Equine Practical Exam Flashcards
What needle gauge for IM injection of a horse?
Describe how to give intramuscular injections correctly (appropriate sites and needle gauges).
18 gauge
* Knock on the site with the back of your hand whilst holding the needle between your thumb and first finger, then push the needle boldly through the skin perpendicular
* Check that no blood comes through the needle, if so, redirect
* Neck is preferred site if abscesses occur, easier to drain and neck muscles not primarily involved with propulsion
* avoid the scapula, cervical vertebrae, nuchal ligament and crest fat. Drugs are not absorbed adequately when injected into fat or ligament
* Triangle:
in front of the scapula
below the nuchal ligament and crest fat
above the cervical vertebrae
Safely approach and catch a horse and put on a head collar
Approach from the left side “near side”– near the shoulder slightly off to the side
Tie a horse up with a quick release knot.
https://www.youtube.com/watch?v=rdgSDdwhKAI
Put on a horse rug correctly
https://www.youtube.com/watch?v=DvewE7zYFgs
Pick up front and hind limbs safely and hold on to a front and hind hoof leaving both hands free for examination.
https://www.youtube.com/watch?v=vW1PvMRo2PU
Identify all grooming gear
Put on a rearing bit
* Used for leading horses that require a little more restraint than a head collar and lead alone
- Stand on the horses left side and hold the bit in your left hand
- Slide the strap over the head, feeding the bit into the horse’s mouth as you go or undo the strap and fit the bit into the mouth first if the horse is head-shy
- Adjust the bit so it sits in the corner of the mouth to cause a small crease
- Make sure you clip the ring in the middle of the bit together with the ring of the head collar to your lead rope whenever you lead the horse. If you lead the horse only by the bit you can injure the horse’s jaw
- when the horse is to be tied you can leave the bit on the horse but don’t clip the bit to the lead or cross ties as if the horse puls back it may injure its mouth or jaw- only clip the cross ties to either side of the head collar
https: //www.youtube.com/watch?v=Ga_OMmnL1kA
Assess cardinal signs correctly - knowledge of the normal range for heart rate, respiratory rate, temperature and mucous membrane colour is expected as well as the ability to identify normal from abnormal heart and lung sounds on auscultation.
Normal HR: 28-40 beats per minute
Normal resting rate: 8-16 breaths per minute
Normal temperature: 37- 38.4C
MM colour:pale pink and moist (can examine eye- conjunctiva and sclera) and the vagina for others
* Rebreathing bag may be used to cause the horse to breathe more deeply (large reserve) if exam is focused on respiratory system– compare lung sounds in the ventral, mid, and dorsal thorax and between the left and right sides (listen while the bag is in place and immediately after the bag has been removed)
Assess gut sounds correctly.
Auscultate the dorsal and ventral abdomen on both sides. Large colon and caecum fills the ventral abdomen. They produce low rumbing sounds (borborygmi). Small intestinal sounds are heard more dorsally as higher pitch pops and squeaks. The ileocaecal valve sounds (ICVS) is heard at the right paralumbar fossa about every 60 seconds (range 30-90 seconds). It sounds like the drain pipe of an upstairs toilet flushing!! Some horses will kick– so the safest place to stand is at the side of the horse close to the front limb
Estimate the weight of horses to within 50 kg of actual weight
Girth Length x Girth Length x Body Length divided by 330
560 kg e.g.
(right over the withers)
Estimate the height of horses accurately in hands, to within one hand
1 hand = 4 inches= 10.16 cm
Measuring to the withers
- 2 is a horse, anything under is a pony
https: //www.youtube.com/watch?v=lQ0HJGPfHNc
Recognise the information in brands on Standardbreds
Standardbred S
State Postcode
Year of Foaling
Registered No.
Complete an ID certificate correctly - knowledge of horse colours, the ability to correctly describe white markings, whorls, scars and muscular defects and to draw them, using international convention, on an identification sheet
whorls- patch of hair growing in the opposite direction of the rest of the hair
Describe how to give intravenous injections correctly.
