Nature or Nurture? Factors Affecting Foal Development

Dr Andy Dell

Dr. Andy Dell is a retired teacher of Biology and Outdoor Education, from Kendal in Cumbria, where he lives on a smallholding with his partner Jill, along with their family of horses and Shetland Sheepdogs. 

He has been involved with horses since his childhood in Devon, and with raising horses on the smallholding for 35 years, having successfully bred Cleveland Bays under the Endmoor prefix. 

He is a former Council Member, Trustee and Honorary Life Member of the Cleveland Bay Horse Society and in the early “Noughties” was instrumental in putting together a breed management strategy, (adapted from the world of management of captive wildlife in zoos), now known as SPARKS, to control inbreeding and prevent the loss of genetic diversity in the global Cleveland Bay Horse population. 

In 2008 Andy was awarded the Rare Breeds Survival Trust / Marsh Christian Trust Award for Technical Support of Conservation of Biodiversity. 

He completed his Doctorate entitled “Genetic Analysis and Breed Management of the Endangered Cleveland Bay Horse” as an invited mature student at the University of Lincoln in 2010. 

Under the auspices of the RBST (Rare Breeds Survival Trust), SPARKS has been extended to many other critically endangered equine breeds including the Suffolk Horse, the Shire Horse, the Eriskay Pony, the Dales Pony and the Highland Pony as well as to Vaynol Cattle and Andy has been made an Honorary Life Member of various Breed Societies as well as the RBST in recognition of his ongoing work. 

During lockdown Andy was one of four invited speakers at the first online National Equine Forum, “Using Science to Save Our Breeds.” 

In 2025 SPARKS was incorporated into the online studbook management package Grassroots, which is used by the vast majority of rare breeds in the UK, and by various breed societies globally. 

He is the principal author of various peer reviewed papers, including 16 Years of breed management brings substantial improvement in population genetics of the endangered Cleveland Bay Horse, published in the journal Ecology and Evolution. 

He is a Visiting Fellow at Nottingham Trent University, where he is working with others in the field of Livestock Conservation and Bioinformatic including recent projects funded by the Thoroughbred Breeders Association and Weatherbys looking at loss of genetic diversity in the UK and Ireland Thoroughbred population and for the Eriskay Pony Society on the genomic profile of the breed. 

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Dr Jessica Lawson

Dr Lawson graduated from the Royal Veterinary College in 2013 and spent much of her clinical career working in Thoroughbred breeding practice in the USA. Jess returned to the UK to undertake a PhD at the Royal Veterinary College, investigating the incidence, causes and diagnostic features of abortion attributed to an umbilical cord torsion in Thoroughbreds. Following completion of her Doctorate in 2022, Jess has stayed on at the RVC as a Research Fellow and is continuing her work exploring umbilical cord torsion, and causes of Thoroughbred abortion more widely, using epidemiological and genetic methodologies. This work is generously funded by the Alborada Trust with collaborations with Rossdales Laboratories, Prof. de Mestre’s Equine Pregnancy Lab at Cornell University and veterinarians in both the UK and Kentucky.  

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Dr Niamh Lewis

Niamh Lewis graduated from the Royal Dick School of Veterinary Medicine, University of Edinburgh in 2008 and spent several years in clinical practice focusing on equine reproduction in Ireland, Australia, UK, USA and Saudi Arabia. Niamh Lewis then completed a residency programme at the University of Liverpool, subsequently becoming a European and American registered specialist in Equine Reproduction in 2015. Niamh Lewis’s PhD entitled "A metabolic approach towards optimising equine in vitro maturation", was a collaborative BBSRC funded project between the University of Liverpool, University of Manchester and Texas A&M University. Niamh Lewis joined UCD School of Veterinary Medicine in 2021 and is continuing research into metabolic peri-conception and pregnancy related factors that influence foal health. Niamh Lewis also works closely with veterinarians and breeders in the field through the infertility referral service at UCD and regularly consults on both individual mare/stallion cases as well as reproductive issues at a farm level 

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Dr Rebecca Mouncey

Rebecca graduated as a veterinary surgeon from the RVC in 2003. She worked for 16 years in clinical practice in various roles, predominantly involved in Thoroughbred racing and breeding in the UK and Middle East. In 2018 she returned to the RVC, to undertake a PhD investigating the epidemiology of disease and injury in Thoroughbred foals and yearlings, which she was awarded in July 2022. She is currently a Horserace Betting Levy Board funded Post-Doctoral Research Fellow investigating early-life determinants of Thoroughbred performance, the economics of Thoroughbred breeding and the epidemiology and genetics of congenital musculoskeletal disorders in neonatal Thoroughbreds 

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