Diseases of the Peri Parturient Ewe 2

What percentage of ewe deaths occur around the lambing period? What is the annual mortality rate target?

• 75%

• Annual target: 1-3%

What are the different options for approach to dystocia?

• Vaginal delivery

• Caesarian

• Embryotomy

• Euthanasia

How is a simple embryotomy performed?

• Forelimbs removed

  • Cur through skin round leg above carpus then up towards elbow

  • Undermine attachment should to chest wall

  • Pull leg off

• Use a lot of lubrication

What are indication for a C section in a ewe?

• Over sized lamb

• Ringwomb

• Vaginal Prolapse

• Foetal monster

• Malpresentation

What are the contraindications for a c section?

• Rotten lamb/ smelly fluids unless can exteriorise uterus

  • Embryotomy or euthanasia best

In what position is a c section performed?

• Lateral recumbency- left side up

What are the options for c -section anaesthesia?

• Local infiltration procaine (40ml total)

• Inverted L block

• Paravertebral - 5 ml procaine per site

• Plus sacrococcygeal epidural for analgesia and straining reduction

What is the incision site for a c section in a ewe?

• 10-15 cm below midpoint between last rib and wing of ileum

• 15cm invision

Green line most common approach^

Outline how a c section is performed

• Cut through skin, sub cut tissues then use scissors to incise EAO, then lift transverse muscle before incising so don't puncture rumen

• Grasp uterine horn and exteriorise

• Incise 10-12cm

• Remove lamb

• Check for another

• Close wound

Explain how you would close a wound in a c section?

• Continuous inverting (usually using cat gut) to suture uterus, check for leakage and replace

• Peritoneum and transverse internal and external oblique (one or two layers) simple continuous cat gut

• Skin forward inter locking simple interruptued, nylon

What is very important to do after a c section?

Feed lambs

What bacteria causes metritis in ewes?

Opportunistic environmental bacteria including clostridium tetani

What can cause metritis in ewes?

• Dystocia

  • Poor hygiene

  • Dead lambs

• Post abortion

What are the clinical signs of metritis?

• Dull, depressed, recumbant

• Toxaemia congested mucous membranes

• Red/brown or purulent vaginal discharge

How is metritis treated and prevented?

• Antibiotics (e.g.- IV oxytetracycline) NSAIDs

• Guarded prognosis

• May affect milk production monitor lambs

• Prevention- review hygiene measures, dystocia mangement, environmental hygiene, clostridial vaccination

When is vaginal prolapse common?

Last 4 weeks of pregancy (1-2%)

What are the causes of vaginal prolapse?

Not one cause- following can contribute:

• Age

• Litter size

• Prolific breeds> hill breeds

• 35-40% will re-prolapse

• Nutritional factors- obesity, bulky feed, hypocal, lack of trough spaces

• Stocking rates

How can you treat mild and uncomplicated vaginal prolapses?

• Retention devices

  

• Harnesses

  

• NSAIDS

• LA antibiotic

What are the limitations of retention devices for vaginal prolapse?

• Discomfort

• Irritation mucosa

• Secondary infection

How is a vaginal prolapse treated surgically?

• Epidural anaesthesia

• NSAIDS and antibiotics

• Clean and assess- chlorhex

• Replace prolapse- gentle palm of hand, raise back end of ewe

• Suture

• Mark ewe, remove sutures before lambing

Explain how you would perform an epidural on a sheep with a prolapse?

• Sacrococcygeal or 1st intercoccygeal space

• Give 1.75 ml 2% procaine for short action

• Or 1.75 ml procaine + 0.25ml 2% xylazine for longer action (24h+)

How would you place a suture for a vaginal prolapse?

• Obstetrical tape

• Purse string (leave 1.5cm opening)

• Buhner

If a ewe is prolapsing whilst lambing what should you do?

Caesarian

What are some complication of vaginal prolapse? How would you remediate this?

Rectal prolapse

• Replace and epidural, purse string suture

How are prolapses prevented?

• Review and address farm risk factors

• Cull

  • Inc risk reprolapse

  • Put harness on before prolapse occurs next pregnancy

What is being shown here?

• Intestinal prolapse through vaginal wall due to tear

  • Euthanase if seen alive

How is uterine prolapse treated?

• Epidural

• Clean

• Remove or trim placenta

• Replace carefully and ensure fully inverted

• Suture

• Antibiotics and NSAIDs

How would you treat a cervical prolpase post lambing?

• Treat as vaginal pre lambing

• Mark for culling

What is the typical prevalance of mastitis in a flock?

4-5%

What are the three main clinical presentations of mastitis in ewes?

• Peracute/gangrenous/ toxic mastitis

• Acute mastitis

• Chronic mastitis

When does peracute/ gangrenous mastitis commonly occur?

• Often 4-8 weeks post lambing when ewe is in peak lactation

  • Can occur immediately post lambing

What are the clinical signs of per acute/ gangrenous mastitis?

• Ewe sick, toxaemia, tachycardia, rumen stasis, inappetant, lame, recumbent

• Lambs hungry

• Udder swollen, cold blue, clear boundary between diseased and healthy tissue, well eventually slough

• Milk severely discoloured

When does acute mastitis most commonly occur?

• Immediately post lambing or often 4-8 weeks when ewe is in peak lactation

What are the clinical signs of acute mastitis?

• Ewe fevere, lame, lambs hungry

• Udder red, painful, swolllen

• Milk abnormal appearance, discoloured, clots, watery

  

When is chronic mastitis often detected?

• When ewe is dry at weaning or culling time when udder checked

What are the clinical signs of chronic mastitis?

• Ewe not systemically ill

• Udder abscesses, swollen or light purulent discharge from teats

What are the most common bacteria involved in mastitis in the UK and what is the ROI?

Most cases enter through teat end

• Staphylococcus aureus- from teat skin

• Mannheimia haemolytica- from lambs mouth

Bacteriology can help determine source

What are the soruces of infection with mastitis?

1. Teat skin and lambs mouth (S. aureus, M. haemolytica)

2. Previous chronic infections in udder (emerges in next lactation)

3. Environment: E. coli, streps

Explain how mastitis tends to occur in the ewe

• Milk supply demand mismatch

• Ewes under supply, lamb over suckling

• Immune suppression from metabolic stress and teat damage caused by lamb

• Allows bacteria to invade

What are the risk factors for mastitis in ewes?

• Genetic factors- fast lamb growth rates and low milk prod ewes

• Prolificacy- multiple lambs

• Age- younger or older

• Udder confirmation- abnormal teat position

• Udder abscesses/ chronic infections

• Teat lesions- orf, chapping, over sucking

• Concurrent disease

What can be done to manage risk factors for mastitis?

• Farm management factors

• Nutrition- don't underfeed in late preg and lactation, keep good BCS, Vit E/Sel, ensure good lamb nutrition (creep feeding- takes pressure off ewe)

• Review weaning policy

• Don't turn out with triplets

• Control concurrent disease

• Prevent orf

• Hygiene

• Milking practices

• Cull ewes over 7, those with udder lumps, broken mouthed, abnormal teat position

How is gangrenous mastitis treated?

Euthanasia

How is acute mastitis treated?

• Systemic antibiotics (based on C&S)

  • First line amoxicillin min 5 days

  • Tilmicosin licensed prod (vet only admin)

• Strip udder to remove toxins

• NSAIDs

• IV fluids

• Supportive care

How is chronic mastitis treated?

Culling

What are the most common causes of teat lesions?

• Damage from

  • Over sucking

  • Chilling- chapped teats

  • Poor conformation

  • Orf

Predisp to 2° infection