Sulfur-induced polioencephalomalacia in a herd of rotationally grazed beef cattle

Central nervous system disease occurred in a herd of rotationally grazed beef cattle consuming water containing 3400 ppm sulfate. Clinical signs, pathologic findings, and high water sulfate levels confirmed the diagnosis of sulfur-induced polioencephalomalacia. The incidence of disease reduced when the herd was switched to a low sulfate water source.     

Acute lead poisoning in cows due to feeding of lead contaminated ash residue

In a dairy herd of 21 cows which were on pasture during the day at the end of May 2002, four eight years old cows were suddenly inappetent and showed severe diarrhoea consisting of black discolorate feces. A few days after the onset of the disease, three affected cows exhibited neurological disorders. These cows were admitted to the IInd Medical Clinic of the University for Veterinary Medicine in Vienna. Following clinical signs were observed: circulatory weakness, anorexia, atony of the rumen, diarrhoea and in accordance with acute lead poisoning typical signs of the central nervous system. One cow died and the other two animals were euthanized. Results of blood testing were anaemia, basophil spotting of erythrocytes, increase of liver enzymes and CK, hypocalcaemia, decrease of potassium and phosphate. The cerebrospinal fluid of two cows showed increased CK-, LDH- and AST-values. The lead contents of whole blood samples were between 0.486 and 0.928 mg/kg, of liver samples 13.3 to 114.4 mg/kg, of kidney samples 172.2 to 448 mg/kg and of rumen content 59 mg/kg fresh matter. At necropsy, enteritis, liver fluke disease and severe interstitial and alveolar pulmonary emphysema were found. Pathohistologically typical ischaemic necrosis of neurons predominantly at the tips of the gyri, disseminated petechial hemorrhages and moderate diffuse neovascularisation, but no acid-fast intranucleolar inclusion bodies in the renal tubules were observed. As causative agent of the acute lead poisoning a residue on combustion, taken up by the cows on the pasture, was confirmed. The ash residue was formed by combustion of three tires which contained 450 g heavy weights of 96.5% lead for wheel balance. The lead content of the ash residue was between 2.9 and 28 g/kg dry matter.     

Reproductive and some peri-natal variables in a mixed breed beef cattle herd

SUMMARY: Calving success (CS), days to calving (DC), birth weight (BW) and calving ease (CE) were studied in a mixed breed (Hereford, Jersey × Hereford and Simmental × Hereford) beef cattle herd. DC was not normally distributed and a number of transformations failed in normalising it. Repeatabilities were estimated by analysis of variance. Inclusion (or exclusion) of non calvers and the transformations studied had little effect on the repeatability of DC, which ranged from 0.10 to 0.12. The repeatabilities for CS, BW and CE were 0.08, 0.26 and 0.03, respectively. The residual correlations of CS with DC and functions of DC were high (-0.68 or greater), whereas the correlations among DC and functions of DC were close to one. The correlations of DC with BW and CE varied little with the transformation applied to DC, ranging from 0.26 to 0.28 and 0.10 to 0.12, respectively. The correlation between BW and CE was 0.06. The study points to a number of problems associated with the use of DC as a reproductive variable in beef cattle. It is concluded that although DC is currently a useful field reproductive variable, the search for appropriate female reproductive traits should continue. ZUSAMMENFASSUNG: Reproduktions- und Perinatal-Variable in einer gemischtrassigen Fleisch-Rinderherde Abkalbeerfolg (CS), Tage bis Abkalbung (DC), Geburtsgewicht (BW) und Kalbeleichtigkeit (CE) wurden in einer gemischtrassigen (Hereford, Jersey × Hereford und Simmental × Hereford) Mutterkuhherde untersucht. DC waren nicht normalverteilt und konnte auch durch eine Reihe von Transformationen nicht normalisiert werden. Wiederholbarkeiten wurden mit Varianzanalyse gesch?tzt. Berücksichtigung (oder Nichtberücksichtigung) von Nichtkalbungen und die Transformationen hatten wenig Wirkung auf Wiederholbarkeit von DC, die zwischen 0,10 und 0,12 war. Wiederholbarkeiten für CS, BW und CE waren 0,08, 0,26 und 0,03. Die Restkorrelation von CS mit DC und Funktionen von DC waren hoch (- 0,68 oder st?rker), w?hrend Korrelationen zwischen DC und Funktionen von DC auch nahe 1 waren. Die Korrelationen von DC mit BW und CE schwankten wenig nach den verschiedenen Transformationen und bewegten sich zwischen 0,26 und 0,28 sowie 0,10 und 0,12. Die Korrelation zwischen BW und CE war 0,06. Die Untersuchung weist auf eine Reihe von Problemen, die sich durch die Verwendung von DC als Reproduktionsvariable von Fleischrindern ergeben. Es wird der Schlu? gezogen, da? DC derzeit zwar nützliche Information für die Praxis ist, da? aber das Suchen nach wissenschaftlich angemessenen weiblichen Reproduktionsmerkmalen fortgesetzt werden sollte. RESUMEN: Variables reproductivas y peri-natales en un rodeo de vacunos de carne de varias razas Las variables éxito al parto (CS), dias al parto (DC), peso al nacer (BW) y facilidad de parto (CE) se estudiaron en un rodeo de vacunos de carne compuesto de varias razas (Hereford, Jersey × Hereford y Simmental × Hereford). DC no estaba normalmente distribuida y una serie de transformaciones ensayadas fracasaron en normalizar esta variable. Las repetibilidades se estimaron por análisis de variancia. La inclusión (o exclusión) de las vacas falladas (no paridas) del análisis y las transformaciones estudiadas tuvieron poco efecto en la repetibilidad de DC, que varió de 0.10 a 0.12. Las repetibilidades de CS, BW y CE fueron 0.08, 0.26 y 0.03, respectivamente. Las correlaciones residuales de CS con DC y con funciones de DC fueron altas (valor absoluto 0.68 o mayor), mientras que las correlaciones entre DC y funciones de DC fueron cerca de uno. Las correlaciones de DC con BW y CE variaron poco con la transformación aplicada a DC, yendo (en valor absoluto) de 0.26 a 0.28 y 0.10 a 0.12, respectivamente. La correlación entre BW y CE fue de 0.06. El estudio apunta a una serie de problemas asociados con el uso de DC como variable reproductiva en vacunos de carne. Se concluye que aunque DC es actualmente una útil variable reproductiva de campo, la búsqueda de rasgos reproductivos de la hembra a ser incluídos en esquemas de evaluación genética de vacunos de carne debe continuar.     