Jugular vein– usually left jugular vein for a right handed person
* 1.5” needle of 20 to 18 gauge is recommended
- Position the horse with its head and neck slightly extended and straight to make the vein easier to see
- Swab the jugular groove
- Take the needle off the syringe
- Raise the jugular vein by occluding it with one thumb approximately 1/2 to 2/3 of the way down the neck. Intermittently releasing and then reoccluding the jugular numerous times over several seconds will send a wave up the distended jugular that may make it easier to ID.
- Angle the needle at about 30 degrees to the skin directly over and aligned with the jugular vein. If the needle is not in the vein try not to withdraw the needle through the skin. It is preferable to just re-direct the needle into the vein from the original puncture site
- Pass the needle fully into the vein until the hub of the needle is firmly against the skin. If you do not insert the needle fully, when you attach the syringe, the needle tends to be pushed in further and comes out of the vein (both hands are used to attach syringe, so the vein is collapsed at this time). If the syringe is attached successfully without the needle coming out of the vein, when you push the syringe plunger in, the needle can be pushed in further and may come out of the vein
- Attach syringe, occlude and distend vein and withdraw blood into the syringe to check the needle is still in the vein after the syringe has been attached. It is important that the vein is distended before you attempt to withdraw blood, if it is not, the vein wall is likely to be sucked onto and occlude the bevelled edge of the needle.
- Press the plunger to administer contents of the syringe if the horse moves during administration, stop injecting and confirm the needle is still in the vein by withdrawing blood into the syringe before continuing.
Apply a twitch efficiently.
Nose twitch
Step 1 firmly grasp muzzle with several fingers and thumb through the loop
Step 2 place loop over end of nose
** causes release of natural analgesic chemicals in the brain– endogenous opiates or endorphins– which then likely mask both the discomfort at the nose and discomfort elsewhere.
No longer than 10 minutes!
Estimate the age of a horse by interpreting any brands and looking at the incisor teeth.
* Teeth appear, develop, wear, change form and are shed with regularity (not an exact science due to quality of feed, environmental factors, heredity, and disease)
* Eruption times of each of the incisors
* Shape and appearance of the occlusal surface of the lower incisors
* Bite alignent of the incisor arcades
* Presence of hooks and grooves on the upper corner incisors
Official Guide for Determining the Age of the Horse
6 days- central incisors present
6 weeks- centrals and intermediates present
- 6 months all incisors present (corners just erupted)
- 12 months- dental star present in centrals and corners not in wear (molar 1 present)
- 18 months - corners in wear
- 24 months- dental star in all lower incisors (molar 2 present)
…
2.5 years- permanent central incisors erupted (but not in wear)
3 years- centrals in wear
3.5 years- intermediates erupted (not in wear)
4 years- centrals and intermediates in wear
4.5 years- corners erupted (not in wear)
5 years- all incisors in wear (the dentition is complete at this age)
6 years- corner incisors in full labial occlusal contact
7 years- lower corner incisors in full occlusal contact lingually
After this age, the accuracy of ageing by dentition decreases as it relies solely on occlusal forces causing attrition
* As the tooth wears, the infundibulum becomes shallower and smaller and moves lingually (towards the tongue)
Identify basic farrier/hoof equipment including a hoof knife, hoof rasp, nippers, pincers and nail pullers
Use hoof testers effectively and perform flexion tests.
Briefly discuss a suitable drug or drug combination for sedation of the horse in common clinical situations.
