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Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trace mineral supplementation of beef cattle is essential for efficient reproduction and herd health. Understanding regional differences in cow trace mineral status could inform decisions about risks of deficiencies and supplementation management. Cow–calf surveillance projects provided three opportunities to evaluate the trace mineral status of Canadian beef cow herds. Blood samples were collected at pregnancy testing in 2014 from 102 cow–calf herds and in 2016 from 86 cow–calf herds in Western Canada. In 2019, blood samples were collected at pregnancy testing from cows in 163 cow–calf herds from Eastern and Western Canada. Serum samples were analyzed for copper, selenium, and molybdenum concentrations using a plasma mass spectrometer. The prevalence of copper deficient cows sampled from the Western provinces ranged from 24% to 43% across the three periods, and was 20% from Eastern Canada in 2019. The prevalence of selenium deficient cows ranged from 0.2% to 0.4% across the three projects in Western Canada, but was higher in Eastern Canada at 4.6% in 2019. High serum molybdenum was identified in 9.4% to 14% of cows across the three periods in Western Canada and in 15% of cows sampled in Eastern Canada in 2019. Serum copper, selenium, and molybdenum concentrations varied by cow age and month of sample collection. Serum selenium and molybdenum concentrations, but not copper, varied by soil type associated with the location of the farm. A subsample of samples from cows from Western Canadian herds provided body condition score (BCS) data, pregnancy status, and calf survival data and were used to estimate updated serum reference values for adequate concentrations. Age-specific values were required for selenium and molybdenum. Reference intervals (80%) were estimated from 2,406 pregnant beef cows from 99 herds with each cow having a BCS ≥ 2.5/5 and a live calf at 3 wk with no retained placenta: copper for all cows (0.379 to 0.717 ppm), selenium for cows <4 yr (0.052 to 0.152 ppm), and selenium for cows ≥4 yr (0.064 to 0.184 ppm). Upper 90% reference limits were also estimated for serum molybdenum for cows <4 yr (>0.104 ppm) and cows ≥4 yr (>0.110 ppm). The lower limits for the reference intervals for adequate copper and selenium are below those previously reported; nevertheless, they represent a large sample that was specifically applicable to extensively managed beef animals in western Canada. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The cow-calf industry in North America is in a period of rapid consolidation with corresponding increases in herd sizes and changes in management. The objectives of this study were to examine longitudinal data on reproductive performance in cow-calf herds and identify benchmarks for the most critical measures and important sources of differences among herds. To address these questions, a surveillance network was established in western Canada to collect data between 2013 to 2017 privately owned cow-calf herds during calving (n = 105 herds) and at pregnancy testing (n = 94 herds). Data were summarized for a number of indices of herd performance. However, the values considered to be most reliable and accurate were the percentage of females not pregnant when tested by a veterinarian, the percentage of calves dead within 24 hours of birth, and the percentage of calves dead from 24 hours to weaning. The mean and variation between herds for heifers, measured using standard deviation, was greater than for cows for: non-pregnancy (cows 6.8% (mean)±3.4%(SD), heifers 9.7%±8.2%), calf death from birth to 24 hours (cows 2.1%±1.6%, heifers 3.6%±4.5%), and calf death from 24 hours to weaning (cows 2.5%±2.4%, heifers 2.9%±3.9%). Benchmarks or performance targets derived from the 25th percentiles of these data for both cows and heifers were <5% for non-pregnancy risk and <1% for calf loss within 24 hours of birth. The suggested benchmark for calf loss from 24 hours to weaning was <2% for cows and <1% for heifers. All outcomes consistently displayed greater variation between herds as compared to year to year differences within herds with the exception of calf loss before 24 hours in cows. The timing of the start of breeding season was a consistent source of variation in risks of non-pregnancy and calf losses. Cows bred in April or earlier to start calving in late December or January were at increased risk of low pregnancy percentages (p<0.001) and calf losses at birth (p<0.04), as well as increased calf loss before weaning in both cows and heifers (p<0.02). There was also an increase in the risk of non-pregnancy for cows and heifers (p<0.001) where first exposure to breeding was not until July or August. In contrast, the risks of calf loss within 24 hrs of birth (p<0.001) and from 24 hrs to weaning in cows (p<0.02) first exposed to breeding in July and August were significantly lower than for herds that had earlier breeding seasons. