Bacterial contamination of colostrum fed to newborn calves in Québec dairy herds

A convenience sample of 234 colostral specimens, collected directly from the nursing bottle immediately prior to the first feeding, was studied. Samples originated from 6 farms and were collected over 24 months. Routine bacteriologic techniques were used to quantify the bacterial load of the colostrum, as well as to identify the bacteria. Overall, at least 1 microorganism was cultured from 221 colostral samples (94.4%). By using the upper tolerance level of 100,000 bacteria/mL, 84 samples (35.9%) were considered contaminated. Staphylococcus spp. (57.7%), gram-negative rods (47.9%), coliforms (44.0%), and Streptococcus uberis (20.5%) were among the most frequently isolated bacteria. The relative risk (RR) of contamination with more than 100,000 bacteria/mL was significantly greater in warm months [RR = 2.55, 95% confidence interval (CI): 1.63 to 4.02] than in cool months and in colostrum offered to male calves (RR = 1.55, 95% CI: 1.09 to 2.20). Bacterial load was also associated with the farm of origin (P < 0.0001). When assessing colostrum management, one should consider bacterial contamination. Multiple factors are likely associated with the degree of contamination, and farm-specific factors may be important. Further studies are necessary to evaluate the impact of bacterial contamination of colostrum on neonatal health.     

Vertical and horizontal transmission of Neospora caninum in dairy herds in Québec

Neospora caninum is an important cause of abortion in dairy cattle. The objective of this observational study was to estimate the rate of vertical transmission of N. caninum in dairy herds in Québec and to investigate horizontal transmission in the same herds. The genealogy of cows from 23 dairy herds were examined. Prevalence of seropositive animals in herds studied varied from 4.3% to 61.8% (average, 21.9%). The overall rate of vertical transmission was estimated to be 44.4%, varying from 0% to 85.7%. Seven cases of horizontal transmission were identified in 6 of the 23 herds studied. Estimated vertical transmission rate varied from herd to herd, but appeared to be higher in herds with a high prevalence of seropositive animals. Although horizontal transmission was identified in 6 herds, it does not appear to be the major route of infection for N. caninum.     

Epidemiological study of Yersinia enterocolitica in swine herds in Québec

The objectives of this study were the identification of the different contamination sources of Yersinia enterocolitica, as well as the determination of the prevalence and the distribution of the different genotypes in swine herds. The owners of 20 farms, located in the Richelieu-Yamaska region, agreed to participate in the study. Each farm was visited a minimum of 5 times between May and October 1997, and, at each visit, 20 environmental and 10 fecal samples were collected. Yersinia enterocolitica isolates were identified, serotyped, and submitted to a genetic characterization by pulsed-field gel electrophoresis. The correlation coefficient (0.61) between prevalence in environment and in feces was significant (P = 0.004). Among the 153 positive samples, 93.5% belonged to serotype 0:3. The comparison of PFGE profiles revealed that all environmental Y. enterocolitica isolates had a profile identical to that of isolates recovered in feces from the corresponding farms. Also, when the genetic profiles of isolates recovered from feces collected at the first visit were compared with the profiles of isolates obtained from the subsequent visits, the same profile was observed on every farm. We concluded that environment does not represent the main source of contamination of swine by Y. enterocolitica and that, in most instances, the same strain persists in a barn from one production lot to another.     

Prevalence of contagious mastitis pathogens in bulk tank milk in Québec

The objective of this study was to estimate the prevalence of mycoplasma, Staphylococcus aureus, and Streptococcus agalactiae in bulk tank milk (BTM) in Québec dairy herds. BTM was sampled 3 times a month in 117 randomly selected dairy herds. Samples were submitted for S. aureus, S. agalactiae, and mycoplasma and for direct mycoplasma detection by polymerase chain reaction (PCR). Mycoplasma spp. was identified at least once in 3 herds (2.6%) by primary culture and/or PCR and in 4 herds (3.4%) by enrichment culture and/or PCR. Staphylococcus aureus was isolated at least once in 99 (84.6%) and 112 (95.7%) herds in primary culture and after enrichment, respectively. Streptococcus agalactiae was isolated at least once in 9 (7.7%) and 10 (8.6%) herds in primary culture and after enrichment, respectively. Herd prevalence of mycoplasma was similar to that previously reported in Canada. Staphylococcus aureus is still by far the most important contagious mastitis pathogen.     

