Effect of thiamine concentration on animal health, feedlot performance, carcass characteristics, and ruminal hydrogen sulfide concentrations in lambs fed diets based on 60% distillers dried grains plus solubles.

Limited data are available regarding the influence of thiamine supplementation on the incidence of polioencephalomalacia (PEM) in lambs fed diets containing increased concentrations of S in the diet (>0.7%). Therefore, our objective was to evaluate the influence of thiamine supplementation on feedlot performance, carcass quality, ruminal hydrogen sulfide gas concentrations, and incidence of PEM in lambs fed a finishing diet containing 60% distillers dried grains with solubles (DDGS; DM basis). Two studies were conducted using completely randomized designs to evaluate the influence of concentration of thiamine supplementation. Study 1 used 240 lambs fed in 16 pens, whereas study 2 used 55 individually fed lambs. Lamb finishing diets contained 60% DDGS, which resulted in a dietary S concentration of 0.73% (DM basis). Treatments diets were based on the amount of supplemental thiamine provided: 1) no supplemental thiamine (CON), 2) 50 mg/animal per day (LO), 3) 100 mg/animal per day (MED), or 4) 150 mg/animal per day (HI). Additionally, in study 2, a fifth treatment was included, which contained 0.87% S (DM basis; increased S provided by addition of dilute sulfuric acid) and provided 150 mg of thiamine/animal per day (HI+S). In study 1, ADG decreased quadratically (P = 0.04), with lambs fed the CON, LO, and MED diets gaining BW at a greater rate than lambs fed the HI diet. In study 1, DMI responded quadratically (P < 0.01), whereas G:F tended to differ linearly (P = 0.08) to concentration of thiamine supplementation, with MED lambs having greater DMI and decreased G:F. No differences (P > or = 0.17) in lamb performance were observed in study 2. In both studies, most carcass characteristics were unaffected, with the exception of a tendency for decreased carcass conformation (study 1; P = 0.09) and greater flank streaking (study 2; P = 0.03). No differences in ruminal hydrogen sulfide concentration (P > 0.05) among treatments were apparent until d 10, at which point lambs fed the LO diet had less hydrogen sulfide concentrations than all other treatments. Lambs fed HI had the greatest concentrations of hydrogen sulfide on d 31 (1.07 g of hydrogen sulfide /m(3); P < 0.009). Ruminal pH did not differ (P = 0.13) and averaged 5.6 +/- 0.06. No clinical cases of PEM were observed during the course of either study. The use of thiamine as a dietary additive to aid in the prevention of PEM in finishing lambs does not appear to be necessary under the conditions of this study.

The economic impact of West Nile virus infection in horses in the North Dakota equine industry in 2002.

This study estimated economic impacts associated with the West Nile virus (WNV) outbreak in horses for North Dakota in 2002. The 2002 epidemic in the United States was the largest meningoencephalitis epidemic reported in the Western Hemisphere. Over 15,257 horse cases were reported in 43 states with most cases occurring in central United States. North Dakota reported over 569 horse cases, with a mortality rate of 22%. The total costs incurred by the state were approximately US$1.9 million. The costs incurred by horse owners were about US$1.5 million. Of the US$1.5 million, about US$781,203 and US$802,790 were spent on medical costs and losses due to inability to use animals because of the disease, respectively. Medical costs included the cost of vaccinating 152 horses, and the treatment costs for 345 horses which were US$4,803 and US$524,400 respectively. Costs associated with mortality were US$252,000 for the 126 horses which died of WNV. The state government spent US*$400,000 on WNV monitoring, control, and surveillance under the WNV-control program in 2002. Despite these conservative estimates, the data suggest that economic costs attributable to WNV epidemic to horse owners in North Dakota were substantial.

A review of management practices for the control of anthrax in animals: the 2005 anthrax epizootic in North Dakota--case study.

Outbreaks of anthrax have diverse consequences on society. Establishing the appropriate control strategies is very important and crucial in reducing the socio-economic impact of the disease. Control measures are aimed at breaking the cycle of infection, and their implementation must be adhered to rigorously. The objectives of this paper were: (i) to review the control strategies currently used in management of anthrax in animals and (ii) to describe management strategies used by producers in North Dakota during the 2005 anthrax outbreak in livestock. Anthrax control strategies were divided in to strategies that apply before, during, and after an anthrax outbreak. This paper also highlights the problems or constraints faced by North Dakota producers in controlling anthrax during the outbreak of 2005.

