Information for veterinarians, veterinary nurses, and veterinary and nursing students. It is also provided to horse owners and trainers who hopefully will find much of the content both educational and informative.
The section is categorized alphabetically by system. The search dialogue will identify topics through keywords.
Special thanks to the many colleagues over the years for their help in providing some of the information listed here.



Cardiology


AV-Short-Axis

Aortic Valve Regurgitation

The aortic valve opens when the heart contracts (systole), allowing oxygenated blood to leave the left ventricle and be distributed...
normecg

Atrial Fibrillation (AF)

Atrial fibrillation is the most common arrhythmia of clinical significance in horses. In many horses it is clinically silent but...
MV-echo

Mitral valve regurgitation

Leakage of blood across the mitral valve occurs relatively commonly, and when moderate can contribute to poor athletic performance, congestive...
ZAMENSIN_200-600x600

Monensin (ionophore) toxicosis

Ionophore antibiotics are commonly used in food producing species as a treatment for coccidiosis in poultry and as a growth...
myocarditis cartoon

Myocarditis

As the name suggests 'myocarditis' describes inflammation of the heart muscle (myocardium). Myocarditis can occur with or following bacterial or...
normecg

Second degree atrioventricular (AV) block

This is the most common physiologic arrhythmia in the horse. Approximately 15% of horses on a resting ECG and up...
normecg

Supraventricular (atrial) premature depolarizations (SVPD)

Supraventricular premature depolarizations (SVPDs) are also known as atrial premature contractions (APCs). An occasional SVPD is common in healthy horses...
TR screen shot

Tricuspid valve regurgitation

The tricuspid valve lies on the right side of the heart and separates the right atrium and right ventricle. The...

Dermatology


CULICOIDES TAIL_1

Culicoides Hypersensitivity (Queensland itch)

Culicoides hypersensitivity is described by numerous terms including Queensland itch, summer itch, summer eczema, or sweet itch (in the UK)....
Habronema-shoulder

Cutaneous Habronemiasis (Summer sores)

Habronemiasis is also referred to as Habronematidosis in some articles and text books. Of the 12 species of Habronema known...
Urticaria4

Hives (urticaria)

Hives is a symptom rather than a specific disease. Of all the domestic species horses are the most likely to...
Ana-Day-1-9-12-2014-Sox-for-Horses (1)

Pastern Dermatitis

Equine pastern dermatitis (EPD) is a cutaneous reaction that better fits a syndrome, rather than a specific disease entity. From...
pemphigus_1

Pemphigus foliaceus

Pemphigus foliaceus is an auto-immune disease which results from autoantibodies forming against the proteins responsible for holding the keratinocytes together...
Photosensitization

Photosensitization

Photosensitization is an unusual skin condition that can occur after ingestion of certain plants or, more commonly, in association with...
DSC_0085.JPG

Ringworm (Dermatophytosis)

A common condition of horses, especially younger animals. Older horses can be re-infected, but the signs are usually milder. Transmission...
DSC_0074

Sporotrichosis

Sporotrichosis is caused by the fungal agent, Sporotrichium (Sporothrix) schenckii. The disease in horses is initiated through contamination of a...
Singing nettle UF IFAS

Stinging Nettle (Urtica genus)

Plants of the Urtica genus are found around the world. There are estimated to be around 100 species of nettle,...

Endocrine and Metabolic


DSC_0008-1

Equine Metabolic Syndrome

This is a complicated topic, and this review is directed to veterinarians, vet students, veterinary nurses, and nursing students. However,...
hyperlipemic donkey

Hyperlipidaemia and hyperlipaemia

This is a relatively common problem in certain breeds of horse and pony. Hyperlipidaemia is defined as the presence of...
PPID-Hypertrichosis-1

Pituitary Pars Intermedia Dysfunction (PPID)

This condition is more commonly referred to as Equine Cushing's, but strictly speaking this is not an accurate term. Cushing's...

