Small ruminants Flashcards
what are the three main ways of managing infectious/parasitic disease?
biosecurity
reduce disease challenge
improve animal resistance
what are the three periods of a ewes years?
dry (3 months)
pregnant (5 months)
lactating (4 months)
what are common issues associated with inefficiency in sheep?
ewe/lamb mortality
chronic wasting diseases
poor nutrition
parasites, lameness, mastitis…
what characteristics are need in the stratification system?
lamb vigor
good mothering
growth rates
disease resistance
what are some of the main estimated breeding values of sheep?
litter size
maternal ability
scan weight lamb
carcass composition/conformation
mature size
worm resistance
what is the deadweight for lamb?
£5-6 per kilo
what is the price of a live lamb?
£250
what is the cost of a replacement ewe?
£200
what is the cost of a cull ewe?
£90
what are the general KPIs of sheep?
scanning %
lambing %
ewe mortality
culling ewe
ewe:tup ratio
lamb mortality
are sheep short or long day breeders?
short
what is the main advantage of spring lambing?
easy management and good grass growth
what is the main advantage of Christmas lambing?
better lamb prices at easter market
what are store lambs?
lambs that haven’t been finished that summer so are minimally fed through winter (no growth) for compensatory growth the following spring
why do store lambs not grow over winter?
concentrates are too expensive
how does seasonality work? (brain)
light enters eye
travels in optic nerve through hypothalamus to the superior cervical ganglion and then pineal gland
pineal gland then does/doesnt produce melatonin
what effect does light have on melatonin production?
blocks production
in spring melatonin decreases, how does this effect the GnRH of sheep?
decreases the pulses and hence decreases FSH and LH so the sheep doesn’t cycle
what do follicles produce? and what does this do?
oestrogen that suppresses the FSH
how long is the oestrus cycle in sheep?
16-18 days
how many follicular waves do sheep have?
2-5 waves
what is the ideal ewe to ram ratio?
1 ram per 30 ewes
why isn’t artificial insemination used as commonly in sheep?
structure of the cervix is different (has to be done laparoscopically)
low number of straws per ejaculate compared to cattle
what determines the fecundity of sheep?
bone morphometric protein signalling from ovary
what is the ram effect?
introduction of a male after 2 weeks of male absence (also works if new ram is introduced) that triggers cyclicality in ewes
what happens to the oestrus activity after male introduction? (ram effect)
1st ovulation (can be silent)
19 days - second ovulation (first for some)
25 days - second ovulation for ones that had silent first
what is the name of the ram often used for the ram effect?
teaser - vasectomies
how can seasonality be manipulated?
expose to artificial light (difficult with sheep)
melatonin supplement
genetic selection
how can the ram effect be used to alter seasonality?
alter the rams seasonality (melatonin…) then introduce to ewes and they will alter their seasonality due to the ram effect
how is melatonin given to a sheep?
ear implant (regulin)
what is done on day 1 of a melatonin plan to induce seasonality?
30 weeks prior to lambing move ewes out of sight/sound/smell of ram
what is done on day 7 of a melatonin plan to induce seasonality?
implant melatonin in ear base
what is done on day 42 of a melatonin plan to induce seasonality?
introduce ram (30-40 days post implant)
what is the short term effect of flushing?
effects the current follicular wave (3-7 days)
what is the long term effect of flushing?
allows sheep to come out of seasonal trough in fertility sooner (6-8 weeks)
what is the static effect of flushing?
ewes with higher BCS have higher ovulation rate
what is the dynamic effect of flushing?
ewes that are increasing in BCS have a higher ovulation rate
what is the only method to hormonally synchronise ewes?
chronogest - progesterone sponge
how long do progesterone sponges go in the vagina for?
12-14 days
what is the issue with progesterone sponges?
progesterone is an immunosuppressant so can get vaginitis
when combined with PMSG injection at sponge removal, when does oestrus occur?
36-72 hours after sponge removal
what hormone does PMSG have the same activity as?
FSH
how long should you wait after removal of the progesterone sponge (with PMSG injection) before introducing the ram? and why?
48 hours to ensure ram doesn’t over serve first ewes coming into oestrus and deplete their semen reserves (then most ewes will be in heat)
how long is a CIDR left in a sheep?
12 days and eCG on removal
how can lambing be induced?
dexamethasone injection (dexafort) from day 140 after ram has been in - this isn’t authorised
how long after inducing a ewe with dexamethasone will they lamb?
around 40 hours later
when are most replacement ewes introduced to the flock?
19 months
what is the optimal BCS of a ewe at mating?
3.5
how long does it take sperm to develop in ewes?
roughly 60 days (ensure you check rams well before mating)
what is the optimal BCS of a ram before breeding?
3.5
what is the rough gestation of a sheep?
145 days
how much should a ewe be fed from conception to 42 days?
just maintenance
how much should a ewe be fed from 42-90 days gestation?
maintenance plus 2 MJ/day
why is it important to feed well from day 42-90 of gestation?
considerable placental growth - underfeeding retards placenta and hence foetal growth
what type of scanning head is used to PD ewes?
sector - broader range of vision into the abdomen
roughly when are ewes scanned?
70 days (ensure ram has been out for 28 days)
why is nutrition important from 90 days to parturition in ewes?
rapid foetal growth
colostrum quality/quantity (mammary development)
prevent metabolic disease
how much food do ewes require at lambing time?
2x maintenance (concentrates)
how should a vasectomy be closed?
don’t use nice opposing sutures - want to leave a scar to be able to identify the ram
what is checked on a ram pre-breeding examination?
feet
brisket (sores for raddle…)
caseous lymphadenitis (lymph nodes)
scrotal measurement and palpation (30cm, firm, even…)
exteriorise penis and vermiform appendage
semen examination
libido testing (mounting ewes)
where is the sperm stored?
epididymis
what are some bacteria that can cause epididymitis?
Actinobacillus seminis
Haemophilus somnus
Histophilus ovis
what is epididymitis associated with?
ascending urinary tract infection
intensively reared trough fed rams (lie down more)
how can epididymitis spread be prevent between rams?
have small groups that graze and rotate between clean paddocks
what should be done at the time of treating inguinal hernias in rams?
castrate - stop possible genetic/congenital spread
what is the usual cause of testicular degeneration or hypoplasia?
specific local injury
(can also be due to extreme fatness, stress, inflammation…)
how does scrotal mange appear in rams?
crusty scabs on lower 1/3 of scrotum
sore weeping dermis
what causes scrotal mange?
Chorioptes bovis
how can scrotal mange be confirmed?
skin scrape in multiple places (low mite number)
what is an effective treatment of scrotal mange in rams?
doramection (ivermectin also used)
diazinon sheep dip is effective
what is balanoposthitis also known as?
pizzle rot
how does pizzle rot present?
small ulcers and discharge at prepuce
scabbing and fly strike
what bacteria is pizzle rot associated with?
