Farm Animal cardiac disease Flashcards
How is the history used to assess the bovine cardiovascular system?
- Presenting sign
- Stage of production
- Past disease
- Pneumonia
- Rumenitis - acidosis - Management
- Mixing
- Worming
How can cattle be subjectively examined for signs of cardiac disease
- Examine undisturbed
- Condition score
- Visible oedema: inter-mandibular, brisket
- Posture – E.g. in traumatic pericarditis they will stand with the elbows adducted to open the chest wall
- Respiratory effort – noticeable, visible effort
List the non-cardiac signs of cardiac disease
- Reduced production
- Exercise intolerance – last into milking (at the back but not lame). Oestrus activity monitors.
- Increased urine output
- Syncope – falling down, collapsing, looking frail
- Poor appetite when failing
How is skin tone used to examine for cardiac disease and its stages?
4-6% loss = Normal (PCV 40%)
6-8% = Tenting 2-4 secs (PCV 50%) dry nose, mouth.
8-10% = Tenting 6-10 secs (PCV 55%) cold extremities, ± recumbent.
10-12% = Tenting 20+ secs (PCV 60+%) comatose, shock.
12+% = Death
Regional temperatures act as an indicator for?
Perfusion - ears are best
How are mucous membranes used to examine for cardiac disease and its stages?
- Mouth, Conjunctiva, Vulva
- Refill time, dry, cold, distension of veins in right-sided failure
- Colour
What are the 2 major causes of pale mucous membranes?
- Anaemia
- Poor perfusion
What are the causes of anaemia in cattle?
- Deficiencies - Iron, copper, cobalt
- Toxicities - Kale, nitrate/nitrite, molybdenum
- Blood / Protein loss
- Haemonchosis
- Fascioliasis
- Johnes
- Sucking lice
- PGE
- Red water
- Acute leptospirosis
What are the 3 causes of poor perfusion in cattle?
Shock (Right Displaced Abomasum)
Heart Failure
Thrombosis
List the causes of red mucous membranes in cattle
- Toxaemia
- Salmonellosis – reportable. Farmer should take a sample and test it.
- Pasturellosis
- Malignant Catarrhal Fever – associated with co-grazing with sheep
- Infectious Bovine Kerato-conjunctivitis
- Infectious Bovine Rhinotracheitis
List the causes of cyanotic mucous membranes in cattle?
Respiratory Failure
Nitrate/Nitrite, Metaldehyde poisoning
Congenital cardiac abnormality - Calves
List the causes of jaundice mucous membranes in cattle?
- Hepatitis
- Haemolytic Anaemia (Babesia – Red Water)
- Photosensitisation
- Ragwort, Kale, Lupin, Copper poisoning
- Post-partum haemoglobinuria
- Leptospirosis
List the causes of haemorrhagic mucous membranes in cattle?
Anthrax
Bracken
Sweet vernal grass poisoning
Copper toxicity (acute)
Leptospirosis
Mycotoxicosis
Where can the pulse be felt in cattle?
Middle Coccygeal - 10cm below anus
External maxillary
Medial, inside forelimb - arterial sample
Caudal auricular
What is the normal pulse of cattle and calves
Calves 100 - 120
Cattle 50 – 80, High yielders up to 95 (120+ suggestive of primary cardiac disease)
An increased amplitude of the pulse indicates?
Aortic valve incompetence
A decreased amplitude of the pulse indicates?
Myocardial weakness
Toxaemia
Shock
When does distention of the jugular and subcutaneous abdominal (milk) veins occur?
In right sided heart failure
Describe the normal and abnormal jugular pulse
Normal up to 1/3rd way up
All the way up in:
- Endocarditis, Pericarditis, haemothorax, hydrothorax, congestive heart failure, valvular stenosis or insufficiency
- Sporadic bovine leukosis - Thymic form
- Enzootic bovine leukosis - Cardiac form
Describe the normal anatomy of the heart and where each structure is auscultated
- Base = 3rd to 6th rib
- Apex = 6th rib at articulation of rib to sternum, 2 cm cranial to diaphragm
- Left contact = 3rd rib to 4th intercostal space
- Right contact = ventral part of 4th rib
- Pulmonary valve = 3rd intercostal space
- Aortic valve = 4th rib 12cm above sternum
- Left A-V valve = 4th intercostal space.
