http://british-breeding.com/news/i7797/first-uk-study-identifies-peak-risk-period-for-lawsonia-seroconversion-in-foals EN en 2026-08-03 First UK study identifies peak risk period for Lawsonia seroconversion in foals First UK study identifies peak risk period for Lawsonia seroconversion in foals   THE UK’s first seroprevalence <a href="https://doi.org/10.1111/eve.70115" style="text-decoration: none;">study</a> of Lawsonia intracellularis in foals has identified the age at which they are most likely to be exposed to the bacterium, helping stud farms determine the optimal time for vaccination. Vets from <a href="https://www.rossdales.com/" style="text-decoration: none;">Rossdales Equine Hospital</a>, in collaboration with the <a href="https://www.vetpartners.co.uk/" style="text-decoration: none;">VetPartners</a> Clinical Board Support Team, conducted the study into Lawsonia intracellularis, the bacterium responsible for equine proliferative enteropathy (EPE). The bacterium can cause sporadic disease in foals, but until now, it has been unclear how frequently foals in the UK are exposed to it. Caroline Ribonnet and Emily Floyd, both RCVS Recognised Specialists in Equine Internal Medicine, and Vicky Colgate, a veterinary researcher with an MSc in Veterinary Epidemiology and Public Health, all from the world-renowned Rossdales Equine Hospital in Exning, near Newmarket, collaborated to determine antibodies to, and faecal shedding of, Lawsonia Intracellularis in foals from UK Thoroughbred Stud farms.     A total of 47 foals from six farms were enrolled and monitored from birth, with testing carried out every three months until 12 months of age. Complete data was obtained for 37 foals. The main objective of the study was to determine the seroprevalence of L. intracellularis in mares and in foals during the first year of life on Thoroughbred stud farms in the UK. As well as the timing of seroconversion in foals, the research team were also interested in identifying any clinical signs, changes in clinicopathologic parameters and evidence of faecal shedding associated with L. intracellularis. Findings from the study revealed that at timepoint 0 (parturition), 77% of mares and 64% of foals were seropositive, indicating significant colostral transfer of maternal antibodies to the foals. Over the course of the study, 75% of foals seroconverted, meaning they became seropositive following a previous negative test, indicating exposure to the bacterium following loss of maternal antibodies. Only 22% (8 out of 37) of foals that completed the study did not seroconvert, and at least one seroconversion event was recorded on every participating farm. The research also identified a clear peak period of exposure: most seroconversions occurred between six and nine months of age, particularly between September and January, the autumn and winter period. As the samples were taken before vaccination against Lawsonia intracellularis became widespread in the UK, the findings provide valuable insight to guide vaccination strategies on UK Thoroughbred stud farms. With the vaccine requiring administration 30 days prior to anticipated disease, the study’s results suggest that vaccination protocols should be commenced before the peak epidemiological exposure period of autumn/winter, and before 6-9 months of age. Additionally, the study provides comparative seroprevalence data against which future studies could explore the effect of introducing routine vaccination protocols. The initial concept for the study came from Rossdales Clinical Director Emily Floyd, who works within their Neonatal Intensive Care Unit. Funding for the project was obtained from the Horserace Betting Levy Board (HBLB) Small Project Research Grant 2014 and the Thoroughbred Breeders Association (TBA). Natalie Robinson, from VetPartners’ Clinical Board Support Team (CBST), joined the research to support with statistical analysis. The CBST has both clinical and extensive research experience and empower VetPartners clinical teams to undertake clinical quality improvement and research.  