Corynebacterium renale
what are the risk factors for pizzle rot?
high protein concentrates and lush grass
what metabolic diseases are seen around lambing time?
pregnancy toxaemia (twin lamb disease)
hypocalcaemia
hypomagnesaemia
when are lambs usually weaned?
early summer (summer period to recover before tupping)
what is the target BCS of a ewe at weaning?
2.5
what is the target BCS at tupping for a lowland ewe?
3.0-3.5
how much of an increase in BCS is aimed for when flushing sheep?
0.5
why is appropriate feeding important in mid pregnancy of ewes?
placental development (underfed means low birth weight)
mammary development
what are the aims of feeding the ewe in late pregnancy?
support lamb growth
support mammary tissue development
colostrum production
prevent pregnancy toxaemia (ketosis)
ensure strong healthy lamb
underfeeding related to mastitis and maternal behaviour
what is the most important aspect of ewe nutritional ration in late pregnancy?
good quality forage
what factors could be used to split ewes into feeding groups?
single, twins, triplets
BCS
lambing dates
separate young ewes
why does care need to be taken with trough space in pregnant ewes?
ewes are fatter so require more room
what are the three main requirements of colostrum?
energy, protein, antibodies
what is used as a rough estimate of milk production in ewes?
8 week weight of lamb
what age will lambs start to eat grass?
6 weeks old
what age of lambs weaned?
10-16 weeks
what may indicate there is an issue with peri-parturient ewe nutrition?
twin lamb disease
hypocalcaemia
lamb mortality/morbidity (weak small lambs, watery mouth, joint ill/infection, hypothermia…)
mastitis
lamb growth
what is pregnancy toxaemia?
energy deficiency (hypoglycaemia and hyperketonaemia)
what are the risk factors for pregnancy toxaemia?
last 6 weeks of pregnancy
thin/fat ewes
stress
broken mouth
concurrent disease
multiple foetuses
inadequate/change in diet
what are the clinical signs of pregnancy toxaemia?
(neurological due to low glucose)
separate from group
inappetent
blindness, tremors, hyperaesthesia, star gazing
recumbency and death
what can be measured to confirm pregnancy toxaemia?
beta-hydroxybutyrate (greater than 3mmol and they will show clinical signs)
what is done to treat pregnancy toxaemia?
separate and give fresh food/water
IV glucose (dextrose)
propylene glycol
calcium supplement
NSAIDs (meloxicam…)
what can be considered if a pregnant ewe isn’t improving from pregnancy toxaemia?
induce with dexamethasone (after 135 days gestation)
caesarian or euthanasia
what mechanism mediates the mobilisation of calcium from bones? (hypocalcaemia)
parathyroid hormone and vitamin D
what is the difference between when hypocalcaemia occurs in sheep and cattle?
sheep usually occurs pre-lambing (6 weeks)
what are possible risk factors for hypocalcaemia in ewes?
stress (transport, snow, gathering…)
acidosis
older ewes
rapid growing lush pasture
what are the clinical signs of hypocalcaemia?
weakness and excitability
recumbency
dilated pupils, constipation, bloat, coma
death
what is done to treat hypocalcaemia?
slow IV calcium
SC calcium
what is the classic history for hypomagnesaemia in ewes?
post lambing at peak lactation
lush grass or bare pasture
what are the clinical signs of hypomagnesaemia?
(neurological)
excitable, tremors, convulsions
death
what are some key points about dealing with dystocia as a vet?
wear gloves/be clean
lots of lubricant
NSAIDs
epidural
antibiotics (5 days)
colostrum to lamb
what is the method of a simple embryotomy?
remove fore limbs - cut through skin above carpus then up to elbow, undermine attachment of shoulder and remove leg
repeat for other leg
what are some possible issues to look at when getting dystocia related deaths?
ewe age
ram breed/size/characteristics
ewe BCS
hygiene lambing/pens
staff numbers/training
what are the indications for caesareans?
oversized lamb
ringwomb
vaginal prolapse
foetal monster
malpresentation
what are the contraindications for caesarians?
rotten smelly lambs (contamination into abdomen and wound breakdown)
how should a ewe be placed for caesarian?
right lateral recumbency (left side up)
what are the options for anaesthetic for caesarians?
line block (local infiltration) - procaine
inverted L block
paravertebral - T13, L1-3
sacra-coccygeal epidural
what is the site for making an incision for caesarians in sheep?
15cm incision between last rib and wing of ileum 10cm below transverse process
what type of suture is used for the uterus in caesarians?
continuous inverting pattern (catgut often used)
what is metritis?
infection of all the layers of the uterus (endothelium to muscle)
what usually causes metritis?
opportunistic environmental bacteria
what are the risk factors for metritis?
dystocia
poor hygiene
dead lambs or abortion
what are the clinical signs of metritis?
dull, depressed, recumbent (systemic illness)
toxaemic with congested MM
red/brown or purulent vaginal discharge
what is done to treat metritis?
IV antibiotics - oxytetracycline
NSAIDs
what are some possible risk factors for vaginal prolapses?
hill breeds
litter size
age
history of prolapse
nutritional - obesity, hypocalcaemia, bulky poor quality forage
high stocking rates
slopes
(anything increasing intra-abdominal pressure and reduced pelvic floor strength)
what are possible treatments for mild prolapse cases?
retention device
harnesses
NSAIDs
LA antibiotics
how are prolapses treated surgically?
epidural (1.75ml procaine and 0.25ml xylazine)
NSAIDs
antibiotics
clean, replace and suture shut (purse string)
mark to remove sutures
when does mastitis occur in sheep?
after lambing
what are the three main presentations of mastitis?
peracute/gangrenous/toxic
acute
chronic
why is mastitis often more serious in sheep?
can’t monitor them as closely because they don’t go through a milking parlour everyday
when does gangrenous mastitis occur?
4-8 weeks post lambing (peak lactation)
how does the udder/milk of a ewe with gangrenous mastitis present?
swollen, cold, blue
boundary between diseased and normal tissue
diseased tissue often sloughs off
milk severely discoloured
how will a ewe with gangrenous mastitis present?
sick ewe
toxaemia, rumen stasis, inappetent, lame, recumbent
(lambs will be hungry - making noise)
when does acute mastitis occur?
immediately post-lambing or 4-8 weeks later at peak lactation
how does the udder and milk present in acute mastitis cases?
swollen, red, painful
clots, discoloured, watery
when is chronic mastitis often detected in ewes?
at drying off/weaning or possibly culling
how does the udder and milk present in chronic mastitis cases?
abscesses, swollen
light purulent discharge
what are the most common bacteria causing mastitis in UK ewes?
