A living lab approach to understanding dairy farmers' needs of technologies and data to improve herd health: Focus groups from 6 European countries

For successful development and adoption of technology on dairy farms, farmers need to be included in the innovation process. However, the design of agricultural technologies usually takes a top-down approach with little involvement of end-users at the early stages. Living Labs offer a methodology that involve end-users throughout the development process and emphasize the importance of understanding users' needs. Currently, exploration of dairy farmers' needs of technologies has been limited to specific types of technology (e.g., smartphone apps) and adult cattle. The aim of this study was to use a Living Lab approach to identify dairy farmers' needs of data and technologies to improve herd health and inform innovation development. Eighteen focus groups were conducted with, in total, 80 dairy farmers from Belgium, Ireland, the Netherlands, Norway, Sweden, and the UK. Data were analyzed using Template Analysis and 6 themes were generated which represented the fundamental needs of autonomy, comfort, competence, community and relatedness, purpose, and security. Farmers favored technologies that provided them with convenience, facilitated their knowledge and understanding of problems on farm, and allowed them to be self-reliant. Issues with data sharing and accessibility, and usability of software were barriers to technology use. Furthermore, farmers were facing problems around recruitment and management of labor and needed ways to reduce stress. Controlling aspects of the barn environment, such as air quality, hygiene, and stocking density, was a particular concern in relation to youngstock management. In conclusion, the findings suggest that developers of farm technologies may want to include farmers in the design process to ensure a positive user experience and improve accessibility. The needs identified in this study can be used as a framework when designing farm technologies to strengthen need satisfaction and reduce any potential harm toward needs.

Enhancing bovine abortion surveillance: A learning experience

Abortions and perinatal mortalities (APM) substantially affect cattle industry efficiency. Various infectious and noninfectious factors have been associated with bovine APM worldwide. Infections are often considered pivotal due to their abortifacient potential, leading laboratories to primarily investigate relevant infectious agents for APM cases. Some infectious causes, such as Brucella abortus, have also a zoonotic impact, necessitating monitoring for both animal and human health. However, underreporting of bovine APM is a global issue, affecting early detection of infectious and zoonotic causes. Previous studies identified factors influencing case submission, but regional characteristics may affect results. In Belgium, farmers are obliged to report cases of APM within the context of a national brucellosis monitoring program. The inclusion criteria for this monitoring program cover abortions (gestation length of 42-260 d) and perinatal mortalities of (pre)mature calves following a gestation length of more than 260 d, which were stillborn or died within 48 h after birth. The objective of the present study was to describe the evolution in submission of APM cases within a mandatory abortion monitoring program in relation to subsidized initiatives in the northern part of Belgium. Based on the proportion of APM submissions versus the proportion of bovine reproductive females, an APM proportion (APMPR) was calculated, and factors at both animal and herd level that may influence this APMPR were explored by using linear models. This evaluation revealed that the APMPR increased with the introduction of an extensive analytical panel of abortifacient agents and a free on-farm sample collection from 0.44% to 0.94%. Additionally, an increase of the APMPR was associated with an outbreak of an emerging abortifacient pathogen (Schmallenberg virus; 1.23%), and the introduction of a mandatory eradication program for bovine viral diarrhea virus (BVDv; 1.20%). The APMPR was higher in beef compared with dairy cattle, and it was higher in winter compared with fall, spring, and summer. Smaller herds categorized in the first quartile had a higher APMPR compared with larger herds. Herds that submitted an APM in the previous year had a higher APMPR in the next year compared with herds without an APM submission. Finally, herds for which there was evidence of the presence of BVDv had a higher APMPR compared with herds without evidence of the presence of BVDv. In conclusion, the number of APM submissions increased after the introduction of a free on-farm sample collection and an extensive pathogen screening panel. Production type (beef), season (winter), smaller herd size, previous APM, and presence of BVDv seemed to have a positive effect on APMPR. However, even under mandatory circumstances, APM still seems to be underreported, since the APMPR was lower than the expected minimal rate of 2%. Therefore, further research is necessary to identify the drivers that convince farmers to submit APM cases to improve submission rates and ensure an efficient monitoring program for APM and eventually associated zoonotic pathogens.

Short communication: Circadian variations and day-to-day variability of clinical signs used for the early diagnosis of pneumonia within and between calves

For rational antimicrobial use, a timely and correct diagnosis of bovine respiratory disease, especially pneumonia, in calves is required. Current approaches often rely on clinical signs observed at a single time point, and do not take potential diurnal patterns in the manifestation of these clinical signs into account. Therefore, the aim of this pilot study was to investigate how clinical signs utilized for the (early) detection of pneumonia vary both within and between calves, throughout the day and across days. A longitudinal study was conducted in which 36 pre-weaned Holstein-Friesian calves were clinically examined eight times over the course of 48 h. The following parameters were considered: respiratory rate, type of respiration, dyspnea, stridor, induced cough (trachea reflex), spontaneous cough, eye and nasal discharge, ear positions, head tilt, rectal temperature, diarrhea, milk residue, body posture, Wisconsin and Davis BRD scorecard. The advent of thoracic ultrasonography (TUS) enables detection of (sub)clinical pneumonia in a more reliable way, compared to the diagnosis based solely on clinical signs. In this study, 14% (5/36) of the calves had an ultrasound confirmed pneumonia (consolidation ≥1 cm in depth). No variations were observed in the prevalence of clinical signs at the various time points of the day. However, we did observe a difference in the manifestation of clinical signs in individual calves (intra) and between (inter) them. Due to the significant intra-calf variability, diagnosing pneumonia based solely on a single observation of clinical signs, is likely to be insufficient. Hence, misdiagnosis might lead to incorrect use of antimicrobials.

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves - Part 1: Ammonia, air microbial count, particulate matter and endotoxins

Bovine respiratory disease (BRD) is one of the leading causes of mortality and morbidity in calves across diverse management systems. Despite expert opinion often citing the influence of housing environment on the level of respiratory disease in calf groups, there have been few reviews of environmental factors that predispose to BRD. This systematic review was undertaken to identify the measurable environmental variables associated with respiratory disease in housed preweaned calves. To achieve this Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion, publications had to be fully published in English, published before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection. Twelve publications were included in this review. These examined a wide range of risk factors including air microbial count (four publications), air particulate matter (one publication); air endotoxins (one publication) and air ammonia (four publications). From the included publications, a statistically significant relationship to BRD was identified in 2/4 examining air microbial count, 1/1 examining air particulate matter, 1/1 examining air endotoxins and 2/4 examining air ammonia. This review indicated a paucity of evidence from the peer-review literature demonstrating a significant association between the many investigated exposure factors and BRD occurrence. An optimal environment for housed calves could not be clearly identified in this review.

