Background: Recently, in-feed medicinal zinc has been phased out in pig production in the European Union. This makes updated knowledge about porcine post-weaning diarrhea (PWD) crucial. The objectives of the present study were to investigate (i) the clinical presentation of PWD in pigs housed in Danish herds that did not use medicinal zinc, specifically the prevalence of diarrhea and whether PWD was associated to clinical signs of dehydration or altered body temperature; (ii) which microorganism are associated to PWD; and iii) whether measurements of the fecal pH have a potential to be used diagnostically to differentiate between infectious etiologies in cases of PWD.Results: The prevalence of diarrhea varied considerably between the outbreaks in the nine studied herds (median = 0.58, range = 0.10; 0.94). In a cross-sectional design (n = 923), diarrhea was associated with reduced rectal temperature and alkaline feces. Diarrhea was also associated with observably reduced skin elasticity, possibly indicating dehydration. In both diarrheic case pigs (n = 87) and control pigs (n = 86), the presence ofBrachyspira pilosicoli,Clostridium perfringens,Cryptosporidiumspp.,Cystoisopora suis,enterotoxigenicEscherichia coli,Lawsonia intracellularis, porcine circovirus types 2 and 3, rotavirus A, B, C, and H,Samonella enterica spp. enterica, andTrichuris suiswas described. PWD was associated with high levels of enterotoxigenicE. colishedding (odds ratio versus noE. colidetection = 4.79 [CI 1.14; 12.62]). Diarrhea was associated with high levels of rotavirus A shedding (odds ratio versus no/low rotavirus A = 3.80 [CI 1.33; 7.97]). The association between microbiological findings in diarrheic pigs and fecal pH was negligible.Conclusions: EnterotoxigenicE. coliwas confirmed to be a cause of PWD; however, cases of PWD where enterotoxigenicE. coliwas not detected in high levels occurred commonly, and this adds to the increasing evidence suggesting that PWD is not necessarily a result of enteric colibacillosis. Rotaviral enteritis might be a differential diagnosis of PWD. pH-measurements cannot be used to differentiate between differential diagnoses for PWD.

Aided by their advising veterinarians, pig producers need to make difficult decisions regarding herd health management strategies. For instance, the preventive use of antimicrobials and medicinal zinc oxide must be substituted with more sustainable preventive approaches to porcine post-weaning diarrhea. Veterinarians and pig producers may find assistance in knowledge based on evidence in this regard; however, the overwhelming scientific literature is not always readily available. The overall aim of this paper is to suggest herd health management decision-support tools that can aid veterinary-assisted decision making in the control of porcine post-weaning diarrhea at a tactical level. The first objective was to validate the need for a herd health management concept, including two decision-support tools. The second objective was to develop evidence-based recommendations that can aid veterinary-assisted decision-making for the herd health management of post-weaning diarrhea. The first objective was investigated by a questionnaire-based study among veterinary pig practitioners in Denmark. For the second objective, we conducted a scientific summary based on scientific review papers identified through a systematic search in three databases. From the papers, we synthesized and extracted 79 specific recommendations. In this paper, we report comprehensive evidence-based recommendations for the herd health management of post-weaning diarrhea.

Neomycin is a concentration-dependant aminoglycoside antimicrobial used to treat enterotoxigenic Escherichiacoli(ETEC)-related post-weaning diarrhoea (PWD) in pigs. The objective was to compare the efficacy of neomycin administered in a single high dose (50,000 IU/kg) and a standard dose and frequency (25,000 IU/kg daily for 3 consecutive days) in reducing the number of pigs with clinical PWD. We also aimed to evaluate the development of antimicrobial resistance inE. colifollowing neomycin treatment. The study was performed in a Danish herd not using medicinal zinc oxide and experiencing outbreaks of PWD caused by ETEC in the first week after weaning. Pigs from six batches with perianal faecal staining on days 4–6 after weaning and a faecal score of 3–4 were ear tagged and treated with neomycin. Pens were randomly assigned to a treatment group before inclusion. A total of 772 pigs (471 in the control group and 301 in the experimental group) were included and treated orally. The apparent prevalence of diarrhoea on the first day of inclusion across six batches (n = 1,875) was 27%. The efficacy of the neomycin treatment strategy was 86% for the control group and 91% for the single high-dose group (p = 0.043), and the mean percentage (standard deviation (sd)) of haemolyticE. coli-like colonies was 12% (26) and 26% (37) (p < 0.001), respectively. Neomycin resistance did not differ between groups. Before treatment, all analysed isolates were identified as ETEC (n = 142), while after treatment, 91% were identified as ETEC (n = 69) and 9% (n = 7) as non-ETECE. coli(without fimbria or toxins). A higher cure rate in the single high-dose group suggests that ETEC-related PWD can be treated with a single high dose of 50,000 IU/kg of neomycin, thereby reducing antimicrobial use by 33% compared to the standard treatment of 25,000 IU/kg for 3 consecutive days. The study indicated a higher number of haemolyticE. coliin the single high-dose group after treatment, but no evidence of increased neomycin resistance in coliforms was observed compared to the standard treatment.