Transmission and control of leptospiral infection in a beef cattle herd in southern alberta

Leptospiral antibodies were detected in unvaccinated cattle on a 17 000 hectare ranch in the arid southeast region of Alberta. Antibody to serovar hardjo was present before the breeding season in 7% of 42 yearling bulls, 86% of 29 two year old bulls and 5% of 519 cows. Pomona antibody was confined to 3.7% of the cows. Bulls were treated once with dihydrostreptomycin, 25 mg/kg. Bulls and cows were vaccinated twice at a six week interval, with pomona-hardjo-gripptotyphosa bacterin before breeding and cows were revaccinated the next year. Leptospires were demonstrated in urine, kidney and spinal fluid of vaccinated and treated cattle. New infections occurred on range in vaccinates. Eighteen months after the last vaccination, hardjo and pomona antibody prevalences in cows were 3.6 and 3.2% respectively. A group of 250 seronegative cows on the same ranch were not vaccinated. They remained seronegative throughout the 2.5 years of the study. These cows, in contrast to infected groups, were excluded from pastures adjacent to perimeter herds and grazing leases, and they were bred by artificial inseminstion. Rotation through pastures in common with infected groups, and exposure to seropositive heat detector bulls, did not result in seroconversion in these cows. The study showed the potential of range bulls to amplify and transmit hardjo infection, limitations to the value of treatment and vaccination with available agents, and the potential of management practices to maintain an uninfected herd in close proximity to cattle carrying hardjo infection.     

Evidence of point-source exposure to Neospora caninum and protective immunity in a herd of beef cows

OBJECTIVE: To determine whether cows with evidence of previous infection with Neospora caninum were less likely to abort or give birth prematurely during an outbreak of neosporosis, compared with herdmates with evidence of primary infection. DESIGN: Cohort study. ANIMALS: 208 pregnant beef cows. PROCEDURES: Aborted fetuses and calves born prematurely were examined during an outbreak of neosporosis in a herd of beef cows. Sera were collected from all cows during the outbreak and again 71 days later. Cows were classified into groups on the basis of normal and abnormal reproductive outcomes. Sera were examined, using an avidity ELISA procedure for N caninum, and results were compared between groups and among time points. RESULTS: Antibody concentrations decreased significantly and IgG avidity values increased significantly over time. During the outbreak, cows with normal reproductive outcomes were significantly more likely to have high IgG avidity values than cows with abnormal reproductive outcomes. CONCLUSIONS AND CLINICAL RELEVANCE: The herd had numerous abortions and premature births with evidence of recent point-source exposure to N caninum. Therefore, to reduce risk of transmission of N caninum to cattle, attempts should be made to prevent canine feces from contaminating feed, especially feedstuffs used to prepare mixed rations for cattle. Cows with evidence of previous exposure to N caninum were less likely to abort or give birth prematurely during the outbreak than cows with primary infections with N caninum; this finding suggests development of protective immunity in previously infected cows.     