Staph aureus
Mannheimia haemolytica
what is the source of Staph aureus that leads to mastitis?
teat skin
what is the source of Mannheimia haemolytica that leads to mastitis?
lambs mouths
what are the risk factors for mastitis?
under nutrition in late pregnancy and lactation (metabolic stress)
over suckling lambs and teat lesions
concurrent disease
multiple lambs
older ewes
abnormal udder confirmation
how is gangrenous mastitis treated?
euthanasia or cull
how is acute mastitis treated?
systemic antibiotics (culture and sensitivity) - amoxicillin as first line
strip udder
IV fluids
NSAIDs
how is chronic mastitis treated?
cull
how can mastitis be prevented?
good ewe and lamb nutrition (creep feed)
wean abruptly
control disease (orf, worms…)
cull older and diseased ewes
good bedding hygiene
what is a neonatal lamb?
period straight after birth (<2 weeks old)
what does perinatal mean?
the time around parturition
what can causes death in the first 0-24 hours of a lamb being born?
birth stress (results in failure to suck, hypothermia…)
anoxia/hypoxia
ruptured liver
fractured ribs
brain haemorrhage
what are some possible infections that lambs can get postpartum?
watery mouth
salmonella
cryptosporidia
septicaemia
meningitis
joint ill
clostridial disease
pasteurellosis
what are the three overall factors which result in lamb loss?
lamb factors (weight, vigour, vaccination…)
ewe factors (genetics, stress, colostrum…)
environment (hygiene, equipment, shepherds…)
how much colostrum does a lamb require in the first feed?
50 ml/kg
how much colostrum does a lamb require in the first 24 hours?
200 ml/kg
how can failure of passive transfer be measured?
serum total protein (should be greater than 5.5g/dL
what are some risk factors for poor colostrum intake?
concurrent disease
ewe undernutrition
breeding - mothering…
ewe age
multiple births
lambing environment - stress, weather, shepherd…
what can be used to help strip out ewes?
oxytocin
what are the risk factors for primary hypothermia of lambs?
outdoor lambing
younger ewes
wet weather
low birth weight
feed failures
what is done to treat lambs with hypothermia?
give glucose and place in warming box (intraperitoneal glucose)
why is it important to give hypothermic lambs glucose before warming?
as they warm and metabolism starts they will have a hypoglycaemic fit
how is an intraperitoneal injection done?
just to one side of the naval at a 45 degree angle
what age do lambs get watery mouth?
12-72 hours
what are the clinical signs of watery mouth?
dull
unwilling to suck
normothermic
saliva drool on muzzle (watery mouth)
profuse lacrimation
abomasal tympany
constipation or retained meconium
what is the main finding on post mortem of a lamb with watery mouth?
distended abomasum with gas, saliva and milk clots
(bacteraemia signs)
what causes the clinical signs of watery mouth?
endotaemia (large numbers of endotoxin in blood)
what is there proposed hypothesis of why watery mouth occurs?
bacteria enter the abomasum before milk and is absorbed using the same transporters as milk
these bacteria multiply in blood and then mass lysis leads to endotoxin release
what are the main risk factors for watery mouth?
dirty environment
large litters
poor colostrum intake
what can be used to treat watery mouth?
enteral/parenteral antibiotics (streptomycin orally, amoxicillin injection…)
glucose/electrolytes stomach tube
withhold milk until lamb can suck
does metaphylactic use of antibiotics work for watery mouth?
yes - but just as well as good colostrum intake (this is a management failure - colostrum and hygiene)
what causes lamb dysentery?
Clostridium perfringens type B (beta and epsilon toxins)
what age lambs is lamb dysentery seen in?
1-3 days old
what are the clinical signs of lamb dysentery?
sudden death and haemorrhagic diarrhoea (occasionally)
what is found on post mortem of lambs with lamb dysentery?
dark red intestines
blood stained peritoneal fluid
pale friable liver
how can lamb dysentery be prevented?
vaccinate ewes with multivalent clostridial vaccines
how often is enterotoxigenic E. coli seen?
uncommon
what age is enterotoxigenic E. coli seen in lambs?
24-48 hours
what is the main clinical sign of enterotoxigenic E. coli?
watery brown diarrhoea
what are the clinical signs of neonatal salmonellosis?
weakness
profuse watery diarrhoea (blood stained)
dehydration
death
why does care need to be taken when treating lambs with neonatal salmonellosis?
it is zoonotic
what is the pathogenesis of cryptosporidium?
villous atrophy in distal small intestine causing malabsorption and diarrhoea
what is drunken lamb syndrome also known as?
lamb nephrosis
what age is drunken lamb syndrome seen?
7-10 days
1-2 months
what causes the clinical signs associated with drunken lamb syndrome?
increased D-lactate
what produces D lactate?
bacterial fermentation
what can be used to treat drunken lamb syndrome?
sodium bicarbonate solution
what age is joint ill seen?
2-3 weeks old
what is the main clinical sign of joint ill?
sudden onset lameness (single/multiple joints)
what can be done to treat joint ill?
antibiotics and NSAIDs (often poor response)
what is the main bacteria causing joint ill in lambs?
Streptococcus dysgalatiae
how can joint ill be prevented?
colostrum, hygiene, naval dipping… (multiple factors)
what antibiotic is Streptococcus dysgalatiae joint ill resistant to?
tetracyclines
what is a much less common cause of joint ill, but is seen in lambs from 6 weeks old to 6 months old?
Erysipelothrix rhusiopathie
what is naval ill?
ascending infection of the naval leading to abscessation and omphalophlebitis
what are some possible sequelae of naval ill?
peritonitis, liver abscessation, systemic infection, polyarthritis…
what can Fusobacterium necrophorum cause in naval ill cases?
hepatic necrobacillosis
what is the characteristic appearance of hepatic necrobacilosis?
white spots on liver (areas of necrosis)
what can be done to prevent/control naval ill?
iodine naval within 15 minutes then repeat a few hours later
goof hygiene
colostrum
treat - penicillin, potentiated amoxicillin
what substance can predispose to iodine deficiency in sheep?
thiocyanate (contained in some plants - root crops…)
how does iodine deficiency present relating to the neonatal lamb?
goitre of newborn
late abortions
minimal fleece on lambs
how much should a thyroid gland weigh at birth?
> 0.4 g/kg live weight
how can iodine deficiency be prevented?
ewe supplementation (inject/bolus/drench)
treat lamb with oral potassium iodide
what are some antagonists found in soil that can lead to copper deficiency?
iron, molybdenum, sulphur
what does copper deficiency cause in lambs?
swayback
head tremor
osteoporosis
tendon abnormalities
depigmented and poor quality wool (steely wool)
anaemia
what is used to diagnose copper deficiency in lambs?
clinical signs
histopathology of brain/spinal cord
liver copper concentration
how is copper deficiency treated in lambs?
euthanasia (no effective treatment)
how can copper deficiency of lambs be prevented?
supplement ewe during pregnancy (care with toxicity of certain breeds…)
what can be used to supplement copper in ewes?
chelated copper injection
mineral drench/supplements
capsules/bolus
(only use one source… toxicity!!)
what causes white muscle disease?
vitamin E and selenium deficiency
what is white muscle disease also known as?
nutritional muscular atrophy
stiff lamb disease
what are the clinical and pathological signs of white muscle disease in lambs?
weak lambs that don’t suck
histopathology of cardiac musculature
what is used to treat white muscle disease?
vitamin E
potassium selenate
how can white muscle disease be prevented?
supplementation at least 6 weeks before lambing
what is atresia ani?
failure of anus and sometimes part of colon/rectum to form properly
what is entropion?
in turned eyelids (usually lower)
what is the most successful way to treat entropion?
surgery
how are prolapsed intestines through the umbilicus treated?
general anaesthetic and surgically prepare/clean intestines
enlarge the hole, replace and suture closed
before opening a lamb up for post mortem, what should be done?
weigh (excessive suggested dystocia)
look at feet - hardened means they’ve walked
meconium staining, trauma, swelling, scour…
when opening a lamb carcass, what should be inspected?
brown fat around kidneys (energy supply)
milk/colostrum in abomasum
lung aeration
haemorrhage and trauma
evidence of infection
what are signs on lamb post mortem of dystocia?
meconium staining
swollen head/tongue
head/shoulder oedema
fractures
haemorrhage
what are signs of lamb post mortem of hypothermia/starvation?
no brown fat
minimal body fat
no milk in abomasum
what are the main differential diagnoses for diarrhoea in lambs?