Vicky said: “This study has helped us identify when foals on UK stud farms are most likely to encounter Lawsonia intracellularis for the first time. The results suggest that exposure most commonly occurs between six and nine months of age, after maternal immunity has declined, which provides valuable information when considering vaccination strategies. By understanding this risk period more clearly, breeders and veterinarians can make more informed decisions about protecting youngstock from this potentially serious disease.” Caroline added: “As the first UK study to investigate the seroprevalence and timing of Lawsonia intracellularis exposure in foals, these findings provide an important foundation for future research. The work improves our understanding of how widely the bacterium is present on stud farms and offers evidence that can help guide both disease surveillance and preventative healthcare strategies in the years ahead.” <ul> <li aria-level="1" dir="ltr"> Read the study here: <a href="https://url.uk.m.mimecastprotect.com/s/WlMOC02AzfEZ4QpFwf9f963ac?domain=doi.org" style="text-decoration: none;">https://doi.org/10.1111/eve.70115</a> </li> </ul> Bio details: Caroline Ribonnet MVetMed, DipECEIM, MRCVS is an RCVS Recognised Specialist in Equine Internal Medicine and a Diplomate of the European College of Equine Internal Medicine (ECEIM). After graduating from Ghent University in 2016, she completed an internship in equine medicine and surgery before undertaking a residency in Equine Internal Medicine in Belgium, achieving Diplomate status in 2023. Caroline joined Rossdales Equine Hospital as a medicine clinician. Between two maternity cover periods at Rossdales, she spent a year as head of internal medicine at Via Nova Equine Services in Belgium, focusing on equine sports medicine. During her time at Rossdales, she was first author of a study investigating the prevalence of Lawsonia intracellularis infection in the UK equine population, conducted in collaboration with Rossdales and VetPartners. Caroline is currently a medicine clinician at Bell Equine Veterinary Clinic in Kent. Dr. Victoria A. Colgate MA VetMB MSc MRCVS qualified from the University of Cambridge in 2014. After graduating she completed a Clinical Training Scholarship at the Cambridge Equine Hospital before working in a busy polo practice in Ascot. She joined Rossdales Equine Hospital in June 2017 as the Margaret Giffen Resident in Clinical Research, where in addition to carrying out research projects she attained an MSc in Veterinary Epidemiology and Public Health. After time away in a specialist role as a Veterinary Epidemiologist at Equine Infectious Disease Surveillance (EIDS), Vicky returned to Rossdales in July 2023 as a Research Associate, a role kindly funded by the Margaret Giffen Charitable Trust. She has a strong interest in the care and welfare of sports horses and drives forward the practice's application of evidence-based medicine through implementation of clinic-based research and production of associated publications. Emily F. Floyd BVSc, DipACVIM, CertAVP (Veterinary Dermatology), MRCVS is an RCVS Recognised Specialist in Equine Medicine (Internal Medicine) and Diplomate of the American College of Veterinary Internal Medicine. Emily is a member of the <a href="https://url.uk.m.mimecastprotect.com/s/C7YLC7nDKiPoq4nC8fXfoCSOb?domain=rossdales.com/" style="text-decoration: none;">internal medicine</a> team at Rossdales Equine Hospital and has a particular interest in equine <a href="https://url.uk.m.mimecastprotect.com/s/J1EXC8oXLFJLrDBh1hkfyk1V8?domain=rossdales.com/" style="text-decoration: none;">neonatology</a>. She joined Rossdales in 2009 and became a partner in April 2016 and a clinical director in 2021. Emily’s main role is working within the <a href="https://url.uk.m.mimecastprotect.com/s/6HvgC9p3MfZ91LrC3ilfqMwT4?domain=rossdales.com/" style="text-decoration: none;">Neonatal Intensive Care Unit</a>, in addition to working within the internal medicine department. In 2012, she became an RCVS Specialist in Equine Medicine (Internal Medicine), having been awarded recognised specialist status by the Royal College of Veterinary Surgeons (RCVS). She is also a Diplomate of the American College of Veterinary Internal Medicine, which she achieved during 3 years at the University of California’s Veterinary Medical Teaching Hospital at Davis prior to joining Rossdales. She has completed a number of research projects related to neonatal foal conditions and has published and lectured widely on the subject. Emily also has a keen interest in veterinary dermatology and in 2025 she was awarded the Certificate in Advanced Veterinary Practice in Veterinary Dermatology.   