Prevalence and pathogenicity of Cryptosporidium andersoni in one herd of beef cattle

Over a 35-week period from January to July 2002, a breed of Hereford beef cattle (H) and their hybrids were monitored. Five hundred and ninety-nine individual fecal samples from calves and 96 samples from their mothers were examined. First excretion of Cryptosporidium andersoni oocysts in calves was found in the 9th week after the start of calving (a calf 63-day old). The prevalence of C. andersoni in calves ranged from 11.1 to 92.9% depending on age. The mean prevalence in their mothers was found to be 43.8%. The size of oocysts was 8.48 +/- 0.78 x 6.41 +/- 0.59 microm. Infection intensity in calves ranged from 32 000 to 4 375 000 oocysts per gram (OPG) and in mothers from 78 000 to 2 552 000 OPG. Three cases of abomasal cryptosporidiosis slaughtered at the age of 81, 157 and 236 days were examined histologically and ultrastructurally [transmission electron microscopy (TEM) and scanning electron microscopy (SEM)]. Cryptosporidium infection of the abomasum was located in the upper half of the mucosal glands in the plicae spirales of the fundus, corpus and near the ostium omasoabomasicum. Cryptosporidia were not located in the glandular epithelium of the pars pylorica in the abomasum minimally 10 cm from pylorus. Histopathological changes in the site of cryptosporidial infection in the abomasum had a non-inflammatory character and included distinctive dilatation of infected parts of the glands with atrophy and metaplasia of the glandular epithelial cells, goblet cell activation and mucus hyperproduction. The TEM revealed a relatively small number of Cryptosporidium life cycle stages attached to glandular epithelial cells. In SEM the inner mucosal abomasal surface appeared swollen but was never infected by cryptosporidia.     

Investigation of bovine viral diarrhea virus infections in a range beef cattle herd

Bovine viral diarrhea virus (BVDV) infections resulting in clinical disease developed in calves, despite vaccination of dams and high maternal BVDV antibody titers in calves. Eight persistently infected (PI) calves born to immunocompetent dams were identified in the herd. Neutralizing BVDV antibody titers of PI calves had decreased greatly by the time the calves were 1 to 2 months old. Antibody titers of PI calves decreased more rapidly than antibody titers of calves that were not PI. Reduced antibody titers in PI calves allowed detection of BVDV in serum specimens of all PI calves by the time they were 8 weeks old. Persistent infection in suspect calves was detectable serologically and was confirmed by virologic examination of serum specimens 4 months after weaning, when the calves were 9 months old. Growth rates were reduced in viremic calves.     

Toxic effects in dairy cattle following the ingestion of a large volume of canola oil

The clinical and laboratory findings of a group of 9 dairy cattle that accidentally ingested large volumes of canola oil are described. Four of the animals died, and 3 were necropsied. No specific cause of death was found, although a number of theories are advanced. This is the first report of such an occurrence.     

Tremorgenic syndrome in a cattle herd after feeding silage contaminated with A. clavatus

The clinical signs, pathological and laboratory findings of cattle suffering from a tremorgenic syndrome are described. Animals on a farm with a total of 22 cows, 18 heifers and 9 calves were fed mouldy grass and spent malt-grain silage. Five heifers were affected with muscular tremor, hyperexcitability and hypersensitivity. They were ataxic or in sternal recumbency, while their appetite remained normal. Haematology and blood chemistry in two heifers as well as cerebrospinal fluid from one sick animal were unremarkable. The pathological examination of one animal brought no macroscopic changes to light. Histological examination, however, revealed the degeneration of motor neurones in the midbrain, brain stem and spinal cord. Analysis of a silage sample provided evidence of the presence of Aspergillus clavatus, a mould capable of producing neurotoxic tremorgenic mycotoxins. Epidemiology, clinical findings, pathology and microbiological examination suggest that the five cattle were suffering from neuromycotoxicosis.     

Optic neuropathy in a herd of beef cattle in Alberta associated with consumption of moldy corn

A group of beef cattle in eastern Alberta was investigated due to sudden onset of blindness after grazing on standing corn in mid-winter. Fumonisin-producing Fusarium spp. were isolated from the corn. Blindness was due to an optic nerve degeneration suspected to be secondary to fumonisin mycotoxin.     

Investigation of an outbreak of mucosal disease in a beef cattle herd in southwestern Saskatchewan.

