following is reproduced by kind permission of Irish
Setter Health website
oesophagus is the muscular tube that takes food from the mouth to the stomach.
This is done by waves of muscular contractions, called peristalsis, which push
the food down the tube.
(MO) refers to a large, flabby oesophagus which makes it difficult or
impossible for food to reach the stomach because the peristaltic action does
not happen as it should, probably because the nerves are not functioning
properly. Food cannot enter the stomach normally, but instead simply
sits in the enlarged oesophagus and is eventually regurgitated.
is different from vomiting: Vomiting occurs when the contents of the
stomach are expelled by muscular contractions of the abdomen.
Regurgitation is purely the return of food that has not reached the stomach
and, as such, retching does not happen. As it happens very quickly and
with little effort littermates or mum may clean up the results before the
breeder realizes it has happened.
University of Illinois has an excellent article which describes the difference
between vomiting and regurgitation.
cases of MO in Irish Setters are congenital, ie present at birth, but it may
not be noticed that the pup has any problem until it is weaned when he will
regurgitate food through the mouth and maybe fluids through the nose. It
may cough and make gurgling, rattling sounds.
affected pup generally will not thrive and will probably be smaller than his
symptoms of MO are as follows:
Regurgitation may be considered the most typical sign of MO. Weight loss
with possible muscle wasting and a failure to thrive with a general
weakness are common. Increased swallowing motions with excessive
drooling and dehydration are possible. A ravenous appetite but with
stunted growth are usual, as is coughing, difficulty in breathing and
MO pups may not exhibit all of these symptoms, or even any of them to a
significant degree. Sometimes the only signs may be repeated bouts of
aspiration pneumonia, or a wet cough that fails to clear up. Some pups
grow out of the disorder and go on to enjoy a normal quality of life but
others will be significantly affected and need careful food management for the
rest of their lives. If the problem is severe, however, the pup will not
be able to get enough food and will have to be euthanased.
definitive diagnosis can be obtained by giving a barium meal. In the
normal pup, the barium will move into and through the stomach, but in the dog
with MO, most of it will be seen collected in the oesophageal pouch in front
of the stomach.
reason for congenital MO is a vascular ring anomaly such as persistent right
aortic arch. Foetal blood vessels that should have disappeared at
birth create a fibrous band that constricts the oesophagus. This causes
the oesophagus above the constriction to expand as the food cannot pass
through the constricted area. If caught in time, the vascular ring can
be cut and the oesophagus often returns to normal. Delaying surgery may
cause irreparable oesophageal damage.
dilation and vascular ring anomalies are both believed to have a hereditary
component because there is a breed disposition and a probable family
you believe your pet has MO then you will need veterinary advice. If
confirmed it is important to let your breeder know as well as the secretary of
one of the breed clubs as information is being collected on the problem.
is one of the twenty inheritable gastro-intestinal diseases listed in the Merck
Veterinary Manual and is listed as a severe trait in the
“Hierarchy of Disagreeableness of a Genetic Trait”.
the next link to an excellent article on MO with clear X rays of a dog without
MO and one with MO. There is also a very clear visual of a dog with MO trying
MO doesn’t happen until later in life, maybe through trauma or being
associated with other health problems but this form is not generally a problem
with Irish Setters.
information on Irish setters with MO
Ross, health representative for the Irish Setter Club of Wales, is still
collecting information on Megaoesophagus and would like to hear from you
about any Irish Setter that has had MO confirmed.
asked for are:-
A copy of the letter from your Vet confirming MO by Barium Xray and date
A four generation pedigree
Date of birth and whether the dog/bitch is alive or has died or been
euthanaised and if so the date and age at the time this occurred.
Information whether the Irish's DNA has been sent to the Animal Health Trust
either by blood sample or cheek swab, marked clearly as MO afflicted.
Any information of diet and and contents (fluid and /or solids)
on health conditions of parents and siblings, including any history of MO.
information is treated with strict confidence and data collected will be given
to Professor Ed Hall, Breed Health Coordinator and Chairman of the Breed
Clubs Health Coordinators Group.
for contacting Greta are:- email: Greta@autumnglow.co.uk
Tel: 01873 840291
Address: Brynhyfryd, Llanfair Kilgeddin, Monmouthshire, NP7 9DY.