Foals


Rhodococcus-belly-abscess

Equine Proliferative Enteropathy (EPE)

Equine Proliferative Enteropathy (EPE) is a disease predominately of weanling foals in the 3-8 month age group. Although less common,...
Gastroc rupture

Gastrocnemius rupture

The gastrocnemius muscle and associated tendon are critical for rising and weight bearing. The function of the gastrocnemius muscle is...
Colitis-foal

Glycogen Branching Enzyme Deficiency (GBED)

Glycogen branching enzyme deficiency (GBED) is a fatal disease of newborn Quarter Horse and Paint foals. GBED is an inherited...
vlcsnap-2022-04-26-10h44m39s786

Juvenile Epilepsy of Arabian Foals

There is a well described syndrome of epilepsy in young Arabian foals of Egyptian lineage. Seizures are usually noticed by...
DSC_0181

Neonatal Isoerythrolysis (NI)

Neonatal isoerythrolysis (NI) is an acquired disease of foals caused by the ingestion of incompatible colostrum. The colostrum contains antibodies...
charlotte-venema-Et-sgI7yT1I-unsplash

Severe Combined Immunodeficiency (SCID) foals

Severe combined immunodeficiency (SCID) is an inherited disease of Arabian foals. The disease was first reported around 50 years ago....

Gastrointestinal diseases


TTW-Parascaris

Ascarids (Parascaris species)

Ascarid (roundworm) infections are very common in foals. There are two ascarid species that are known to infect horses, Parascaris...
Choke 1

Choke (Oesphageal obstruction)

The term 'choke' is used to describe horses that have an obstruction of their oesophagus, the section of the digestive...
Equine-Colic-pawing

Colic in Adult Horses

Colic is not a specific disease, rather a clinical sign. Colic simply describes abdominal pain and it could originate from...
ENTEROLITH-SCALPEL

Enterolithiasis

Intestinal calculi that form in the large intestine are termed enteroliths. Although all breeds are affected, Arabians are over-represented. The...
OLYMPUS DIGITAL CAMERA

Equine Coronavirus (ECoV)

Infection of adult horses with Equine Coronavirus (ECoV) is now being reported worldwide with an increasing incidence. This is primarily...
Rhodococcus-belly-abscess

Equine Proliferative Enteropathy (EPE)

Equine Proliferative Enteropathy (EPE) is a disease predominately of weanling foals in the 3-8 month age group. Although less common,...
image-16

Gastric Impactions

Gastric impactions are often diagnosed when horses are 'gastroscoped' as a check for ulcers. The reality is that nearly all...
Strongylus-vulgaris-arterit

Large Strongyles

There are three Strongylus species that infect horses, Strongylus vulgaris, Strongylus edentatus and Strongylus equinus. Of these only S. vulgaris...
PBZ toxicity pony

Phenylbutazone toxicity

Over-dosage of phenylbutazone can lead to a variety of problems including gastrointestinal tract ulceration including oral ulceration, renal medullary crest...
bots knee

Stomach Bots (Gasterophilus species)

Many horse owners are horrified to see bot fly larvae in the stomach of their horses when checked for gastric...
tapeworm

Tapeworms

The principal tapeworm (cestode) of the horse is Anoplocephala perfoliata. There are two other species of tapeworm that infect horses,...

Haemopoietic system


DSC_0240

Autoimmune haemolytic anaemia (AIHA)

Autoimmune haemolytic anaemia (AIHA) results as a consequence to antibodies directed to the surface of red blood cells. Once the...
Blood-administration

Blood Loss Anaemia

Generally blood loss in all species is separated into 4 categories, based on if the blood loss is internal or...
jamie-street-45OO_7pjjJA-unsplash

Equine Infectious Anaemia (EIA)

Equine Infectious Anaemia (EIA) occurs in most countries around the world, including Australia, where it occurs in small pockets along...
dmitry-shamis-C4Hv33BE02E-unsplash

Hendra virus

Hendra virus is a significant pathogen in the context of both human and horse health. The condition is relatively uncommon,...
DSC_0181

Neonatal Isoerythrolysis (NI)

Neonatal isoerythrolysis (NI) is an acquired disease of foals caused by the ingestion of incompatible colostrum. The colostrum contains antibodies...
PXL_20220520_042339844.MP_

Red Maple Leaf Toxicity

Red Maple (Acer rubrum) leaf toxicity is a relatively common cause of "oxidant-induced" anaemia. The toxicity occurs through ingestion of...