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves - Part 2: Temperature, relative humidity and bedding

Bovine respiratory disease (BRD) is a challenge in all housed farming systems that raise calves. Farm to farm variation in BRD prevalence can be partially attributed to variation in host immunity, pathogens and housing environment. Unlike host immunity and BRD pathogens, housing environment has not been well investigated. The objective of this systematic review was to identify the measurable environmental variables associated with BRD in housed preweaned calves. Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion publications had to be published in English, before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection. In total 12 publications were included in this review. In this second part of the systematic review the environmental variables identified were; temperature (9 publications); relative humidity (8 publications); bedding (5 publications); ventilation (1 publication); air CO2 concentration (1 publication) and air velocity (4 publications). Of the publications that were examined a statistically significant relationship to BRD was identified in 4/9 publications examining temperature, 3/8 examining relative humidity, 2/4 examining air velocity, 2/5 examining bedding, 0/1 examining ventilation rates and 0/1 examining CO2 concentration. From this review it is clear high airspeed at calf level should be avoided as should deep, wet pack bedding. The relationship between BRD prevalence and both high and low temperature requires more investigation to identify temperature thresholds associated with increased risk of BRD as well as the most influential modifiers. An optimal environment for housed calves could not be clearly identified in this review.

Detection of Chlamydia and Chlamydia-like organisms in bovine placental tissue

This study aimed to investigate the presence of Chlamydia spp. and Parachlamydia acanthamoebae in bovine placental tissue originating from abortion and non-abortion cases in Belgium. Placentas of 164 late term bovine abortions (last trimester of gestation) and 41 non-abortion (collected after calving) cases were analyzed by PCR for Chlamydia spp., Chlamydia abortus, Chlamydia psittaci, and Parachlamydia acanthamoebae. Additionally, a subset of 101 (75 abortion and 26 non-abortion cases) of these placenta samples were also analyzed by histopathology to detect possible Chlamydia-induced lesions. In 5.4% (11/205) of the cases, Chlamydia spp. were detected, and 3 of those cases were positive for Chlamydia psittaci. Parachlamydia acanthamoebae was detected in 36% (75/205) of the cases, being 44% (n = 72) in abortions and 7.3% (n = 3) in non-abortions cases (P < 0.001). None of the cases was positive for Chlamydia abortus. Purulent and/or necrotizing placentitis with or without vasculitis was observed in 18.8% (19/101) of the histopathologically analyzed placenta samples. In 5.9% (6/101) of the cases, placentitis was observed along with vasculitis. In the abortion cases, 24% (18/75) of the samples showed purulent and/or necrotizing placentitis, while purulent and/or necrotizing placentitis was visible in 3.9% (1/26) of the non-abortion cases. Placental lesions of inflammation and/or necrosis were present in 44% (15/34) of the cases where P. acanthamoebae was detected, while inflammation and/or necrosis was present in 20.9% (14/67) of the negative cases (P < 0.05). The detection of Chlamydia spp. and especially Parachlamydia acanthamoebae, in combination with correlated histological lesions such as purulent and/or necrotizing placentitis and/or vasculitis in placental tissue following abortion, suggests a potential role of this pathogen in cases of bovine abortion in Belgium. Further in-depth studies are necessary to unravel the role of these species as abortifacient agents in cattle and to include them in bovine abortion monitoring programs.

Pathogen-oriented approaches for neonatal calf diarrhea

Neonatal calf diarrhea (NCD) is the leading health concern in calves during the first weeks of their lives. In this narrative review, the potential for pathogen-oriented approaches for NCD is discussed. The literature on NCD clearly shows substantial differences in spread and characteristics between the major NCD pathogens, making pathogen-oriented approaches possible, justifying the use of etiological diagnostics. For enterotoxic Escherichia coli, colostrum delivery and dam vaccination, biosecurity around calving and antimicrobial therapy are key. Both for bovine coronavirus (BCV) and bovine rotavirus (BRV), biosecurity and disinfection, dam vaccination in combination with adequate and prolonged colostrum delivery are the essentials. However, a different focus concerning biosecurity is necessary given the airborne spread of BCV and higher environmental persistence of BRV. For an effective Cryptosporidium spp. control, the use of disinfectants that kill oocysts is crucial. Evidence supporting the prophylactic use of halofuginone lactate to reduce shedding and diarrhea, is available, but in terms of biosecurity, attention should be placed on the proper use of this product. In case of a Salmonella enterica outbreak, antimicrobial use remains important, and biosecurity wise, attention should be paid to shedding of periparturient cows in the calving pen and administration of infected colostrum. Both for S. enterica and cryptosporidiosis, farm staff should be informed on how to protect themselves against these zoonotic infections. Nutritional factors play an additional role within NCD. Improper nutrition management can induce diarrhea or can further enhance infectious NCD through osmosis or dysbiosis. In conclusion, the suggested pathogen-oriented approaches can aid to economize labor and financial investments, limit the environmental impact of NCD control and prevention and valorize tailor-made farm advisory work.

Three cases of alloimmune mediated pancytopenia in calves resembling bovine neonatal pancytopenia

Background

Between 2007 and 2011 several thousands of calves died from bovine neonatal pancytopenia (BNP), a bleeding syndrome triggered by vaccine induced alloantibodies from the dams. Following withdrawal of the involved bovine viral diarrhoea virus (BVDv) vaccine, the incidence of this condition rapidly decreased, with no reported cases in the last 5 years. Here, we report a recent immune-mediated pancytopenia in three calves from two different suckler herds, clinically indistinguishable from BNP.

Case presentation

Three Belgian Blue suckler calves from two different farms, aged around two weeks, showed multiple bleedings disseminated on the skin and petechiae and ecchymoses on the mucosae. Blood examination confirmed anaemia, leukopenia and thrombocytopenia. BVDv infection was excluded. Despite blood transfusion and cortisone therapy, all three animals died. Necropsy and histology confirmed bone marrow depletion. Binding of IgG from the dams on leukocytes of the calves was demonstrated by flow cytometry. Two calves, originating from the same farm, received colostrum from the same dam. None of the calves were given colostrum replacers or colostrum supplements. No link with the BNP causing BVDv vaccine could be evidenced. However, dams had been vaccinated against bovine herpesvirus 1, parainfluenza-3 virus, bovine respiratory syncytial virus and bluetongue virus serotype 8.

Conclusions

Alloimmune mediated pancytopenia was evidenced in three animals, clinically and pathologically indistinguishable from BNP. Whether this disease is again vaccine mediated remains to be determined.

Retrospective study of factors associated with bovine infectious abortion and perinatal mortality

Abortion and perinatal mortality, leading causes of economic loss in cattle industry, are the consequence of both non-infectious and a wide range of infectious causes. However, the relative contribution of pathogens to bovine abortion and perinatal mortality is poorly documented, since available studies involved only a limited number of pathogens. Therefore, the objectives of the present monitoring study were to determine the prevalence of infectious agents associated with bovine abortion and perinatal mortality, and to identify differences in production type, gestation length, parity and seasonality by using mixed effect models (logistic regression). A pre-established sampling protocol based on the collection of the aborted fetus/calf and a corresponding maternal blood sample, involving diagnostic testing for 10 pathogens, was performed. At least one potential causal agent of the abortion or perinatal mortality was detected in 39 % of cases. In these diagnosed cases, Neospora caninum was the most detected pathogen, followed by Trueperella pyogenes, BVDv, Escherichia coli, and Aspergillus fumigatus. Neospora caninum [odds ratio (OR): 0.4; 95 % confidence interval (CI): 0.3-0.7] and Aspergillus fumigatus (OR: 0.1; 95 % CI: 0.1-0.3) were detected less in late versus early gestation. Aspergillus fumigatus was less common in dairy in comparison to beef abortion cases (OR: 0.2; 95 % CI: 0.1-0.6). Winter was associated with a lower positivity for Neospora caninum and BVDv in comparison to warmer seasons. Despite extensive diagnostic testing, an etiological diagnosis was not reached in 61 % of cases, highlighting the need for even more extensive (non-)infectious disease testing or more accurate tests.