Nematodirus battus
PGE
coccidiosis
Cryptosporidium
acidosis
Clostridium perfringens type B (lamb dysentery) and D (pulpy kidney)
E. coli
Salmonella spp.
what does Clostridium perfringens type B cause in lambs?
lamb dysentery
what does Clostridium perfringens type D cause in lambs?
pulpy kidney
what are the clinical signs of cryptosporidiosis in lambs?
profuse diarrhoea (blood)
dehydration
death
what age lambs does cryptosporidiosis effect?
3-7 days old
how can cryptosporidiosis in lambs be diagnosed?
faecal sample 6-10 from infected group and stain smear
post mortem histopathology
how is cryptosporidiosis treated?
supportive
oral fluids multiple times a day
(no licensed drugs)
what are ways of preventing cryptosporidiosis?
hygiene, reduced stocking density, clean pasture
lamb nutrition/colostrum
what type of organism is cryptosporidium?
protozoa
what type of organism is coccidia?
protozoa
what is the source of coccidia infection?
ewes or older lambs
what are the risk factors for coccidiosis?
high stocking rates
poor colostrum
stress, concurrent infection and mixed ages
is finding coccidia species in faeces a definitive diagnosis?
no - many of the strains are non-pathogenic
what age lambs are often infected with coccidiosis?
4-8 weeks old
what are the clinical signs of coccidiosis?
diarrhoea, tenesmus, fever, weight loss, death
(sub-clinical infections lead to poor growth)
how can coccidiosis be diagnosed?
faecal sample 6-10 from group then do a coccidial count (will need speciation as well to confirm pathogenic strains - usually treat whilst awaiting these results)
how is coccidiosis treated?
supportive
oral fluids multiple times a day
drugs - toltrazuril or diclurazil (can use metaphylactically)
how can coccidiosis be prevented?
hygiene, stocking rates, colostrum, nutrition
batch rearing
prophylactic/metaphylactic treatment
what causes acidosis in lambs?
consumption of rapidly fermentable carbohydrates (grain…)
what events occur leading to acidosis when a lamb consumes high volumes of concentrates?
fall in rumen pH due to lactic acid production which causes inflammation (rumenitis) leading to the blood being acidotic
what are possible sequelae of acidosis in lambs?
liver abscessation
fungal (overgrowth) rumenitis
death
what are the clinical signs of acidosis in lambs?
death
dull, depressed, teeth grinding, colic, bloat, ataxic, recumbent
dehydration, diarrhoea, no rumen sounds
how can acidosis be diagnosed?
clinical signs
rumenocentesis (pH <5.5)
post mortem
how can acidosis of lambs be treated?
IV fluids (plus bicarbonate)
oral fluids and multivitamins
good quality hay
penicillin
what are the possible causes of rumen bloat in sheep?
grain overload, oesophageal obstruction, legumes (frothy)
what side will be distended if a sheep has rumen bloat?
left
what can be done to treat rumen bloat of sheep?
stomach tube, dimeticone, trochar (red devil)
what age is lamb nephrosis syndrome seen?
2-12 weeks old
how can lamb nephrosis be diagnosed?
raised urea, creatine and hyperkalaemia
swollen kidneys and necrosis on post mortem
what is cobalt deficiency of lambs known as?
ill thrift
what vitamin is cobalt a constituent of?
B12
where is vitamin B12 synthesised in lambs?
rumen
what is cobalt important for?
red blood cell development
amino acid synthesis
energy metabolism
what are the clinical signs of cobalt deficiency?
weight loss
anaemia
slow growth
debility
watery eye discharge
(just generally don’t do very well)
how is cobalt deficiency diagnosed?
cobalt and vitamin B12 levels in blood/liver
what can be used to treat cobalt deficiency?
cobalt bolus/drench
vitamin B12 injection
cobalt in creep
pasture treatment
what are the functions of selenium?
anti-oxidant
immune function
what effects will a selenium deficiency have on lambs/ewes?
white muscles disease
poor reproductive performance
what are the consequences of iodine deficiency?
death and weakness
late abortions
thyroid goitre
(neonates are more susceptible to disease)
what are the clinical signs of copper poisoning?
ataxic, head pressing, jaundice, haemoglobinuria, recumbency, death
what can be used to treat copper poisoning?
(no specific treatment)
sodium calcium EDTA
supportive
remove copper source
add molybdenum and sulphur to water (binds copper)
what are bacterial causes of pneumonia in lambs?
Mycoplasma spp.
Mannheimia haemolytica
Pasturella multocida
what respiratory viruses can cause pneumonia in lambs?
parainfluenza virus
respiratory syncytial virus
what lung worm effects lambs?
Dictyocaulus filaria
when is Mannheimia haemolytica found as a commensal in sheep?
upper respiratory tract - nasopharynx (causes disease when it enters the lungs)
what is usually the driving factor for Mannheimia haemolytica to move into the lungs and cause pneumonic pasturellosis?
stress/disease - diet change, worms, ticks, housing, transport, bad weather…
what are the clinical signs of Mannheimia haemolytica respiratory disease?
pyrexia, mucopurulent nasal discharge, cough, increased RR/depth
what can be used to treat pneumonic pasteurellosis (Mannheimia haemolytica)?
oxytetracycline, amoxicillin, macrolides (5-7 days) - long acting is useful
how is pneumonic pasteurellosis (Mannheimia haemolytica) diagnosed?
consolidated lungs and culture
what can be done to prevent pneumonic pasteurellosis (Mannheimia haemolytica)?
vaccination - heptavac P, ovipast
investigating underlying problem/risk factors - stress
what are the clinical signs of mycoplasma pneumonia?
(more chronic disease)
cough, slight nasal discharge, increased RR/depth
low grade pneumonia
what group of animals is mycoplasma pneumonia mainly seen in?
housed over stocked lambs
what can be used to treat mycoplasma pneumonia?
long acting oxytetracycline and macrolides
what time of year is lung worm seen in sheep?
summer/autumn lambs at pasture
how is lung worm diagnosed?
larva in faeces (baermans test)
at is used to treat lung worm?
anthelmintics (BZ, ML, LV)
antibiotics
NSAIDs and supportive treated
what should the 8 week growth rate of a lamb be?
