Size of supernumerary teats in sheep correlates with complexity of the anatomy and microenvironment.

Supernumerary nipples or teats (polythelia) are congenital accessory structures that may develop at any location along the milk line and have been implicated in the pathogenesis of mastitis. We describe the anatomy and histology of 27 spontaneously occurring supernumerary teats from 16 sheep, delineating two groups of teats - simple and anatomically complex - according to the complexity of the anatomy and microenvironment. Anatomically complex supernumerary teats exhibited significantly increased length and barrel diameter compared with simple supernumerary teats. A teat canal and/or teat cistern was present in anatomically complex teats, with smooth muscle fibres forming a variably well-organised encircling teat sphincter. Complex supernumerary teats also exhibited immune cell infiltrates similar to those of normal teats, including lymphoid follicle-like structures at the folds of the teat cistern-teat canal junction, and macrophages that infiltrated the peri-cisternal glandular tissue. One complex supernumerary teat exhibited teat end hyperkeratosis. These anatomical and histological features allow inference that supernumerary teats may be susceptible to bacterial ingress through the teat canal and we hypothesise that this may be more likely in those teats with less well-organised encircling smooth muscle. The teat cistern of anatomically complex teats may also constitute a focus of milk accumulation and thus a possible nidus for bacterial infection, potentially predisposing to mastitis. We suggest that size of the supernumerary teat, and relationship to the main teats, particularly in the case of 'cluster teats', should be considerations if surgical removal is contemplated.

Overview of the practices of on-farm emergency slaughter of cattle in the Nordic countries.

On farm mortality is an increasing problem in cattle production systems in the Nordic countries. It represents an economic loss to the farmer and raises questions of sustainability, food waste and animal welfare. On-farm emergency slaughter (OFES) represents, in some situations, an opportunity for a farmer to salvage some of the economic value from an animal that cannot be transported to a slaughterhouse. The basis of the regulation of OFES in the Nordic countries originates largely from legislation from the European Union. However, this review has found that the availability and practice of OFES in the Nordic countries differs considerably. For example, in Norway 4.2% of all cattle slaughter is OFES, whilst in Iceland OFES has never been recorded. National food safety authorities have issued differing regulations and guidelines regarding the suitability of sick and injured animals for OFES. This review shows there is a paucity of data regarding the incidence and reasons for the use of OFES of cattle in the Nordic countries and points out the need for more investigation into this area to improve veterinary education, consumer protection and animal welfare.

Occurrence and reasons for on-farm emergency slaughter of cattle in Norway.

On-farm emergency slaughter (OFES) accounts for more than 4% of all cattle slaughter in Norway. The practice raises questions about animal welfare, public health, and the sustainability of cattle production. The objective of this study was to describe the reasons for OFES as stated on the OFES veterinary certificate. Veterinary certificates for OFES for each animal slaughtered in four chosen slaughterhouses from 4 months (January-April-July-October) in 2018 were transcribed into a database. Secondary data were extracted from national cattle databases and used to supplement primary data with information on breed, sex, and birth date. Breeds were divided into dairy and beef cattle. The reasons for slaughter were reported in text on the certificates and were categorized in the study into 5 reasons: recumbency, mammary gland, obstetrics, locomotion, and other, with a total of 20 subcategories for detail. In total, 2,229 forms were included in the study. Thirteen breeds were represented, although dominated by Norwegian Red within dairy and crossbreed within beef. Of the cattle in the study, 46% were slaughtered for locomotion reasons, thereof almost half for lameness. Furthermore, 23% of the cattle in the study were slaughtered for recumbency and 17% for prolapse or dystocia. A higher proportion of dairy cows were slaughtered because of reasons related to mammary glands than beef cows, 10 and 2%, respectively. Almost 30% of beef cows were slaughtered for obstetrics reasons compared to 12% of dairy cows. The results of this study shed light on the reasons for OFES, which is highly relevant to greater discussions of sustainability in cattle production and animal welfare related to on-farm mortality.

Molecular detection and genotype characterization of Streptococcus dysgalactiae from sheep flocks with outbreaks of infectious arthritis.