Particulate matter and airborne endotoxin concentration in calf barns and their association with lung consolidation, inflammation, and infection

Agricultural operations are important sources of organic dust containing particulate matter (PM) and endotoxins, which have possible negative health consequences for both humans and animals. Dust concentrations and composition in calf barns, as well as the potential health effects for these animals, are scarcely documented. The objective of this study was to measure PM fractions and endotoxin concentrations in calf barns and study their associations with lung consolidation, respiratory tract inflammation, and infection in group-housed calves. In this cross-sectional study, samples from 24 dairy farms and 23 beef farms were collected in Belgium from January to April 2017. PM_1.0, PM_2.5 and PM₁₀ (defined as particulate matter passing through a size-selective inlet with a 50% efficiency cut-off at a 1.0-μm, 2.5-μm, and 10-μm aerodynamic diameter, respectively) were sampled during a 24-h period using a Grimm aerosol spectrometer (Grimm Aerosol Technik Ainring GmbH & Co. KG). Endotoxin concentration was measured in the PM₁₀ fraction. Thoracic ultrasonography was performed and broncho-alveolar lavage fluid was collected for cytology and bacteriology. Average PM concentrations were 16.3 µg/m³ (standard deviation, SD: 17.1; range: 0.20-771), 25.0 µg/m³ (SD: 25.3; range: 0.50-144.9), and 70.3 µg/m³ (SD: 54.5; range: 1.6-251.2) for PM_1.0, PM_2.5, and PM₁₀, respectively. Mean endotoxin in the PM₁₀ fraction was 4.2 endotoxin units (EU)/µg (SD: 5.50; range: 0.03-30.3). Concentrations in air were 205.7 EU/m³ (SD: 197.5; range: 2.32-901.0). Lung consolidations with a depth of ≥1, ≥3, and ≥6 cm were present in 43.1% (146/339), 27.4% (93/339), and 15.3% (52/339) of the calves, respectively. Exposure to fine (PM_1.0) PM fractions was associated with increased odds of lung consolidations of ≥1 cm (odds ratio, OR: 3.3; confidence interval (CI): 1.5-7.1), ≥3 cm (OR: 2.8; CI: 1.2-7.1), and ≥6 cm (OR: 12.3; CI: 1.2-125.0). The odds of having lung consolidations of ≥1 cm (OR: 13.9; CI: 3.4-58.8) and ≥3 cm (OR: 6.7; 1.7-27.0) were higher when endotoxin concentrations in the dust mass exceeded 8.5 EU/µg. Broncho-alveolar lavage fluid neutrophil percentage was positively associated with PM₁₀ concentration, and epithelial cell percentage was negatively associated with this fraction. Concentration of PM_2.5 was positively associated with epithelial cell percentage and isolation of Pasteurella multocida. Although concentrations of fine dust are lower in calf barns than in poultry and pig housings, in this study they were associated with pneumonia in calves. Dust control strategies for reducing fine dust fractions in calf barns may benefit human and animal respiratory health.

Evaluation of the agreement between Brix refractometry and serum immunoglobulin concentration in neonatal piglets

Neonatal piglets lack immunoglobulins at birth. Sufficient colostrum intake (CI) and immunoglobulin absorption are essential for an appropriate passive transfer of immunity via the colostrum. Most methods to measure immunoglobulins in serum of piglets are labour-intensive, expensive or imprecise and not designed for on-farm use. The present diagnostic test study evaluated digital Brix refractometry to measure immunoglobulins in serum of neonatal piglets and to suggest thresholds for different serum immunoglobulin concentration. Additionally, agreements between Brix refractometry and optical refractometer (serum total protein, STP) and between Brix refractometry and ELISA (immunoglobulin G, IgG) were also investigated. Forty-five sows and 269 piglets from three different farms were enrolled in the study. Piglets were weighed at birth and 24 h later to calculate the CI. Serum was collected at 24 h after birth and analysed for STP, γ-globulins (electrophoresis), % Brix and IgG. In piglets, median (interquartile range, IQR) CI was 412 (196) g per piglet. Median (IQR) STP, γ-globulin and % Brix concentrations in piglet serum were 60 (11) g/L, 35 (10) g/L and 8 (2) %, respectively. Average (±SD) IgG concentration was 49 ± 23 g/L. Passing-Bablok regression revealed a strong concordance between % Brix and STP (Kendall's tau (Τ): 0.620, P < 0.0001, n = 267) and % Brix and γ-globulin concentration (Kendall's Τ: 0.575, P < 0.0001, n = 267). The agreement between the Brix refractometer and IgG concentration was poor (Kendall's Τ: 0.267, P < 0.0001, n = 269). Receiver operating characteristic curves were performed to evaluate test characteristics of Brix refractometry for three γ-globulin cut-off values, i.e. 10, 20 and 30 g/L. The % Brix cut-off values resulting in the optimal combination of sensitivity and specificity were 5.4 (100 and 98.5%), 7.0 (100 and 89.3%) and 7.9 (90.1 and 80.6%), respectively. In conclusion, digital Brix refractometry is a sufficiently fast and practical method to assess serum γ-globulin concentrations in neonatal piglets on-farm and to evaluate them by considering the thresholds found in this study. Further studies are needed to validate those thresholds regarding piglet's survival in the pre-weaning period.

Pathogen-specific risk factors in acute outbreaks of respiratory disease in calves

Respiratory tract infections (bovine respiratory disease) are a major concern in calf rearing. The objective of this study was to identify pathogen-specific risk factors associated with epidemic respiratory disease in calves. A cross-sectional study was conducted, involving 128 outbreaks (29 dairy, 58 dairy-mixed, and 41 beef) in Belgium (2016–2018). A semiquantitative PCR for 7 respiratory pathogens was done on a pooled nonendoscopic bronchoalveolar lavage sample for each herd. Potential risk factors were collected by questionnaire and derived from the national cattle registration databank. Most outbreaks occurred between October and March, and single and multiple viral infections were detected in 58.6% (75/128) and 13.3% (17/128), respectively. Bovine coronavirus (BCV) was the most frequently isolated virus (38.4%), followed by bovine respiratory syncytial virus (bRSV; 29.4%) and parainfluenzavirus type 3 (PI-3; 8.1%). Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni were detected in 33.3, 41.2, 89.1, and 36.4% of the herds, respectively. Specific risk factors for BCV detection were detection of M. haemolytica [odds ratio (OR) = 2.8 (95% confidence interval = 1.1–7.5)], increasing herd size [OR = 1.3 (1.0–1.8) for each increase with 100 animals] and detection of BCV by antigen ELISA on feces in calves in the last year [OR = 3.6 (1.2–11.1)]. A seasonal effect was shown for bRSV only {more in winter compared with autumn [OR = 10.3 (2.8–37.5)]}. Other factors associated with bRSV were PI-3 detection [OR = 13.4 (2.1–86.0)], prevalence of calves with respiratory disease [OR = 1.02 (1.00–1.04) per 1% increase], and number of days with respiratory signs before sampling [OR = 0.99 (0.98–0.99) per day increase]. Next to its association with BCV, M. haemolytica was more frequently detected in herds with 5 to 10 animals per pen [OR = 8.0 (1.4–46.9)] compared with <5 animals, and in herds with sawdust as bedding [OR = 18.3 (1.8–191.6)]. Also, for H. somni, housing on sawdust was a risk factor [OR = 5.2 (1.2–23.0)]. Purchase of cattle [OR = 2.9 (1.0–8.0)] and housing of recently purchased animals in the same airspace [OR = 5.0 (1.5–16.5)] were risk factors for M. bovis. This study identified pathogen-specific risk factors that might be useful for the development of customized control and prevention and for the design of decision support tools to justify antimicrobial use by predicting the most likely pathogen before sampling results are available.