Environmental and ecological determinants of West Nile virus occurrence in horses in North Dakota, 2002.

West Nile virus (WNV) outbreak in North Dakota in 2002 included over 569 horse cases, clustered mainly in the eastern and northeastern parts of the state. The pattern of occurrence observed suggested existence of specific environmental and ecological factors that increased the risk for infection and illness in those locations. We developed a predictive model with factors that explained the pattern of WNV occurrence observed. Results indicated that surface elevation, temperature, precipitation, reported WNV-positive birds, reported WNV-positive humans, and reported WNV-positive mosquitoes were important predictors of occurrence in horses. However, case distance from water bodies was not significant in the model. Future predictive models of WNV occurrence in horses should take into account these factors in order to improve accuracy and reliability. Research into other potential determinants such as horse management factors are required to determine more differential risk factors associated with WNV occurrence in horses.

Pulmonary mycoplasmosis in farmed white-tailed deer (Odocoileus virginianus).

An outbreak of respiratory disease at a farmed cervid facility resulted in isolation and identification of Mycoplasma boris in four affected white-tailed deer (Odocoileus virginianus) fawns. Microscopically, pulmonary lesions similar to those associated with M. bovis infections in calves, inclulding lymphoplasmacytic peribronchiolar cuffing and caseonecrotic bronchiectasis, were present. Arcanobacterium pyogenes was recovered from lung tissue as well. This report indicates that M. bovis can be associated with respiratory disease in white-tailed deer.

Cloning and sequencing of cnf1 from Escherichia coli incriminated in mink and bovine colibacillosis.

Colibacillosis is responsible for significant losses to the mink and cattle industries. Previous work in our laboratory and by others has suggested that possession of cnf1, the gene encoding cytotoxic necrotizing factor (CNF1), may contribute to the virulence of isolates of E. coli from mink and cattle. The cnf1 gene from E. coli isolated from a mink with colisepticaemia and a bovid with scours was amplified and cloned as a 3.5 kb fragment, and the fragment was sequenced. The cnf1 sequences from the mink and bovine isolates of E. coli were compared to each other and to cnf1 sequences of E. coli from urinary tract and diarrhoea-associated infections of humans. The difference was only 7 nucleotides between the cnf1 sequences of the mink and bovine isolates of E. coli, which translated into 7 differences in amino acids. The cnf1 sequence of the mink isolate of E. coli had 15 nucleotide differences from the cnf1 sequences of the human isolate of E. coli (GenBank X70670), which translated into 11 differences in amino acids between these proteins. The cnf1 sequence of the bovine isolate of E. coli had 14 nucleotide differences from the cnf1 sequence of the human isolate of E. coli (GenBank X70670), which translated into 10 differences in amino acids between these proteins. The highly conserved sequences of the amino acids of CNF1 proteins make them a promising target for detection and control of the CNF1-producing E. coli involved in disease among various host species.

Characterization of Escherichia coli isolates incriminated in colisepticaemia in mink.

Colisepticaemia is a major health and economic concern for the mink industry, yet little information is available about the Escherichia coli that cause this disease. In this study, 40 E. coli, isolated from mink clinically diagnosed with colisepticaemia that had been submitted to the North Dakota State University Veterinary Diagnostic Laboratory, were randomly selected for characterization. These isolates were serotyped and screened for resistance to 18 antimicrobials, possession of transmissible R plasmids, and the presence of several virulence traits or genes using bioassays or the polymerase chain reaction. Several serotypes were identified that have previously been associated with septicaemia in other animal species. The majority of the isolates exhibited multiple antimicrobial resistance phenotypes. Common resistance phenotypes observed included those to tetracycline, sulfamethoxazole, streptomycin, ampicillin and kanamycin. Several of the isolates that could be studied by conjugation contained transmissible R plasmids coding for multiple antimicrobial resistance phenotypes. About half of the isolates produced colicin; all produced enterobactin: and all but one-quarter produced aerobactin. None of the isolates tested produced enterohaemolysin, and one-fifth were considered to be beta haemolytic. About half appeared to contain the gene encoding cytotoxic necrotizing factor-1; three contained the gene encoding EAE, but none appeared to contain the genes coding for LT, Sta/b, SLT-I/II or CNF-II toxins or K99 antigen. Approximately one-third of the isolates elaborated capsule. The results show that the E. coli isolates implicated in mink colisepticaemia possess similar virulence traits and antimicrobial resistance phenotypes to those associated with diarrhoeal diseases in food animals.

