Ovine Fertility Reprod & Obstetrics Flashcards
What main 4 factors to Poor fertility performance in ewes?
- Nutrition
- seasonality - short day breeders
- Infectious dx
- Stress
What are some infectious causes of poor fertility?
**- Chalmydophilia abortus aka enzootic abortion of ewes (EAE)
- Toxoplasma gondii **
- Campy fetus fetus
- Salmoinella
- Q-fever
- Listeria M
- Border dx
- Schmallenberg
- Bluetongue
Describe the direct & indirect effect of EQE on lambs?
- Inflammation which affects nutrient transition and hormonal contorl of preganncy
- Inflammation of organs of lamb
Describe latent infection of EAE
- Infection of ewe >6 weeks from lambing result sin abortion around 2-3 weeks before lambing
- Infection of ewes closer to lambing can result in latent infection in lining of uterus
= aboriton next breeding season
= abortion storms
What happens to lambs born from infected ewe?
Become carriers
What is the main finding from EAE?
Necrotic placentitis - oedema of intercotyledonary area of placenta
Physiology of Toxoplasma in early pregnancy?
- No immune response from foetus
Early foetal loss, barren, mistaken for infertility
Physiology of ToxoP mid pregnancy?
Foetal loss, or mummification of foetuses (alongside alive lamb) delivered at term
Physiology fo ToxoP late Pregnancy?
Foetus is immune competent, lamb liekly born alove but weak and infected
Describe toxoplasma broadly?
- Second most common cause i UK
- Protozoan parasite
- focal necrosis of cotyledons - strawberry appearance
Describe ‘life cycle’ of toxoplasma transmission?
PATHOPHYSIOLOGY OF BORDER DX?
Describe Campylobacter as Abortion cause?
- 3rd most common cause in UK
- Infected from contaminated water/feed or from material
Infection -> bacteraemia -> placental infection -> abortion, stillbirth, or full term lambs weak
Excretion for 42 d after infection
Carrier sheep
Describe Salmonella infection?
S.dublin, typhi, montevido
- Systemically infected -> high mortality
- Sudden death and rotten lambs
What is Q fever?
Coxiella brunetti
Describe Coxiella b?
- Last week of preganncy
- Goats more affected
- Organism shed in placenta & fluids at parturition
- Diagnosis - detection in foetus : placenta
- Zoonotic
describe Listeria & abortion
- Any stage of pregnancy
- Within 7 days of spoiled feed
- sick, pyrexic ewes
- necrosis of cotyledons and septicaemic foetus
- yellow /white foci on liver of foetus
- Diagnosis - cultured stimach contents
- Associated with RFM & metritis
- Zoonotic
CLS for main causes of abortion ?
What steps to take when abortion happens?
When is an investigation of abortion warranted?
- > 2% of total
- Or 2+ abortion over 2-3 days
How do we diagnose abortion?
- Fresh samples (avoid autolyzed/mummified)
- Minimum lab samples:
maternal serology,
foetus/ foetal fluid from abdo & thorax
foetus stomach contents
Fresh spleen
Placenta > 1 cotyledon
Which samples can be used for what?
Detail Tx & control of abortions
- Prevention: vaccination for EAE & toxo
- Control cat populations
- Feed production & storage (listeria)
- Tx fo individuals with ABs
- Flock level admin of oxytet?
CLOSED FLOCK SYSTEM
Nutritional causes of poor fertility?
-> assess energy balance in sheep with metabolic profiling
- poor nutrition = bad ovulation rate, early embryonic loss, etc
What can we supplement sheep with?
- Copper
- Iodine
- Cobalt
- Selenium
Describe Copper in sheep?
- Molybdenum, iron, and sulphur in soil can result in poor absorption of copper
- Seasonal variation in pastures
Why do we see copper being too low? what does it cause?
- Low levels ass with rapidly growing grass -> often late winter and spring
in ewes -> causes swayback in lambs - Required for myelination of CNs in utero
What will we see in lambs due to low copper?
Weakness & paralysis in lambs due to spinal cord damage
Poor quality coat - loss of pigmentation
Diagnosis low coppeR?
serum samples & liver samples
Role of iodine?
- Iodine required for thyroid function
- Low iodine causes impairment of thyroid and thyroid hormone
- Rq for bone, brain , & will development of foetuses
When is iodine important?
Mid-late pregnancy
- Causing aboprtions and stillbirths in ewes, or born weak with high incidence of neonatal deaths in the flock
When is more supp needed?
Brassicas high in goitrogens -> more supp needed (turnips)
Dx & Tx poor iodine?
Dx: thyroid sample from PM; Blood sample fro iodine
tx: supp, bolus
Selenium deficiency also calleD?
White muscle disease
How does selenium impact fertility?