The treatment of diarrhea in the postweaning period is a common reason for the use of antimicrobials in pig production, and Escherichia coli is the single most important causative agent for this condition. Colistin has recently been classified as a critically important antimicrobial for human health, as it is a last-resort drug against certain multi-drug-resistant Gram-negative bacteria. Therefore, the use of colistin has been significantly reduced in some countries, including Denmark. Despite this, the drug is still commonly used to treat diarrhea in pigs in many countries, and there is a need to understand the risks associated with this practice. We performed a prospective cohort study to investigate the effect of colistin treatment on the changes in the average minimum inhibitory concentration (MIC) in commensal E. coli in a pig herd where no colistin-resistant bacteria were detectable before treatment. One group of pigs was batch treated with colistin after the clinical observation of diarrhea, one group was batch treated with colistin approximately 10 days before the expected onset of diarrhea, and a control group was not treated with colistin but provided with nonantimicrobial antidiarrheal feed supplement. Treatment with colistin in the dose and time combinations used did not result in a significant increase in the average colistin MIC values in E. coli. Moreover, no E. coli strains showed a MIC above the breakpoint of >2 mg/L against colistin. Co-selection of resistance to other antimicrobials was not observed.

Background: Veterinary telemedicine has only been adopted to some degree. One aspect that needs to be evaluated is clinical examinations using video. The objective of this study was to evaluate agreement between a traditional physical clinical examination and a clinical examination using recorded video using finishing pigs with umbilical outpouchings (umbilical hernias, cysts, and abscesses) as the study unit. A total of 102 finisher pigs with umbilical outpouchings were clinically examined and recorded on video. Four experienced pig veterinarians were allowed to examine each pig for approximately 10 min and were individually asked to fill out a predesigned clinical record. Approximately 1 month after the physical examinations, the veterinarians individually reexamined all 102 pigs in a blinded manner, utilizing the video recordings and filling in a predesigned clinical record. Results: For all measurements using a ruler, a high Pearson correlation coefficient was observed between physical and video examinations (range 0.69–0.95). In comparison, the visual bodyweight estimation had a lower Pearson correlation coefficient (range 0.57–0.64). Substantial to almost perfect agreement was observed between the physical and video examinations for abnormal weight distribution on any leg, restricted gait movements, lameness, signs of pain, fitness for transportation, presence of wounds, and categorization of the number of wounds > 4 cm² on the umbilical outpouching (mean Kappa range 0.67–0.87). Fair agreement was observed for the presence of perineal soiling, ear wounds, pendulation of umbilical outpouching, umbilical outpouching touching the legs, skin not movable over the umbilical outpouching, and umbilical outpouching wound characteristics: type, presence of crusts, active bleeding, thick wound edges, connective tissue (mean Kappa range 0.21–0.40). Slight agreement was observed for umbilical outpouching characteristics: shape, macroscopic vascularization of the skin covering the outpouching, and the presence of scars, excoriations, and fistulas (mean Kappa range 0.10–0.20). Poor agreement was observed for the presence of granulation tissue (mean Kappa = − 0.05). Conclusions: The agreement between a physical clinical examination and a clinical examination using recorded video of the same pig varies from poor to almost perfect, depending on the clinical sign and the executing veterinarian.

Background: Post weaning diarrhoea is expected to become an increasing problem in pig herds following the outphasing of medicinal Zinc Oxide. Currently, no equally effective substitute has been found and an increase in metaphylactic batch medication with antibiotics is expected. However, prudent use of antibiotics is needed to mitigate antibiotic resistance development and one option could be pre-treatment diagnostics. Employing a point-of-care test in a herd could provide fast diagnostics and help guide antibiotic treatment. Hence, the aim of this study was to evaluate the diagnostic performance of a commercially available point-of-care test for enterotoxigenic Escherichia coli (ETEC) F4, ETEC F18 and rotavirus in weaned pigs. Results: In total 115 diarrheic samples from two conventional herds were included in the evaluation of the Rainbow Piglet Scours test, which was compared to microbiological PCR analyses. The comparison yielded a diagnostic sensitivity, diagnostic specificity, positive and negative predictive value of 0.28, 0.99, 0.92 and 0.70 for ETEC F4, 0.40, 0.92, 0.91 and 0.45 for ETEC F18 and 0.67, 0.88, 0.91 and 0.61 for rotavirus. Conclusions: The point-of-care test yielded a low diagnostic sensitivity and a high diagnostic specificity for ETEC F4, ETEC F18 and rotavirus. Due to the high level of false negatives, the test cannot be recommended for individual diagnostics on pig-level.