Anaesthetic 1: xylazine and ketamine/ diazepam
* Acepromazine given, clin exam, place catheter, wash mouth out, draw up xylazine, ketamine and diazepam in separate syringes
Premed: give 1 mg/kg xylazine IV via catheter and flush, wait for hose to appear heavily sedating before induction
Induction: 2.5 mg/kg ketamine and 0.05 mg/kg diazepam IV via catheter and flush
Anaesthetic 2: romifidine and Zoletil (zolazepam/tiletamine)
* Acepromazine given, clin exam, place catheter, wash mouth out, reconstitute zoletil with water to a combined strength of 100 mg per ml, label and date bottle, draw up romifidine and Zoletil in separate syringes
Premed: give 0.08 mg/kg romifidine IV and flush (wait to appear heavily sedated before induction)
Induction: give 1.65 mg/kg IV zoletil (1.65 mg/kg combined tiletamine and zolazepam not 1.65 mg/kg of each drug), IV via catheter and flush
Anaesthetic 3: romifidine and ketamine/ diazepam followed by “triple drip” maintenance (xylazine/ketamine/GGE– Giafen= guaiphenesin) for surgical castration
* Acepromazine given, clin exam, place catheter, wash mouth out, draw up romifidine premed, draw up ketamine and diazepam induction, Make up triple drip:
– GGE 10% (100 mg/ml) + xylazine (1mg/ml) + ketamine (2 mg/ml). So for 500 ml bottle of 10% GGE, you need to add 500 mg (5mL) xylazine and 1000 mg (10mL) ketamine. Insert an administration set into the bottle and run fluid through the line so there is no air in the line… decide on rate for trip drip– starting pt may be 1 mL/kg/hr (given to effect– giving sets deliver 20 drips per mL), calculate the drops per second rate for administering 1 mL/kg/hr to your horse
Premed: 0.08 mg/kg romifidine IV via catheter and flush (wait for heavily sedated to induce)
Induction: give ketamine 2.2 mg/kg and diazepam 0.05 mg/kg IV via catheter and flush
Maintenance:
- after your horse is induced and laterally recumbent, attach your trip drip to your catheter and begin to run your mixture at the pre-prepared rate
- monitor pulse rate/ RR and cranial nerve reflexes
- Maintain this protocol throughout castration
Palpate and clearly identify the important anatomic structures of the horse discussed in practical classes including the superficial and deep digital flexor tendons, the suspensory ligament and its branches, the joints of the limbs and the sites for injection into fetlock, carpal, tarsocrural and femoropatellar joints; superficial landmarks of the maxillary and frontal sinuses
Identify sites for the
- palmar digital, abaxial sesamoid and four point nerve blocks
- auriculopalpebral nerve block
Pectoral IM injection– potential complication?
Could develop pectoral oedema after injection
Gluteal muscles as IM injection spot?
Middle of the gluteal muscle avoiding the area of the tuber sacrale, tuber coxae, tuber ischia, hip joint and sciatic nerve
* this location depends on the temperment of the horse
Caudal thigh as a location for IM injection
Semimembranosis, semitendinosis
avoid the furrow between these
If the horse is difficult during injection, what do you do?
Physical restraint methods
A. minimum restraint- halter or head collar and lead rope
B. Rearing bit
C. Chain over nose
D. Neck twitch with hand
E. Nose twitch
F. Ear Twitch
G. Lip or gum chain
H. Lifting a limb
I. Cross ties
J. Stocks
Ear twitch or lip or gum chain
Other methods of restraint aside from physical?
Verbal– a soothing, reassuring tone can help in calming a difficult horse. An authoritative tone accompanied by a tug on hte lead rope may help keep a fidgety horse in place
Chemical– may alter some PE findings– can be used alone or with other techniques or devices. C
Restraint of foals
* Control the mare first
* Never pull on a foals head and never tie a foal like an adult horse
* Lateral recumbency for procedures– handler sit with one leg under the foal’sneck and the other over the foal’s forequarters– another person may have to restrain the foals legs by kneeling with them squeezed between their thighs
For gaining compliance, the three basic messages you are sending to the horse:
T or F A horse that is trying to get to its feet may be assisted by pulling up on its tail
True– horses regain control of front end before their hind quarters
** Sitting on their head/ upper neck will prevent them from repeatedly hitting their heads when attempting to rise too early
** Leave a severely lame limb upper most
How to connect a drip set to a 500 ml glass bottle of Giafen?
You will need an additional needle for air intake if fluid is to flow out of the bottle
Induction of anaesthesia in horses in a field setting?
Stand in front of the horse as it is most unlikely the horse will lunge forward
Ketamine must never be given unless the horse is profoundly sedated. T or F?