- Early embryogenic death
- Poor scanning figures
- Male fertility
Role of selenium?
Works with iodine in thyroid function
Important in metabolism of brown adipose tissue in newborn lambs - impacts on lamb vitality
Dx & Tx selenium?
Dx -> test for GSH -Px - enzyme containing selenium
Tx: oral selenium suppelmeentation
Describe the breeding seasonality of sheep?
- Short day breeders
- Inc melatonin levels which is made during the night
- Melatonin activates the hypothalamus - pituitary-gonadal axis -> eval of GnRH, FSH, LH
What two options for manipulation of seaosnality?
- Hormone manipulation
- Natural manipulation
Why do we synchronise sheep?
- Shorter lambing window
- Labour costs, beter grazing management
- Advancing season
- Earlier lambing
- Earlier marketing of lambs = better price
- Showing - larger lambs
- Use of advanced breeding methods like AI and embryop transfer to improve genetics
- Access to superior rams
Describe the options for breeding manipulation
What days do we treat for Regulin?
Day 1, 7, 41 (35 d after implantation)
Describe Day 1 of Regulin?
(30 weeks before intended start of lambing).
As the presence of any ram (and also male goats) will interfere with the ovulatory process, isolate ewes from all males. The
ewes should be out of sight, sound and smell. Separating males into the next field from females is not adequate.
Day 7 of Regulin?
- Implant ewes at the base of the ear. Do not administer if sheep are wet or dirty. Ewes must remain isolated from male sheep
and goats.
Day 42 Regulin?
The period between implanting and introduction of the males must be not less than 30 days and no more than 40 days.
Introduce rams, but expect a delay of 14-21 days before mating activity commences. Vasectomised rams may be used for the
first 14 days to ensure a more compact lambing period. The peak of mating activity will occur 25-35 days after introduction of
the rams.
Describe rams
- 50% of flock!
- 70-75% of rams at optimal fertility
Poor libido, physical defects dx, nutrition ,
heat stress impact sperm production
zinc, selenium & cobalt for good semen
BCS rams?
checked 6-8 weeks before breeding seasons -> should be at least 3-4 at start of breeding
10-15% body weight loss
How to do Ram MOT?
Toes (locomotion)
Teeth (overshot jaw
Testicles (firmness)
Tone (BCS 3.5-4.0)
Treat (vaccinations etc)
What does a breeding soundness exam involve?
Which key areas of investigation & improvement ?
- Genetics
- Nutrition
- Infectious disease status
- Ewe selection
- Tup selection
- Tup:ewe ratio
- Management of young sheep/replacement ewes
- Trained personnel
What is the scanning percentage?
= (number of lambs scanned in total / n° of ewes put to tup) x 100
Why can we have poor scanning rate?
Describe barren ewes
- Aim for <2% at scanning
- > 4% investigate
- Due to : Poor conception rates OR Earluy Embryonic death
What can cause poor conception rates?
- Not cycling at start of mating period
- Returns to oestrus
- Ram subfertility
What can cause early embryonic death?
- Conception rate fine
- infectious dx
- Nutrition
- Other stressors during early implantation
What other considerations of ‘barren ewes’?
What is the lambing percentage?
= n° lambs scanned - n° lambs born alive
What types of dystocia do we see in the ewe?
- Obstructional dystocia (malpresentation, materno-foetal disproportion, ringwomb, vaginal prolapse)
- Primary uterine intertia (hypoca, preg tox)
What is ringwomb?
- incompletely dilated cervix
- Multiparous ewes
- cause unknown (trace elements? )
- associated with vaginal prolapse
- Lack of progression to 2nf stage labor
Tx of ringwomb?
- Manual dilation - massage cervix for 20-30 mins -> high risk of trauma
- Pharmacological dilation (unsuccessful usually)
- C -seciton
Describe Vaginal prolapse
1% of sheep
BEFORE lambing
Difficult to distinguish from 2st stage labour
Risk factors to prolapse?
- Excessive BCS
- Multiples
- High fibre diet
- Limited exercise
- Lameness
- Short docked tails
- Hills
- Hypocalcaemia?
Signs, pg for vaginal prolapse?
Separation straining, lying, vocalizing
Pg: variable
TX for vaginal prolapse?
- epidural
- Clean
- Lubricate
- Manual replacement
- harness, spoon,
- Buhner suture -nsaid?
- ABs,
Risk factors to Uterine prolapse?
- Prolonged dystocia
- Lambing difficulty
- ERxcess traction
48h after lambing
Tx for uterine prolapse?
- Epidural
- Clean
Lub, herness, spoon, buhner, oxytocin, nsald, ab
Prevention for uterine prolapse?
- Early intervention with lambing
- Factors reducing rate of dystocia