Infectious diseases


Botulism1

Botulism

Botulism is a form of paralysis that can be highly fatal if not recognized and treated early. The neuromuscular paralysis...
OLYMPUS DIGITAL CAMERA

Equine Coronavirus (ECoV)

Infection of adult horses with Equine Coronavirus (ECoV) is now being reported worldwide with an increasing incidence. This is primarily...
EHV-1-mare-standing

Equine Herpesvirus Myeloencephalopathy (EHM)

In certain regions of the world outbreaks of EHM appear to be increasing in frequency over the past 25 years....
jamie-street-45OO_7pjjJA-unsplash

Equine Infectious Anaemia (EIA)

Equine Infectious Anaemia (EIA) occurs in most countries around the world, including Australia, where it occurs in small pockets along...
Rabies-self-mutilation

Rabies and Australian Bat Lyssavirus (ABLV)

Australia is considered to be free of rabies in our mammalian populations. In countries with terrestrial rabies the dog is...
DSC_0085.JPG

Ringworm (Dermatophytosis)

A common condition of horses, especially younger animals. Older horses can be re-infected, but the signs are usually milder. Transmission...
Tetanus-saw-horse-stance

Tetanus

Tetanus is a serious infectious disease of horses that is highly preventable. Despite the availability of an affordable and highly...

Liver


Choleliths

Cholelithiasis (Biliary calculi/stones)

Choleliths are calculi that develop within the biliary tree. Their formation can be associated with signs of liver disease, and...
HE head pressing

Hepatic Encephalopathy (HE)

The liver is critical for the removal of circulating toxins. When liver function fails due to disease there is an...
Photosensitization

Photosensitization

Photosensitization is an unusual skin condition that can occur after ingestion of certain plants or, more commonly, in association with...
crotalaria-retusa

Pyrrolizidine Alkaloid Toxicosis

Ingestion of pyrrolizidine alkaloid containing plants is the most common cause of chronic liver injury worldwide. Australian species include cotton...

Musculoskeletal system


Sycamore maple

Atypical Myopathy

This seasonal myopathy is attributed to the toxin, hypoglycin A, found in seeds (samara) of the box elder tree (Acer...
fibrotic myopathy

Fibrotic myopathy

Fibrotic myopathy is a condition that is most commonly associated with sliding stops (see video below) by reining Quarter Horses...
Gastroc rupture

Gastrocnemius rupture

The gastrocnemius muscle and associated tendon are critical for rising and weight bearing. The function of the gastrocnemius muscle is...
Colitis-foal

Glycogen Branching Enzyme Deficiency (GBED)

Glycogen branching enzyme deficiency (GBED) is a fatal disease of newborn Quarter Horse and Paint foals. GBED is an inherited...
L1000527

Peroneus (Fibularis) tertius rupture

The peroneus tertius muscle is an important component of the reciprocal apparatus of the hindlimb. This apparatus is necessary to...
PSSM1

Polysaccharide Storage Myopathy (PSSM)

Polysaccharide storage myopathy (PSSM) is a genetic disease where both normal and abnormal glycogen are stored in muscle. The condition...
Stifle lock

Stifle lock (Upward fixation of the patella)

This is a fairly common problem of ponies and young horses. Stifle lock is referred to upward or proximal patellar...
DSC_0033

Subsolar (Foot) abscess

A subsolar abscess occurs after a penetrating injury to the sole. It is the most common cause of a sudden...

Neurology


Rygrass seeds infected

Annual ryegrass toxicity (ARGT)

Annual Ryegrass toxicity (ARGT) is seen most commonly in WA over the summer months with the feeding of contaminated hay....
Figure-5

Birdsville Indigo and Creeping Indigo poisoning

There is well defined syndrome associated with the ingestion of Birdsville Indigo (Indigofera linnaei) or Creeping Indigo (Indigofera spicata). Birdsville...
Botulism1

Botulism

Botulism is a form of paralysis that can be highly fatal if not recognized and treated early. The neuromuscular paralysis...
C6

Cervical Radiculopathy/Nerve Root Signature (Root sign)

The condition of nerve root signature or nerve root sign is poorly described in the horse literature. However there is...
CSM resized

Cervical Stenotic Myelopathy (CSM) – Wobbler Syndrome

This syndrome is defined by limb ataxia and weakness caused by developmental anomalies or degenerative conditions of the cervical vertebrae....
EHV-1-mare-standing

Equine Herpesvirus Myeloencephalopathy (EHM)

In certain regions of the world outbreaks of EHM appear to be increasing in frequency over the past 25 years....
Fluphenazine-reaction-2