300-500g/day
what efficacy means that there is resistancd to the anthelmintic?
<95% efficacy
what are the possible ways in which nematodes can cause disease?
damage lining of guts (reduce absorption)
remove nutrients
remove blood
damage/provoke host immune response
what age sheep is Nematodirus battus seen in?
6-12 weeks old
what is the main clinical sign of Nematodirus battus?
acute severe diarrhoea
what age and time of year is type one Telodorsagia infection seen?
FSG lambs in mid summer onwards
what age and time of year is type 2 Telodorsagia infection seen?
yearling in winter months
what is the classic clinical sign of Trichostrongylus?
black scour
what age and time of year is Trichostrongylus seen?
lambs in later summer to autumn
what is the classic clinical sign of Haemonchus contortus?
acute regenerative anaemia and bottle jaw (no diarrhoea)
what is the typical Trichostrongyle lifecycle?
eggs passed in dung and develop to L1 and L2, L3 is then dispersed onto pasture and ingested by the sheep where they devlop to L4 and adults to produce eggs
what is the prepatent period of a typical trichostrongyle lifecycle?
21 days
what parasites have a typical trichostrongyle lifecycle?
Telodorsagia, Trichostrongylus and Haemonchus
what does infectivity of pasture with nematodes peak in late summer?
shorter lifecycle due to warmer weather and large output from lambs
where the majority of the eggs in Haemonchus come from?
sheep (don’t overwinter well on pasture)
what is hypobiosis?
L3 in late autumn have arrested development over the winter period
how does Nematodirus battus infect the pasture?
eggs shed by lambs remain on the pasture until the following year and then hatched when triggered by prolonged chill and temperature increase to infect the next set of lambs
when do lambs begin to develop resistance to nematodes?
5-6 months old
what are the five groups of anthelmintic?
benzimadazole
levamisole
macrocytic lactones
amino-acetonitrile
spiroindoles
what colour are benzimadazole drenches?
white
what colour are levamisole drenches?
yellow
what colour are macrocytic lactone drenches?
clear
what colour are amino-acetonitrile drenches?
orange
what colour are spiroindoles?
purple
how do benzimadazoles work?
tubulin binding to prevent glucose uptake
how do levamisole’s work?
ganglionic blocking causing paralysis
how do macrocytic lactones work?
block chloride and GABA channels causing paralysis
what colour are microcytic lactone drenches?
clear
what internal parasites can benzimadazoles be used for?
broad spectrum against roundworms tapeworms
albendazole work against fluke
what causes anthelmintic resistance?
natural genetics
selection pressures
what ways can you test for anthelmintic resistance?
faecal egg count reduction test
drench test (FEC after drenching)
what result on faecal egg count reduction tests would suggest resistance?
a reduction of 95% or less
what are the SCOPS principles?
always make sure treatment is fully effective
reduce dependance on anthelmintics using management and monitoring
avoid bringing in resistant worms/parasites
minimise the selection for resistant worms
what anthelmintic groups should be used for biosecurity dosing against nematodes?
4 and 5 (amino-acetonitrile and spiroindoles)
when is the best time of year to treat adult sheep for nematodes?
at lambing (reduces pasture contamination) but leave a portion untreated (ideally ones that will have a high egg output)
what can be done if haemonchus is an issue in adult sheep?
vaccinate
how can reliance on anthelmintics be reduced in grazing lambs?
pasture management - rotation…
group ages
manage concurrent disease
good nutrition
breed for resistance
vaccinate (haemonchus)
what monitoring tools are available to target anthelmintic treatment?
FEC
live weight gain
forecast
FAMANCHA - guide to measuring anaemia for haemonchus
how often should groups of lambs have FEC done?
every 2-4 weeks
what nematode is FEC not suitable for monitoring?
Nematodirus battus
what is the biosecurity strategy in terms of anthelmintic control for brought in sheep?
dose with monopantel/derquantel and hold off pasture for 24-48 hours for treatment to work and then turnout onto contaminated pasture
what is the main issues of tapeworm infections in sheep?
carcass condemnations
zoonosis (Echinococcus granulosus)
gid cysts in brain
where are Taenia hydatigena cysts found in sheep?
liver
where are Taenia ovis cysts found in sheep?
muscles
where are Taenia multiceps cysts found in sheep?
brain
where are Echinococcus granulosus cysts found in sheep?
liver and lungs
how are tapeworms for which sheep are the intermediate host treated?
praziquantel for intermediate hosts (dogs)
don’t allow dog to access sheep pasture or carcass
why is liver fluke a larger issue in sheep compared to cows?
sheep don’t develop immunity
what is the intermediate host of liver fluke?
mud snail (Galba truncatula)
what are the two factors needed for liver fluke spread?
rain
temperature above 10
what time of year does the lifecycle of liver fluke begin?
around spring
what is the rough lifecycle of liver fluke?
eggs shed in faeces and develops miracidium which hatches and swims to find a snail
in the snail they develop into cercaria which exit the snail and develop to metacercariae and are ingested
is the prepatent period of liver fluke?
8-12 weeks
when is acute liver fluke most commonly seen?
autumn
when is chronic liver fluke infection most commonly seen?
winter/spring
what causes acute fasciolosis?
large number of metacercariae release onto pasture in late summer causing severe liver damage
what causes chronic fasciolosis in sheep?
ingestion of low numbers of fluke over winter/spring
how does liver fluke cause acute disease?
migration of immature stages through the liver causes haemorrhage
how does liver fluke cause chronic disease?
blood feeding adults in the bile duct leading to fibrosis and cholongitis
what are the clinical signs of chronic liver fluke infection?
anaemia, weight loss, submandibular oedema, enlarged liver
(secondary clostridial infection - blacks disease)
how can fluke be diagnosed?
history/clinical signs
post mortem/abattoir reports
forecasts
faecal egg counts (needs adults)
coproantigen ELISA
serum ELISA antibody
what drug is capable of killing any stage of fluke?
triclabendazole (extensive resistance)
what should be done immediately after fluke treatment?
move onto low risk pasture as drugs have no residual activity
what drugs can be used to kill adult stages of fluke?
albendazole, oxyclozanide, nitroxynil, closantel
what drug has minimal resistance and is also able to treat most stages of fluke?
nitroxynil
what dental diseases need to be checked for in sheep?
broken mouth and uneven molar wear (sharp/painful)
how many incisors do sheep erupt each year?
2 (1 year has 2 incisors… 4 years has 8 incisors)
what is examined externally when doing a sheep dental exam?
jaw, lymph nodes, face, halitosis, pain
what possible infections can sheep get in their mouth/pharynx?
Fusobacterium necrophorum - necrotic stomatitis
Actinobacillosis lignerisei (facial abscess) - wooden tongue
Caseous lymphadenitis
what is a common cause of pharyngeal trauma?
dosing gun injuries
what are the clinical signs of pharyngeal trauma due to dosing gun injuries?
dull, depressed, inappetent, halitosis, pain, cellulitiis
what does Johnes cause?
weight loss, ewe mortality, poor performance
what causes Johnes?
