overall mortality was 30%. the most freque ...	1984	6442654
hyperbilirubinemia in sick cattle.	hyperbilirubinemia was present in 387 out of 1279 sick cattle admitted to the clinic of the ontario veterinary college. one hundred and ninety five of these had a total serum bilirubin of 17 mumol/l or greater. clinical records, laboratory data and when available, pathology reports from these 195 animals were examined in an attempt to explain the reason for the high bilirubin levels. the hyperbilirubinemia in 187 of these was mainly due to an increase in unconjugated bilirubin. jaundice, liver d ...	1984	6478294
somatic cell counts: associated factors and relationship to production.	factors affecting somatic cell counts and the association between somatic cell counts and milk production were evaluated. data were collected from 748 ontario dairy herd improvement corporation supervised herds that were on production and somatic cell count programs between april 1981 and march 1983. two data files were created; one, the lactation summary file, contained one record per cow on each of 9406 holsteins and the other, the test day file, included results of all tests during the comple ...	1984	6478296
subclinical ketosis: prevalence and associations with production and disease.	cows in 32 southern ontario holstein herds were monitored for subclinical ketosis for a period of two and one half years. milk samples were routinely collected and the level of milk ketone bodies determined by the use of a commercial nitroprusside based test powder (reactions scored as negative, +1 or +2). approximately 92% of positive reactions were observed in the first 65 days of lactation and for that time period the prevalence of ketosis was 12.1%. based on this prevalence, the minimum poss ...	1984	6713247
fatal mastitis of dairy cows: a retrospective study.	the necropsy records of dairy cows with mastitis were reviewed from the provincial veterinary laboratory in guelph (44 cases of mastitis in nine years) and from the ontario veterinary college (168 cases in 14 years). mastitis was considered to be the primary cause of death in 167 of 212 cows (79%). of these 167 cases of mastitis, escherichia coli was involved in 107 (64%), klebsiella sp. in 12 (7%) and staphylococcus aureus in 11 (7%). bacteriology was not reported in 22 cases. coliform mastitis ...	1984	6722641
characterization of strains of corynebacterium bovis.	the biochemical and morphological characteristics of 104 strains of corynebacterium bovis isolated from bovine milk samples and the c. bovis reference strain were found to be uniform. valuable criteria for identification were presence of catalase and oxidase, production of acid from glucose and fructose and a requirement for enriched basal media. six strains of human and three strains of bovine origin were found to be inconsistent with the reference strain.	1984	6722650
some respiratory and enteric diseases of cattle: an update.	fibrinous pneumonia caused 40-45% of death losses in cattle shipped into bruce county, ontario. feeding corn silage within the first 2 weeks of arrival increased mortality. commingling cattle from different sources and keeping more than 110 cattle in a pen were detrimental. while use of antimicrobials in the starter ration was beneficial, prophylactic use of antimicrobials in the water was not. mortality was directly proportional to morbidity and treatment costs. vaccinating against any respirat ...	1984	6738491
campylobacter fetus in artificial insemination unit and slaughterhouse bulls in ontario.	preputial fluid samples were collected from 90 bulls in two ontario artificial insemination units using a penial glove swab technique previously developed by one of us for use in donor bulls. no campylobacter fetus organisms were identified from the prepuce or from samples of semen collected at the same time from these bulls. the distal genitalia of 200 bulls were collected at a slaughter house. one isolation of a campylobacter fetus subspecies venerealis was obtained on a culture from the forni ...	1985	3893662
a mail survey of the efficacy of prophylactic medication in feed and/or water of feedlot calves.	a mail survey of feedlot owners was conducted to evaluate the efficacy of prophylactic antimicrobials, given in the water, or in the ration at preventing illness and/or death. one hundred and twenty-seven farmers from southwestern ontario collaborated in the study. the percentage of calves requiring individual antimicrobial treatment, for any reason within 28 days of arrival was 22.6% (median 17.8%) and 0.6% (median 0.2%) died in that period. the use of medicated starter rations was not associat ...	1985	3986676
