Objective—To estimate the risk of subclinical Mycobacterium avium subsp paratuberculosis (MAP) infection in cows that ingested MAP DNA–positive raw colostrum as calves, compared with risk in cows that ingested MAP DNA–negative raw colostrum as calves. Animals—205 calves born in 12 commercial dairy herds. Procedures—Each calf was separated from its dam within 30 to 60 minutes after birth and fed raw colostrum. For each calf, samples of the colostrum fed were collected and tested for the presence of MAP DNA by use of a nested PCR assay for the target gene ISMAP02. Calves fed colostrum positive or negative for MAP DNA were classified into exposed (n = 69) and unexposed (136) groups, respectively. Each calf was tested for MAP infection at 30, 42, and 54 months of age by use of a serum ELISA and bacterial culture of feces. Weibull hazard regression models were used to evaluate the association between exposure to MAP DNA–positive colostrum and time to testing positive for MAP infection. Results—Hazard of MAP infection was not different between groups (exposed vs unexposed) when serum ELISA, bacterial culture of feces, or both diagnostic tests (parallel interpretation) were positive. Conclusions and Clinical Relevance—Heifer calves fed MAP DNA–positive colostrum were at no greater risk of MAP infection, compared with heifer calves fed MAP DNA–negative colostrum. This result contradicts findings from other studies and should be interpreted with caution.

Among grow-to-finish pigs from 10 herds in Alberta and Saskatchewan, 23 (16%) of 144 fecal samples were culture-positive and 40 (28%) of 144 pigs were seropositive for Salmonella. With a Bayesian model specifying dependence between the 2 tests, the sensitivity (Se) of culture and real-time polymerase chain reaction (RT-PCR) was 79% to 86%, depending on the cut-off value for the enzyme-linked immunosorbent assay (ELISA). Culture specificity (Sp) was assumed to be 100%; RT-PCR Sp was found to be 94%. The ELISA Se was 76% and 51% at optical density cut-off values ≥ 20% and ≥ 40%, respectively; the Sp was 94% at each cut-off value. The model showed some sensitivity to ELISA prior information, the ELISA Se being approximately 8% lower when informative prior information was specified in the model. When there was no adjustment for dependence between culture and RT-PCR, the posterior estimates for both culture and RT-PCR Se were 11% higher than with the conditional-dependence model and had considerably narrower probability intervals, which suggests that correlation between culture and PCR is important and should be adjusted for in future studies.

Ranked among the top threats to conservation worldwide, infectious disease is of particular concern for wild canids because domestic dogs (Canis familiaris) may serve as sources and reservoirs of infection. On British Columbia’s largely undeveloped but rapidly changing central and north coasts, little is known about diseases in wolves (Canis lupus) or other wildlife. However, several threats exist for transfer of diseases among unvaccinated dogs and wolves. To gain baseline data on infectious agents in this area, including those with zoonotic potential, we collected blood and stool samples from 107 dogs in 5 remote communities in May and September 2007. Serology revealed that the dogs had been exposed to canine parvovirus, canine distemper virus, Bordetella bronchiseptica, canine respiratory coronavirus, and Leptospira interrogans. No dogs showed evidence of exposure to Ehrlichia canis, Anaplasma phagocytophilum, Borrelia burgdorferi, Dirofilaria immitis, or Cryptococcus gattii. Of 75 stool samples, 31 contained at least 1 parasitic infection, including Taeniid tapeworms, the nematodes Toxocara canis and Toxascaris leonina, and the protozoans Isospora sp., Giardia sp., Cryptosporidium sp., and Sarcocystis sp. This work provides a sound baseline for future monitoring of infectious agents that could affect dogs, sympatric wild canids, other wildlife, and humans.

Objective--To evaluate effects of a Salmonella Newport siderophore receptor and porin protein (SRP) vaccine on cattle health and performance and on prevalence of fecal shedding of Salmonella bacteria in feedlot cattle. Animals--1,591 beef cattle. Procedures--Cattle were randomly allocated within a replicate (n = 10 replicates [20 total pens]), administered 2 mL of a Salmonella Newport SRP vaccine (n = 795 cattle) or a placebo (796), and revaccinated approximately 21 days after the first administration. Health and performance data were recorded by trained feedlot personnel who were blinded to treatment. Fresh fecal samples (n = 25) were collected from pen floors on days 0, 60, and 120 and within 24 hours of cattle harvest and were subjected to selective Salmonella culture and serotyping by laboratory personnel who were blinded to treatment. Pen-level mixed models were used to analyze data. Results--Significant differences in fecal prevalence of Salmonella bacteria or health and performance variables were not detected between vaccinated and control cattle. Salmonella bacteria were recovered from all 10 replicates, and cumulative prevalence estimates ranged from 1.5% to 22%. Overall prevalence of fecal shedding of Salmonella bacteria was 10.2% and 10.9% in vaccinated and control cattle, respectively. Overall morbidity risk was 34.8% for both vaccinated and control cattle. Overall mortality risks were 1.9% and 1.1% for vaccinated and control cattle, respectively. Conclusions and Clinical Relevance--In this setting, administration of the Salmonella Newport SRP vaccine in feedlot cattle had no effect on fecal prevalence of Salmonella bacteria or cattle health and performance.

A farm trial was conducted to evaluate the effect of in-water iodine on piglet growth, the incidence of diarrhea, and the development of deleterious oral and dental conditions. A total of 208 weaned piglets were included in the study. Piglets were weighed 3 times: within 24 h of weaning, and 3 wk and 6 wk after weaning. A concentration of 1 ppm iodine was provided in their drinking water. Swabs were taken from all water nipples and water lines and pooled fecal samples were collected from all pen floors. Fecal samples were also collected from sows at weaning. The swabs and fecal samples were tested for the presence of Salmonella and Escherichia coli. Within 24 h of each weighing, a complete oral examination was performed on each piglet. No significant difference in growth (P > 0.05) or dental conditions (P > 0.05) was found among treatment groups during the period that iodine was added to the drinking water. After weaning, all deleterious oral conditions increased (oral lesions from weaning to 6 wk, staining and caries from weaning to 3 wk, gingivitis from 3 wk to 6 wk; P < 0.05). Only gingivitis was found to be negatively associated with piglet weight (P < 0.05). Salmonella was cultured only twice from fecal samples and never from water nipples. Only 1 sow tested positive for Salmonella and E. coli O139: K82 and O157:K“V17 were cultured only rarely from the water nipples. No signs of diarrhea were noted throughout the study. Adding an aqueous iodine supplement to nursery pigs, therefore, did not provide an advantage for either growth or oral condition. Deleterious oral conditions do increase after weaning, with gingivitis being associated with lower piglet weight.