Mycobacterium avian paratuberculosis
how is Mycobacterium avian paratuberculosis spread?
faeces, colostrum, milk, in utero
what is the key risk period for infection of Johnes disease?
first 3-4 months of life
where does Mycobacterium avian paratuberculosis replicate in the body?
GI lymph nodes and gut
what age do sheep usually show signs of clinical Johnes?
3-4 years old
what pathology does Johnes cause?
cellular infiltration and thickening of intestines leads to malabsorption and protein losing enteropathy causing hypoalbuminaemia
what are the classic clinical signs of Johnes disease?
weight loss, anaemia, bottle jaw, high parasite burden
why is Johnes diagnosis difficult?
tests have a low sensitivity
intermittently shed
many animals subclinically infected
what is found on post mortem of sheep with johnes disease?
enlarged distal mesenteric lymph node
histopathology at ileocaecal junction
what tests are available for johnes?
serology ELISA antibody
PCR test faeces
faecal culture
how are flock screening tests carried out for johnes?
older thinner ewes selected and PCR faecal antigen is carried out along with culture
post mortems of older thinner cull ewes
what are the benefits of the johnes vaccine?
reduces clinical cases and excretion of bacteria (doesn’t prevent infection)
when is the johnes vaccine given to sheep?
4-16 weeks old then repeated annually
what is red gut?
torsion of intestines caused by sudden introduction of lush pasture legume diet (often found dead)
what are the common respiratory diseases of adult sheep?
chronic suppurative pneumonia
maedi visna
ovine pulmonary adenomatosis
laryngeal chondritis
Mannhaemia haemolytica
what causes ovine pulmonary adenomatosis?
a retrovirus
how is ovine pulmonary adenomatosis spread?
aerosols, lung fluid, milk, colostrum
why is ovine pulmonary adenomatosis an iceberg disease?
incubation period of 2-4 years (lot of sheep effected before clinical signs are seen
what are the clinical signs of ovine pulmonary adenomatosis?
older thin sheep that have increased respiratory rate and exercise intolerance
sudden death
how is ovine pulmonary adenomatosis diagnosed?
clinical signs and crackles/wheeze on lungs
ultrasound lung consolidation
wheelbarrow test (controversial)
what is done if there is a positive result on a wheelbarrow test?
euthansia
what is done to treat ovine pulmonary adenomatosis?
no treatment
what causes maedi visna?
lentivirus
what are the two forms of maedi visna?
maedi (chronic respiratory and mastitic disease)
visna (neurological)
why is maedi visna an iceberg disease?
slow progressive disease (long incubation)
how is maedi visna transmitted?
milk, colostrum, lung discharge from mothers
how is maedi visna transmitted?
milk, colostrum, lung discharge from mothers
what are the clinical signs of respiratory maedi visna?
weight loss
increased respiratory effort
exercise intolerance
what are the clinical signs of neurological maedi visna?
weight loss
abnormal gait, ataxia, paralysis
circling, head tremor…
(much less common)
how is maedi visna controlled?
test and cull (good test available)
what is the main bacteria causing chronic suppurative pneumonia?
Trueperella pyogenes
what are the clinical signs of chronic suppurative pneumonia?
chronic weight loss
increased respiratory effort
cough
nasal discharge
pyrexia
what breeds is laryngeal chondritis most commonly seen in?
beltex and texels (rams most commonly)
what is the pathology seen in laryngeal chondritis?
narrow/swollen larynx, nodules, abscesses
why are texels so predisposed to laryngeal chondritis?
shorter larynx and vocal cords are closer and narrows to a funnel
how can laryngeal chondritis be treated?
corticosteroids and broad spectrum antibiotics (penicillin)
temporary tracheostomy
(may never recover or reoccur)
what is pink eye also known as?
ovine infectious keratoconjunctivitis
what causes ovine infectious keratoconjuntivitis?
Mycoplasma conjunctivae
how can ovine infectious keratoconjuntivitis be treated?
isolate sheep and remove risk factors
LA oxytetracycline or macrolide
what is anterior uveitis also known as?
silage eye
what causes anterior uveitis?
Listeria monocytogenes
what are the clinical signs of silage eye?
blepharospasm
cloudy cornea
swollen folded iris
material in front of eye chamber
how is silage eye treated?
subconjunctival oxytetracycline and dexamethasone
systemic penicillin
what are the main diseases of the foot associated with lameness?
footrot (scald, interdigital dermatitis)
CODD - contagious ovine digital dermatitis
white line
toe granuloma
foot abscess
how does the foot appear in cases of benign footrot?
interdigital skin inflamed and discharging but there is no separation of the horn
(cheesy smell)
what are some risk factors for benign footrot?
moisture (main one) - both indoors and outdoors
anything causing damage to the skin (frost, thistles…)
warmth
genetic susceptibility
what is the main bacteria associated with benign footrot?
Dichelobacter nodosus
what is a secondary bacteria often isolated from benign footrot cases?
Fusobacterium necrophorum
what is the classic group of sheep that benign footrot is seen in?
growing lambs
what is virulent footrot?
interdigital dermatitis (benign footrot) that progresses to under running of the sole of hoof horn starting medially and progressing laterally
how does virulent footrot present?
grey necrotic pungent smelling horn with interdigital dermatitis
how long does Dichelobacter nodosus survive in the environment?
7 days
is Dichelobacter a opportunistic or obligate pathogen of sheep feet?
opportunistic (found in normal feet)
how is interdigital dermatitis (benign footrot) treated?
topical - oxytetracycline, footbath (formalin, zinc sulphate, disinfectant)
what factors need to be controlled to ensure footbathing sheep is effective?
appropriate exposure (2 minutes)
clean feet prior to bathing
correct concentration and depth
allow feet to dry afterwards (stand on concrete)
how is virulent footrot treated?
isolate lame sheep
LA oxytetracylcine or amoxicillin
macrolides - tilmicosin, gamithromycin
do not trim (unless really necissary)
how is virulent footrot treated?
isolate lame sheep
LA oxytetracylcine or amoxicillin
macrolides - tilmicosin, gamithromycin
do not trim (unless really necessary)
why shouldn’t you trim cases of footrot as a treatment?
delays healing and aids spreading to other sheep
how bad is the lameness caused by CODD?
very severe
how do the feet of sheep with CODD appear?
ulcerative/proliferative lesion that starts at coronary band
progressive underrunning of hoof wall
hoof sloughs off
what is a grade 1 CODD lesion?
just a coronary band lesion
what is a grade 2 CODD lesion?
coronary band lesion with less than 50% of the hoof capsule separated
what is a grade 3 CODD lesion?
50-100% of hoof capsule has sloughed off
is a grade 4CODD lesion?
a healing but still active lesion (still inflamed…)
how extensive is the damage caused by CODD?
very severe inflammation and lameness that can even attack the bone
what bacteria is associated with CODD?