True
** Maximally sedated with an alpha 2 agonist– usually 3-5 minutes after receiving an alpha 2 agonist
Horse shoe
Parts of a physical exam
* Observe the horse from a distance
- stance and behaviour, general mentation, RR and RE, body condition
* Head collar and lead rope
* Check both nostrils for airflow and equal on both sides (flared can indicate pain or increased RE) (nasal discharge, unilateral/bilateral, colour, quantity)– odour of mouth and nostrils esp. anaerobic infection– pleuropneumonia, dental problems, face symmetry, eyes
* nose to tail left side
* nose to tail right side
* MM CRT< 2
* facial artery palpated at the ventral aspect of the mandible to assess the pulse
* Ear palpation if they permit it for temperature if suspicion the horse is in hypovolaemic or CV shock and experiencing poor peripheral perfusion
* Intramandibular space for submandibular lymphadenopathy
* Left jugular vein occluded and palpated to evaluate jugular fill and examine for thrombophlebitis… examine jugular veins for patency and filling– good estimation of hydratin status– that and skin turgor
* Heart Auscultation
* Lung Auscultation
* Gut sounds
* FIrm, upward palpation of ventral thorax to evaluate for ventral oedema
* Inguinal area to eval external repro organs
* Pulses obtained on the median artery on the medial aspect of the carpus next to the cephalic vein
* Temperature
Safely obtain a temperature
Heart and CV assessment
* Heart auscultated on the left side of the chest behind the left elbow
* Left forelimb must be slightly in front of the right
* 28-40 bpm
* Then auscultated in three locations on the cranial ventral thorax: over the pulmonic, aortic, and mitral valves
* Start at the apex beat on the left side of the chest then move progressively further forward and upward (cranial and dorsal).
* Listen on the right as well
* you may hear dropped beats (2nd degree AV block) in normal horses or soft physiological murmurs (during systole near the base of the heart = turbulence in the wide diameter vessels)
* A pulse can be obtained from the median artery on the medial aspect of the carpus next to the very visible cephalic vein. This is the one pulse that can be reached at the same time as auscultating the chest
* As you run your hand down the limb consider the temperature of the distal limb– normally the digital pulse in the medial and lateral digital vessels is faint– horses with a foot problem such as foot abscess and horses with/ developing laminitis often have strong digital pulses
Recognise the information in brands on Thoroughbreds.
Breeder must register with the Australian stud book
* A stud, station, owner or agent’s distinguishing brand with letters or symbols
* A sequence number signifies the order in which the foals were branded
* initially the odontoblastic seal the tubule with secondary dentine– secondary dentine is dark brown in colour= dental star– a white spot appears in the centre of the dental star
* After 7 years of age, the shape of the occlusal surface, presence or absence of hooks and grooves, angle of the bite plan as well as the loss of the infundibulum (cup) and appearance of the dental star are used to estimate age. The older horse, the more subjective ageing becomes (it pays to examine brands, etc.)
Hoof knife
Used to trim frog and sole of hoof
hoof rasp
Used to finish trim and smooth out edges of hoof
Nippers/ hoof pincers
Used to trim hoof wall
Nail pullers
Clin exam of musculoskeletal system of the horse
- Examination of the horse at rest
- Begin at the left forelimb then work down the back to the left hind limb. Repeat all procedures on the right forelimb followed by the right hind limb. For each limb start proximally and work down so that the horse can anticipate what you are doing and you can get a feel for how the horse will tolerate the procedure
- The point of the shoulder is palpated for pain in the underlying bicipetal bursa. It is rare to be able to detect swelling in the shoulder and elbow joints due to their depth.
- Carpus: The carpus is then observed and palpated. Swelling of the antebrachiocarpal and midcarpal joint can be observed dorsally. There is a palmar pouch of the antebrachiocarpal joint on the lateral aspect immediately palmar to the radius and proximal to the accessory carpal bone which will only be observed when there is joint effusion. The carpal canal will swell at a similar site.
- Metacarpus: Palpate the flexor tendons and the suspensory ligament (interosseous m.) at the palmar aspect of the metacarpus. The suspensory ligament is divided into 3 important parts which make up the proximal, middle and distal thirds of the metacarpus; origin (between the splint bones proximally and therefore difficult to palpate), the body and the branches distally.