Outbreaks of infectious arthritis in young lambs are a growing concern for the Norwegian sheep industry. In other countries, Streptococcus dysgalactiae subspecies dysgalactiae (SDSD) is a frequent cause of such outbreaks. The objectives of this study were to investigate the causes of outbreaks of infections arthritis in Norwegian sheep flocks, and describe the sources, colonization patterns and genetic diversity of SDSD in affected and healthy sheep flocks. Almost 2000 samples from joints, animal body sites and the indoor environment were analysed by qPCR and culturing for SDSD, which was detected in 27 of 30 flocks. The proportion of positive samples was greater in outbreak flocks compared to healthy flocks. Altogether, SDSD was detected in 48 % of the samples from lambs, 27 % of the samples from ewes and 48 % of environmental samples. A relatively high proportion (67 %) of ear tag wounds were SDSD positive. These wounds may provide a port of entry for SDSD. Whole genome sequencing revealed a clonal distribution of SDSD-isolates, and identified four different multi locus sequence types (STs), among which two STs, ST454 and ST531, dominated. These STs were found in geographically distant flocks. ST454 was almost exclusively found in outbreak flocks. The current study points to skin, wounds and mucous membranes of animals as the main reservoir of SDSD in sheep flocks. However, a significantly higher proportion of SDSD-positive environmental samples in outbreak flocks compared to healthy flocks suggests that also indirect transmission may play a role.

Overview and Evaluation of Existing Guidelines for Rational Antimicrobial Use in Small-Animal Veterinary Practice in Europe.

Antimicrobial stewardship guidelines (ASGs) represent an important tool to help veterinarians optimize their antimicrobial use with the objective of decreasing antimicrobial resistance. The aim of this study was to map and qualitatively assess the ASGs for antimicrobial use in cats and dogs in Europe. Country representatives of the European Network for Optimization of Veterinary Antimicrobial Treatment (ENOVAT) were asked to identify ASGs published in their countries. All collated ASGs updated since January 2010 containing recommendations on antimicrobial therapy for at least three conditions affecting different organ systems in cats and dogs underwent detailed review including AGREE II analysis. Out of forty countries investigated, fifteen ASGs from eleven countries met the inclusion criteria. Several critical principles of antimicrobial use were identified, providing a framework that should assist development of stewardship guidance. The AGREE II analysis highlighted several methodological limitations of the currently available ASGs. This study sheds light on the lack of national ASGs for dogs and cats in multiple European countries and should encourage national bodies to prioritize guideline development in small animals. A greater awareness of the need to use a structured approach to guideline development could improve the quality of ASGs in the future.

Flock-level risk factors for outbreaks of infectious arthritis in lambs, Norway 2018.

BACKGROUND: Outbreaks of infectious arthritis in young lambs associated with Streptococcus dysgalactiae subspecies dysgalactiae (SDSD) lead to reduced animal welfare, increased use of antibiotics and economic losses for sheep farmers. Understanding risk factors is essential when developing strategies to prevent such outbreaks. This questionnaire-based cross-sectional study classified sheep flocks of respondents as cases or controls. Flock-level risk factors for outbreaks of infectious arthritis were assessed using a multivariable logistic regression model. RESULTS: Eighty-four of 1498 respondents (5.6%) experienced an outbreak of infectious arthritis in their flock in 2018, the year of study. Factors associated with a higher risk of outbreak were larger flock size (OR 1.3, 95% CI 1.1-1.4, per 100 lambs), plastic mesh flooring in the lambing pen (OR 3.0, 95% CI 1.7-5.3) and a lambing percentage greater than 200 (OR 2.0, 95% CI 1.1-3.5). Flocks where farmers observed infections around the ear tags of lambs also had an increased risk of outbreak (OR 2.6, 95% CI 1.6-4.3). CONCLUSIONS: The risk factors identified in this study are characteristic of modern and intensively managed sheep farms in Norway. A distinguishing feature of Norwegian sheep farming is winter housing and indoor lambing. One might expect that this in itself is a risk factor because of high stocking densities during lambing. However, outbreaks of infectious arthritis in young lambs are reported by the industry to be a more recent phenomenon. The current study indicates that intensification of indoor management systems with larger flocks and higher production per ewe may predispose to outbreaks. The results provide a basis for further studies on transmission dynamics of SDSD in sheep flocks with indoor lambing.

Antimicrobial resistance in ovine bacteria: A sheep in wolf's clothing?