Serotypes of Streptococcus agalactiae cultured from dairy milk samples in Québec

Streptococcus agalactiae remains an important pathogen of dairy herds in Québec, but data about antigenic characteristics of this microorganism are sparse. This study was conducted to determine the variety of S. agalactiae serotypes in dairy herds in Québec. Two hundred and ninety-five isolates cultured from the milk of individual cows from 7 regions of Québec were serotyped. Sixty-two percent of the isolates were untypable. Among the 38% of typeable isolates, serotype III was found most frequently. In conclusion, the heterogeneity found among antigenic determinants of isolates from bovine milk suggests that an immunological method for the detection of S. agalactiae performed directly on bovine milk would not be a practical approach.     

Evaluation of strategies to enhance biosecurity compliance on poultry farms in Québec: effect of audits and cameras

Biosecurity compliance is generally poor in all types of animal production systems around the world. Therefore, it is essential to define strategies to improve the implementation of biosecurity measures. This study evaluated the value of audits and visible cameras on compliance with biosecurity measures required when entering and exiting poultry barns on 24 poultry farms in Québec, Canada. Short term (first two weeks) and medium term (six months later) compliance were determined. Application of biosecurity measures was evaluated using hidden cameras. Video viewing revealed a total of 2748 visits by 259 different individuals. Results showed that bimonthly audits did not have any impact on medium term compliance. Visible cameras had a significant impact on changing boots (OR=9.6; 1.9-48.4) and respecting areas (contaminated vs. clean) during the visit (OR=14.5; 1.2-175.1) for the short term period. However, six months later, compliance declined and was no longer significantly different from controls. Duration and moment of the visit, presence of the grower or an observer, barn entrance design, number of barns, number of biosecurity measures requested, type of boots worn, gender and being a member of a grower's family were significantly associated with biosecurity compliance.     

Swine reproductive and respiratory syndrome in Québec: Isolation of an enveloped virus serologically-related to Lelystad virus

Sera were collected from convalescent sows and sick piglets from six pig farms in southern Quebec that have experienced outbreaks of the so-called porcine reproductive and respiratory syndrome. By indirect immunoperoxidase, a few of these sera (4 of 14) (28.6%) were found to be positive for antibody to the Lelystad virus, whereas by indirect immunofluorescence 30 of 36 (83.3%) were positive for antibody to the antigenically-related American isolate ATCC-VR2332. Pregnant sows inoculated intranasally with filtered homogenates prepared from the lungs of necropsied piglets obtained from a seropositive farm developed fever, inappetence, and reproductive failure characterized by stillbirths and various stages of mummification. Lesions of interstitial pneumonia were induced in experimentally-infected specific pathogen-free piglets. A virus, having morphological and biological characteristics of viruses assigned to the family Togaviridae, was isolated from lung tissues of experimentally-infected animals; it could only be propagated in primary cultures of porcine alveolar macrophages. Identification of the virus was confirmed by indirect immunofluorescence using a monoclonal antibody directed against the nucleocapsid protein of the ATCC-VR2332 isolate and porcine sera that were found positive for antibody to both the Lelystad and ATCC-VR2332 isolates.     