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Veterinary Research / Revue Canadienne de Recherche Vétérinaire is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Risk factors for the development of canine appendicular osteosarcoma (OSA) have been investigated in numerous studies, but with contradictory results. The aim of this study was to analyze weight, age, breed, sex, neuter status, body condition score, and previous lameness in a population of large and giant breed dogs in western Canada with and without appendicular OSA., Animals and Procedure: Medical records of 227 large or giant breed dogs diagnosed with appendicular OSA were compared to records from a control population of 454 large and giant breed dogs from the years 2000 to 2020., Results: Gonadectomized dogs, body condition score (BCS), and a history of lameness condition(s) (other than OSA) were associated with increased odds for presentation with OSA. Breeds shown to have increased odds for appendicular OSA occurrence included Rottweilers and Great Danes relative to Labrador retrievers., Conclusion and Clinical Relevance: Obesity and lameness appear to be independently associated with appendicular osteosarcoma. This study demonstrated that spayed females had the greatest risk compared to other sex and neuter status combinations; further investigation of these factors would be beneficial., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Biosecurity practices of beef cow-calf herds in western Canada have not been studied extensively nor is there a good understanding of their association with herd health. A survey was sent to 103 cow-calf producers of the Western Canadian Cow-Calf Surveillance Network. Eighty completed questionnaires were returned. Bulls were purchased for all herds during the 2014 to 2017 study period; 54% of herds purchased heifers and 42% purchased cows. The use of standard biosecurity practices was generally low with 30% of producers keeping purchased animals separate and 30% vaccinating new additions. None of the evaluated biosecurity practices were associated with reporting Johne's disease. The purchase of > 10 bulls, the purchase of cows, not vaccinating animals bought into the herd, and use of community pasture were associated with a bovine respiratory disease outbreak. Outbreaks of calf diarrhea were associated with the purchase of 10 or more bulls, the use of a community pasture, and leasing or sharing bulls., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Background: Species of Trichinella are globally important foodborne parasites infecting a number of domestic and wild vertebrates, including humans. Free-ranging carnivores can act as sentinel species for detection of Trichinella spp. Knowledge of the epidemiology of these parasites may help prevent Trichinella spp. infections in northern Canadian animals and people. Previous research on Trichinella spp. in wildlife from Yukon did not identify risk factors associated with infection, or the diversity and identity of species of Trichinella in regional circulation, based on geographically extensive sampling with large sample sizes., Methods: In a cross-sectional study, we determined the prevalence, infection intensity, risk factors, and species or genotypes of Trichinella in wolverine (Gulo gulo) in two regions of Yukon, Canada, from 2013-2017. A double separatory funnel digestion method followed by mutiplex PCR and PCR-RFLP were used to recover and identify species of Trichinella, respectively., Results: We found larvae of Trichinella in the tongues of 78% (95% CI 73-82) of 338 wolverine sampled. The odds of adult (≥ 2 years) and yearling (1 year) wolverine being Trichinella spp.-positive were four and two times higher, respectively, compared to juveniles (<1 year). The odds of Trichinella spp. presence were three times higher in wolverine from southeast than northwest Yukon. The mean intensity of infection was 22.6 ± 39 (SD, range 0.1-295) larvae per gram. Trichinella T6 was the predominant genotype (76%), followed by T. nativa (8%); mixed infections with Trichinella T6 and T. nativa (12%) were observed. In addition, T. spiralis was detected in one wolverine. Out of 22 isolates initially identified as T. nativa in multiplex PCR, 14 were analyzed by PCR-RFLP to distinguish them from T. chanchalensis, a recently discovered cryptic species, which cannot be distinguished from the T. nativa on multiplex PCR. Ten isolates were identified either as T. chanchalensis alone (n = 7), or mixed infection with T. chanchalensis and T. nativa (n = 2) or T. chanchalensis and Trichinella T6 (n = 1)]., Conclusions: Wolverine hosted high prevalence, high larval intensity, and multiple species of Trichinella, likely due to their scavenging habits, apex position in the food chain, and wide home range. Wolverine (especially adult males) should be considered as a sentinel species for surveys for Trichinella spp. across their distributional range.

