Clinical sickness was observed in domestic ducks, geese, horses and swine during October 1973. All species showed upper alimentary distress with mortalities occurring in the geese. Barley derived from a common source had been fed. Examination of the barley revealed invasion by Fusarium spp and detection of a high level of dermatitic fusariotoxins. (+info)
(2/3381) Epidemiological field studies of animal populations.
Numerous survey designs have been developed for epidemiological field studies of human populations, most of which are also applicable to field studies of animal poulations. Each design has its own advantages and disadvantages. The final design selected for a particular study depends upon such factors as the overall purpose of the study, the geographic dimensions of the study area, the diseases incidence or prevalence and species to be studied as well as the planned use for the data. Population dynamics including the distribution and density of the species to be studied are factors that should also be considered in the initial design of a study. A surveillance system, using mailed questionnaire data and a subsequent survey using direct interviews of validate the data in a statewide study of swine birth defects are used to illustrate some of the techniques that can be applied to domestic animal populations in a fairly large geographic area. The type of data collected, its use and its limitations are also considered. (+info)
(3/3381) Antimicrobial drug use and related management practices among Ontario swine producers.
A mail survey of swine producers in Ontario was undertaken during 1991 to describe the types, frequency, and motives for antimicrobial use. Two hundred operations that marketed fewer than 350 hogs per year, and 800 that marketed more than 350 per year were sent questionnaires, 63% of which were completed and returned. Most operations (86%) added antimicrobials to starter (weanling pig) rations, while fewer (29%) added these drugs to finisher pig rations. The most commonly used antimicrobials were tylosin, carbadox, and furazolidone in weanling pigs, and tylosin, lincomycin, and tetracycline in finishers. Water medication of grower-finisher pigs was practised on 25% of farms; 80% of farms had injected at least some grower-finisher pigs with antimicrobials in the 12 mo preceding the survey. Approximately 20% of operations that added antimicrobials to finisher rations did so for growth promotion purposes only, while others used them for disease treatment, prevention, control, or a combination of reasons. Among those not using antimicrobials in finisher rations, 83% did not believe they were necessary and 37% were concerned about the potential for residues in marketed hogs. (+info)
(4/3381) The effect of cyclopiazonic acid on the development of pale, soft, and exudative pork from pigs of defined malignant hyperthermia genotype.
Malignant hyperthermia (MH) and the mycotoxin cyclopiazonic acid (CPA) are each associated with abnormal calcium homeostasis in skeletal muscle, a key underlying factor in the development of pale, soft, and exudative (PSE) pork. To determine whether the natural presence of CPA in livestock feed ingredients contributes to the varying incidence of PSE in the pork industry, various levels of CPA (.1 to 50 mg/kg of diet) were included in the diets of market weight hogs (n = 52) of defined malignant hyperthermia genotype (NN = normal, Nn = a MH carrier, and nn = MH-positive). Animals with two copies of the MH mutation (nn) displayed improved live animal performance compared with NN and Nn animals (increased feed intake, average daily gain, and feed efficiency) but yielded lower quality loin chops as indicated by lower 45-min pH (P<.01), higher Commission Internationale de l'Eclairage (CIE) L* color coordinate values (P<.05), and higher drip losses (P<.01). The effects of CPA varied. In the first feeding trial, conducted under normal outside temperatures (2 degrees C), CPA had no effect (P> .2) on either live animal performance or meat quality. During the second trial, conducted under extreme outside temperatures (-18 degrees C), CPA-dependent reductions (P<.05) in feed intake, average daily gain, and 45-min pH in nn hogs support the possibility of interactions between malignant hyperthermia and dietary CPA on skeletal muscle calcium homeostasis and the development of PSE pork. These results suggest that this interaction may require stressful environmental conditions or the ingestion of CPA doses much higher than occur under natural conditions. (+info)
(5/3381) Contributory and exacerbating roles of gaseous ammonia and organic dust in the etiology of atrophic rhinitis.