Mycotic rumenitis in American bison (Bison bison).

Necropsies were performed on 2 American bison (Bison bison) cows, I of which died acutely and the other that died after a week of illness. Gross and microscopic lesions were consistent with severe mycotic infection of the forestomachs. Both animals had been abruptly placed on a breeder ration 1 month after calving, and had developed acidosis and subsequent fungal invasion of tissues. History and lesions in this case indicate that bison are susceptible to rumen acidosis and its sequelae.

Haemophilus somnus bronchopneumonia in American bison (Bison bison).

Immunoperoxidase assays were performed on 21 archived formalin-fixed, paraffin-embedded tissues from from American bison (Bison bison) with bronchopneumonia. Seven of the 21 bison had positive staining for Haemophilus somnus in alveolar exudate, visceral pleura, lung parenchyma, and chronic necrotic lesions, and H. somnus was isolated from tissues from 1 of these 7 animals. Results suggest that H. somnus is a respiratory pathogen in bison.

Seasonal incidence and antibiotic susceptibility patterns of Pasteurellaceae isolated from American bison (Bison bison).

Ninety pharyngeal tonsils were collected from 2-year-old American bison (Bison bison) bulls and sampled for members of the Pasteurellaceae family. Particular attention was paid to seasonal incidence and antimicrobial resistance in serotypes and biovariants. Multiple strains of Pasteurella haemolytica (39%), P. trehalosi (68%), P. multocida (34%) and Haemophilus somnus (13%) were cultured from 86 out of the 90 (96%) tonsil samples. Pasteurella trehalosi was the most common and evenly distributed of the organisms recovered. Pasteurella haemolytica was found in fewer numbers than P. trehalosi, but showed an increase in number of isolates recovered with each sampling period. Pasteurella multocida, both A and D capsular types, was recovered from all sampling periods. No serotype pattern was observed in any of the animal groups sampled. One hundred twenty-seven of 147 (86%) of the isolates were resistant to at least 1 antibiotic, 95/147 (65%) to at least 2 different antibiotics, and 16/147 (11%) to at least 3 antibiotics. The most common resistance pattern observed was to neomycin and spectinomycin (73/147) (49%).

Nonsuppurative meningoencephalitis associated with Aleutian mink disease parvovirus infection in ranch mink.

Severe nonsuppurative meningoencephalitis associated with Aleutian mink disease parvovirus (ADV) infection was observed in adult ranch mink. Brain lesions included severe, locally extensive to coalescing lymphoplasmacytic meningoencephalitis with accompanying gliosis, satellitosis, and mild extension of inflammation into the leptomeninges. ADV was identified in mesenteric lymph node, spleen, brain, and liver of affected mink by polymerase chain reaction techniques. Sequences of the ADV isolate (TH5) revealed 2 unique residues in the region of the viral genome that determines pathogenicity. These findings suggest that certain strains of ADV may preferentially cause disease in the nervous system. ADV infection should be considered in the differential diagnosis of neurologic disorders in mink.

Chromobacteriosis in a Chinese red panda (Ailurus fulgens styani).

An adult Chinese red panda (Ailurus fulgens styani) transported by airplane from Florida to a North Dakota zoo died 1 week after arrival. Grossly, an interscapular abscess, subcutaneous inflammation, lymphadenitis, and pulmonary abscesses were observed. Microscopic findings included necrotizing inflammation in liver, lung, lymph node, and spleen. Chromobacterium violaceum was cultured from the interscapular abscess, liver, lung, and spleen and was injected into Swiss Webster mice. These mice died 18 hours postinoculation, and C. violaceum was cultured from liver, lung, and spleen. Chromobacterium violaceum is a sporadically reported but highly virulent pathogenic bacterium of both animals and humans typically found as a soil and water inhabitant of tropical and subtropical regions.

Pasteurellaceae isolated from tonsillar samples of commercially-reared American bison (Bison bison).