Short communication: Herd-level analysis of antimicrobial use and mortality in veal calves: Do herds with low usage face higher mortality?

The veal calf sector fears that a too-rapid and large decrease in antimicrobial use (AMU) as demanded by European authorities would increase mortality, causing economic and welfare issues. To determine whether this concern is justified, the relationship between AMU (total and different classes) and mortality in dairy-type white veal calves, managed by 2 large veal companies, was explored. A retrospective cohort study was performed on electronically collected antimicrobial consumption and mortality data from the largest Belgian veal practice during the period 2014 to 2016. Mixed linear [mortality (%) as continuous outcome] and generalized linear mixed models with binary outcome for event and trial approach were built to identify factors associated with mortality. Data consisted of 76 production cycles from 29 farms managed by 2 veal companies (1 and 2) and covering 45,001 calves. Average AMU was 30.1 ± 10.4 defined daily doses for animals per year (± standard deviation) and was higher in veal company 2 than in veal company 1 (35.9 ± 9.3 and 22.4 ± 5.7 defined daily doses for animals per year, respectively). In contrast, mean mortality was lower in veal company 2 (2.3 ± 1.4%) than in veal company 1 (4.1 ± 1.4%). Both models showed a positive association between AMU and mortality in veal company 1 and no association in veal company 2. The final linear model identified increasing herd size and the use of third- or fourth-generation cephalosporins as risk factors for mortality and the use of long-acting macrolides as a protective factor. The final logistic model identified an increased mortality risk with increased use of third- or fourth-generation cephalosporins and sulfonamides-trimethoprim and decreased mortality when using long-acting macrolides. Based on these data, at the current levels of AMU in Belgian veal calves, an increase in mortality when reducing AMU could not be evidenced. Differences in herd size and factors other than AMU likely better explain why one veal company faces almost double the mortality of another one. Abandoning the use of long-acting macrolides might have negative consequences for mortality under the current state of the industry. The most ethical way to further reduce AMU in veal calves is likely simultaneously monitoring AMU and animal welfare parameters, starting with, but not limited to, mortality.

Diagnostische parameters voor klinische wintercyathostominose bij paarden

Wintercyathostominose is een van de belangrijkste parasitaire aandoeningen bij het grazende paard. Deze studie werd opgezet om de meest significante parameters te identificeren die geassocieerd zijn met klinische wintercyathostominose. Het betreft een retrospectief onderzoek van 307 paarden die tussen 2008 en 2018 aangeboden werden op de Faculteit Diergeneeskunde van de Universiteit Gent. Paarden ouder dan drie maanden die op de faculteit een mestonderzoek ondergingen en diarree hadden, werden opgenomen in de studie. De diagnose van larvale cyathostominose werd gesteld op basis van een positief mestonderzoek, i.e. het aantonen van L4- larven in de feces. De gegevens van paarden met larvale cyathostominose zonder diarree werden niet in de studie opgenomen. Klinische, biochemische, hematologische en parasitaire parameters werden onderzocht. Na statistische analyse van deze retrospectieve gegevens kwam albumine als meest significante parameter naar voor. Een serum-albuminegehalte dat lager was dan 20 g/L, had een hoge gevoeligheid voor het voorspellen van een positief mestonderzoek. De combinatie van het serum-albuminegehalte, het geslacht, de lichaamstemperatuur, het neutrofielenpercentage en het seizoen was volgens het finale statistische model de beste combinatie om de aanwezigheid van wintercyathostominose te voorspellen. Aan de hand van de diagnostische accuraatheid van het finale model werd aangetoond dat hiermee echter geen sluitende diagnose van larvale cyathostominose kan gesteld worden en dat een mestonderzoek nog steeds noodzakelijk is om het vermoeden van larvale cyathostominose te bevestigen.

General anesthesia for surgical treatment of urethral obstruction in nine goats

Nine pygmy goats underwent surgical treatment for obstructive urolithiasis in a period of six months. In two cases, (second) revision surgery was necessary resulting in a total of twelve procedures under general anesthesia. Different anesthetic protocols were applied: analgesia was provided by an opioid (12/12) combined with either benzodiazepine (10/12) or an alpha-2 agonist (2/12). Anesthesia was induced with propofol (10/12) or ketamine (2/12) and maintained with isoflurane (8/12) or sevoflurane (4/12) in oxygen in a semi-closed circle system with continuous monitoring during anesthesia. Minor complications were mild bradycardia (4/12), hypotension (3/12), metabolic acidosis (1/12) and hypothermia (12/12). In four cases, epidural anesthesia was performed; in one of those four cases, severe complications developed (paralysis, 1/4). The goat was euthanized later. Although urethral obstruction increases the risk of general anesthesia, the selection of an appropriate anesthetic protocol, adequate preoperative examination/ preparation and detailed monitoring throughout anesthesia reduced the incidence of severe complications in this case series.

Risk factors for antimicrobial use in veal calves and the association with mortality

The intensive use of antimicrobials in the veal industry is heavily criticized, but drivers for antimicrobial usage (AMU) are still poorly understood. The industry fears that a drastic reduction in AMU would increase mortality, creating an unacceptable welfare issue. The objectives of the present study were to identify risk factors for AMU and to explore the relationship between AMU and mortality. A retrospective cohort study was performed on the antimicrobial registration data from the largest Belgian veterinary veal practice. The data set contained 295 production cycles from 78 farms, representing 146,014 calves and 8 veal companies (also called integrations). The average AMU was 32.3 defined daily dose animal per year (standard deviation: 11.04), of which 76.2% was administered orally and 23.8% parentally. The AMU remained stable between 2014 and 2016 with only a slight, but significant increase in total AMU between 2015 (31.0 defined daily dose animal per year, standard deviation: 10.5) and 2016 (35.1, 10.8). Use of almost all antimicrobial classes decreased over 2014 to 2016; however, use of long-acting macrolides, doxycycline, and aminosides increased significantly. Analysis identified breed (higher use in beef calves compared with dairy and crossbreeds), month of arrival (lower use when arrived in April or May compared with winter months), and veal company as risk factors. The veal company not only significantly affected total AMU, but also affected the majority of the antimicrobial classes. Additionally, breed differences were present for oxytetracycline, colistin, and classic macrolides, and a month effect was present for doxycycline only. These data illustrate that this veterinary practice realized a reduction of 46% in total AMU and of 96% in critically important antibiotics (fluoroquinolones, cephalosporins of the third and fourth generation) compared with the Belgian benchmark from 2007 to 2009. Replacement of critically important drugs by an increased use of long-acting macrolides is worrisome. Mortality risk was very low compared with benchmarks referenced internationally and did not increase with decreasing AMU. Use of trimethoprim-sulfonamides was a risk factor, whereas use of oxytetracycline was a protective factor for mortality. The absence of a relationship with mortality at the current levels of AMU suggests that a further rational reduction is possible. Attention should be paid to consider different AMU benchmarks for different breeds and to include the veal company as a target for antibiotic awareness campaigns.

