Small Ruminants Flashcards
What is the farmer really seeing?
* Pulled wool, which means itchy sheep
A- Lice (signs of pulled wool)
B- Fleece rot
C- Lumpy wool
D- Scours
C
* could be grass seeds, broken vegetable matter, lice (is it moving?)
C
**sucking lice vs. biting lice– biting lice feeding off scurf, not blood– therefore ensure proper treatment
** E– (D do not need to treat sheep that cannot get into direct contact with infected mob)… it is a temporary treatment to prevent ongoing losses/damage to wool
* if you want to get rid of lice you have to apply a chemical toa all sheep on the farm at some point
B- possible, C- possible, D- not all lice products kill lice immediately– usually a number of weeks
A- Avenge- relatively new product very effective
B- Cypermethrin- resistance is common, not worth anything
C- Diflubenzuron- IGR- resistance is common
D- Diazinon- Eureka Gold- very effective anti-lice treatment but super toxic, operator hazard, still used as a dipping fluid
E- Spinosad- no withholding period- can be used off shears– less potent chemical, so not very effective on lice
A- read the label
B- reasonable especially if we don’t know what was used
E-** show me how you did it
Investigation you would conduct?
- History– what information do you seek?
- Clinical examination of sheep
- Additional testing– what samples could/should you take? Not practically necessary to take a sample to know bacterial spp involved in secondary infection– broad spectrum AMs, different part of the world– invasion of new world screw worm fly?? Not in Southern Australia.
- Determine risk factors for disease occurrence: scouring, pizzle strike in whethers from pizzle rot, last shearing, breed, existing prevention, what chemical have you used so far if any & how did you use it
- What treatment now and what future prevention? Broad spectrum AMs, change chemicals or apply properly
What species other than sheep can get Bovicola ovis?
Goats
Short wool with prelambing treatment in June or July in case flies turn up in spring. Normally nice dry summer, does not generally treat in February for flies. Cross bred sheep, ewes, body strike. Other risk factors?
Fleece rot, Dermo, unseasonably wet conditions in the summer (often just from shear number of flies)
A (+/- with body strike), B, C, E, F
A- compeling reasons to shear now or B
C or D- IGRs do not kill maggots… not Dicyclanil (Clik) because of wool harvest interval– because it is long– 3 months
Routine protection for body strike and breech strike going into spring season which is normally fly season
December shorn sheep…. DDX?
Dermo, itch mite, (ked), Bovicola ovis infestation, (not sheep pox in AUS), (not fleece rot as not itchy), (sheep scab exotic, so maybe in Scotland)
Pink eye
* Sporadic, often self-limiting if just a few cases
* Consider whether it is worth yarding the mob or not
* Organisms are typically Chlamydophila or Mycoplasma
* Not as strongly seasonal as cattle disease
* Grazing around spikey plants can contribue to the condition
* Tx: Parenteral oxytetracycling
** DDX: FBs especially barley grass seeds
When is there routine pregnancy diagnosis in mares, cows, and sheep?
* Mare: day 14
* Cow: day 28
* Sheep: day 75
When might ewes be in anoestrus?
* Haven’t reach puberty yet either due to being too young or too lightweight
* Have reach puberty but too low bodyweight/CS
* Wrong time of year- short-day breeders (less seasonal breeders can be induced with ram effect)
* Some toxins affect reproductive hormones and suppress oestrus (e.g. coumestans from lucerne/ white clover)
If ewes are old enough, right season, and no toxins… what is the largest factor on fertility?
Condition score aim for 3 at mating and lambing
** Short-term increased protein intake pre-mating
For Merinos: Extra 1 CS (7-10 kg bodyweight)= extra 10-20% lambs born
When may rams not inseminate ewes?
* Poor libido
* Balanoposthitis (knob rot)
* Musculoskeletal problems
* 5 T’s: Teeth, torso, toes, tossle, testes
* Poor sperm output (not enough testis- size)
* Poor semen quality (heat: fever, scrotal mange; orchitis)
How do you interpret failure of fertilization in a ewe who returns to service? Who doesn’t return to service?
* Returns to service: something impairs sperm fertilizing egg but doesn’t disrupt normal oestrus cycle e.g. oestrogenic clover, mating young ewes
* Does not return to service: Pregnancy loss after maternal recognition of pregnancy, mating period coincides with beginning or end of normal breeding season, oestrus may cease if ewes are under severe nutritional stress
What does Campvax protect against?