- Right A-V valve = 4th rib right hand side 10 cm above sternum.
What causes the ‘lub’ heart sound?
Ventricular contraction and A-V valve closure - systolic
What causes the ‘dup’ heart sound?
Closure of aortic/pulmonary valves - diastolic
What causes the 3rd heart sound?
Atrial contraction
How does an increase in heart contraction affect the heart sound?
Lub sound is louder
How does an increase in the pressure of the heart vessel affect the heart sound?
Dup sound is louder
Atrial fibrillation occurs secondary to?
GIT or electrolyte disturbances
What are the 2 causes of valvular murmurs?
Endocarditis
Congenital
How stenosis affect the heart sounds?
Become rough and harsh
How regurgitation affect the heart sounds?
Softer, purr
How does a pre-systolic valvular murmur present?
(brr-lub-dup) – vibration sound before heart sounds
How does a systolic valvular murmur present?
(lub-brr-dup) – vibration in the middle of the heart sounds
How does a diastolic valvular murmur present?
(lub-dup-brr) – vibration at the end of the heart sounds
Where is endocarditis seen in the heart?
Right or occ. left A-V valve
What is the cause of endocarditis?
Needs persistent bacteraemia to occur e.g. after traumatic reticulitis, nephritis, metritis, mastitis
How will cattle with endocarditis present?
Get persistent fever, pain on pinch test, HR 100+, shifting polyarthritis etc due to emboli. Pulsation of mammary veins
Describe the haematology results in a cow with endocarditis
Need 20+ml blood during pyrexia for culture
Neutrophilia with left shift, increased fibrinogen (any serosal inflammation).
Name 5 congenital abnormalities of the heart seen in calves
Ventricular septal defects
Patent ductus arteriosus
Patent foramen ovale
Tetralogy of Fallot
Aortic stenosis
Describe the main features of ventricular septal defects in calves
Often just ventral to aorta - systolic murmur, range from no effect to stunted growth to sudden death, no cyanosis - commonest
Describe the main features of a patent ductus arteriosus in calves
Normally closes on 1st day def. by day 5 - machinery murmur as blood passes from aorta to pulmonary artery, exercise intolerance and weakness, no cyanosis -relatively common
Describe the main features of a patent foramen ovale in calves
Normally 7 to 10 days to close, blood left to right, no cyanosis unless significant right ventricular hypertrophy (relatively common)
Name the 4 features of a tetralogy of fallot
Ventricular septal defect
Pulmonary stenosis
Dextroposed aorta
Secondary ventricular hypertrophy
Describe the main features of aortic stenosis in calves
Persistent right aortic arch - milk regurgitation, very uncommon
List the causes of myocardial weakness
- Septicaemia & Infection: Clostridium chauvoei (Blackleg), EBL - cardiac form, Foot and Mouth, Tetanus
- Nutritional deficiency: Copper, Selenium, Vitamin E
- Poisoning: Arsenic, Cotton seed, Phosphorus, Selenium
- Congenital: Poll Herefords in Australia, simple recessive
List 4 extracardiac conditions that can interfere with blood flow and turbulence
Vagal indigestion
Diaphragmatic hernia
Ruminal tympany
Oesophageal obstruction
Which 2 organisms (additional to those that cause endocarditis) also cause pericarditis
Haemophilus somnus
Mycobacterium Bovis
What are the tests for pericarditis?
Grunt or Eric Williams Test, bar (xiphisternum) test, withers pinch
- Determine pain
What is the presentation of a cow with pericarditis?