Fluphenazine reactions

Fluphenazine decanoate (Modecate, Prolixin) is potent long-acting sedative that is used in horses to facilitate handling and early training in...
Kimball-Davis-Upper-Class-10-27-08-18-for-web-220x165-1

Guttural Pouch Mycosis

The guttural pouches are predisposed to fungal infections (mycosis). Infection can occur in one or both pouches. Each pouch is...
Head shaker murdoch muzzle net

Head Shaking

Head shaking can prevent otherwise healthy horses from performing normal driving or riding tasks. There are also safety concerns with...
HE head pressing

Hepatic Encephalopathy (HE)

The liver is critical for the removal of circulating toxins. When liver function fails due to disease there is an...
vlcsnap-2022-04-26-10h44m39s786

Juvenile Epilepsy of Arabian Foals

There is a well described syndrome of epilepsy in young Arabian foals of Egyptian lineage. Seizures are usually noticed by...
Rabies-self-mutilation

Rabies and Australian Bat Lyssavirus (ABLV)

Australia is considered to be free of rabies in our mammalian populations. In countries with terrestrial rabies the dog is...
Shivers PSSM

Shivering (shivers)

Shivering or Shivers is a condition most seen in the Draught, Warmblood and Thoroughbred breeds, although other breeds can be...
Stringhalt-murdoch-recent

Stringhalt

Also known as “Springhalt” and “Hahnentritt”. Stringhalt is an unusual disease that can affect adult horses of any breed. The...
Swainsona canescens 2

Swainsona poisoning

There are seven species of Swainsona in Australia that are capable of causing disease in horses and other livestock. Some...
sweeny

Sweeny (Suprascapular nerve)

The term 'sweeny-syndrome' (also spelled 'sweeney') was introduced more than a century ago to describe a syndrome of muscle atrophy...
Figure2

Temporohyoid osteoarthropathy (THO)

Temporohyoid osteoarthropathy (THO) is a progressive syndrome that describes a primary degenerative joint disease of the temporohyoid joint, ultimately leading...
Tetanus-saw-horse-stance

Tetanus

Tetanus is a serious infectious disease of horses that is highly preventable. Despite the availability of an affordable and highly...

Parasites


TTW-Parascaris

Ascarids (Parascaris species)

Ascarid (roundworm) infections are very common in foals. There are two ascarid species that are known to infect horses, Parascaris...
Habronema-shoulder

Cutaneous Habronemiasis (Summer sores)

Habronemiasis is also referred to as Habronematidosis in some articles and text books. Of the 12 species of Habronema known...
Strongylus-vulgaris-arterit

Large Strongyles

There are three Strongylus species that infect horses, Strongylus vulgaris, Strongylus edentatus and Strongylus equinus. Of these only S. vulgaris...
bots knee

Stomach Bots (Gasterophilus species)

Many horse owners are horrified to see bot fly larvae in the stomach of their horses when checked for gastric...
tapeworm

Tapeworms

The principal tapeworm (cestode) of the horse is Anoplocephala perfoliata. There are two other species of tapeworm that infect horses,...

Pharmacology


image17-816

Aminoglycoside antibiotics

Drugs Gentamicin; Amikacin; Framycetin (aka Neomycin, Soframycin); Tobramycin; Streptomycin; Paromomycin; Kanamycin; Sisomicin; Netilmicin. Of these only gentamicin is relevant for...
inctable-baytril

Fluoroquinolones

There are no registered fluoroquinolone antibiotics available for use in horses. Based on theoretical and observed orthopaedic problems in foals...
metro tabs

Metronidazole

Metronidazole has an important role in equine health, but many questions remain as to dosing, side-effects, and efficacy. It has...
Sotalol 2

Sotalol

Sotalol hydrochloride is used in equine practice primarily as an antiarrhythmic. It's primary indication is in the management of atrial...

Renal


DSC_0006_1

Haematuria (Blood in urine)

Haematuria is a relative common problem of adult horses. There are a number of potential causes (see below). Investigation should...
Cestrum_diurnum

Vitamin D Toxicity

There are several plant species that contain vitamin D3 or a metabolite of vitamin D3. This causes calcium absorption resulting...