reproductive efficiency and calf survival in ontario beef cow-calf herds: a cross-sectional mail survey.	a survey of the efficiency of production of ontario beef cow-calf herds was conducted using a stratified systematic random sample of ontario producers. in general, about 87% of females exposed to breeding produced a live calf and 6% of these died before reaching four weeks of age. the herd to herd variation in these rates was quite large, the coefficient of variation being about 17%. the stillbirth rate was 1.7% and the abortion rate 1.2%. in general, herds in northern ontario and herds whose ow ...	1985	3986678
susceptibility of psychrotrophic pseudomonads of milk origin to psychrotrophic bacteriophages.	a total of 47 psychrotrophic pseudomonads isolated from raw milk came from newfoundland (19 isolates), british columbia (6 isolates), ontario (19 isolates), and cork, ireland (3 isolates). the susceptibility of these was tested against 30 bacteriophages isolated from cold-storage beef. distinct lysotypes were observed with isolates representing different geographic regions. phages as agents in the control of bacterial populations in milk is discussed.	1986	3954353
a path model of factors influencing morbidity and mortality in ontario feedlot calves.	the principles of path analysis and causal modelling are discussed. path analysis was applied to three data sets to assess the relationship between group characteristics (number per group and "mixing" subgroups of cattle, feeding-management of the group and processing factors (vaccination and prophylactic antimicrobials) and subsequent morbidity and mortality in feedlot cattle. the major findings agree with previously reported results but the timing and pathways of the effects are elaborated. in ...	1986	3742352
the relationship among current management systems, production, disease and drug usage on ontario dairy farms.	the study involved 110 randomly selected dairy farms located in the ontario, canada counties of bruce, grey, huron, oxford, perth, waterloo and wellington. herds were classified as "intensive" and "extensive". on extensive farms, data were collected at the herd level only, while on intensive farms, data were recorded at both the individual animal and herd level. data collection continued for approximately two and one-half years. at each visit, technicians collected production data from the most ...	1986	3742360
rate of campylobacter spp. isolation in three regions of ontario, canada, from 1978 to 1985.	isolation rates of campylobacter spp. were analyzed for an 8-year period, 1978 through 1985. three laboratories of the ontario ministry of health examined 146,842 human feces samples for bacterial pathogens, including campylobacter jejuni and campylobacter coli. campylobacter spp. were isolated from 5,580 specimens (3.8%), with monthly isolation rates ranging from 1.1 to 7.4%. the data showed a seasonal distribution of isolations, with peaks during the summer months (june to september). most inf ...	1986	3771774
an epidemiological study of selected calf pathogens on holstein dairy farms in southwestern ontario.	fecal samples from calves on 78 randomly selected holstein dairy farms in southwestern ontario were screened for salmonella, campylobacter jejuni/coli, enteropathogenic escherichia coli, rotavirus and coronavirus. based on the observed prevalence, 22% of farms had calves infected with salmonella, 13% with campylobacter jejuni/coli, 41% with enteropathogenic e. coli, 19% with rotavirus and 5% with coronavirus. these estimates can be modified, using a method developed by mullen and prost (1983) fo ...	1986	3017528
isolation of leptospira hardjo from kidneys of ontario cattle at slaughter.	kidneys from 117 cattle from 110 ontario farms were examined at slaughter for leptospires. leptospira hardjo (hardjo-bovis a) was isolated from 11 kidneys and l. kennewicki from one. the isolations were all made (12/89, 13.5%) from beef cattle from feedlots, no isolates being obtained from dairy or beef cattle from extensive farms (0/28). isolations were only made from cattle with antibody titers (greater than or equal to 20) against the serovars recovered. isolation was more sensitive than immu ...	1987	3300922
bovine reservoir for verotoxin-producing escherichia coli o157:h7.		1987	2879192
infant feeding practices: 1984-85 versus 1977-78.	in 1979 and 1980 the canadian paediatric society's nutrition committee published guidelines for professionals counselling mothers of infants on feeding practices. the practices in 1984-85 of mothers in toronto were determined for comparison with the practices identified in a similar study conducted in toronto and montreal in 1977-78 to ascertain if practices had changed in favour of the recommendations. between july 1984 and february 1985, 404 metropolitan toronto mothers of infants were intervi ...	1987	3567809
factors associated with the presence of salmonella spp. in dairy farm families in southwestern ontario.		1988	2856842