- Fetlock: The fetlock joint has a dorsal pouch and palmar pouches. The palmar pouches lie between the third metacarpal bone and the suspensory branch and can extend up the button of the splint bone. It is important to differentiate swelling here with swelling of the digital sheath which will be palmar to the suspensory branch (commonly called windgalls by horse people). Also palpate the lateral and medial sesamoid bones.
- Pastern: Fluid swelling of the proximal interphalangeal joint (pastern joint) is rare. Joint swelling is usually firm and fibrous or bony in long standing cases and will appear as a thickened pastern predominantly distally. The flexor tendons should be palpated on the palmar aspect of the pastern. The SDFT branches and inserts on either side to proximal P2.
- Foot: Palpate digital pulses at level of fetlock or palmar pastern. Amplitude is more important than rate for assessment of inflammation within the foot. They should be difficult to feel in a normal horse. If they are easy to feel then they are probably elevated in amplitude. Palpate the coronary band. An indentation of the band if palpable when there is sinking or rotation of the pedal bone with laminitis. Swelling and pain may be palpable with a foot abscess that is about to break out at the coronary band.
- Examination moving horse
- Walk straight line
- Trot straight line
- Lunging on both reins
- Ridden
- Diagnostic analgesic techniques
- Imaging
Non weight bearing exam
Non-weight bearing examination
Pick the foot up. Examine the solar surface of the foot. The sole must be cleaned first with a hoof pick or hoof knife. Determine where the foot is weight bearing, and is it balanced mediolaterally. Turn around and palpate up the limb concentrating on the flexor tendons at the pastern and metacarpus and the suspensory ligament.
At the metacarpus separate the SDFT and the DDFT gently. The SDFT has relatively sharp lateral and medial borders whereas the DDFT is more rounded in cross section. The flexor tendons should not be painful when squeezed with moderate pressure. There should be no pain when pressing on the branches of the suspensory ligament but it is normal for the horse to react to pressure on the suspensory ligament body.
Flexion test
Non-weight bearing examination
Pick the foot up. Examine the solar surface of the foot. The sole must be cleaned first with a hoof pick or hoof knife. Determine where the foot is weight bearing, and is it balanced mediolaterally. Turn around and palpate up the limb concentrating on the flexor tendons at the pastern and metacarpus and the suspensory ligament.
At the metacarpus separate the SDFT and the DDFT gently. The SDFT has relatively sharp lateral and medial borders whereas the DDFT is more rounded in cross section. The flexor tendons should not be painful when squeezed with moderate pressure. There should be no pain when pressing on the branches of the suspensory ligament but it is normal for the horse to react to pressure on the suspensory ligament body.
**Performing a fetlock flexion test. The carpus is positioned in the armpit at 90 degrees of flexion and the toe pulled upwards to apply pressure to the fetlock and interphalangeal joints.
Hoof testers
Hoof testers
Hoof testers should be applied to all the feet. This is done with the foot held between the legs for a forelimb and resting on the legs for the hindlimb. Never try to place a hind limb between your legs or you risk getting kicked. Start at one heel and work your way slowly around the hoof wall to the opposite heel. Feel for the horse pulling away from you with your legs. As soon as you get a slight response stop. Keep going around the foot then come back and check if the original spot gives a pain response repeatably. Apply across the frog as well.
Diagnostic analgesia
This is the only way of objectively determining if there is pain at a site in the limb that is causing lameness. Nerve blocks are used to localise a lameness where there are no localising signs and to confirm a findings as the cause of a lameness where it is not clear. They are contraindicated when a stress fracture is suspected due to the risk of a complete fracture developing. Nerve blocks can be either regional (blocking of the nerve supplying a region) or intrasynovial (local anaesthetic placed in a joint or tendonsheath). Where there is a choice I prefer regional blocks due to the decreased risk of complications and the more complete block achieved of an area. Begin with distally and work proximally to block out each area sequentially.