http://british-breeding.com/external-news/i7748/abbie-bevan-secures-horse-of-the-year-show-qualification-at-bogenraith-gfs-saddles-senior-newcomers-championship-second-round BreedingBritish en 2026-07-06 Abbie Bevan Secures Horse of the Year Show Qualification at Bogenraith GFS Saddles Senior Newcomers Championship Second Round Abbie Bevan Secures Horse of the Year Show Qualification at Bogenraith GFS Saddles Senior Newcomers Championship Second Round http://british-breeding.com/external-news/i7749/jack-whitaker-showcases-a-masterclass-win-in-the-al-shira-aa-four-star-grand-prix-at-al-shira-aa-bolesworth-international BreedingBritish en 2026-07-06 Jack Whitaker showcases a masterclass win in the Al Shira’aa four-star Grand Prix at Al Shira’aa Bolesworth International Jack Whitaker showcases a masterclass win in the Al Shira’aa four-star Grand Prix at Al Shira’aa Bolesworth International http://british-breeding.com/external-news/i7750/holly-smith-and-nike-van-het-singraven-continued-their-sensational-run-of-form-at-al-shira-aa-bolesworth-international BreedingBritish en 2026-07-06 Holly Smith and Nike van het Singraven continued their sensational run of form at Al Shira’aa Bolesworth International Holly Smith and Nike van het Singraven continued their sensational run of form at Al Shira’aa Bolesworth International http://british-breeding.com/external-news/i7751/sam-hutton-races-to-victory-at-the-i-love-new-york-horse-show-in-lake-placid-with-etincelle-d-ellipse BreedingBritish en 2026-07-06 Sam Hutton races to victory at the I Love New York Horse Show in Lake Placid with Etincelle D’Ellipse Sam Hutton races to victory at the I Love New York Horse Show in Lake Placid with Etincelle D’Ellipse http://british-breeding.com/external-news/i7761/british-showjumping-s-team-audevard-announced-for-csio5-hickstead-fei-nations-cup BreedingBritish en 2026-07-13 British Showjumping’s Team Audevard announced for CSIO5* Hickstead FEI Nations Cup British Showjumping’s Team Audevard announced for CSIO5* Hickstead FEI Nations Cup http://british-breeding.com/external-news/i7762/great-britain-s-team-audevard-jumped-into-sixth-place-in-the-csio5-agria-falsterbo-nations-cup-against-tough-opposition BreedingBritish en 2026-07-13 Great Britain’s Team Audevard jumped into sixth place in the CSIO5* Agria Falsterbo Nations Cup against tough opposition Great Britain’s Team Audevard jumped into sixth place in the CSIO5* Agria Falsterbo Nations Cup against tough opposition http://british-breeding.com/external-news/i7763/harry-charles-claims-a-spectacular-winning-double-at-valkenswaard-s-summer-classic BreedingBritish en 2026-07-13 Harry Charles claims a spectacular winning double at Valkenswaard’s Summer Classic Harry Charles claims a spectacular winning double at Valkenswaard’s Summer Classic http://british-breeding.com/external-news/i7764/entries-and-stabling-now-live-for-the-club-just-for-schools-academy-championships BreedingBritish en 2026-07-09 Entries and Stabling Now Live for the Club, Just For Schools & Academy Championships Entries and Stabling Now Live for the Club, Just For Schools & Academy Championships http://british-breeding.com/external-news/i7765/lucy-townley-tops-the-podium-at-bicton-redpost-equestrian-senior-foxhunter-second-round BreedingBritish en 2026-07-09 Lucy Townley Tops the Podium at Bicton Redpost Equestrian Senior Foxhunter Second Round Lucy Townley Tops the Podium at Bicton Redpost Equestrian Senior Foxhunter Second Round http://british-breeding.com/external-news/i7766/lola-rae-travers-triumphs-at-ariat-senior-british-novice-championship-second-round BreedingBritish en 2026-07-08 Lola-Rae Travers Triumphs at Ariat Senior British Novice Championship Second Round Lola-Rae Travers Triumphs at Ariat Senior British Novice Championship Second Round http://british-breeding.com/external-news/i7767/emma-smith-claims-nupafeed-supplements-senior-discovery-second-round-victory-at-norfolk-show-jumping-club BreedingBritish en 2026-07-08 Emma Smith Claims Nupafeed Supplements Senior Discovery Second Round Victory at Norfolk Show Jumping Club Emma Smith Claims Nupafeed Supplements Senior Discovery Second Round Victory at Norfolk Show Jumping Club http://british-breeding.com/external-news/i7768/adam-botham-books-horse-of-the-year-show-ticket-at-bicton-gfs-saddles-senior-newcomers-championship-second-round BreedingBritish en 2026-07-07 Adam Botham Books Horse of the Year Show Ticket at Bicton GFS Saddles Senior Newcomers Championship Second Round Adam Botham Books Horse of the Year Show Ticket at Bicton GFS Saddles Senior Newcomers Championship Second Round http://british-breeding.com/external-news/i7769/douglas-edward-and-golden-boy-de-jarsay-strike-gold-at-bogenraith-redpost-foxhunter-second-round BreedingBritish en 2026-07-07 Douglas Edward and Golden Boy De