Risk factors for antimicrobial use in food-producing animals: disease prevention and socio-economic factors as the main drivers?

The European Union requests an urgent decrease in antimicrobial use (AMU) in food producinganimals to reduce antimicrobial resistance in animals and humans and safeguard the efficacy of antimicrobials for future generations. The identification of risk factors (RFs) for AMU is essential to obtain a rapid reduction. The aim of this review was to summarize the current knowledge of RFs for AMU in veal calves, pigs and poultry. Thirty-three observational studies were included. Well-identified RFs for an increased AMU are frequent purchase of animals, herd size (large or small depending on the animal species), and a lack of selected biosecurity measures. Also in beef breed calves, more antimicrobials are used than in Holstein calves. AMU is influenced by the farmer, the veterinarian and by the integration. In general, socio-economic RFs are largely unexplored. The causal factors for AMU are multiple and complex, with possible confounding factors and unidentified interactions. Additional knowledge of socio-economic drivers appears particularly urgent to create tailor-made guidelines and awareness campaigns for each sector.

Paratuberculosis in dairy and pygmy goats: an underestimated problem?

Paratuberculosis is a chronic intestinal disease affecting goats and other ruminants worldwide. The objective of this review was to summarize current knowledge on the prevalence, diagnostic possibilities and possible prevention and control measures for paratuberculosis in dairy and pygmy goats in Europe. The herd level prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goat farms is very high, namely 71%, 63% and 86% in Germany, France and the Netherlands, respectively. The prevalence in pygmy goats is undocumented. Antibody ELISA, fecal culture and PCR testing are readily available for diagnosis. A highly suggestive finding for paratuberculosis is the presence of enlarged intestinal lymph nodes on abdominal ultrasonography. To control the disease a combination of ‘test and cull’ and environmental hygienic measures are recommended. In contrast to cattle, vaccination is available and might be an additional tool in the control program for goats. Vaccine antibodies are no longer detectable after one year, and therefore serological monitoring can be continued on vaccinating herds. The worrisome prevalence data from neighboring countries indicate the need for a prevalence study on dairy goat farms in Belgium.

Rational antimicrobial therapy for sepsis in cattle in face of the new legislation on critically important antimicrobials

Sepsis is a life-threatening condition in cattle, as in humans. Successful sepsis treatment requires a fast initiation of antimicrobial therapy with a broad-spectrum, bactericidal drug, administered intravenously. However, the new legislation limits the use of critically important fluoroquinolones and cephalosporins in food animal medicine, drugs which are considered highly effective for sepsis treatment and were previously frequently used for this indication. This article aims at providing an overview of the current knowledge of sepsis in cattle to aid practitioners in adapting their decision making process to treat sepsis. Sepsis incidence in cattle is likely seriously underestimated. This disease is almost unexplored in cattle, which makes it particularly difficult to design species specific guidelines. Sepsis diagnosis by blood culture reaches sufficient accuracy with the current laboratory technology. When adapting this procedure to a field environment, difficulties might arise, and the availability of adapted incubators in veterinary laboratories may be limited. However, these difficulties are likely to be overcome. Severe sepsis and septic shock are likely the only indications where the ‘urgency’ criterion of the new legislation would apply, but it is important to realize that alternative antimicrobial treatments with possibly similar efficacy are available.

Short communication: Effect of freezer storage time and thawing method on the recovery of Mycoplasma bovis from bovine colostrum

Mycoplasma bovis is an important cause of mastitis in dairy cattle, and pneumonia, arthritis, and otitis in calves. Milk and colostrum are considered important sources of infection for calves. knowledge on the effect of on-farm freezing (-18°C) and thawing methods on the recovery of M. bovis from colostrum samples is missing. In this study, 2 separate experiments were performed. The first experiment consisted of a longitudinal study examining the survival [as measured by log(10) reduction] of 2 M. bovis strains in frozen colostrum over 14 wk. The second experiment examined the effect of different thawing temperatures (45 and 20°C), thawing frequencies (once or twice), and initial colostrum titer (10⁴ or 10⁶ cfu/mL) on M. bovis survival. A single freeze-thaw cycle led to an approximate 1 log reduction of M. bovis titer, independent of the thawing temperature. Freezing for 14 wk did not significantly further reduce the titer of bacteria compared with freezing for 2 wk. A second freeze-thaw cycle further reduced the M. bovis count by approximately 0.5 log compared with a single freeze-thaw cycle. Thawing temperature and initial bacterial concentration did not significantly affect M. bovis reduction. In conclusion, storage of colostrum samples in the freezer at -18°C during epidemiological studies, herd monitoring, or test and cull programs will probably have little influence on qualitative bacteriological test results for M. bovis. The epidemiological or clinical relevance of an approximate 1 log reduction of M. bovis in colostrum is currently unclear.

A Deep Nasopharyngeal Swab Versus Nonendoscopic Bronchoalveolar Lavage for Isolation of Bacterial Pathogens from Preweaned Calves With Respiratory Disease

Background

Nonendoscopic bronchoalveolar lavage (BAL) is a practical alternative for a deep nasopharyngeal swab (DNS) to sample the airways of a large number of calves in a short period of time. The extent of commensal overgrowth and agreement of BAL with DNS culture results in preweaned calves are unknown.

Objectives

To compare commensal overgrowth and bacterial culture results between DNS and BAL samples.

Animals

A total of 183 preweaned calves (144 with bovine respiratory disease and 39 healthy animals).

Methods

Cross‐sectional study. Deep nasopharyngeal swab and BAL samples were taken from each calf and cultured to detect Pasteurellaceae and Mycoplasma bovis. Agreement and associations between culture results of DNS and BAL samples were determined by kappa statistics and logistic regression.

Results

Bronchoalveolar lavage samples were less often polymicrobial, more frequently negative and yielded more pure cultures compared to DNS, leading to a clinically interpretable culture result in 79.2% of the cases compared to only in 31.2% of the DNS samples. Isolation rates were lower in healthy animals, but not different between DNS and BAL samples. Only Histophilus somni was more likely to be isolated from BAL samples. In clinical cases, a polymicrobial DNS culture result did not increase the probability of a polymicrobial BAL result by ≥30%, nor did it influence the probability of a negative culture. A significant herd effect was noted for all observed relationships.

Conclusions and Clinical Relevance

Nonendoscopic BAL samples are far less overgrown by bacteria compared to DNS samples under the conditions of this study, facilitating clinical interpretation and resulting in a higher return on investment in bacteriologic culturing.

Nosocomial Intravascular Catheter Infections with Extended-spectrum Beta-lactamase-producing Escherichia coli in Calves after Strain Introduction from a Commercial Herd

An outbreak of intravascular catheter-related infections by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in calves in an animal teaching hospital is reported. Pulsed-field gel electrophoresis was used for strain typing to determine the origin and dissemination of these strains. All 19 strains harboured the blaCTX-M-14, and six strains also overexpressed their chromosomal AmpC gene. Evidence on the introduction of the strain from a beef herd, experiencing neonatal diarrhoea and increased mortality, to the clinic through admission of diarrhoeic calves was provided. Strains isolated from phlebitis cases from other herds up to 5 months later showed a high similarity with the initial strain, suggesting that the strain had become nosocomial. The catheter infections with ESBL/AmpC-producing E. coli resulted in a prolonged hospitalization, increased anti-microbial use and mortality. This report points towards the potential dangers of the emergence of ESBL/AmpC-producing bacteria in susceptible food animals and warns farmers and veterinarians for the facility by which they are introduced into another environment.

