A review of reproductive and congenital diseases with treatment options in Friesian horses

master's thesis

• Title (croatian): Proučavanje reproduktivnih i urođenih bolesti s mogućnostima liječenja kod frizijskih konja
• Author: Jessica Rose Platts
• Mentor: Nikica Prvanović Babić (mentor)
• Committee member: Ivan Folnožić (predsjednik povjerenstva)
• Committee member: Nikica Prvanović Babić (član povjerenstva)
• Committee member: Iva Getz (član povjerenstva)
• Committee member: Silvijo Vince (član povjerenstva)
• Granter: University of Zagreb; Faculty of Veterinary Medicine; Zagreb
• Defense date and country: 2024-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Veterinary Medicine; Veterinary Clinical Sciences

Abstract

The Friesian horse population has a higher than generally accepted level of inbreeding. Congenital
disorders such as hydrocephalus and dwarfism occur in a higher prevalence than other breeds of
horses, widely accepted to be a consequence of this inbreeding. The most common cause of
hydrocephalus in Friesian horses is stenosis of the jugular foramen due to a mutation in the
B3GALNT2 gene. This mutation is carried by approximately 10% of stallions and 17% of mares.
Dwarfism in Friesian horses has a prevalence of 0.25% and is caused by a mutation on the
B4GALT7 gene. Foals born affected by this disease are smaller than unaffected horses and have
very lax flexor tendons. This mutation gives rise to the possibility of a ‘pony type’ Friesian,
however ethics and welfare of breeding for such characteristics need to be considered. Friesian
mares are at risk of retained foetal membranes 54% of the time. Owners and vets must be quick to
act and treat this complication correctly to prevent further complications and protect the health of
the mare. Current recommended therapy includes uterine lavages and oxytocin.
Friesian stallions undergo rigorous testing to be accepted into the studbook and 50% of them are
rejected. Younger stallions have poorer quality semen than older ones and inbreeding does not
influence semen quality in Friesian horses. There is contradicting data from studies in other breeds
regarding inbreeding effects on semen quality, so more research is required.

Abstract (croatian)

Populacija frizijskih konja ima višu razinu parenja u srodstvu od one općeprihvaćene.
Urođeni poremećaji poput hidrocefalusa i patuljastog rasta javljaju se u većoj prevalenciji
nego kod drugih pasmina konja, a široko je prihvaćeno da su posljedica navedenog parenja u
srodstvu. Najčešći uzrok hidrocefalusa kod frizijskih konja je stenoza jugularnog otvora zbog
mutacije na genu B3GALNT2. Ovu mutaciju nosi otprilike 10% pastuha i 17% kobila.
Patuljasti rast kod frizijskih konja ima prevalenciju od 0,25% i uzrokovan je mutacijom na
genu B4GALT7. Ždrebad koja je rođena s ovom bolešću manja je od nezaraženih konja i
imaju vrlo slabe tetive fleksora. Ova mutacija dovodi do mogućnosti stvaranja frizijske
pasmine u „tipu ponija“, međutim potrebno je uzeti u obzir etiku i dobrobit uzgoja za takve
karakteristike. Frizijske kobile su u 54% slučajeva izložene riziku od zadržavanja plodnih
ovoja. Vlasnici i veterinari moraju brzo djelovati i pravilno liječiti ovu komplikaciju kako bi
spriječili daljnje komplikacije i zaštitili zdravlje kobile. Trenutno preporučena terapija
uključuje ispiranje maternice i oksitocin.
Frizijski pastusi podvrgavaju se rigoroznom testiranju kako bi bili primljeni u matičnu knjigu
pastuha i 50% njih biva odbijeno. Mlađi pastusi imaju lošiju kvalitetu sjemena od starijih i
srodstvo ne utječe na kvalitetu sjemena frizijskog konja. Postoje kontradiktorni podaci iz
studija na drugim pasminama u vezi s učincima parenja u srodstvu na kvalitetu sjemena, pa
su potrebna daljnja istraživanja.

• Keywords: inbreeding; congenital diseases; genetic; Friesian horse
• Keywords (croatian): parenje u srodstvu; urođene bolesti; genetika; frizijski konj
• Language: english
• URN:NBN: urn:nbn:hr:178:373877
• Study programme: Title: Veterinary Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica veterinarske medicine (doktor/doktorica veterinarske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-10-31 11:25:38