Shallow abdominal breathing, abducted elbows when standing
What is the consequence of fibrinous pericarditis?
Can lead to adhesions of pericardium to epicardium with foci of pus
Dilated cardiomyopathy is seen in which cattle?
Well–grown 2-3 year-old Holstein cattle.
Progeny of certain bulls suggesting genetic component.
Describe the presentation/signs of dilated cardiomyopathy in cattle
Peripheral oedema, jugular distension,
Fluid accumulations in the body cavities.
Enlargement of the heart with a rounded “globose” shape.
Describe the macroscopic/histological features of dilated cardiomyopathy
- Both ventricle chambers are distinctively dilated.
- Hypertrophy and vacuolation of cardiac muscle fibers with interstitial fibrosis are observed. Hematoxylin and eosin
What is caudal vena cava thrombosis?
Thrombosis between liver and right atrium
Caudal vena cava thrombosis occurs secondary to …?
Liver abscesses
Which cattle present with caudal vena cava thrombosis?
1-3yo
Acidosis
Rumenitis
How does peracute caudal vena cava thrombosis present?
Dead in a pool of blood from the nose
How does acute caudal vena cava thrombosis present?
Respiratory distress, pain and pyrexia
Describe the effects of caudal vena cava thrombosis on the respiratory system
- Cardiac failure secondary to pulmonary hypertension due to pulmonary disease leading to cor pulmonal (right sided hypertrophy).
- Pulmonary oedema in acute cardiac failure - less in chronic due to compensatory increase in lymphatic drainage.
- Nasal discharge - Oedema - white and frothy,
- Bilateral epistaxis - in pulmonary embolism.
- Tachypnoea, cough – no pyrexia unless secondary infection
Describe the effects of caudal vena cava thrombosis on the abdomen
- Bilateral ventral distension due to ascites
- Liver enlargement - palpate right-side behind ribs.
- G-I disease common cause of cardiac arrhythmias due to vagal stimulation by abdominal distension, acid-base and electrolyte imbalance and sympathetic tone increases due to pain.
- Traumatic reticulitis – pericarditis
How is caudal vena cava thrombosis treated?
- Frusemide – Dimazon (Lasix) i.v. - Udder oedema
- Antibiotics
- Want high plasma conc e.g. amoxicillin
- Long duration: Persistent or repeated
Tend to die - Fallen stock
Why is cardiac muscle more likely to undergo degenerative changes?
Because of its continuous activity
Describe the cardiac degenerative changes in farm animals
Fatty change: reversible
Atrophy: common in ruminants
Mineralization: organomercurial poisoning in cattle
Xanthosis: abnormal brown pigmentation of myocardium, especially in Ayrshire cattle
What are the causes of myocardial necrosis?
- High mortality Foot-and-Mouth Disease in neonates
- Histophilus somni infection causing myocardial infarction and sudden death
- Clostridial infections, except blackleg
- Vitamin E and selenium-responsive syndrome
- Saccharated iron toxicity in piglets
- Porcine stress syndrome
What is vitamin E and selenium responsive syndrome?
A nutritional myopathy found in calves, lambs and pigs - also known as:
- Nutritional muscular dystrophy
- White muscle disease
- Stiff lamb disease
- Mulberry heart disease in growing weaned pigs
Name the two syndromes in cattle caused by myocardial degeneration and necrosis?
Abortion and perinatal mortality
Sudden death in neonatal calves
What are the predisposing factors of Abortion and perinatal mortality in cattle?
Low bioavailability of Se or Vit E in ration of dam including in forages and pasture from seven months gestation onwards; antagonism to absorption occurs with excess Cu relative to Se in dam’s ration
Describe Vitamin E / Selenium supplementation in cattle
- Treatment or neonate or prevention given to the day in late pregnancy (ewes)
- Vitesel injection i/m (Norbrook)
- Included in several worming drenches
- Oral multi mineral boluses
- Check diet supplementation with nutritionalist / feed mill