Solid feed provision reduces fecal clostridial excretion in veal calves

Enterotoxemia is characterized by a highly fatal hemorrhagic enteritis in cattle, caused by Clostridium perfringens. Production systems with intensive feeding, such as the veal industry, are predisposed. The primary objective of this study was to determine the effect of solid feed provision on fecal C. perfringens excretion in veal calves. Ten Holstein Friesian bull veal calves were randomly assigned to one of two test diets. Group 1 received solemnly milk replacer twice daily, while group 2 received milk replacer and a maximum of 300g solid feed/day, consisting of a mixture of 30% barley, 30% corn, 30% hulled wheat and 10% chopped straw. The number of C. perfringens per g feces or fecal clostridial counts (FCC) were determined for all calves. Mean FCC were significantly lower in the calves fed milk replacer and solid feed, than in the calves fed solemnly milk replacer. Although the correlation between FCC and enterotoxemia risk remains to be determined, the provision of solid feed to veal calves reduced clostridial excretion, which might contribute to the prevention of this disease.

Non-toxic perfringolysin O and α-toxin derivatives as potential vaccine candidates against bovine necrohaemorrhagic enteritis

Bovine necrohaemorrhagic enteritis is a fatal Clostridium perfringens type A-induced disease that is characterised by sudden death. Recently the involvement of perfringolysin O and α-toxin in the development of necrohaemorrhagic lesions in the gut of calves was suggested, and thus derivatives of these toxins are potentially suitable as vaccine antigens. In the current study, the perfringolysin O derivative PFO^L491D, alone or in combination with α-toxin derivative GST-cpa_247-370, was evaluated as possible vaccine candidate, using in vitro assays. PFO^L491D showed no haemolytic effect on horse red blood cells and no cytotoxic effect on bovine endothelial cells. Furthermore, calves immunised with PFO^L491D raised antibodies against perfringolysin O that could inhibit the perfringolysin O-associated haemolytic activity on horse red blood cells. Antisera from calves immunised with PFO^L491D had a significantly higher neutralising capacity against the cytotoxic effect of C. perfringens culture supernatant to bovine endothelial cells than serum from control calves (P <0.05). Immunisation of calves with PFO^L491D in combination with GST-cpa_247-370 elicited antibodies against perfringolysin O and α-toxin and consequently inhibited both the perfringolysin O-associated haemolytic activity and the α-toxin-associated lecithinase activity in vitro. Additionally, the neutralising ability of these antisera on the cytotoxic effect of C. perfringens culture supernatant to bovine endothelial cells was significantly higher than that from calves immunised with PFO^L491D (P <0.001). In conclusion, perfringolysin O derivative PFO^L491D is an immunogenic antigen that can potentially be used to produce vaccine against bovine necrohaemorrhagic enteritis. Including α-toxin derivative GST-cpa_247-370 has an additional protective effect and therefore vaccination of calves with a combination of both antigens seems even more promising.

Multicentric B-cell lymphoma in a pygmy goat

A six-year-old, male pygmy goat was referred with a sudden onset of peripheral lymphadenopathy, which initially started as enlarged inguinal lymph nodes. Clinical examination showed swollen retropharyngeal, prescapular and inguinal lymph nodes. Serologic testing for bovine leukemia, caprine arthritis-encephalitis virus and caseous lymphadenitis was negative. Fine needle aspirates of the prescapular lymph nodes were taken and revealed multiple, large lymphoblastic cells on cytology. Because of the poor prognosis and clinical deterioration, the animal was euthanized. Full necropsy was performed and showed generalized lymphadenopathy. Further histological and immunohistochemical investigation of the lymph nodes characterized this neoplasia as a multicentric large B-cell lymphoma.

Atrial Premature Depolarization-Induced Changes in QRS and T Wave Morphology on Resting Electrocardiograms in Horses

Background

The electrocardiographic differentiation between atrial (APDs) and ventricular (VPDs) premature depolarizations is important. P wave prematurity and normal QRS and T wave morphology generally are used as discriminating criteria for APDs.

Hypothesis/Objectives

The aim of this study was to determine whether P, Q, R, S, and T wave amplitude, PQ interval, QRS and P wave duration and P and T wave morphology differ between APDs and sinus beats. To determine the relationship between the RR coupling interval and the change in S wave amplitude between sinus beats and APDs.

Methods

Case–control study. From a modified base‐apex configuration of 30 horses with APDs at rest, sinus beat and APD associated preceding RR interval, P, PQ and QRS duration and P, R, S, and T wave amplitudes were measured. Linear mixed models and logistic regression were used to determine the effect of APDs on the ECG variables studied.

Results

In comparison to sinus beats, APDs were associated with a significant (P < .001) change in P amplitude (−0.03 ± 0.01 mV) and increase in S (0.20 ± 0.02 mV) and T (0.08 ± 0.03 mV) amplitude. PQ (−20.3 ± 5.2 ms) and RR (−519 ± 14 ms) interval and P duration (−21.1 ± 3.0 ms) decreased (P < .001). APDs were significantly associated with a singular positive P wave (OR: 11.0, P < .001) and were more likely to have a monophasic positive T wave (OR: 9.2, P < .001). A smaller RR coupling interval was associated with an increased relative difference in S amplitude (P < .01).

Conclusions

Atrial premature depolarizations may lead to changes in QRS and T wave morphology. Knowledge of these changes is important to avoid interpreting certain APDs as VPDs.

Orale ivermectine-intoxicatie op een vleeskalverbedrijf

In deze casus wordt een vermoedelijk kwaadwillige, orale ivermectine-intoxicatie op een Vlaams vleeskalverbedrijf besproken. Alle 330 kalveren van twee tot vier weken oud werden in de eerste week na aankomst op het bedrijf getroffen. De symptomen waren ernstige depressie, het neerliggen in laterale of sternale positie, tremor en kopschudden. Uiteindelijk stierf 13,6% van de kalveren. De overige dieren herstelden gradueel met ondersteunende orale rehydratatietherapie over een termijn van vijf tot zeven dagen. In de kunstmelk kon een ivermectinegehalte van 35 mg/kg aangetoond worden. In het serum van drie kalveren werden ivermectinegehaltes van 0,75 mg/kg tot 1,1 mg/kg gevonden. De vermoedelijk toegediende dosering was 1,75 mg/kg lichaamsgewicht voor een gemiddeld kalf (40 kg). In deze casus wordt aangetoond dat orale toxiciteitsverschijnselen van ivermectine bij kalveren van twee tot vier weken oud kunnen optreden aan een dosis die 8,75 keer hoger is dan de geregistreerde therapeutische dosis voor subcutane toediening bij rundvee.