BACKGROUND: To monitor the prevalence of antimicrobial resistance (AMR), methods for interpretation of susceptibility phenotypes of bacteria are needed. Reference limits to declare resistance are generally based on or dominated by data from human bacterial isolates and may not reflect clinical relevance or wild type (WT) populations in livestock or other hosts. METHODS: We compared the observed prevalence of AMR using standard and bespoke interpretations based on clinical breakpoints or epidemiological cut-offs (ECOFF) using gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria from sheep as exemplars. Isolates were obtained from a cross-sectional study in three lowland sheep flocks in Scotland, and from a longitudinal study in one flock in Norway. S. aureus (n = 101) was predominantly isolated from milk or mammary glands whilst E. coli (n = 103) was mostly isolated from faecal samples. Disc diffusion testing was used to determine inhibition zone diameters, which were interpreted using either clinical breakpoints or ECOFF, which distinguish the bacterial wild type population from bacteria with acquired or mutational resistance to the compound of interest (non-wild type). Standard ECOFF values were considered as well as sheep-specific values calculated from the data using Normalized Resistance Interpretation (NRI) methodology. RESULTS: The prevalence of AMR as measured based on clinical breakpoints was low, e.g. 4.0% for penicillin resistance in S. aureus. Estimation of AMR prevalence based on standard ECOFFs was hampered by lack of relevant reference values. In addition, standard ECOFFS, which are predominantly based on human data, bisected the normal distribution of inhibition zone diameters for several compounds in our analysis of sheep isolates. This contravenes recommendations for ECOFF setting based on NRI methodology and may lead to high apparent AMR prevalence. Using bespoke ECOFF values based on NRI, S. aureus showed non-wild type for less than 4% of isolates across 13 compounds, and ca. 13% non-wild type for amoxicillin and ampicillin, while E. coli showed non-wild type for less than 3% of isolates across 12 compounds, and ca. 13% non-wild type for tetracyclines and sulfamethoxazole-trimethoprim. CONCLUSION: The apparent prevalence of AMR in bacteria isolated from sheep is highly dependent on interpretation criteria. The sheep industry may want to establish bespoke cut-off values for AMR monitoring to avoid the use of cut-offs developed for other host species. The latter could lead to high apparent prevalence of resistance, including to critically important antimicrobial classes such as 4th generation cephalosporins and carbapenems, suggesting an AMR problem that may not actually exist.

Increasing importance of anthelmintic resistance in European livestock: creation and meta-analysis of an open database.

Helminth infections are ubiquitous in grazing ruminant production systems, and are responsible for significant costs and production losses. Anthelmintic Resistance (AR) in parasites is now widespread throughout Europe, although there are still gaps in our knowledge in some regions and countries. AR is a major threat to the sustainability of modern ruminant livestock production, resulting in reduced productivity, compromised animal health and welfare, and increased greenhouse gas emissions through increased parasitism and farm inputs. A better understanding of the extent of AR in Europe is needed to develop and advocate more sustainable parasite control approaches. A database of European published and unpublished AR research on gastrointestinal nematodes (GIN) and liver fluke (Fasciola hepatica) was collated by members of the European COST Action "COMBAR" (Combatting Anthelmintic Resistance in Ruminants), and combined with data from a previous systematic review of AR in GIN. A total of 197 publications on AR in GIN were available for analysis, representing 535 studies in 22 countries and spanning the period 1980-2020. Reports of AR were present throughout the European continent and some reports indicated high within-country prevalence. Heuristic sample size-weighted estimates of European AR prevalence over the whole study period, stratified by anthelmintic class, varied between 0 and 48%. Estimated regional (country) prevalence was highly heterogeneous, ranging between 0% and 100% depending on livestock sector and anthelmintic class, and generally increased with increasing research effort in a country. In the few countries with adequate longitudinal data, there was a tendency towards increasing AR over time for all anthelmintic classes in GIN: aggregated results in sheep and goats since 2010 reveal an average prevalence of resistance to benzimidazoles (BZ) of 86%, macrocyclic lactones except moxidectin (ML) 52%, levamisole (LEV) 48%, and moxidectin (MOX) 21%. All major GIN genera survived treatment in various studies. In cattle, prevalence of AR varied between anthelmintic classes from 0-100% (BZ and ML), 0-17% (LEV) and 0-73% (MOX), and both Cooperia and Ostertagia survived treatment. Suspected AR in F. hepatica was reported in 21 studies spanning 6 countries. For GIN and particularly F. hepatica, there was a bias towards preferential sampling of individual farms with suspected AR, and research effort was biased towards Western Europe and particularly the United Kingdom. Ongoing capture of future results in the live database, efforts to avoid bias in farm recruitment, more accurate tests for AR, and stronger appreciation of the importance of AR among the agricultural industry and policy makers, will support more sophisticated analyses of factors contributing to AR and effective strategies to slow its spread.