Campylobacter fetus subsp fetus and C. jejuni
What is a common cause of failed fertilization due to bacterial disease? What does it cause? How does it spread? What do you do to the flock?
Brucella ovis– mainly male infertility… epididymis & testicular granulomas, ewe abortions rare
* Homosexual spread mechanical between male to male
*Lifelong infection, need to eradicate– cull and replace from accredited flock OR test and slaughter– serology 2-3 weeks apart
What are some signs of oestrogenic clover disease? Cause? Diagnosis?
* Signs: more older dry ewes, increased teat length, precocious lactation, enlarged genitalia in wethers and dry ewes, vaginal or uterine prolapse
* Caused by phytoestrogens– impaired sperm transport or chronic uterine change
* Diagnosis: identify clover, wether teat length assay, uterine histopathology
* Treatment: avoid risk pastures near joining, cull at younger age, graze cattle, reduce stocking rate to increase grass and decrease clover, pasture renovation
Common causes of embryonic or foetal loss in small ruminants and when in gestation
Onion grass poisoning can cause early abortion
* toxin from fungus growing on grass
* Can cause neurological signs as well (staggers) in adults
Why campylobacter is transmitted through ewe or doe mob
Campylobacter foetal liver
Campylobacter abortion placentitis
Listeria abortion
Toxoplasma focal cotyledon lesions
What is pregnancy rate? Conception rate? Lambing rate? Marking rate? Weaning rate?
When is the onset of puberty in sheep? Goats? Cycle length in sheep and goats?
A few examples of sheep and goats and their duration of breeding season (months)? Progeny? Gestation length?
Alpaca what kind of ovulation? When do they reach puberty? When are they bred?
* Induced ovulators
* Urinary hormones indicate ovarian activity from 6 months of age
* But aim for 65% of mature body weight (Australian conditions about 1 year)
How big are alpaca ovaries?
Ovaries are the size of a peanut when no structures present
When is the CL seen in an alpaca?
Because they are induced ovulators, only see a CL after mating
Simple explanation of what synthetic melatonin does? Ovastim vaccination? PGF2alpha? Glucocorticoids?
How does ovarian function tie in with sexual behaviour?
As follicles grow, increase in oestrogen–> sexual receptivity
* Non seasonal breeders so ovarian follicular activity occurs all year. Follicle waves continue during lactation and early pregnancy (up to 6 months gestation)
Where do alpacas deposit semen?
Inside the uterus
When are alpaca males fertile?
All males should be fertile (able to exteriorize the penis) by 3 yo, 10% at 1 year, 60-80% at 2 years
** Aim is 18 months, culled if not fertile by 3
Semen characteristics of alpacas? Size of testes where we would expect the male is fertile?
Vast variation in semen quality across different males
* testes > 4 cm
What does it mean if the female spits?
Active CL on the ovary (Progesterone levels are high) and throughout pregnancy
What is the ram effect? When do you use it?
* Use it in natural breeding, paddock mating situation
How do you induce cycling in less seasonal breeds e.g. Merinos out of season– how??
Using Regulin (melatonin) +/- teasers
What males can be used as teaser rams/ bucks?
Vasectomized disadvantages: get them mixed up, expensive to get the vasectomy, creates permanent teaser that you’ll have for several years, vas can re-canalise and animal becomes fertile again
Advantages and disadvantages of regulin?
* Increases ovulation rate
* Relatively expensive, need to separate ewes > 6 weeks before joining, reduced fertility if mating is delayed
** You have to commit, if you miss your window, the ewes will be in profound anoestrous afterwards
Gestation length of an alpaca?
342 days but a huge range 300-380
What do alpacas deliver first?
Head first
Rule of thumb for when to intervene in an cria birth? How long does it take for a cria to attempt to stand?
* never let the sunset on an alpaca giving birth (normally give birth between 7am-2pm)
* cria should be attempting to stand within an hour
Difference in feed in late pregnancy between twinning and triplet bearing ewes? At lambing CS, grazing?
Below what percentage will the flock no long be self replacing?
65%
How does conception rate increase with ewe bodyweight?
* + 1 kg = to approx 0.5% (maiden ewes) to + 1.5 - 3% (mature ewes) more labms
Progesterone source during pregnancy in sheep? Goats?
* Sheep- CL only d 0-75. Also from placenta from d 50-75 onwards
* Goats- CL only d 0-150
Effect of photoperiod in ewe and doe?