Treponeme (same as digital dermatitis of cattle)
Dichelobacter nodosus and Fusobacterium necrophorum also found
what are the risk factors for CODD?
late summer to early autumn trend
large flock size
moist, lush, lowland pasture
how is CODD treated?
isolate and treat rapidly
LA amoxicillin
macrolides - tilmicosin, gamithromycin…
what is the five point plan for lameness control/management?
vaccinate twice yearly with footvax
treat lame sheep quickly
biosecurity
environmental challenge
cull chronically lame sheep
why is footvax (footrot vaccine) useful?
treats and prevents footrot (and possibly CODD)
what is footvax and vaccine for?
footrot (Dichelobacter nodosus strains)
when should footvax not be used?
prior to shearing or lambing (oily injection site lumps and abortion risk)
if sheep have had recent moxidectin treatment
what is the vaccination protocol for footvax?
initial 2 doses 4-6 weeks apart then 6 monthly boosters
what is the culling advice for lame sheep?
if they have had 2-3 cases of lameness they should be culled
why should chronically lame sheep be culled?
harbour infection in the feet (spreads to flock)
production - less likely to get pregant and rear lambs
welfare
gets rid of genetically susceptible sheep
what is white line disease also known as?
shelly hoof
what is white line disease?
separation at the white line of the hoof
how lame are sheep with white line disease?
only lame if sensitive tissue is effected (impaction wit stones/mud or abscesses)
how is white line disease treated if there is no infection present?
leave and carefully trim area of separation
how is white line disease treated if there is no infection?
leave alone and carefully trim area of separation
how is white line disease treated if an abscess is present?
trim to release pus but avoid sensitive tissue
what is the usual cause of toe granulomas in sheep?
over trimming
how are toe granulomas treated?
local anaesthetic then cut back granulation tissue and cauterise (ensure granuloma removed)
how do sheep with laminitis present?
lame on all four limbs with them all tucked under abdomen
digits warm to the touch
what is the main cause of laminitis in sheep?
high energy or cereal based feed
what causes pedal joint abscess?
extension of interdigital infection into the distal interphalangeal joint structure
often seen secondary to white line abscesses
what are the clinical signs of pedal joint abscess?
severe lameness
foot is swollen
widened interdigital space
purulent discharging sinus tract
how can pedal joint abscesses be treated?
flush and provide antibiotics
digit amputation
what is strawberry footrot?
proliferative scab lesions on distal limb
what is usually the cause of strawberry footrot?
orf and dermatophilus
how is strawberry footrot treated?
move to a dry field/housing and give systematic/topical antibiotics
what is used to diagnose white muscle disease?
raised glutathione peroxidase in blood
what are some infectious causes of arthritis?
neonatal infections (Strep dysgalactiae)
tick pyaemia
Erysipelothrix rhusiopathie
what is the most common joint for degenerative joint disease to occur in?
elbow
what areas can you narrow down a neurological condition to?
cerebrum
cerebellum
vestibular system
brain stem
spinal cord
what are the clinical signs of diffuse damage to the cerebrum?
altered mental state - depressed, hyperexcitable, disorientated
blindness
seizures
opisthotonus - recumbent, extended forelimbs and flexed hindlimbs
what is opisthotonus?
extended forelimbs and flexed hindlimbs (recumbent)
what are some causes of diffuse cerebrum damage?
bacterial meningitis
cerebrocortical necrosis
pregnancy toxaemia
what are the clinical signs of local cerebral damage?
contralateral blindness
circling
proprioceptive deficits
what are some examples of causes of local cerebral damage?
GID cyst
brain abscess
trauma
what are the clinical signs of cerebellar disease?
altered head carriage
ataxia(not weakness)
dysmetria - high stepping
intention tremors
what are some possible causes of cerebellar damage?
congenital - cerebellar hypoplasia
border disease (hairy shakers)
abscesses
what are the clinical signs of vestibular system damage?
head tilt to affected side
loss of balance
circling
falling/rolling to one side
spontaneous nystagmus
what can cause vestibular system damage?
middle earn infection
what are the clinical signs of brainstem damage?
depression
cranial nerve deficits
ipsilateral hemiparesis
what is the main condition that causes brainstem damage?
listeriosis
what are some causes of spinal cord lesions?
spinal abscess (joint ill, tick pyaemia…)
wobblers syndrome
trauma
congenital abnormality
what needs to be determined when examining lambs with neurological conditions?
congenital or acquired
what are some common neurological problem in young lambs?
border disease
congenital swayback
drunken lamb syndrome
bacterial meningitis
tetanus
how are spinal abscesses of young lambs treated?
dexamethasone (1ml/kg)
penicillin - 5 days
what transmits louping ill?
ticks
what are the clinical signs of louping ill?
head pressing
trembling/tremors
nystagmus
lip twitching
louping gait (front and back legs move together)
what are common neurological conditions of older lambs?
CCN - cerebrocortical necrosis
listeriosis
gid
trauma
louping ill (if in tick area)
what causes CCN?
vitamin B1 (thiamine) deficiency
what are the clinical signs of CCN?
dull, disorientated, blind, tremors, recumbency, opisthotonus, convulsions
what is the classic history of a lamb with CCN?
fats growing lamb with a diet change (weaned and ate a lot of concentrates)
how is CCN treated?
vitamin B1 - every 12 hours for 3 days
NSAIDs
what is listeriosis associated with?
feeding poorly preserved silage with soil contamination (mouldy)
what are the clinical signs of listeriosis?
anorexia, depression
unilateral hemiparesis
trigeminal nerve paralysis (salivation and food impaction)
facial nerve paralysis
how is listeriosis treated?
benzylpenicillin or procaine penicillin
dexamethasone
what causes gid?
Taenia multiceps
what are the clinical signs of gid?
circling
unilateral blindness
head tilt
skull softening
how is gid controlled in sheep?
worm dogs every 6 weeks with praziquantel
keep dogs away from sheep carcass
how is pregnancy toxaemia diagnosed?
BOHB levels in blood
(mainly clinical signs)
how is scrapie transmitted?
mother to offspring prenatally, colostrum and milk
birthing fluids and placenta
what are the clinical signs of scrapie?
2-5 years old
skin issues
weight loss
altered mental state (excitable), trembling, high step ataxia, recumbency
what is orf also known as?
contagious pustular dermatitis
what type of virus causes orf?
parapox
what type of lesions are seen with orf?
painful vesicular/proliferative scabby lesions around mouth, head and teats
what is the duration of orf?
4-6 weeks
how if orf transmitted?
contact - usually required damaged skin
what is required for orf to survive the winter?
a carrier animal (doesn’t overwinter)
how is orf controlled?
isolate clinical cases
thorough cleaning/biosecurity
no treatment (secondary infection antibiotics)
vaccine
when is the orf vaccine used?
only on infected farms
why does orf need to be confirmed on the farm before vaccination?
it is a live vaccine so will infect the sheep if uninfected
how is the orf vaccine applied?
scratching skin (these scabs will be infection so put in armpit where they won’t likely touch other animals/farmer)
what are the main mites effecting sheep?
Psoroptes ovis
Chorioptes bovis
Trombiculus
what is the main louse effecting sheep?