TITLE: Importance croissante de la résistance aux anthelminthiques chez les ruminants européens : création et méta-analyse d'une base de données ouverte. ABSTRACT: Les helminthes sont omniprésents dans les systèmes de production de ruminants au pâturage et sont responsables de coûts et de pertes de production importants. La résistance aux anthelminthiques (RA) des parasites est maintenant répandue dans toute l'Europe, bien qu'il existe encore des lacunes dans nos connaissances dans certaines régions et certains pays. La RA est une menace majeure pour la pérennité de la production moderne de ruminants, en diminuant la productivité, en compromettant la santé et le bien-être des animaux, et en augmentant les émissions de gaz à effet de serre au travers d'une augmentation du parasitisme et des intrants agricoles. Une meilleure compréhension de l'étendue de la RA en Europe est nécessaire pour développer et préconiser des approches de lutte antiparasitaire plus durables. Une base de données intégrant des informations publiées et non publiées en Europe concernant la RA des nématodes gastro-intestinaux (NGI) et de la douve du foie (Fasciola hepatica) a été compilée par les membres de l'action européenne COST « COMBAR ¼ (« Combattre la résistance aux anthelminthiques chez les ruminants ¼) et combinée avec les données d'une précédente étude systématique concernant la RA des NGI. Au total, 197 publications sur la RA des NGI étaient disponibles pour analyse, représentant 535 études dans 22 pays et couvrant la période 1980­2020. Des signalements de RA étaient présents sur tout le continent européen et certains rapports indiquaient une forte prévalence nationale. Les estimations heuristiques pondérées par la taille de l'échantillon de la prévalence de la RA en Europe sur toute la période d'étude, stratifiées par classe d'anthelminthiques, variaient de 0 à 48 %. La prévalence régionale (nationale) estimée était très hétérogène, variant entre 0 % et 100 % selon le secteur de l'élevage et la classe d'anthelminthique, et augmentait généralement avec les efforts de recherche dans le pays. Dans les quelques pays disposant de données longitudinales adéquates, il y avait une tendance à l'augmentation de la RA au fil du temps pour toutes les classes d'anthelminthiques des NGI : les résultats agrégés chez les ovins et caprins depuis 2010 révèlent une prévalence moyenne de résistance aux benzimidazoles (BZ) de 86 %, aux lactones macrocycliques sauf moxidectine (ML) de 52 %, au lévamisole (LEV) de 48 % et à la moxidectine (MOX) de 21 %. Tous les genres principaux de NGI ont survécu au traitement dans diverses études. Chez les bovins, la prévalence de la RA variait selon les classes d'anthelminthiques de 0 à 100 % (BZ et ML), 0 à 17 % (LEV) et 0 à 73 % (MOX), et Cooperia et Ostertagia ont survécu aux traitements. Une RA suspectée chez F. hepatica a été signalée dans 21 études portant sur 6 pays. Pour les NGI, et encore plus pour F. hepatica, il y avait un biais d'échantillonnage en faveur des exploitations individuelles suspectées de RA, et l'effort de recherche était biaisé vers l'Europe occidentale et en particulier le Royaume-Uni. La capture continue des résultats futurs dans la base de données, en direct, les efforts pour éviter les biais dans le recrutement des exploitations, des tests plus précis pour la RA et une meilleure appréciation de l'importance de la RA parmi l'industrie agricole et les décideurs politiques, soutiendront des analyses plus sophistiquées des facteurs contribuant à la RA, et des stratégies efficaces pour ralentir sa propagation.

Highs and Lows of Lambing Time: Sheep Farmers' Perceptions of the First Outbreak of Schmallenberg Disease in South West England on Their Well-Being.