There is a paucity of information from western Canadian beef cow-calf producers about how they control gastrointestinal nematodes. The objectives of this study were to describe cow-calf producers' management practices related to control of gastrointestinal nematodes including pasture management and use of parasite control products. A questionnaire was distributed to 105 producers in May 2015. Responses from 97 producers revealed the almost uniform dependence on the use of a pour-on macrocyclic lactone parasite control product in the fall as part of a routine farm management program. Control of external parasites was the primary reason for treatment, while none of the producers chose to treat specifically to manage internal parasites. The predominant management practices identified through this study increase the risk of development of anthelmintic resistance. The results also highlight the need to raise awareness of the importance of an evidence-based gastrointestinal nematode control program in beef cow-calf herds., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

One hundred cow-calf producers in western Canada were surveyed to determine their perceptions regarding antimicrobial use (AMU) and how these perceptions and other herd management factors were associated with AMU. Veterinarians were the most important source of AMU information. Half of the producers considered antimicrobial resistance (AMR) when choosing antimicrobials, while 24% considered the influence of AMU on AMR in human health. Younger producers < 30 y were most likely to consider AMR when choosing antimicrobials. Injectable products were used for disease prevention in 17% of herds; 5% used medically important antimicrobials in feed and 6% in water. Use of injectable antimicrobials of very high importance to human health was reported in 34% of herds. Producers with higher calf mortality were more likely to report AMU in feed or water. The use of Health Canada Category I antimicrobials was most common when calves were retained after weaning.

The aims of this study were to describe when and how vaccines are administered during the production cycle in cow-calf herds in western Canada, as well as the factors that influence vaccine usage as reported by producers. The most commonly used vaccines were bovine viral diarrhea virus/infectious bovine rhinotracheitis (BVDV/IBR) in adult animals and clostridial vaccines in calves. While there has been improvement in usage of reproductive and respiratory viral vaccines since previous studies, there are still several areas in which uptake could be improved. Only 72% of herd owners vaccinated their bulls for at least 1 disease. Not all producers are vaccinating their calves for clostridial diseases, and 15% of producers did not vaccinate their calves for respiratory disease before weaning. One goal of increasing vaccine use is to obtain better infection prevention and control and decrease antimicrobial use in cow-calf herds. Two areas in which antimicrobials are commonly used, but vaccine uptake is limited, are foot rot in adult cows and diarrhea in calves.

While ongoing surveillance and research initiatives have provided some information on antimicrobial use (AMU) in many livestock commodities, there are no recent reports for Canadian cow-calf herds. Antimicrobial use data were collected in 2014 for bulls, cows, and calves from 100 herds participating in the Western Canadian Cow-Calf Surveillance Network. Lameness was the most common reason for treatment in cows and bulls, with oxytetracycline being the treatment of choice. Herd owners were most likely to treat calves before weaning with florfenicol, oxytetracycline, and sulfamethazine for respiratory disease or diarrhea. The most frequently reported reason for antimicrobial use in weaned calves was respiratory disease and the most reported product was florfenicol. While 98% of herds reported treating ≥ 1 animal with antimicrobials, most cattle did not receive antimicrobials for either treatment or disease prevention on participating cow-calf operations.

Members of the Western Canadian Association of Bovine Practitioners were surveyed regarding their use of antimicrobials in bovine abdominal surgery. Perioperative antimicrobials were used in 100% of abdominal surgeries by 96 of 98 respondents. Although postoperative administration was the most common perioperative period for antimicrobial use, intraoperative intraperitoneal use was reported by more than half of the veterinarians surveyed. Procaine penicillin G and oxytetracycline were the most commonly administered perioperative antimicrobials.

The emergence of severe porcine circoviral disease in North America is associated with Porcine circovirus-2 genotype b (PCV-2b), which has led to speculation that PCV-2b is more virulent than PCV-2a. The objectives of this study were to 1) correlate the PCV-2 DNA concentration and lesions in wasting (WST) and age-matched healthy (HLTH) pigs from 2 clinically affected farms, and unaffected (UNFCT) pigs from a farm with no prior clinical or diagnostic history of PCVD; and 2) to determine the initial estimates of sensitivity and specificity of PCV-2 quantitative polymerase chain reaction (qPCR). PCV-2b was confirmed in all 3 farms. Compared with HLTH pigs, WST pigs demonstrated significantly more prevalent thymic atrophy, failure of normal pulmonary collapse, and ascites (P < 0.017 for all). The HLTH and UNFCT pigs had significantly more pronounced lymphoid germinal centers and proliferative paracortical T-dependent zones, compared with WST pigs (P < 0.017). Across all tissues, PCV-2 DNA concentrations were significantly higher in WST compared with HLTH and UNFCT pigs (P < 0.017 for all). The PCV-2 DNA concentrations were strongly correlated with PCV-2 nucleocapsid staining intensity in lymph node, spleen, Peyer's patches, lung, liver, and kidney (0.60 < or = r < or = 0.84). In the current study, the PCV-2 DNA log10 cutoff concentrations best able to distinguish WST from HLTH and UNFCT pigs were between 7.0 and 8.0 per gram for tissues, and between 4.0 and 5.0 per milliliter for sera. The presence of PCV-2b in UNFCT pigs is evidence that PCV-2b by itself is not sufficient to induce severe disease.