* Day length decreases–> melatonin secretion by pineal gland–> increase GnRH from hypothalamus–> increase FSH from anterior pituitary (released in waves stimulates the primordial ovarian follicle growth and maturation to Graafian follicle–> develops to ova and also produces and releases oestrogen–> oestrogen increase stimulates more FSH release–> increases frequency and concentration of LH–> stimulates sexual behaviour (needs brain to have been primed by previous exposure to progesterone) and reproductive tract changes
Cause of Enzootic posthitis/ balanoposthitis (pizzle rot) in wethers?
Cause of scrotal mange in rams? Consequences? Treatment?
Chorioptes bovis
Progesterones impact on the reproductive cycle
* Progesterone acts as a negative feedback on the hypothalamus and the pituitary gland–> inhibits GnRH and FSH release/ stimulates continued LH production–> stimulates thecal cells to maintain progesterone production. Progesterone promotes uterine recognition of pregnancy and embryonic implantation.
Control and eradication of Brucella ovis in ram flocks? Accreditation?
What is Ovastim/ Fecundin?
* Used to increase number of twins & triplets
* Protein conjugated onto an ovarian steroid- presence of protein induces an immune response against the steroid, normally the steroid has a negative feedback effect on the hypothalamus, reducing FSH and LH secretion, antibodies to the steroid prevent it having this inhibitory effect on the hypothalamic- pituitary axis–> FSH and LH secretion is greater–> more follicles are stimulated
* Need two initial doses: 2 months & 1 month before joining and annual boosters
* Not widely used because erratic results– neonatal mortality– ewes must be in good body condition (separate twin-lambers from dry and single lambers??)
** works better in non-Merinos (better mothers, fatter)
What is Regulin?
* Synthetic melatonin
* Slow release SQ melatonin used to bring seasonal breeds into oestrus +/- teasers
* e.g. use for Oct-Dec joining in Merinos, Coopworths, 1st cross ewes (not Border Leicester and other strong seasonal breeders)
* Implant 30-40 days before mating start date
** MUST separate rams from ewes for 6 weeks pre-mating e.g. ram effect is important too
What happens if you give Prostaglandin F2alpha to sheep or goats?
* Effective after day 5 after ovulation– luteolytic for hastening return to oestrus after ovulation or terminating pregnancy
** Sheep- effective to d 50 of pregnancy…. goats effective throughout pregnancy
* Oestrus 2-3 days later
* Can use to synchronise ewes/does but not reliable enough for fixed time AI
What is dexamethasone isonicotinate (Voren) IM used for in sheep?
* Inducing parturition in the last 10 days of pregnancy
Can you use teaser rams prior to AI?
No because you cannot tell specifically when the sheep ovulated. Sheep just do not show obvious enough behaviour
Advantages and disadvantages of testosterone to use on mature wethers to induce male sexual behaviour to be teasers?
* Need several injections of a monitored pharmaceutical that is illegal in some jurisdictions– testosterone is one of a handful of chemicals that is specifically prohibited from being used off-label (e.g. the only registered use for testosterone for sheep is to treat/ prevent pizzle rot in wethers)
Why would you try to breed out of season? When is lambing “out of season”? Disadvantages?
* Chasing apparent profit in Southern Australia, helpful elsewhere in the world– clients may still want this even if you try to talk them out of it
* Autumn lambing
* Would spend money on supplementary feed
Timetable for laparoscopic AI in sheep
When is optimum time of year in Australia for lambing? How long? When do you mate? What is different about about merinos?
Late winter to spring in Australia which fits with natural mating patterns
** Compact mating and lambing– over 5-6 weeks optimally
** Sooo mate in autumn to give birth in spring
* Merinos- can mate any time of year but spring joining period has to be longer (e.g. 8 weeks) to get all ewes pregnant, because not all ewes cycle regularly, 17 day cycles when ram is introduced (whereas, non-Merino breeds e.g. Suffolk, Romney Marsh are more seasonally oestrus than Merinos and ewes will tend to only display oestrus in late- summer onwards)
Who is most impacted by clinical mastitis in the sheep world? Most common causes?
Terminal sires 5% (ewes which are bred to provide lambs for meat), first cross next about 2%, merino- 1 or 2%
Diagnosis of mastitis in small ruminants
Samples for aetiological diagnosis and sensitivity
Consequences of black mastitis
Most common pathogens associated with sub clinical mastitis in sheep? At what cell count do we start to get worried for mastitis in sheep?