As commercial producers of American bison (Bison bison) become more numerous, concerns relative to bison health management increase. Since loss due to respiratory disease associated with Pasteurella and related Pasteurellaceae is a major concern for cattle producers, a study was conducted to determine what types of Pasteurellaceae are carried by bison to evaluate the potential of pneumonic pasteurellosis in bison herds where management practices are comparable to those used for cattle. Tonsillar biopsies, collected in May (n = 29) and August (n = 25) 1997 from 24- to 30-month-old bison bulls, at the time of slaughter were cultured for Pasteurellaceae. Pasteurella spp. were isolated from all the samples collected in May. These included isolates identified as P. haemolytica, trehalosi, testudinis, and multocida subsp. multocida a and multocida b. Actinobacillus spp. and Haemophilus somnus were also isolated from some samples. Pasteurella spp., haemolytica, trehalosi, and multocida subsp. multocida a, multocida b and septica, plus 2 nonspeciated indole-positive biotypes, U2 and U16, were isolated from the second group of tonsil samples. Most of these organisms, including P. haemolytica, P. multocida subsp., and H. somnus are associated with disease in domestic livestock and should be regarded as potential pathogens for bison, particularly in animals which become stressed by management practices commonly used with cattle such as herding, crowding, and shipping.

Characterization of putative Haemophilus somnus isolates from tonsils of American bison (Bison bison).

Three Haemophilus somnus isolates (2a, 3a, and 27b) and one H. somnus-like (13b) isolate from tonsils of commercially reared American bison were compared with 2 known H. somnus isolates from cattle, namely, 2336, shown to cause respiratory disease, and 129Pt, from the prepuce of an asymptomatic bull. All H. somnus isolates, but not the H. somnus-like isolate, required CO2 for growth. Biochemical utilization profiles were identical for bison and bovine H. somnus isolates with the exception of alpha-fucosidase production by isolate 3a. Isolate 27a varied from 2a, 2336 and 129Pt by hemolysis of bovine erythrocytes. Isolate 13b hemolyzed sheep but not bovine or bison erythrocytes and varied from other isolates in biochemical utilization tests. Outer membrane protein profiles of 2a, 3a and 27a were almost identical with those of bovine isolate 2336 and similar to that of 129Pt, but quite different from that of 13b. Western blots of bison isolates were similar to that of the virulent bovine 2336 isolate, including detection of high molecular mass antigens above 100 kDa and the 76 kDa antigens associated with bovine IgG2 Fc binding characteristic of virulent strains, as well as antigens of approximately 78, 60 and 40 kDa. Producers and veterinarians should be aware that H. somnus may be carried by bison and may have potential for causing diseases in bison similar to those described in cattle and sheep.

Plague in free-ranging mammals in western North Dakota.

From July through October of 1996, 48 blood samples were collected from coyotes (Canis latrans), badgers (Taxidea taxus), and raccoons (Procyon lotor) in western North Dakota (USA) for the purposes of determining antibody titers to the plague bacterium, Yersniia pestis. The passive hemagglutination paper-strip blood-sampling technique was utilized with hemagglutination inhibition controls. Two positive samples were obtained from McKenzie county, one from a coyote with a titer of 1:64 and one from a badger with a titer of 1:256. Considering coyote and badger population dynamics, this study documents plague in western North Dakota.

Pneumocystosis associated with canine distemper virus infection in a mink.

An adult mink from a farm experiencing 100% mortality in affected animals was submitted for diagnostic examination. Clinical history included signs of respiratory disease, oculonasal discharge, and thickening of footpads. Canine distemper virus and Pneumocystis carinii were identified in lung tissue, suggesting immunosuppresion and secondary infection due to morbillivirus disease.

Morphological effects of Pasteurella multocida type-D dermonecrotoxin on rat osteosarcoma cells in a nude mouse model.

Of 15 athymic nude mice that received subcutaneous implants of a rat osteosarcoma cell line, two groups of four subsequently received either a short (group 1) or a more prolonged (group 2) course of subcutaneous injections of the dermonecrotic toxin (DNT) of Pasteurella multocida type D. The remaining seven mice (controls) received no DNT. Both groups of DNT-treated mice lost body weight as compared with controls. Tumour weight, expressed as a percentage of body weight, increased in the four group 1 mice. Tumours in this group 1 were consistently larger than those in appropriate controls, indicating that this percentage was not simply a function of decreased body weight. The immunohistochemical labelling of proliferating cell nuclear antigen (PCNA) and morphometric analysis of intratumoral necrosis suggested that the DNT had a mitogenic effect and contributed to the neoplastic growth. The presence of foci of neoplastic osteoblasts in the lungs of some DNT-treated mice suggested that the enhanced tumour growth led to an increased incidence of metastasis.