Jarsay Strike Gold at Bogenraith Redpost Foxhunter Second Round Douglas Edward and Golden Boy De Jarsay Strike Gold at Bogenraith Redpost Foxhunter Second Round http://british-breeding.com/external-news/i7770/katie-robinson-tops-naf-five-star-summer-bronze-league-qualifier-at-northallerton-equestrian-centre BreedingBritish en 2026-07-20 Katie Robinson Tops NAF Five Star Summer Bronze League Qualifier at Northallerton Equestrian Centre Katie Robinson Tops NAF Five Star Summer Bronze League Qualifier at Northallerton Equestrian Centre http://british-breeding.com/external-news/i7771/british-riders-post-wins-in-europe-and-the-usa-in-this-week-s-international-round-up BreedingBritish en 2026-07-20 British riders post wins in Europe and The USA in this week’s international round-up British riders post wins in Europe and The USA in this week’s international round-up http://british-breeding.com/external-news/i7772/ben-maher-scores-his-first-big-win-with-the-promising-maddox-van-het-haringvliet-z-on-his-first-visit-to-chard-equestrian BreedingBritish en 2026-07-20 Ben Maher scores his first big win with the promising Maddox Van Het Haringvliet Z on his first visit to Chard Equestrian Ben Maher scores his first big win with the promising Maddox Van Het Haringvliet Z on his first visit to Chard Equestrian http://british-breeding.com/external-news/i7773/kate-anderson-and-goodwin-junior-soar-in-stx-uk-pony-foxhunter-second-round-at-bogenraith-equestrian BreedingBritish en 2026-07-17 Kate Anderson and Goodwin Junior Soar in STX-UK Pony Foxhunter Second Round at Bogenraith Equestrian Kate Anderson and Goodwin Junior Soar in STX-UK Pony Foxhunter Second Round at Bogenraith Equestrian http://british-breeding.com/external-news/i7774/oliver-betteridge-and-drummin-flyer-claim-stx-uk-pony-british-novice-second-round-victory-at-kelsall-hill-e-c BreedingBritish en 2026-07-17 Oliver Betteridge and Drummin Flyer Claim STX-UK Pony British Novice Second Round Victory at Kelsall Hill E.C. Oliver Betteridge and Drummin Flyer Claim STX-UK Pony British Novice Second Round Victory at Kelsall Hill E.C. http://british-breeding.com/external-news/i7775/stx-uk-pony-british-novice-pony-discovery-second-rounds-venue-update BreedingBritish en 2026-07-16 STX UK Pony British Novice & Pony Discovery Second Rounds – Venue Update STX UK Pony British Novice & Pony Discovery Second Rounds – Venue Update http://british-breeding.com/external-news/i7776/joseph-trunkfield-and-no-mercy-ph-triumph-in-redpost-equestrian-senior-foxhunter-second-round-at-arena-uk BreedingBritish en 2026-07-16 Joseph Trunkfield and No Mercy PH Triumph in Redpost Equestrian Senior Foxhunter Second Round at Arena UK Joseph Trunkfield and No Mercy PH Triumph in Redpost Equestrian Senior Foxhunter Second Round at Arena UK http://british-breeding.com/external-news/i7777/adam-morgan-and-carrickview-clarissa-secure-gfs-saddles-senior-newcomers-championship-final-ticket-at-arena-uk BreedingBritish en 2026-07-16 Adam Morgan and Carrickview Clarissa Secure GFS Saddles Senior Newcomers Championship Final Ticket at Arena UK Adam Morgan and Carrickview Clarissa Secure GFS Saddles Senior Newcomers Championship Final Ticket at Arena UK http://british-breeding.com/external-news/i7778/summer-pony-premier-delivers-exciting-competition-at-bogenraith-equestrian BreedingBritish en 2026-07-16 Summer Pony Premier Delivers Exciting Competition at Bogenraith Equestrian Summer Pony Premier Delivers Exciting Competition at Bogenraith Equestrian http://british-breeding.com/external-news/i7779/top-treble-clear-for-kerry-harris-in-final-seib-big-star-championship-qualifier-at-arena-uk BreedingBritish en 2026-07-14 Top Treble Clear for Kerry Harris in final SEIB Big Star Championship Qualifier at Arena UK Top Treble Clear for Kerry Harris in final SEIB Big Star Championship Qualifier at Arena UK http://british-breeding.com/external-news/i7780/catherine-housman-claims-horse-of-the-year-show-final-spot-at-chard-naf-five-star-silver-league-semi-final BreedingBritish en 2026-07-27 Catherine Housman Claims Horse of the Year Show Final Spot at Chard NAF Five Star Silver League Semi Final Catherine Housman Claims Horse of the Year Show Final Spot at Chard NAF Five Star Silver League Semi Final http://british-breeding.com/external-news/i7781/golden-glory-and-podium-success-for-great-britain-at-the-fei-jumping-european-championships-for-young-riders-juniors-children BreedingBritish en 2026-07-27 Golden Glory and Podium Success for Great Britain at the FEI Jumping European Championships