Staphylococcus and Streptococcus
500,000- 1,000,000 cell count start to get worried… however extremely variable
(Can cause lowered lamb production due to mastitis)
What can we do about mastitis problems in sheep flocks?
Genetic selection longer term (teat placement, udder depth, degree of separation)– deep udder but not too close to the ground
** Currently: antibiotic: IM, intramammary (lactation vs. drying off, think about withdrawal period), registration
* Anti-inflammatory
Background influences on male reproduction to be considered?
* Age- puberty, sexual maturity, senescence old age
* Mgt: time of joining, length of joining, handling at mating, male to female ratios, sperm per dose in AI, handling semen in AI
* Nutrition (leptin can have an effect on gonadotropin hormones)
* Social interactions- rearing rams
* 10 % of rams show little interest in ewes
* Environment factors
* Pollutants, predators
Clinical signs of body lice
* Rubbing
* fleece derangement- cotting, tassels, colour, wool on fences
* Losses of fleece weight (up to 1 kg clean), discounts due to cotting and colour- can decrease fleece value by 20%
Short wool dipping options for treating lice
* Considerations when dipping sheep to prevent body lice
* Dip between 10 days and 4 weeks off shears
* Use a disinfectant (e.g. Hibitane)
* Use zinc sulphate heptahydrate 1% (preventing Dermatophilus, important– recall his story about powerful sheep owner wanting to sue company that did not add zinc sulphate)
* Vaccinate with 6 in 1
* Dip young sheep first
Options for short-wool backliners/ pour-ons treatment of body lice in sheep
Body lice treatment: long wool options (jetting fluids & backliners)
Considerations with hand jetting (treating for body lice)
What are the common foot lice in sheep in Australia?
Linognathus pedalis
Face lice in sheep? Treatment?
Treatment same as foot lice– closantel and MLs (ivermectin, moxidectin)
Where does it affect the sheep? Transmission?
Chorioptes bovis
* Affects lower legs, scrotum, udder, poll
* Transmission by direct contact (joining, suckling) and pick up from pasture
Chorioptic mange clinical signs
* Pustules, yellowish crusts
* Skin thickening
* Irritation leading to rubbing and biting
* May affect fertility (look for mange as part of pre-joining exam)
* Unusual gait
* Confirm diagnosis with scrapings
Sheep scab clinical signs
* Similar to chorioptic mange but more severe
* Mites puncture epidermis and feed on lymph
* Papules/ pustules with yellow exudate, leading to large scabs
* Irritation leading to rubbing and biting, bleeding, more scabs
* Fleece damage and shedding
* Sheep may lose condition and die
And epi?
* Very rare if not eradicated
* Cool, wet climates
* Poor environmental survival (few days)
* shearing time determines population curve
* persist in protected areas like neck folds after shearing
* transmission by direct contact
* Numbers highest in young sheep
Primary fly strikes? Secondary fly strikes?
* Primary strike flies:
- Lucilia cuprina (most imp.)
- Calliphora spp. (brown blowflies- 5-10% of primary strikes)
* Secondary strike flies:
- Calliphora spp.
- Chrysomya rufifacies (hairy maggot blowfly)
Blowfly life cycle
Blowfly epidemiology
* Flystrike requires flies and susceptible sheep
* Flies breed when temps > 17C and wind speed
* Sheep are susceptible due to moisture: from excreta, exudate, rain, dip
*Often medium-strong wool sheep in high rainfall areas
* Dermo, fleece rot predisposes
* Long woolin the fly season can increase risk
* Brown blowflies cope well with the cold and are the first to emerge in spring
What are the animal welfare standards and guidelines for sheep in regards to mulesing?
What is meant by surgical modification (not mulesing) to prevent blowfly strike in sheep?
* Four clips required for each lamg: two breech clips, two tail clips
* Must be applied by an accredited contractor
* Clips are removed after 8 - 14 days and can be re-used at least once
* Not as effective as mulesing, but some effect
Blowflies chemical prevention jetting and backliners
** Dicyclanil (Clik)- cost depends on where they are treating breech vs. body
What is meant by early jetting to prevent flystrike?
Aetiology? Pathogenesis? Clinical Signs?
What is the significance of fleece rot?
Some stain does not scour and therefore devalues the wool
BUT fleece rot is a very important predisposing factor in body blowfly strike
Fleece rot treatment and prevention?