five-year follow-up of hancock pericardial valves: management of premature failure.	the durability and function of bovine pericardial valves are dependent upon design, preservation, patient factors (age, sex), and site of valve implantation. in 1983, a shelf recall of all hancock bovine pericardial valves (hpv) was instituted by the manufacturer. this report represents the results of an organized 5-year follow-up in a hospital prosthetic valve registry of 129 hpv implanted in 122 patients (79 males, 43 females) between may 1982 and april 1985 using echo doppler and careful clin ...	1988	2980043
the prevalence, incidence, geographical distribution, antimicrobial sensitivity patterns and plasmid profiles of milk filter salmonella isolates from ontario dairy farms.	the prevalence, incidence and geographical distribution of salmonella on dairy farms in southwestern ontario were determined by culturing bulk milk filters from 511 randomly selected dairy farms. milk filters from 22 farms (2.9%) were salmonella-positive, with a cumulative incidence rate of 9.0% per year. positive farms were distributed throughout southwestern ontario, but were regionally clustered. the serotype, biotype, antimicrobial sensitivity pattern and plasmid profile of the salmonella is ...	1988	3349397
serosurvey on the occurrence of coxiella burnetii in ontario cattle.		1988	3355970
seroprevalence and association with abortion of leptospirosis in cattle in ontario.	sera were collected using a systematic random sampling from 348 cattle herds in ontario, in proportion to the cattle population in different areas. one cow in five from 296 dairy herds and one in three from 52 beef herds were sampled. the sera were analyzed for prevalence of antibodies to leptospira interrogans serovar grippotyphosa, hardjo, icterohaemorhagiae and pomona using the microscopic agglutination test. herd seroprevalence (one or more animals with titer greater than or equal to 80) in ...	1988	3370556
monitoring wood shaving litter and animal products for polychlorophenols residues, ontario, canada, 1978-1986.		1988	3130916
the presence of listeria spp. in raw milk in ontario.	raw milk samples from bulk tanks in ontario were analyzed for the presence of listeria species. the overall incidence of listeria species in raw milk was 12.4%. listeria innocua was most frequently isolated and was found in 9.7% (43/445) of the raw milk samples, while l. monocytogenes and l. welshimeri were each found in 1.3% (6/445) of the samples. no other species of listeria was found. of five regions in ontario that were examined, the eastern region had a significantly higher incidence rate ...	1988	3135930
an epidemiological study of paratuberculosis in ontario dairy cattle: study design and lipoarabinomannan antigen elisa test results.		1988	3232609
pcb and dde residues in milk supplies of ontario, canada 1985-1986.		1989	2500993
control of bovine leukemia virus infection in dairy herds by agar gel immunodiffusion test and segregation of reactors.	canadian cattle intended for export, in future, may have to originate from herds which are serologically negative for bovine leukemia virus, in addition to being negative individually by the agar gel immunodiffusion test as currently required. in this study, agar gel immunodiffusion testing of herds and segregation of reactors were examined. the results demonstrated that bovine leukemia virus infection could be controlled when three groups: 1) bovine leukemia virus-positive, 2) bovine leukemia v ...	1989	2536579
the associations between milk production, milk composition and salmonella in the bulk milk supplies of dairy farms in ontario.	the purpose of this study was to assess changes in dairy herd milk production and milk composition associated with changes in salmonella contamination of bulk milk on dairy farms in southwestern ontario. twenty-three dairy farms that had submitted milk filters for culture from which salmonella were isolated (cases) and 23 farms that submitted salmonella-negative milk filters (controls) were included in the study. the rolling herd averages for milk and fat of case and control farms for the months ...	1989	2713783
aspects of the epidemiology of nematode infections in a cow-calf herd in ontario.	on may 29, 1980, 108 cows and calves were placed on a 20 hectare pasture until october 26, except that from september 18 to october 2 they were in a barn. every two weeks during the total period, fecal samples were taken from 17 cows and 14 calves and herbage samples were collected from the pasture. parasite fecal egg counts were estimated using the cornell-wisconsin centrifugation technique and herbage infective larvae by a modified sandwich technique. daily maximum and minimum air temperature ...	1989	2766154