Regional blocks of the forelimb
Palmar digital nerve block
Pastern ring block
Abaxial sesamoid block
Low 4-point block
Subcarpal block
Median and ulnar block
Regional blocks of the hindlimb
Palmar digital block
Pastern ring block
Abaxial sesamoid block
Low 6-point block
Subtarsal block
Tibial and peroneal block
Palmar digital nerve block
Palmar digital nerve block
Holding the limb off the ground with the left hand at the distal metacarpus for a left forelimb allow the fetlock to extend due to the weight of the distal limb. The left thumb is placed on the ergot and it is pulled proximally to tense the ligaments of the ergot which pass distally to the collateral cartilages. These can then be palpated with the right hand. The palmar digital nerves come out from under the ligament of the ergot half way down the pastern and pass directly distally to run under the axial surface of the collateral cartilages. The nerve is difficult to palpate. The injection site is the intersection of the collateral cartilage and the palmar aspect of the pastern. A 25mm 21g needle is passed distally to approximately half its length. Inject 2ml both medially and laterally at this site. This blocks the whole sole, all the foot and its contents except the dorsal coronary band and varying amounts of the pastern depending on the level the nerve is blocked.
Pastern ring block
Pastern ring block
Both the palmar digital nerve and its dorsal branch are blocked mid pastern. The limb is held as for the palmar digital nerve block. The palmar digital nerve is blocked midpastern where is comes out from under the ligament of the ergot. Two ml is injected at this site and the needle is partially withdrawn and redirected dorsally injecting slowly as the needle is pushed forward to expand the subcutaneous space. Another 2ml is deposited approximately 1.5cm dorsal to the first injection site to block the dorsal branch. This blocks the whole foot and distal interphalangeal joint.
Abaxial sesamoid nerve block
Abaxial sesamoid nerve block
The limb is held as for the previous blocks but with the hand slightly higher on the metacarpus. The palmar vein, artery and nerve are palpated on the abaxial surface of the sesamoid bone and a 25mm 21g needle is placed parallel and immediately palmar them to half its length. Two to three ml of local anaesthetic is injected. This blocks the same structures as the pastern ring block as well as the proximal sesamoid bones.
Low four point nerve block
Low four point nerve block
With the foot held between the knees both hands are now free to perform the block. The palmar nerves are blocked midmetacarpus in the groove between the suspensory ligament and the flexor tendons. A 25mm 21g needle can be passed proximally or distally depending on your preference. The palmar metacarpal nerves are then blocked where they emerge from under the buttons of the splint bones. The needle is passed proximally to hit the button of the splint bone. It is then slightly withdrawn before injecting. This is slightly deeper than other blocks.
Subcarpal nerve block
Subcarpal nerve block
Hold the limb as for the low 4 point block. Palpate the palmar aspect of the splint bones proximally. The level of injection should be just below the level of the carpometacarpal joint. The flexor tendons are pushed axially and a 3.75mm 21g needle is passed axial to the splint bone to hit the palmar aspect of the metacarpus at its junction with the splint bone. Three ml of local anaesthetic is injected at both lateral and medial sites.
- Palpate and clearly identify the important anatomic structures of the horse discussed in practical classes including the superficial and deep digital flexor tendons, the suspensory ligament and its branches, the joints of the limbs and the sites for injection into fetlock, carpal, tarsocrural and femoropatellar joints; superficial landmarks of the maxillary and frontal sinuses
carpus joints
maxillary and frontal sinuses
* the roots of the 3rd-6th cheek teeth lie in the maxillary sinuses
The frontal sinus occupies the skull from a point midway between the infraorbital foramen and the medial canthus of the eye to a point midway between the caudal edges of the orbit. The frontal sinus is divided into right and left compartments by a midline septum. The conchofrontal sinus is formed by a communication between the rostromedial frontal sinus and the dorsal conchal sinus. The frontomaxillary aperture is a large area of communication between the frontal sinus and the caudal maxillary sinus, this is important to allow drainage. Blood supply to the frontal sinus is provided by the ethmoidal artery.
Joints in the knee
Joints of the hock
Carpal Joints
Fetlock bones front limb
Coffin joint