The outbreak of a previously unknown and new disease in the United Kingdom, known as 'Schmallenberg disease', a disease associated with abortions, stillbirths and fetal deformities in naïve ewes, was reported for the first time in South West England during the 2012/13 early lambing season. Epidemiological studies confirmed that the Schmallenberg virus (SBV) had a severe negative impact upon animal welfare and the productivity of affected flocks. By contrast, there was a specific lack of research on the impact of SBV on sheep farmer well-being. This study aimed to improve our understanding of sheep farmers' experiences of Schmallenberg disease, and the impact of the first outbreak on sheep farmer well-being during the 2012/13 early lambing season in South West England. Face-to-face, semi-structured interviews with six farmers with small flocks of pedigree and purebred sheep in South West England were conducted in 2013. The data were analysed via thematic analysis. The main themes regarding the impact of disease on farmer well-being included: (i) emotional highs and lows are part of a normal lambing season; (ii) negative emotions and memories associated with the Schmallenberg disease outbreak; and (iii) resilience and coping with the unexpected disease outbreak. These novel data present preliminary findings from a small number of sheep farmers, and indicate that for some farmers, an unexpected outbreak of a new and emerging disease for the first time during lambing, and dealing with high levels of dystocia, deformities and deaths in their animals, had a negative impact on their emotional well-being during the peak period of the sheep production cycle.

Intra- and Inter-Observer Reliability of Qualitative Behaviour Assessments of Housed Sheep in Norway.

This study tested the reliability of a Qualitative Behavioural Assessment (QBA) protocol developed for the Norwegian Sheep House (FåreBygg) project. The aim was to verify whether QBA scores were consistent between different observers, i.e., inter-observer reliability, and between scorings of the same observers on different time points, i.e., intra-observer reliability. Six trained observers, including two veterinary students, two animal welfare inspectors and two sheep farmers observed sheep in 16 videos, and independently scored 14 pre-defined behavioural descriptors on visual analogue scales (VAS). The procedure was repeated one week after the first scoring session. QBA scores were analysed using Principal Component Analysis. Inter- and intra-observer agreement was assessed using Kendall's coefficient of concordance (W). Principal component 1 (PC 1) and 2 (PC 2) combined explained >60% of the total variation in the QBA scores in both scoring sessions. PC 1 (44.5% in sessions 1 and 2) ranged from the positive descriptors calm, content, relaxed and friendly to the negative descriptors uneasy, vigilant and fearful, and was therefore labelled mood. PC 2 (18% in session 1, 16.6% in session 2) ranged from bright to dejected and apathetic, and was therefore labelled arousal. Kendall's coefficient of concordance of PC 1 for all observers was high in the two scoring sessions (W = 0.87 and 0.85, respectively), indicating good inter-observer reliability. For PC 2, the agreement for all observers was moderate in both video sessions (W = 0.45 and 0.65). The intra-observer agreement was very high for all observers for PC 1 (W > 0.9) except for one, where the agreement was considered to be high (W = 0.89). For PC 2, Kendall's coefficient was very high for the veterinary students and interpreted as moderate for the two farmers and welfare inspectors. This study indicates that the QBA approach and the terms included in the Fårebygg protocol were reliable for assessing video recordings of sheep behaviour when applied by trained observers, regardless of whether they were a veterinary student, animal welfare inspector or sheep farmer. Further work is needed to examine the reliability of the QBA protocol when tested on-farms for sheep managed under Norwegian housing systems.

Quantitative Outcomes of a One Health approach to Study Global Health Challenges.

Having gained momentum in the last decade, the One Health initiative promotes a holistic approach to address complex global health issues. Before recommending its adoption to stakeholders, however, it is paramount to first compile quantitative evidence of the benefit of such an approach. The aim of this scoping review was to identify and summarize primary research that describes monetary and non-monetary outcomes following adoption of a One Health approach. An extensive literature search yielded a total of 42,167 references, of which 85 were included in the final analysis. The top two biotic health issues addressed in these studies were rabies and malaria; the top abiotic health issue was air pollution. Most studies described collaborations between human and animal (n = 42), or human and environmental disciplines (n = 41); commonly reported interventions included vector control and animal vaccination. Monetary outcomes were commonly expressed as cost-benefit or cost-utility ratios; non-monetary outcomes were described using disease frequency or disease burden measurements. The majority of the studies reported positive or partially positive outcomes. This paper illustrates the variety of health challenges that can be addressed using a One Health approach, and provides tangible quantitative measures that can be used to evaluate future implementations of the One Health approach.

A pilot survey of farm animal welfare in Serbia, a country preparing for EU accession.