Clinical signs
Dermatophilosis
* Active lesions on wool-producing skin show inflammation leading to exudate which forms a crust and mats the wool fibres, initially at skin level
* Chronic lesions present as scabs or mats of dried exudate grow out with the fleece, few mm to several cm
* Lesions on non-wooled areas are small plaques
* Severe generalized dermo may be seen in young sheep
Key points of dermatophilosis
Key points in fleece rot
Strawberry footrot
Dermatophilosis of the legs
Common in winter with persistent wetting
Weaners and hoggest most susceptible
What is it? Pathogenesis?
Scabby mount (contagious echyma, contagious pustular dermatitis, orf, scabby leg)
* Caused by parapoxivirus
* Infection requires a break in the epithelium
* Small hyperaemic foci develop within 7 days, vesicle forms and bursts, scabs left in areas other than the oral mucosa
* Lesions and disease usually resolve within 3 weeks
What is this? Clinical signs?
Actinobacillosis
* Leather lips
* Actinobacillus lignieresii
* Occasionally causes problems when sheep are on coarse dry feed in late autumn and summer
*
* Areas affected include the lips, face, nose, lower jaw, lower neck and rarely the tongue
* Lesion maybe superficial or a deep honeycomb of small abscesses beneath the skin, often discharging sinuses with yellow-green pus
What is it? Clinical signs?
* Very common on older sheep
* Occur on 2 major exposed areas: vulva, anus, tail and bare mulesed skin and face, planum, lips and especially the ears
* Prevalence influenced by age: 1% typical but can be > 20 % SCC in sheep older tahn 5 years
* SCCs of the perineal region are usually associated with mulesing- trauma to the skin may be a risk factor
Aetiology? Epidemiology?
* Hepatogenous photosensitisation caused by ingestion of the fungal toxin sporidesmin, produced by Pithomyces chartarum
* Fungus is present all year round but requires most warm conditions to multiply sufficiently- late summer/autumn- minimum temps > 15C for 72 hours
* Two growht episodes of 3 days within 3 weeks are usually required for outbreaks of disease
* Fungus prefers freshly dead perennial rye grass with most spores on the bottom 25 mm
* Annual pastures are less dangers
* Suitable conditions can occur after a false break
* OUtbreaks in summer/autumn (e.g. Gippsland February to April)
Clinical signs of Facial eczema
* Serous weeping of the skin as it becomes necrotic and progresses from crusty to black and eventually sloughs leaving raw areas of skin
* Jaundice +/-
* many animals slowly recover but many have permanent liver damage
Treatment of facial eczema
Prevention of facial eczema
* Controlled release capsul available in NZ: 6 weeks protection
* Select for resistance in NZ– highly heritable h^2 = 0.42
* Rams injected with prescribed level of sporodesmin and GGT response measured
What causes lupinosis?
* Caused by phomopsis fungus which grows on lupin stubbles
* Lupin stubbles can provide very good nutrition, supplying about 2-300 kg/Ha of grain
* Under moist warm conditions the fungus proliferates and produces a stable hepatotoxin
* Affected paddocks are dangerous until fresh growth is created
Clinical signs of lupinosis
* Go off feed and isolate themselves from the mob
* Photosensitisation and jaundice may be seen
* Deaths can occur within 3 days
* Sheep that recover often fail to thrive
Diagnosis of lupinosis?
* Based on clinical signs, history and PM findings of acute to chronic liver damage
* Recently shorn, fat sheep (
* Subcutaneous fat on backline heats up
* Hard, black skin after a few days, sloughs, heals over several weeks
* Antibiotics and a fly preventive may be useful
Significance of grass seeds with sheep
* Barley grass, spear grass and corkscrew are the major offenders in southern Australia
* Can affect lamb growth rates
* Seeds are unsightly and publicly unaccetable in meat cuts- heavy carcase contamination can cause downgrading due to heavy trimming
* Mostly a problem in sheep with long wool
* Shear before problem grasses set seed
* Young sheep are of greatest risk, so keep them out of affected paddocks
* Spray graze
* Renovate pastures to displace problem species
Clinical signs that make us think respiratory disease
Risk factors for respiratory disease
URT Diseases in sheep
Lower respiratory tract diseases in sheep
Pneumonia causative organisms in sheep, treatment/prevention?
Pleural/superficial pulmonary abscesses in sheep
Cheesy gland in sheep
CAE Key disease features
CAE diagnosis and certification
CAE Control & Eradication
What important exotic diseases can present with respiratory signs?