Respiratory System


EIPH

Exercise-induced pulmonary haemorrhage (EIPH)

Significant contribution by Dr Ellie Crispe of Simon Miller Racing. High intensity exercise is associated with lung haemorrhage (bleeding) in...
Kimball-Davis-Upper-Class-10-27-08-18-for-web-220x165-1

Guttural Pouch Mycosis

The guttural pouches are predisposed to fungal infections (mycosis). Infection can occur in one or both pouches. Each pouch is...
GP-tympany-1

Guttural Pouch Tympany

Guttural pouch tympany is a rare condition, but occurs more common in filly foals. The condition is usually apparent soon...
2

Severe Equine Asthma (SEA)

The terminology that surrounds Severe Equine Asthma can be confusing. Originally referred to as chronic obstructive pulmonary disease (COPD), chronic...

Toxicities


Rygrass seeds infected

Annual ryegrass toxicity (ARGT)

Annual Ryegrass toxicity (ARGT) is seen most commonly in WA over the summer months with the feeding of contaminated hay....
Sycamore maple

Atypical Myopathy

This seasonal myopathy is attributed to the toxin, hypoglycin A, found in seeds (samara) of the box elder tree (Acer...
avocado

Avocado Poisoning

There are three main 'races' of avocado: the Guatemalan; the Mexican; and the West Indian avocado. These are all variants...
Figure-5

Birdsville Indigo and Creeping Indigo poisoning

There is well defined syndrome associated with the ingestion of Birdsville Indigo (Indigofera linnaei) or Creeping Indigo (Indigofera spicata). Birdsville...
Fluphenazine-reaction-2

Fluphenazine reactions

Fluphenazine decanoate (Modecate, Prolixin) is potent long-acting sedative that is used in horses to facilitate handling and early training in...
Hemlock

Hemlock poisoning

Poison Hemlock (Conium maculatum), Water Hemlock (Cicuta maculata) and Hemlock Water Dropwort (Oenantha crocata) are three species of the family...
ZAMENSIN_200-600x600

Monensin (ionophore) toxicosis

Ionophore antibiotics are commonly used in food producing species as a treatment for coccidiosis in poultry and as a growth...
PBZ toxicity pony

Phenylbutazone toxicity

Over-dosage of phenylbutazone can lead to a variety of problems including gastrointestinal tract ulceration including oral ulceration, renal medullary crest...
Photosensitization

Photosensitization

Photosensitization is an unusual skin condition that can occur after ingestion of certain plants or, more commonly, in association with...
crotalaria-retusa

Pyrrolizidine Alkaloid Toxicosis

Ingestion of pyrrolizidine alkaloid containing plants is the most common cause of chronic liver injury worldwide. Australian species include cotton...
PXL_20220520_042339844.MP_

Red Maple Leaf Toxicity

Red Maple (Acer rubrum) leaf toxicity is a relatively common cause of "oxidant-induced" anaemia. The toxicity occurs through ingestion of...
Dugite-perth-zoo

Snake envenomation

There are many venomous snakes around the world. Australia is notorious for having more than its fair share of highly...
white-tailed-spider

Spider envenomation

Unlike snake bites spider envenomation of horses is very poorly described. In Australia the most venous spiders, in decreasing order...
Singing nettle UF IFAS

Stinging Nettle (Urtica genus)

Plants of the Urtica genus are found around the world. There are estimated to be around 100 species of nettle,...
Swainsona canescens 2

Swainsona poisoning

There are seven species of Swainsona in Australia that are capable of causing disease in horses and other livestock. Some...
Cestrum_diurnum

Vitamin D Toxicity

There are several plant species that contain vitamin D3 or a metabolite of vitamin D3. This causes calcium absorption resulting...
gastrolobium_calycinum

York Road poison, Heart Leaf poison and Box poison

These plants all contain the toxic ingredient, monofluoroacetic acid. York road poison is caused by Gastrolobium calycinum Benth. Heart leaf...

Zoonoses


dmitry-shamis-C4Hv33BE02E-unsplash

Hendra virus

Hendra virus is a significant pathogen in the context of both human and horse health. The condition is relatively uncommon,...
Rabies-self-mutilation

Rabies and Australian Bat Lyssavirus (ABLV)

Australia is considered to be free of rabies in our mammalian populations. In countries with terrestrial rabies the dog is...
DSC_0085.JPG

Ringworm (Dermatophytosis)

A common condition of horses, especially younger animals. Older horses can be re-infected, but the signs are usually milder. Transmission...
DSC_0074

Sporotrichosis

Sporotrichosis is caused by the fungal agent, Sporotrichium (Sporothrix) schenckii. The disease in horses is initiated through contamination of a...