Radiographic and ultrasonographic evaluation of the esophagus in the horse

The purpose of this study was to describe the radiographic and ultrasonographic appearance of the esophagus of ten healthy horses. Contrast radiography showed variations in the long-axis shape of the esophagus at the thoracic inlet. Administration of a large volume contrast medium by intubation showed stasis of contrast material for several minutes in two of the ten horses. The wall thickness of the non-distended esophagus on ultrasound was 2.6 ± 0.3 mm with significant differences depending on the location. Distention of the esophagus by intubation or by a bolus of water or concentrate resulted in a decrease in wall thickness and it facilitated measuring with less variation. Stasis at the thoracic inlet was seen in five of the ten horses, when a water bolus was administered. Ultrasonographic evaluation of 100g spontaneously swallowed commercial concentrate was better than fluid (water bolus or 2.5mL/kg contrast medium) administration via intubation to assess esophageal motility at the thoracic inlet. Stasis seen at the thoracic inlet after bolus administration by intubation should not be regarded as an abnormal finding, and swallowing, with the subsequent peristaltic wave, has a positive influence on the bolus passage time.

Health risks associated with the use of automatic milk feeders in calves

The objective of the present article was to summarize available evidence of the economic benefits and health risks associated with the use of automatic milk feeders (AMFs) in calves. Although AMFs are increasingly used in cattle production, clear evidence of their economic benefits (increased average daily gain, gradual weaning and reduced labor time) for the typical Belgian farm size and management is not available. Especially in smaller farms, where labor time is not a limiting factor, a careful economic consideration should be made. Regarding the association of AMFs with calf disease, studies have only been performed for bovine respiratory disease and confirmed an increased risk. However, since the use of AMFs is strongly related with several other risk factors (group housing at young age, large groups, age difference in a group, continuous system versus all-in/all-out), it is difficult to unequivocally identify the risk associated with AMFs alone. A group size of less than ten calves on a single drinking point, an all-in/allout grouping system and a minimum age at introduction to the automat of three weeks are recommended for farms with AMFs. To the authors’ knowledge, no scientific evidence supporting the presumed association of diarrhea and tongue ulcers with AMFs is available to date.

Gastro-intestinale Clostridium perfringens-infecties: een blijvend gevaar in de Belgische rundveehouderij

De intensivering van de moderne landbouw wordt geassocieerd met een toename van Clostridium perfringens-gerelateerde, gastro-intestinale problemen bij intensief gevoede runderen, zoals “hemorrhagic bowel disease” bij hoogproductief melkvee en enterotoxemie bij kalveren. Waar de pathogenese van hemorrhagic bowel disease nog grotendeels ongekend is, werden er de laatste jaren nieuwe inzichten in de pathogenese van enterotoxemie bekomen die een belangrijke repercussie op de aanpak van deze ziekte onder praktijkomstandigheden hebben. Ook andere clostridiumgeassocieerde maagdarminfecties, zoals “overeating disease” en neonatale clostridiose, worden regelmatig gediagnosticeerd. Overvoedering met structuurarme, eiwitrijke voeders is een overkoepelende risicofactor bij zowel HBD, enterotoxemie als overeating disease. Een goed uitgebalanceerd dieet dat zo stabiel mogelijk gehouden wordt, is dan ook het belangrijkste aandachtspunt op bedrijven die problemen hebben met clostridiose. Daarnaast dient bij jonge kalveren voldoende aandacht gegeven te worden aan een correcte en hygiënische biestverstrekking om problemen met neonatale clostridiose te vermijden.

A new predilection site of Mycoplasma bovis: Postsurgical seromas in beef cattle

Mycoplasma bovis is a highly contagious bacterium, which predominantly causes chronic pneumonia, otitis and arthritis in calves and mastitis in adult cattle. In humans, Mycoplasma species have been associated with post-surgical infections. The present study aimed to identify the bacteria associated with three outbreaks of infected seromas after caesarian section in Belgian Blue beef cattle. A total of 10 cases occurred in three herds which were in close proximity of each other and shared the same veterinary practice. M. bovis could be cultured from seroma fluid in five of the six referred animals, mostly in pure culture and was isolated from multiple chronic sites of infection (arthritis and mastitis) as well. DNA fingerprinting of the isolates targeting two insertion sequence elements suggested spread of M. bovis from chronic sites of infection (udder and joints) to the postsurgical seromas. Identical genetic profiles were demonstrated in two animals from two separate farms, suggesting spread between farms. Mortality rate in the referred animals positive for M. bovis in a seroma was 80% (4/5), despite intensive treatment. A massive increase in antimicrobial use was observed in every affected farm. These observations demonstrate involvement of mycoplasmas in outbreaks of postsurgical seromas in cattle.

Study of the immunomodulatory properties of gamithromycin and dexamethasone in a lipopolysaccharide inflammation model in calves

The aim of this study was to define the in vivo immunomodulatory properties of the macrolide antibiotic gamithromycin in calves, with respect to the acute phase response. Additionally, the corticosteroid dexamethasone was included as a positive control immunomodulatory drug. Both drugs, as well as their combination,were studied in a previously developed inflammation model,which was initiated by an intravenous lipopolysaccharide (LPS) challenge (0.5 μg/kg body weight). Twenty-four 4-week-old male Holstein Friesian calves were randomized into four groups: no pharmacological treatment (n = 6) or a pharmacological treatment with gamithromycin (n= 6), dexamethasone (n= 6) or their combination (n= 6) 1 h prior to LPS administration. Blood collection and clinical scoring were performed at regular time points until 72 h post LPS challenge. Plasma concentrations of selected cytokines (tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6)) and acute phase proteins (serum amyloid A and haptoglobin) were subsequently determined. Gamithromycin did not have any beneficial effect on the LPS-induced clinical signs (dyspnea, fever, anorexia and depression), nor on the studied inflammatory mediators. In the dexamethasone and combination groups, the occurrence of dyspnea and fever was not prominently influenced, although the calves recovered significantly faster from the challenge. Moreover, dexamethasone significantly inhibited the levels of TNF-α and IL-6, suggesting a key role for these cytokines in sickness behaviour. In conclusion, unlike dexamethasone, gamithromycin did not directly reduce cytokine release in an LPS inflammation model in calves.

First confirmed case of bovine besnoitiosis in an imported bull in Belgium

Besnoitia besnoiti is a protozoan parasite known to cause important economic losses in the cattle industry in Africa, Asia and the Mediterranean area. In the last years, (re-) emergence of the parasite has been reported in France, Germany, Hungary and Italy with in some cases, establishment of an endemic infection. In this article, the first case of besnoitiosis in Belgium in a Blonde d’Aquitaine bull imported from the south of France is described. Additionally, a brief overview of the epidemiology of the disease is provided.

Vraag & Antwoord

Behandeling van ileus bij het kalf Wetgeving omtrent het houden van reptielen Het chippen van een landschildpad

Surgical correction of pyelonephritis caused by multidrug-resistant Escherichia coli in a dairy cow

A four-year-old red Holstein Friesian cow was admitted to the clinic with fever and milk drop. Blood analysis revealed the presence of a chronic infection, and the diagnosis of pyelonephritis of the right kidney was made after repeated ultrasound examinations. The animal was treated with procaine benzylpenicillin, sulfadoxine trimethoprim, oxytetracycline and enrofloxacine but this therapy was not successful. Nephrectomy was performed after the left kidney proved to have a normal function. The removed right kidney was greatly enlarged and filled with pus. Escherichia coli was isolated from the kidney. The strain was multidrug-resistant, including resistance to aminopenicillins, streptomycin, sulfonamides and trimethoprim. The cow was treated with amoxicillin and clavulanic acid after the operation. Postoperatively, an abscess developed and a tube drain was placed during a second surgery to enable daily rinsing with a chlorhexidine solution. After a postoperative care period of two months, the animal was sent back to the farm, where it returned to an acceptable level of milk production. This case demonstrates that with basic surgical skills, a good preparation and knowledge of anatomy, nephrectomy is attainable for a first-opinion veterinarian, with an acceptable economic prognosis for the farmer.