Prevalence and risk factors associated with goat gastrointestinal helminthiasis in the Sertão region of Paraíba State,Brazil

Gastrointestinal helminthiasis represents an obstacle to goat raising, causing severe damage to herds such as growth retardation, weight loss, and even death. In this study, we aimed to determine the prevalence and risk factors associated to goat gastrointestinal helminthiasis in the Sertão region of Paraíba State, Brazil. A total of 256 goats from 54 farms were systematically sampled. Blood and fecal samples were collected from each animal for egg per gram (EPG), larval culture, and packed cell volume (PCV) analyses. We found that 79.3 % of the goats investigated were parasitized with gastrointestinal helminths. Significant correlation (p?=?0.004) was observed between the EPG and PCV of the animals studied, and it was observed that the EPG increases as the PCV decreases. In the larval culture, the most prevalent helminth was Haemonchus sp. (83.2 %). Age and sex were significant variables (p?≤?0.20) for the development of gastrointestinal helminths: 86.8 % of animals over 36 months of age and 81.7 % of females were infected. The variable type of animal exploitation was also significant, with 90.3 % (p?≤?0.20) of the animals presenting double suitability (milk and meat). The Sertão region of Paraíba State presents high prevalence of gastrointestinal helminthiasis in goats, and age and type of animal exploitation are the most relevant risk factors to the development of these parasites.     

Case–control study on risk factors associated with Brucella Melitensis in goat farms in Peninsular Malaysia

Caprine brucellosis is a bacterial zoonotic infection affecting goats especially in developing countries all over the world. In Malaysia, the risk factors associated with this infection in farms have not been studied. A case–control study was carried out in goat farms in four states of Malaysia to elucidate the risk factors associated with the infection on the farms using structured questionnaires and face-to-face interviews. Results indicate that the introduction of new animals (OR?=?5.25; 90 % CI?=?1.46, 18.88), younger age category of farms (OR?=?5.53; 90 % CI?=?1.09, 21.66), and farms with single breed of goats (OR?=?8.50; 90 % CI?=?1.27, 41.97) were significant risk factors for brucellosis. In order to control brucellosis or possibly eradicate it in goat farms, these factors need to be dealt with. Enforcing stringent importation protocols or complete ban of goat importation from brucellosis endemic countries will help reduce risk of introducing new infection into the country.     

Seroprevalence and risk factors associated with equineleptospirosis in the metropolitan region of Salvador and Recôncavo Baiano region,Bahia state (NE Brazil)

Tropical Animal Health and Production - Equine leptospirosis, although usually asymptomatic, has been associated with recurrent uveitis, abortion, and other systemic signs, constituting a major...     

Evaluation of the relationship between personality traits, experience, education and biosecurity compliance on poultry farms in Québec, Canada

Biosecurity compliance is an issue in all types of animal production. Poor compliance is frequently related to lack of knowledge or comprehension. Human dimensions, such as personality and attitudes were also suggested as being related to compliance. As part of a larger study, personality traits, experience, education and training of employees, visitors and growers were evaluated to assess their relationship with their compliance with biosecurity measures when entering and exiting poultry barns. Biosecurity compliance was evaluated using hidden cameras. One hundred fourteen individuals involved in a total of 2379 visits on 23 poultry farms responded to a personality test. Results demonstrated that several determinants of compliance exist, and some are related to personality, experience and education. Three personality traits were significantly associated with compliance: responsibility, complexity and action-oriented. Such information has important implications for the selection of job applicants or task attribution and to enhance effectiveness of training programs.     

Seroprevalence and risk factors of bovine leptospirosis in the province of Manabí, Ecuador