Pigs reared commercially indoors are exposed to air heavily contaminated with particulate and gaseous pollutants. Epidemiological surveys have shown an association between the levels of these pollutants and the severity of lesions associated with the upper respiratory tract disease of swine atrophic rhinitis. This study investigated the role of aerial pollutants in the etiology of atrophic rhinitis induced by Pasteurella multocida. Forty, 1-week-old Large White piglets were weaned and divided into eight groups designated A to H. The groups were housed in Rochester exposure chambers and continuously exposed to the following pollutants: ovalbumin (groups A and B), ammonia (groups C and D), ovalbumin plus ammonia (groups E and F), and unpolluted air (groups G and H). The concentrations of pollutants used were 20 mg m-3 total mass and 5 mg m-3 respirable mass for ovalbumin dust and 50 ppm for ammonia. One week after exposure commenced, the pigs in groups A, C, E, and G were infected with P. multocida type D by intranasal inoculation. After 4 weeks of exposure to pollutants, the pigs were killed and the extent of turbinate atrophy was assessed with a morphometric index (MI). Control pigs kept in clean air and not inoculated with P. multocida (group H) had normal turbinate morphology with a mean MI of 41.12% (standard deviation [SD], +/- 1. 59%). In contrast, exposure to pollutants in the absence of P. multocida (groups B, D, and F) induced mild turbinate atrophy with mean MIs of 49.65% (SD, +/-1.96%), 51.04% (SD, +/-2.06%), and 49.88% (SD, +/-3.51%), respectively. A similar level of atrophy was also evoked by inoculation with P. multocida in the absence of pollutants (group G), giving a mean MI of 50.77% (SD, +/-2.07%). However, when P. multocida inoculation was combined with pollutant exposure (groups A, C, and E) moderate to severe turbinate atrophy occurred with mean MIs of 64.93% (SD, +/-4.64%), 59.18% (SD, +/-2.79%), and 73.30% (SD, +/-3.19%), respectively. The severity of atrophy was greatest in pigs exposed simultaneously to dust and ammonia. At the end of the exposure period, higher numbers of P. multocida bacteria were isolated from the tonsils than from the nasal membrane, per gram of tissue. The severity of turbinate atrophy in inoculated pigs was proportional to the number of P. multocida bacteria isolated from tonsils (r2 = 0.909, P < 0.05) and nasal membrane (r2 = 0.628, P < 0.05). These findings indicate that aerial pollutants contribute to the severity of lesions associated with atrophic rhinitis by facilitating colonization of the pig's upper respiratory tract by P. multocida and also by directly evoking mild atrophy. (+info)
(6/3381) Congenital transmission of Schistosoma japonicum in pigs.
Congenital transmission of Schistosoma japonicum in pigs was investigated by experimentally infecting sows at four weeks gestation (n = 3), 10 weeks gestation (n = 3), or a few weeks prior to insemination (n = 2). None of the piglets born to sows infected prior to insemination or in early pregnancy were found to be infected. However, all of the piglets (n = 26) born to sows infected at 10 weeks gestation were found to harbor schistosomes with S. japonicum eggs recovered from both their feces and livers. The findings show that congenital S. japonicum infection of pigs can occur if sows are infected during mid-to-late pregnancy and may have important implications not only for pigs but also for other mammalian hosts of schistosomes, including humans. (+info)
(7/3381) Pulmonary lesions in guinea pigs experimentally infected with Actinobacillus pleuropneumoniae (A.p.) serovar 1.
Pathological studies were carried out on the lungs of guinea pigs intratracheally inoculated with 4.6 x 10(6-8) colony forming units (CFU)/head of Actinobacillus pleuropneumoniae serovar 1. All animals in the highest dose group died within 24 hr post inoculation (hpi) and showed pulmonary lesions being hemorrhagic in nature while all animals in the lowest dose group were killed as scheduled at 11 days post inoculation (dpi) and showed only hyperplasia of peribronchial lymphoid tissues. In the middle dose group, two died within 24 hpi, two died at 9 dpi, and the remaining one was killed at 11 dpi. Two guinea pigs which died at 9 dpi showed fibrinonecrotic pleuropneumonia which is the most characteristic acute pulmonary lesion in swine, and has not yet been reproduced in laboratory animals up to the present time. This suggests that guinea pigs may be a useful laboratory animal for studying the pathogenesis of Actinobacillus pleuropneumoniae infection in swine. (+info)
(8/3381) Weaning anorexia may contribute to local inflammation in the piglet small intestine.
Compromising alterations in villus-crypt structure are common in pigs postweaning. Possible contributions of local inflammatory reactions to villus-crypt alterations during the weaning transition have not been described. This study evaluated local inflammatory responses and their relationship with morphological changes in the intestine in 21-d-old pigs (n = 112) killed either at weaning (Day 0) or 0.5, 1, 2, 4 or 7 d after weaning to either milk- or soy-based pelleted diets. Cumulative intake averaged <100 g during the first 2 d postweaning, regardless of diet. During this period of weaning anorexia, inflammatory T-cell numbers and local expression of the matrix metalloproteinase stromelysin increased while jejunal villus height, crypt depth and major histocompatibility complex (MHC) class I RNA expression decreased. Upon resumption of feed intake by the fourth d postweaning, villus height and crypt depth, CD8(+) T cell numbers, MHC class I RNA expression and local expression of stromelysin returned to Day 0 values. Together the results indicate that inadequate feed intake during the immediate postweaning period may contribute to intestinal inflammation and thereby compromise villus-crypt structure and function. (+info)