Risk factors for recurrence of atrial fibrillation in horses after cardioversion to sinus rhythm

Background

Although atrial fibrillation (AF) can be successfully treated in horses, recurrence occurs frequently. In humans, atrial function after cardioversion can predict recurrence.

Objectives

To examine the prognostic value of atrial mechanical function at 24 hours after cardioversion and other potential predictor variables for AF recurrence in horses.

Animals

117 horses treated for AF at 4 referral centers.

Methods

Retrospective study. Inclusion criteria were successful cardioversion, echocardiography at 24 hours after cardioversion and ≥4 months follow‐up. To determine factors associated with AF recurrence, a multivariable survival model was built.

Results

133 AF episodes in 117 horses were included. AF recurred in 36/100 horses with a first AF episode and in 57/133 AF episodes overall. Factors associated with recurrence in horses with a first episode were previous unsuccessful treatment attempt (hazard ratio HR 2.36, 95% confidence interval CI 1.11–4.99, P = .025) and mild or moderate mitral regurgitation (HR 2.70, 95% CI 1.23–5.91, P = .013). When the last AF episode of all horses was included, previous AF (HR 2.53, 1.33–4.82, P = .005) and active left atrial fractional area change ≤9.6% (HR 3.43, 1.22–9.67, P = .020) were significant predictors.

Conclusions and Clinical Importance

The only echocardiographic variable of left atrial function with significant prognostic value for recurrence was low active left atrial fractional area change. Further research is necessary to evaluate whether echocardiography at a later timepoint could provide more prognostic information.

Intestinal obstruction by Toxocara vitulorum in a calf

A one-month-old Belgian blue bull calf was referred to the animal hospital of the Faculty of Veterinary Medicine (UGhent) because of the sudden onset of severe colic. The animal showed intermittent recumbency, kicking to the abdomen, abdominal distension of the right quadrants, absence of feces and fluid-splashing and the presence of ping sounds on auscultation of the right side. Abdominal ultrasound showed distended, but still contractile small intestines with thickened walls. On exploratory laparotomy, a complete obstruction with adult Toxocara vitulorum extending from duodenum to mid-jejunum was diagnosed. On the punctum maximum of the obstruction, the ascarides were partially removed through an enterotomy. After vermifugation with doramectin, ascarides were found in the animal’s feces in the next days. In contrast to ascaride infections in puppies, piglets and foals, to the author’s knowledge, intestinal obstruction caused by T. vitulorum has not been described previously in calves.

Antimicrobial use in pigs, broilers and veal calves in Belgium

Given the risks associated with antimicrobial resistance and its link with antimicrobial use, available data on antimicrobial use in the Belgian pig, broiler and veal calf production were compared. Allowing for comparison of the data available from three peer-reviewed scientific articles, the unit of measurement for antimicrobial use was the Treatment Incidence (TI), defined as the number of animals per 1000 treated daily with one ‘defined’ (DDDA) or ‘used daily dose animal’ (UDDA). Moreover, extrapolation of farm-level data to national-level data was attempted according to the European Surveillance of Veterinary Antimicrobial Consumption (ESVAC) methodology, to estimate the amount of antimicrobials used in Belgium per species. Although, among the three species, the highest TI was observed in veal calves (TIDDDA=414, TIUDDA=379), based on the extrapolation, it was estimated that most antimicrobials were administered to pigs (159.4 tons). Thus, the most rapid decline in the total use could potentially be achieved by targeting the pig sector. During the process of data collection for comparison and calculation, it became obvious that there is a need for harmonized monitoring programs.

Characteristics and challenges of the modern Belgian veal industry

In this paper, the modern Belgian veal industry is situated in a European context, and an overview is provided of the major past, present and future challenges for veal production. The production of white veal requires a specific diet and housing conditions to assure a controlled iron anemic state resulting in pale carcasses. In response to the increasing public concern about animal welfare, legal limits for hemoglobin (in 1990), the provision of a minimum quality of solid feed to assure ruminal health and group housing from the age of eight weeks on (in 2007), have been implemented sector-wide. The integrated structure of the sector likely made it possible to realize these radical changes at relatively short notice. Despite the pioneers role the veal industry played in the development of quality labels for food safety and all efforts made towards improved nutrition and housing, the veal production remains highly liable to public criticism on welfare issues. Nowadays, especially the intensive antimicrobial use in relation to high levels of antimicrobial resistance in commensal, pathogenic and zoonotic bacteria in veal calves is strongly criticized. The future challenge lies in the development of veal production systems, which require only few antibiotics, but safeguard animal welfare and revenue.

False-positive results in metagenomic virus discovery: a strong case for follow-up diagnosis

A viral metagenomic approach using virion enrichment, random amplification and next-generation sequencing was used to investigate an undiagnosed cluster of dairy cattle presenting with high persistent fever, unresponsive to anti-microbial and anti-inflammatory treatment, diarrhoea and redness of nose and teat. Serum and whole blood samples were taken in the predicted hyperviraemic state of an animal that a few days later presented with these clinical signs. Bioinformatics analysis of the resulting data from the DNA virus identification workflow (a total of 32 757 sequences with average read length 335 bases) initially demonstrated the presence of parvovirus-like sequences in the tested blood sample. Thorough follow-up using specific real-time RT-PCR assays targeting the detected sequence fragments confirmed the presence of these sequences in the original sample as well as in a sample of an additional animal, but a contamination with an identical genetic signature in negative extraction controls was demonstrated. Further investigation using an alternative extraction method identified a contamination of the originally used Qiagen extraction columns with parvovirus-like nucleic acids or virus particles. Although we did not find any relevant virus that could be associated with the disease, these observations clearly illustrate the importance of using a proper control strategy and follow-up diagnostic tests in any viral metagenomic study.

Vraag & Antwoord

"Neonatal respiratory distress syndrome" bij kalveren Lintwormbesmetting in schapenkudden Preventie van strongylideninfecties bij paarden

Spontaneous bleeding in a neonatal calf persistently infected with BVDV1b

A calf developed skin bleeding on the second day of its life. It was referred to the clinic onsuspicion of bovine neonatal pancytopenia (BNP). Hematology showed extreme thrombocytopenia,moderate anemia, but no leukopenia. A PCR test on a heparinized blood sample was bovine viraldiarrhea virus (BVDV) positive, as were the two BVDV antigen ELISAs performed three and tenweeks later. Non-cytopathic BVDV type 1b was isolated from the blood. Although the calf recoveredfrom hemorrhagic disease, and continued to be healthy, it was euthanized at eleven weeks of agebecause of persistent BVDV infection. On the basis of the case history, BNP could be excludedfrom the differential diagnosis. This case illustrates that hemorrhagic disease is not exclusivelyassociated with BVDV type 2 and that the clinical signs in neonatal calves infected with BVDV1bcan be identical to the clinical presentation of BNP.