Management of Disease - Farm Flashcards
Why is a clinical exam and good diagnostics important in farm animal practice?
Allows the correct diagnosis and therefore the most accurate prognosis can be given and the most effective treatment to be used
Provides information to allow an informed decision to be made
Allows he formulation of preventative strategies
What should be taken into account when gathering a clinical history?
what is the animal used for
that stage of production is it in
what is the age of the animal
what is the herd health history on the farm
what is the hygiene like
what is the temperature and ventilation like
what is the food like
how are the other cows looking
what is the stocking density
what are the clinical signs seen, how long have they been going on for, is it a problem with one animal or a number of animals
Describe how you would carry out a clinical exam
- examine from a distance - look at body condition, look at the animal’s demeanour - is it behaving normally? Take a resp rate, assess it’s mobility
- once suitably restrained examine up close. With cows begin at the back and look for symmetry of the pelvis and if female check the udder - check the temperature, consistency, check for pain. If taking a milk sample ensure to discard the first bit of milk as this will be contaminated, for a sterile sample catch the milk after the initial fluid has been released. Look at the colour and consistency of the milk.
- Go round to the left side, listen to heart and lungs, check rumen sounds - should be 2 primary contractions, 1 secondary contraction followed by an eructation every 2 minutes. You can feel this if you place your hand in the sub-lumbar fossa, you can also score the rumen fill our of 5 at this point.
flick along the animals side, if you hear a ping it indicates a displaced abomasum - go around to the right side and again listen to the heart, lungs and gut, abomasum can also be displaced to the right note that ping may not be heard in fat animals.
- go to the front of the animal, look for nasal or ocular discharge, look for any problems in the mouth - capillary refill, mucous membranes, ulceration
- always do the vaginal/ rectal exam last - look for any discharge, check faecal consistency, check for tone and any distension of organs
How many litres of fluid can be pumped into an adult cow via oro-gastric tube?
up to 30 litres
which horn is the calf likely to be in?
the horn where the CL cn be found on the ovary
60% of calves are in the right horn
How can you sex calves in utero and from what age can they be sexed
from day 56 the genital tubercle can be seen
in males it sits behind the umbilicus
in females it sits between the hind legs and tail
from day 70-120 the testes and teats can be used for sexing
How does an ultrasound work and how does the frequency affect the image
ultrasound measures voltage created by the vibrations of the ultrasound waves that are reflected by the tissue
by increasing the frequency you get better resolution but less penetration so decreasing the frequency does the opposite
the denser the tissue, the greater area it has for the waves to hit and reflect so the whiter it appears on the image
From what day can you diagnose a pregnancy in a cow
from 18 days but from day 30 is more common - less chance or resorption
By what day should fotal membranes be adhered to the uterine wall
from day 40, if the foetal fluid is cloudy or the membranes aren’t attached it indicates foetal death or poor health
From what day can the umbilical pulse be seen
day 110
from what day can foetal bone deposition be seen
day 57
What is a castrated bull and ram called
steer
wether
when would a ram become fertile
when would a bull become fertile
4-6 months for a ram
7 months for a bull
Reasons for castration
makes animals safer to handle, reduces aggression
prevents accidental / unwanted pregnancies
possibly better carcass quality - increased fat, taint avoided
Reasons against castration
welfare - pain, stress
reduced growth rates and growth set back
arguably no difference in carcass quality
when is anaesthesia required for castration?