Leptospirosis is a zoonotic disease with worldwide distribution. The disease affects dairy and beef cattle, causing infertility, abortion, and reduced milk yield. A cross-sectional study was conducted to determine the seroprevalence of leptospirosis in cattle and the associated risk factors in the province of Manabí, Ecuador. Serum samples from 749 animals from 55 cattle herds were analyzed using the microscopic agglutination test (MAT). Animals were considered positive when titers were ≥ 1:100. The association between the potential risk factors and the positive Leptospira result was modeled at both animal and herd level using a generalized linear model with a binomial distribution and logarithmic link. The seroprevalence was 56.21% at the individual level and 98.18% at the herd level. The most prevalent serovars were Pomona (28.57%) and Icterohaemorragiae (22.30%). At the animal level, only the age was associated with leptospirosis seropositivity. Seroprevalence in animals over three years of age was 1.197 (95% confidence intervals (CI), 1.032 – 1.390), higher compared to animals up to three years old. The seroprevalence of Leptospira spp. was higher in farms with no veterinary assistance (PR = 1.209; 95%CI 1.053 – 1.388) and without a vaccination program against Leptospira (PR = 1.399; 95%CI 1.09 - 1.794). In addition, herds from Junín canton had a significantly higher seroprevalence of Leptospira spp (PR = 1.548; 95%CI 1.213 - 1.977) compared to the Bolívar canton, which had the lowest seroprevalence. In conclusion, more than half of the animals were positive to Leptospiraspp, and almost all herds had at least one positive animal. Furthermore, veterinary assistance and vaccination of cattle must be considered as essential aspects of the disease control program.     

Prevalence of Neospora caninum antibodies and factors associated with their presence in dairy cattle of the north of Paraná state, Brazil

To determine the prevalence of Neospora caninum antibodies and associated factors, blood sera from 623 female dairy cattle from 23 farms in the north of the state of Paraná, Brazil, were analyzed by means of the indirect immunofluorescent-antibody test (IFAT > or = 25). Serum samples from 134 dogs living on the same farms also were tested for N. caninum antibodies (IFAT > or = 50), and the presence of dogs was associated with the prevalence of N. caninum antibodies in cattle. The overall seroprevalence in cattle was 14.3%, mainly in animals over 24 months of age. Seroprevalence in Holsteins (15.1% of 558) was greater than in mixed-breed cattle (7.7% of 65). Age (> or =24 months) of cattle, feeding silage and/or concentrate produced on the farm were associated; antibodies were found in 21.6% of dogs; and the presence of dogs was associated with the prevalence of N. caninum antibodies in cattle.     

A stochastic model accommodating the FAMACHA© system for estimating worm burdens and associated risk factors in sheep naturally infected with Haemonchus contortus

A previously developed multiple regression algorithm was used as the basis of a stochastic model to simulate worm burdens in sheep naturally infected with Haemonchus contortus over five consecutive Haemonchus seasons (November to January/February) on a farm in the summer rainfall region in South Africa, although only one season is discussed. The algorithm associates haemoglobin levels with worm counts in individual animals. Variables were represented by distributions based on FAMACHA(?) scores and body weights of sheep, and Monte Carlo sampling was used to simulate worm burdens. Under conditions of high disease risk, defined as the sampling event during the worm season with the lowest relative mean haemoglobin level for a class of sheep, the model provided a distribution function for mean class H. contortus burdens and the probability of these occurring. A mean H. contortus burden for ewes (n=130 per sample) of approximately 1000 (range 51-28,768) and 2933 (range 78-44,175) for rams (n=120 per sample) was predicted under these conditions. At the beginning of the worm season when the risk of disease was lowest (i.e. when both classes had their highest estimated mean haemoglobin levels), a mean worm burden of 525 (range 39-4910) for ewes and 651 (range 37-17,260) for rams was predicted. Model indications were that despite being selectively drenched according to FAMACHA(?) evaluation, 72% of the ewes would maintain their mean worm burden below an arbitrarily selected threshold of 1000 even when risk of disease was at its highest. In contrast, far fewer rams (27%) remained below this threshold, especially towards the end of the worm season. The model was most sensitive to changes in haemoglobin value, and thus by extrapolation, the haematocrit, which is used as the gold standard for validating the FAMACHA(?) system. The mean class haemoglobin level at which there was a 50% probability of worm burdens being ≤ 1000 worms was 7.05 g/dl in ewes and 7.92 g/dl in rams.