Bovicola ovis
what tick species effect sheep?
Ixodes ricinus
Haemaphyllis punctuata
what does Psorptes ovis cause?
sheep scab
what type of reaction causes sheep scab?
allergic reaction to the mites
what are the clinical signs of sheep scab?
wool loss, ragged moist yellow fleece, kicking/rubbing, weight loss
where should you sample for Psorptes ovis?
edge of lesion (on the worst sheep)
how is sheep scab diagnosed?
wool pluck and skin scrape
ELISA
what are the morphological features of Psorptes ovis?
pointed mouth parts and bell shaped suckers
how is sheep scab treated?
treat all sheep with organophosphate dip (diazinon)
why is reinfection of sheep scab seen after treatment?
mites survive 19 days off the host
what are some possible treatment options for sheep scab?
organophosphates (diazanon)
macrocylic lactones (ivermectin, doramectin…)
how can sheep scab be prevented?
biosecurity (treat all bought in sheep)
double fence neighbouring stock
cleaning equipment
where is chorioptes bovis found on the sheep?
ventral abdomen and scrotum
what is used to treat Chorioptes bovis?
organophosphates
what type of louse is Bovicola ovis?
chewing
what can be done to treat lice?
shearing
synthetic pyrethroids and organophosphates
when does fly strike occur?
May to October
what flies cause fly strike?
Lucilia sericata
what is the pathogenesis of Lucilia sericata that causes fly strike?
lay eggs that hatch in about 12 hours that release proteolytic enzymes and hook onto the skin using their mouth causing damage
the smell also attracts other flies causing rapid multiplication
what is the most common risk factor for fly strike?
faecal soiling (lush grass causing SARA) in warm wet weather
what is used to treat fly strike?
synthetic pyrethroids (kills maggots)
clean and trim
house
address other risk factors
how can fly strike be prevented/controlled?
tail docking
dagging
shearning
worm control
prophylactic treatment
what products can be used for fly strike control/prevention?
organophosphate dips
pyrethroid pour ons
insect growth regulators
what is the headfly called?
Hydrotea irritans
when does Hydrotea irritans cause the most problems?
when a flock has eye disease - they feed on ocular discharge spreading the disease through the flock (mainly a nuisance fly)
what causes ovine sweet itch?
hypersensitivity to midges (mainly thin places of skin)
what causes peri-orbital eczema?
Staphylococcus aureus
how is peri-orbital eczema spread?
spread through contact (feed troughs…)
how is peri-orbital eczema treated?
penicillin
what causes lumpy wool?
Dermatophilus congolensi
what are the risk factors for Dermatophillus congolensi causing lumpy wool?
wet conditions after shearing
thin wooled breeds
what are the clinical signs of Dermatophillus congolensi?
crusty lesions with wool loss
pruritis
(fly strike)
how is Dermatophillus congolensi treated?
penicillin
what causes caseous lymphadenitis?
Corynebacterium pseudotuberculosis
what is the mopst common lymph node to find caseous lymphadenitis?
parotid
how is caseous lymphadenitis spread?
close contact
fomites (shearing…)
respiratory pathway
what conditions is needed for a tick to feed?
above 85% humidity and 7 degrees
what are the main UK tick born diseases?
tick borne fever
tick pyaemia
louping ill (neurological)
Q fever
(babesiosis in cattle and lyme disease not in sheep)
what causes tick borne fever?
Anaplasma phagocytophilia
what is the effect of tick borne fever?
profound immunosuppression (gateway for other diseases)
fever - abortion and infertility (rams)
is there any immunity to tick borne fever?
yes - with age
what can be done to control louping ill in areas where it is common?
vaccinate
what are the four most common plant poisonings of sheep?
yew
acorn
laurel
rhododendron
what causes pneumonic pasturellosis?
Mannheimia haemolytica
what is used to treat pneumonic pasteurellosis?
LA oxytetracycline or amoxicillin
how can pasturellosis be controlled?
vaccination (reduces severity)
control risk factors
what causes systemic pasteurllosis?
Biebersteina trahalosi
what age lambs are generally effected by systemic pasturellosis?
6-10 months of age
what are risk factors for systemic pasturellosis?
change of grazing
change of weather
concurrent disease
stress (handling…)
what is used to treat systemic pasturellosis?
LA oxytetracycline
wherre are clostridial bacteria found?
farm environment - soil, guts, surfaces…
what are clostridial disease risk factors?
poor hygiene
endoparasites
wounds/trauma/injury
changes to diet
what causes lamb dysentery?
Clostridium perfingens type B
what aged lambs are effected by lamb dysentery?
under 3 weeks old
what are the main clinical signs of lamb dysentery?
water profuse diarrhoea with blood in
severe abdominal pain
what are the main findings on post mortem of a lamb with Clostridium perfingens type B?
haemorrhagic enteritis
blood stained fluid in abdominal cavity and pericardium
what causes pulpy kidney?
Clostridium perfingens type D
what age lambs in pulpy kidney seen in?
4-10 weeks old or 6 months plus
what is a major risk factor for pulpy kidney disease?
high concentrate diet (creep fed)
what does Clostridium sordelli cause?
abomasitis and toxaemia
what sheep is Clostridium sordelli seen to cause disease?
intensively reared concentrate fed 4-10 week old lambs
what causes tetanus?
Clostrium tetani
what are the clinical signs of tetanus?
stiffness, opisthotonus, recumbency, death
what causes braxy?
Clostridium septicum
what are the risk factors for braxy?
autumn/winter - frosty root crops
what causes blacks disease?
Clostridium novyi type B
what is blacks disease often secondary to?
fluke
what are the findings of blacks disease on post mortem?
blood stained fluid in body cavity
necrotic liver
fluke
when should a vaccination course for clostridial disease be started?
3 weeks old (given to ewe 4 weeks before lambing)
what notifiable diseases have been seen in UK sheep?
anthrax
blue tongue
contagious agalactiae
foot and mouth disease
scrapie
what causes anthrax?
Bacillus anthracis
what are the main clinical signs of foot and mouth in sheep?
lameness, blisters on tongue
what are the clinical signs of blue tongue?
fever, mouth ulcers, swelling of head/neck and lameness
what are the clinical signs of contagious agalactia?
mastitis, arthritis, keratoconjunctivitis, abortion
what causes contagious agalactia?
Mycoplasma agalactiae
what are the advantages of a flock health plan?
required for farm assurance schemes
up to date advise for farmer
improves client relationships
improved welfare standards
what are good times of year to do a flock health plan?
summer (weaning) - pre-tupping
pre-lambing (winter)
what are some KPIs for sheep flocks?
scanning %
lambing % (born alive, weaned, sold)
ewe mortality
replacement rate
ewe:tup ratio
lambing mortality (scanning, birth…)
how are KPIs used?
compare to industry standard
compare to farms own goals
what are the main principles of a biosecurity plan on a flock health review?
impossible to have zero risk
business/farm aims discussed
identify the disease the flocks at risk of getting
identify current flock disease status
assess risk of disease introduction
quantify the risk
devise control measures