over 2 months in cattle, 3 months in lambs
what is the anaesthetic protocol for castration
procaine plus adrenaline - lisenced in cattle - 10-15 min onset
inject into spermatic cord, scrotum and testes
epidural can bee used for larger animals
when should rubber rings be applied
48-72 hours after birth
Reasons for dehorning
safety for workers
reduces injury to other animals
where should anaesthesia be injected for de-horning
aim for the cornual branch of the facial nerve and give 3-10 ml of anaesthetic
what is a good sedative for de-horning
xylazine
What are the stages of labour and how long should they last
1st stage - dilation of the cervix - 3-6 hours
2nd stage - expulsion of the foetus - can take severa hours
3rd stage - expulsion of the placenta - up to 12hours post delivery
When to intervene
if no progress has been made within an hour of the water bag showing
if there is bleeding from the vulva
if there has been no progression from 1st to 2nd stage of labour after 6 hours
Causes of dystocia
malpresentation
foeto-maternal oversize
congenital abnormality
primary inertia
How should calving ropes be placed
a double loop above the fetlock and below the fetlock
What are risk factors for uterine torsions
occurs at the onset of parturition most commonly poor rumen fill space in the abdomen hilly land standing up and lying down
indications for a caesarian
Foetal oversize/foeto-maternal disproportion Irreducible uterine torsion Insufficient cervical dilatation Dead/empyhsematous calf Constricted vagina and vestibulum Abnormal calf Foetal malpresentaion Double muscled breeds, Embryo transfer calves - elective
Factors affecting neonatal calf diarrhoea
hygiene stocking density colostrum intake - IgG and IgA nutrition ventilation temperature stress
How much colostrum should a calf be given
3.5-4 litres in the first 6 hours, repeat within the next 12 hours
continue feeding colostrum for the next 4-7 days
What vaccines are available to the mother to aid calf health
ETEC, rotavirus, coronavirus
given 30 days before calvinf
describe coccidiosis with regards to calf scour
usually seen in older calves - 21 days plus
see tenesmus, dark scour sometimes with blood but usually bright in themselves
often associated with poor hygiene
Describe necrotic enteritis in calves
affects calves at 2-6 months
unknown aetiology
usually fatal
see pyrexia, pale mucous membranes, necrotic lesions in GIT, leucopenia and thrombocytopaenia
Describe malabsorptive and hypersecretory diarrhoea and their pathogenic causes
hypersecretory diarrhoea is when enterotoxins stimulate hypersecretion of water and nutrients into the gut lumen. Diarrhoea occurs due to overwhelming the system and to flush out the enterotoxins. E.coli (ETEC) and cholera causes it.
malabsorptive diarrhoea is due to villus damage which reduces absorption from the gut lumen which changes the osmotic gradient so more water moves into the gut lumen. rotavirus, coronavirus, crypto cause it
At what age should a heiffer be first served and have her first calf
13-14 months at first service to calf at 24 months
what puts constraints on calf growth
illness
lack of colostrum
inadequate nutrition - milk and solids
inadequate environment - poo hygiene, temp, ventilation, stocking density
when should a calf be weaned
ideally not until 12 weeks but many weaned at 8-9
What are the 3 most common neonatal diseases in ruminants
diarrhoea
navel ill
septicaemia
Things to look for when examining a neonate
demeanor suck reflex temp resp and heart rate faeces navel hydration status any CNS signs abdominal distention abdominal sounds
risk factors for navel ill
hygiene at calving
patent navel
colostrum intake
what is the outcome if the urachus, umbilical artery or vein is affected in navel ill
remove the infected urachus and umbilical artery
if vein is infected there’s poor prognosis
treatment of joint ill
long course antibiotics
joint lavage
arthrotomy and joint flush
antibiotic impregnated beads in joint
what is the definition of bacteraemia and septicaemia
bacteraemia = bacteria in the blood often secondary
septicaemia is when bacteria are multiplying in the blood, fatal
At what age is septicaemia most commonly seen
between 1-5 days old
Clinical signs of septicaemia
collapsed meningitis shocked (endotoxaemia) Very congested conjunctiva Petechiae DIC CNS signs sometimes diarrhoea is not a sign but septicaemia may occur at same time as diarrhoea
Which is the only diarrhoea pathogen which also invades to cause septicaemia
salmonella
What pathogen causes calf diptheria
fusiformis necrophorum
causes oral lesion, sore mouth with foul smelling odour
treat with penicillin
What are the reasons for metabolic acidosis
loss of bicarbonate
addition of acid
neutrilisation of bicarbonate
dilution of bicarbonate
what problems does dystokia cause the calf
hypoxia due to reduced oxygen delivery
metabolic acidosis due to lactic acid production
respiratory acidosis due to poor lung function
oedema, bruising and fractures
all results in weakness and inability to or inadequacy of colostrum intake and a weakened immune system
how long should it take a calf to get into sternal recumbency after birth
less than 5 minutes
what does colostrum contain?
immunogloblins IgG,A and M
protein, fat, vitamins, growth factors
Why do calves rarely get enough colostrum
heifers have poorer colostrum and less of it
bad calvings result in weak calves
genetics: loss of mothering ability, large teats, poor colostrum quality
what factors affect colostrum quality
mastitis pre-milking length of dry period genetics parity breed pre-partum nutrition
consequences of diarrhoea in calves
dehydration leading to pre-renal failure and shock
metabolic acidosis - loss of bicarbonate into the gut, lactic acid build up from tissues and colonic fermentation
hyperkalaemia secondary to acidosis due to intracellular uptake of H+ in exchange for K+
hypoglyaemia due to starvation