This study describes the epidemiological investigation of an outbreak of mucosal disease that occurred on a ranch in southwestern Saskatchewan. Over a six-month period during the fall and winter of 1991-1992, in a herd of 515 beef cattle and 96 bison, 20 yearling cattle from a group of 105 housed in one feedlot pen died from mucosal disease. A further eight yearlings were slaughtered for salvage because they were at risk of dying from mucosal disease. Mucosal disease mortalities were the first observed evidence of fetal infections with bovine viral diarrhea virus in this herd. Animals that died from mucosal disease exhibited signs of ill thrift prior to death. Deaths from mucosal disease were confined to the progeny of one herd of beef cows. Following an outbreak of fetal infection with bovine viral diarrhea virus during 1989-1990, at least 28 (22%) of the 128 calves born from this herd of cows in the spring of 1990 were persistently infected with bovine viral diarrhea virus. However, only one calf born from this herd in 1991, and five calves born from all herds in 1992 were persistently infected. Of the five persistently infected calves born in 1992, three were born to persistently infected replacement heifers born in 1990. These heifers calved without assistance in 1992, but only one of their calves survived past three days of age, and it was persistently infected. In January 1992, 82% of the total herd had reciprocal antibody titers to bovine viral diarrhea virus of > or = 1024 which suggested a high level of herd immunity to bovine viral diarrhea virus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Salmonellosis in a herd of beef cows

Two postparturient beef cows in a herd of 30 developed acute enteritis, with pyrexia and bloody diarrhea containing intestinal casts. Salmonella typhimurium phage type 66 was isolated from feces of both animals; both recovered after treatment with tetracycline. A third cow had died without treatment after showing similar signs.     

Seasonal distribution of bovine coccidia in beef cattle herd in the university farm

Fecal samples (2,019) from cattle in the university farm, Tohoku University, were examined for coccidian oocysts from April 1986 to January 1987, and 19.3% of them was positive for Eimeria spp. Thirteen Eimeria species were identified. Eimeria bovis (25.7%) was the most dominant species, followed by E. auburnensis (17.6%), E. canadensis (14.5%), E. alabamensis (9.7%), E. ellipsoidalis (8.1%), E. zuernii (7.0%), E. bukidnonensis (5.4%), E. brasiliensis (3.9%), E. cylindrica (1.3%), E. illinoiensis (0.4%), and E. pellita (0.2%). Fecal samples positive for coccidial oocysts amounted to 12.9% and 26.7% on average during grazing on pasture and loose housing, respectively.     

Gossypol toxicosis in a herd of beef calves

A 6-month-old crossbred calf was examined as representative of a herd of calves experiencing dyspnea and death, with few other clinical signs of illness. Physical examination of the calf identified pleural and peritoneal effusion and poor body condition. The calf did not respond to supportive treatment, and necropsy of it and another calf from the herd identified congestive heart failure as the cause of death. Gossypol toxicosis was the cause of congestive heart failure in this herd; the source of the toxin was a cottonseed meal and cottonseed hull ration fed by the owner.     

Experimental rapid infection in market swine following exposure to a Salmonella contaminated environment

The objective of these experiments was to evaluate the possibility of swine becoming infected with Salmonella Typhimurium after a short time interval in a contaminated environment. Two experiments were conducted. Experiment 1 consisted of five trials with eight market weight swine. Pigs were necropsied at 2 (n = 10), 3 (n = 10) and 6 (n = 5) hours after continuous exposure to an environment contaminated with feces shed by swine intranasally inoculated with nalidixic acid-resistant Salmonella Typhimurium (chi 4232). In Experiment 2, pigs were necropsied after 30 minutes (n = 6), 60 minutes (n = 6), 2 hours (n = 6), and 6 hours (n = 3). In addition, control animals with no exposure were also necropsied in both experiments. At necropsy, the superficial inguinal, ileocecal, and mandibular lymph nodes, as well as cecal contents, distal ileum portion, and feces were evaluated. All samples were cultured for the presence of the nalidixic acid-resistant Salmonella. Feces deposited on the floor by intranasally inoculated swine were mixed with water to form slurry with a resulting load of 10(3)-10(5) Salmonella Typhimurium CFU per gram. In Experiment 1, 80% percent of animals with a 2-hour, 60% of animals with a 3-hour, and 100% of animals with a 6-hour exposure to this slurry had at least one sample test positive for the marked Salmonella Typhimurium strain. In Experiment 2, 50% of the 30 minute, 50% of the 60 minute, and 33% of the 2-hour exposed pigs had at least one sample test positive. These experiments show that market swine can become infected during routine resting or holding periods when exposed to relatively low levels (10(3) CFU) of Salmonella in the simulated pre-slaughter environment, and that exposure times as short as 30 minutes are sufficient to produce contaminated gastrointestinal tracts. They also demonstrate the high risk of holding pigs longer than six hours. Intervention at this step in the swine production process may have a significant impact on the safety of pork products.