for Young Riders, Juniors & Children Golden Glory and Podium Success for Great Britain at the FEI Jumping European Championships for Young Riders, Juniors & Children http://british-breeding.com/external-news/i7782/vermento-equals-three-time-king-george-record BreedingBritish en 2026-07-26 Vermento equals three-time King George record Vermento equals three-time King George record http://british-breeding.com/external-news/i7783/ben-maher-was-matchless-against-the-clock-in-the-unex-group-speed-classic BreedingBritish en 2026-07-26 Ben Maher was matchless against the clock in the Unex Group Speed Classic Ben Maher was matchless against the clock in the Unex Group Speed Classic http://british-breeding.com/external-news/i7784/fruselli-back-to-his-best-to-top-queen-s-thriller-at-hickstead BreedingBritish en 2026-07-26 Fruselli back to his best to top Queen’s thriller at Hickstead Fruselli back to his best to top Queen’s thriller at Hickstead http://british-breeding.com/external-news/i7785/great-britain-back-on-top-in-nations-cup BreedingBritish en 2026-07-24 Great Britain back on top in Nations Cup Great Britain back on top in Nations Cup http://british-breeding.com/external-news/i7786/british-showjumping-to-observe-a-two-minute-silence-on-saturday BreedingBritish en 2026-07-24 British Showjumping to Observe a Two-Minute Silence on Saturday British Showjumping to Observe a Two-Minute Silence on Saturday http://british-breeding.com/external-news/i7787/arabella-haynes-and-georgiana-rd-secure-nupafeed-senior-discovery-second-round-success-at-hartpury BreedingBritish en 2026-07-24 Arabella Haynes and Georgiana RD Secure Nupafeed Senior Discovery Second Round Success at Hartpury Arabella Haynes and Georgiana RD Secure Nupafeed Senior Discovery Second Round Success at Hartpury http://british-breeding.com/external-news/i7788/rebecca-marsh-and-stevie-g-step-to-success-in-the-international-stairway-at-the-great-yorkshire-show BreedingBritish en 2026-07-23 Rebecca Marsh and Stevie G Step to Success in the International Stairway at the Great Yorkshire Show Rebecca Marsh and Stevie G Step to Success in the International Stairway at the Great Yorkshire Show http://british-breeding.com/external-news/i7789/big-win-for-aachen-bound-stevens BreedingBritish en 2026-07-23 Big win for Aachen-bound Stevens Big win for Aachen-bound Stevens http://british-breeding.com/external-news/i7790/another-record-on-red-letter-day-for-anya BreedingBritish en 2026-07-23 Another record on red letter day for Anya Another record on red letter day for Anya http://british-breeding.com/external-news/i7791/record-hat-trick-for-11-year-old-anya BreedingBritish en 2026-07-23 Record hat-trick for 11-year-old Anya Record hat-trick for 11-year-old Anya http://british-breeding.com/external-news/i7792/teenager-raphaela-scores-first-hickstead-victory BreedingBritish en 2026-07-22 Teenager Raphaela scores first Hickstead victory Teenager Raphaela scores first Hickstead victory http://british-breeding.com/external-news/i7793/georgia-makes-triumphant-hickstead-return-in-seib-winter-novice-championship-final BreedingBritish en 2026-07-22 Georgia makes triumphant Hickstead return in SEIB Winter Novice Championship Final Georgia makes triumphant Hickstead return in SEIB Winter Novice Championship Final http://british-breeding.com/external-news/i7794/six-sports-one-flag-british-equestrian-announces-definite-entries-for-fei-world-championships-2026 BreedingBritish en 2026-07-22 Six sports, one flag: British Equestrian announces definite entries for FEI World Championships 2026 Six sports, one flag: British Equestrian announces definite entries for FEI World Championships 2026 http://british-breeding.com/external-news/i7795/sophia-cairns-and-wee-vintage-secure-stx-uk-pony-british-novice-second-round-victory-at-tillyoch-equestrian BreedingBritish en 2026-07-21 Sophia Cairns and Wee Vintage Secure STX-UK Pony British Novice Second Round Victory at Tillyoch Equestrian Sophia Cairns and Wee Vintage Secure STX-UK Pony British Novice Second Round Victory at Tillyoch Equestrian http://british-breeding.com/external-news/i7796/peter-grayson-and-one-butterfly-fly-to-victory-in-naf-five-star-summer-silver-league-qualifier-at-northallerton-equestrian-centre BreedingBritish en 2026-07-21 Peter Grayson and One Butterfly Fly to Victory in NAF Five Star Summer Silver League Qualifier at Northallerton Equestrian Centre Peter Grayson and One Butterfly Fly to Victory in NAF Five Star Summer Silver League Qualifier at Northallerton Equestrian Centre