The selection and field application of animal-based welfare measures for pigs, sheep, dairy cows and broilers was the first step towards the future development of welfare improvement schemes for Serbia - a country that is applying for EU accession. The aim of this pilot study was to: (1) test the feasibility of a protocol for monitoring farm animal welfare in Serbia, (2) ascertain preliminary data on animal-based outcomes of farm welfare and (3) gain insight into Serbian farmers' understanding of animal welfare as part of a wider project working towards inclusion of animal-based assessments in a 'higher welfare' voluntary assurance scheme. This study encompasses the first national survey of farm animal welfare in which animal-based outcomes were tested on 105 farms by a total of ten trained assessors. Data on the views and aspirations of the farmers from these 105 farms were also systematically gathered during face-to-face interviews. Existing animal-based measures for pigs, sheep, dairy cows and broilers that have been successfully applied and identified as valid, reliable and feasible measures in other countries, were found to be largely transferable. However, some on-farm protocols, previously used in other countries, had to be shortened for logistical reasons when used in Serbia. Our findings suggest that further refinement may be needed in order to allow local application of all measures. While the term 'animal welfare' has only recently been introduced into the Serbian language, seventy-three percent of farmers had heard of it. Overall, few positive associations were found between farmer satisfaction with animals' living conditions and animal-based data. Many farmers had aspirations to develop and expand their farms, which may potentially enhance animal welfare, but these farmers identified that financial and technical advice and support would be needed in order to achieve these goals.

A comparison of the FECPAK and Mini-FLOTAC faecal egg counting techniques.

Faecal egg counts (FECs) are used for detecting and quantifying nematode infections and are the basis for determining drug efficacy and anthelmintic resistance in faecal egg count reduction tests (FECRTs). Currently, several FEC techniques are available for detecting and quantifying eggs of sheep nematodes. A comparison of the egg counts from the FECPAK (with a minimum detection limit of 30 eggs per gram (epg)) and Mini-FLOTAC (with a minimum detection limit of 5 epg) showed better diagnostic performance with Mini-FLOTAC in terms of measurement error (level of over- or under-estimation of FEC) and precision (variability in FEC). A tendency to under-estimate FEC was observed with the FECPAK particularly at egg densities of less than 500 epg. It is concluded that Mini-FLOTAC is a reliable diagnostic tool offering reduced measurement error and a higher level of precision.

Reliability of indicators of sheep welfare assessed by a group observation method.

Assessments of animal-based outcomes form the core of routine veterinary clinical examinations and are being increasingly used as indicators of animal welfare. A method of group observation that did not require gathering and handling of individual sheep, was used to assess eight animal-based indicators of sheep welfare: demeanour, skin irritation, wool loss, excessive panting, coughing, lameness, and cleanliness of the ventral abdominal and 'breech' (perineum/gluteal/caudal hindlimb) areas. The inter-observer reliability of two or three observers who independently assessed these indicators was tested on 2406 adult sheep and growing lambs across 36 farms and the intra-observer reliability of an experienced, veterinary assessor--the 'test standard observer'--was assessed on 88 adult sheep during four on-farm assessments. Observer reliability was evaluated using Cronbach's alpha (α) comparison of the recorded proportion (%) of sheep affected by each welfare condition and by binomial logistic regression modelling. High levels of inter-observer reliability were identified for the assessment of group lameness (α 0.76-1.00) and cleanliness of the breech area (α 0.97-1.00). Excellent intra-observer reliability was determined for lameness (α 0.99), cleanliness of the breech area (α 0.97), demeanour (α 1.00) and wool loss (α 1.00). In addition, proportion data and logistic regression models identified few between-observer differences. The results suggest that welfare outcomes based on observations of the behaviour and physical appearance of individual animals within a group may offer a reliable and feasible measurement tool for the on-farm assessment of sheep welfare.

Discriminant and multiple regression analysis of anemia and opportunistic infection in Fell pony foals.

A condition resembling acquired immunodeficiency with anemia has been described in British Fell pony foals. The pathogenesis is unknown. The present study involved 322 foals of which 164 were of Fell breed and 12 were affected. Discriminant and multiple regression analyses were used to test the results of all clinical pathology parameters from these foals for statistical association with (1) breed origin and (2) presence of disease. Only hematocrit associated significantly with presence of disease. However, significant associations were found with Fell breed origin, including serum albumin concentration and lymphocyte count. The unexpected discovery of sporadic lymphocytosis in the breed indicates the value of this kind of analysis and may be evidence that Fell foal immunodeficiency is associated with retroviral infection.