the frequency, distribution and effects of antibodies, to seven putative respiratory pathogens, on respiratory disease and weight gain in feedlot calves in ontario.	during 1983-85, 279 calves requiring treatment for bovine respiratory disease and 290 comparison (control) animals from 15 different groups of feedlot calves were bled on arrival and again at 28 days postarrival. their sera were then analyzed for antibodies to seven putative respiratory pathogens. on arrival, the prevalences of indirect agglutination titers to pasteurella haemolytica, p. haemolytica cytotoxin, mycoplasma bovis and m. dispar were greater than 50%, the prevalence of titers to bovi ...	1989	2766158
cadmium levels in bovine liver and kidney from agricultural regions on and off the canadian shield, 1985-1988.		1989	2804412
prevalence of verocytotoxigenic escherichia coli in ground beef, pork, and chicken in southwestern ontario.	samples of ground beef (225), pork (235) and chicken (200) were randomly selected from meat processing plants in the southwestern ontario area. supernatants of broth cultures of the samples were tested for verocytotoxins using a vero cell assay. neutralization of cytotoxic activity using antisera specific for three types of verocytotoxin (verotoxin 1, verotoxin 2 and shiga-like toxin ii) was performed on positive samples. isolation of verocytotoxigenic escherichia coli (vtec) was attempted from ...	1990	2200697
economics of mastitis control.	the frequency of use and the effects of mastitis control practices on scc and milk yield were investigated. a survey of current management practices was combined with dhi production information to determine the relationship between milk yield, scc, management practices, and production and producer characteristics under field conditions. the expected negative relationship between scc and milk, fat, and protein yield was substantiated. the scc for an individual cow was a better indicator of milk l ...	1990	2273158
sire selection decisions and farm profitability relationships for ontario dairy farmers.	the relationship between the relative emphasis of type and production in the sire selection decision and net farm income per cow are examined for a sample of ontario dairy farmers. a significant positive correlation between farm profits and the genetic indices for type and production traits of selected bulls exists, but the direction of causality cannot be determined. net farm income per cow was found to have a significant inverse association with the relative weighting between type and producti ...	1991	1757638
nonfatal farm injuries in eastern ontario: a retrospective survey.	a one-year retrospective survey was conducted to study the incidence of, and potential risk factors for farm-related injuries. one hundred thirteen dairy and beef farms in eastern ontario were surveyed using a personal interview. information was collected on demographic characteristics of the farm owner, workers, and family; characteristics of the farm operation; and information on behaviours potentially affecting injury risk. the crude rate of injury was 9.6 per 100 person years. significantly ...	1991	1772560
associations between dairy production indices and lipoarabinomannan enzyme-immunoassay results for paratuberculosis.	data from an epidemiological study in ontario, involving 304 dairy herds, were used to identify associations between selected production indices and lipoarabinomannan antigen serological test results for paratuberculosis (lam-elisa). analyses were conducted at both the herd and individual cow levels of organization. after analytically controlling for management and cow factors in the respective regression models, positive serological paratuberculosis status (as defined by the lam-elisa test), wa ...	1991	1790492
an epidemiological study of paratuberculosis in dairy cattle in ontario: study design and prevalence estimates.	an observational study involving 304 dairy herds and three abattoirs was conducted between 1986 and 1989 to investigate the epidemiology of paratuberculosis in dairy cattle in ontario. the objectives of this paper were to describe the method of data collection for the study, to present descriptive production statistics and to present estimates of the prevalence of paratuberculosis among dairy cattle in ontario. mycobacterium paratuberculosis was isolated from the distal ileum and/or the ileoceca ...	1991	1889036
a short incubation serum neutralization test for bovine viral diarrhea virus.	a three day serum neutralization (sn) test for the detection of antibodies to bovine viral diarrhea virus (bvdv), which is an improvement on the existing five day test, is described. the improved test results in a more rapid viral cytopathic effect and utilizes madin darby kidney (mdbk) cells, and horse serum as a medium supplement. a comparison of tests utilizing the nadl and the singer strains of bvdv and the use of either secondary bovine kidney cells with calf serum (bkcs) or continuous mdbk ...	1992	1317246