Fertility Problems Flashcards
1
Q
Definitions
- Abortion
- early embryonic loss
- still birth
A
- expulsion of foetus and foetal membranes before full term
- 40-300 days
- most cases at 10 month period = foal at biggest, high demand on mare, if mare ill = detrimental on foetus (space/nutrition/oxygen issues as it gets bigger)
- loss of embryo at 40 days or earlier (had fertilisation and growth of embryo) 15-25% pregancies lost this way in horses
- birth of dead foetus after minmum gestation period
- from 300 days
2
Q
Common causes of abortions UK
A
- umbilical cord abnormalities (vascular compromise) (e.g. torsion, thrombosis) = as foal get bigger and demand more = starved of oxygen/nutrients
- placental abnormalities (e.g. premature separation, placentitis) = no longer recieve 02/nutrients
- twinning (one outcompete the other, still birth, die in uterus = cause death of healthy twin
- maternal illness
- foetal abnormalities
- foetal abnormalities
- infectious causes - herpes
3
Q
Infectious reproductive diseases: Equine herpes virus
- about virus
- causes
- control
A
- EHV-1
- endemic in UK
- virus shed 14 days post infection
- latent infection stage = virus present, horse show no CS
- when go through stress = start to shed and CS
- Causes: respiratory disease, abortion storms, foals born alive but very weak/paralytic
- Control = isolate once identified, good biosecurity, vaccination
4
Q
Infectious reproductive diseases: Equine herpes virus (guidelines for prevention)
A
- Divide pregnant mares into small groups and maintain as isolated group until foaling
- Isolate all new animals for at least 1-21 days
- Do not mix mares carrying first foal with older mares
- If mares are removed then returned, don’t put back into original group
- Maintain all pregnant mares on vaccination programme
- Pregnant mares should be completely isolated from weanlings and all other horses
- Foster mares should not be in contact with pregnant mares
5
Q
Infectious reproductive diseases: Equine coital exanthema
- about virus
A
- EHV-3
- very contagious
- sexually transmitted via naso-genital route (nose to vulva)
- CS: pox like skin lesions on vulva/nose/penis, fever
- often occurs in breeding establishments that dont check/clean horses properly
- if animals have no resistance = go through group fast
- Control: AI (not in contact), barrier management (swabs and tests), treat and disinfect, dont mate if not clear
- Non-venreal form (display more as fever, no lesions)
6
Q
Infectious reproductive diseases: Contagious equine metritis
- about
- transmission
- cs
- diagnosis
- tratment
A
- inflammation of lining of uterus
- caused by = Taylorella equigenetalis (bacteria)
- 1977 first diagnosed in UK, last outbreak 2012
- sexually transmitted
- stalions can be asymptomatic
- cant be killed or use AI to prevent = pass on via semen or infected equipment
- passed on to a foal from infected mare = asymptomatic carrier
- CS: cause abortions, struggle to concieve/embryonic loss, asymptomatic, mucopurolent discharge (acute), less obious discharge (chronic)
- Diagnose: swabs from clitoral fossa and clitoral sinuses. Endometrial swab taken during oestrus from lining of uterus via open cervix
- transported in Aimes Charcoal medium
- carrier mares sometimes produce abs so detect serologically too, stallions dont
- pcr development highly sensitive/specific
- Treatment: antibiotics, clean external genetalia with mild disinfectant
- re-swab before breeding
7
Q
Post breeding endometritis
A
- inflamation of uterine wall
-fertilised embryo may not be able to implant - all mares have this but usually clears within 72 hours - by the time embryo enter womb (day 6) = clears
- acute inflamation
~ neutrophil infiltration = considers embryo foreign body, rely on immune system to accept embryo and conceptus when implant
~ exudate (fluid present in uterine lumen) = conceptus unable to sustane enviro - can lead to acute endometritis (fever and lot of discharge) or chronic endometritis (long term, reccouring issue of discharge)
8
Q
Anovulatory haemorrhagic follicle
A
= follicle has blood in it
- doesnt ovulate = anovulatory
- cant cycle properly or release eggs = no fertilisation
9
Q
Ovarian tumours
A
- granulosa cell tumour
- strange behavioural pattern (possesive, agressive)
- impacts hormones and fertility
- normally just on one ovary
- use hormones to reduce tumours or remove ovary
10
Q
What can be done about fertility problems
A
- Assisted Reproductive Technologies…
- Tests to detect chromosomal abnormalities (blood and hair samples)
- Immune modulators – post-breeding endometritis
- Alternative routes for antibiotic administration
- Determining fertility decline due to age (why happen: genetics, enviro, no. foals mare had)
- Use of blue light to advance breeding season (hood, blue light flash in eyes, trigger melatonin so cycle sooner, TB industry esp as get in foal in febuary)
- Treating anovulatory follicles
11
Q
Non-infectious factors that impact fertility - Internal - Embryonic
A
- Twinning = most liley to end in death to both foals (can crush one embryo)
- Placenta issues - poor formation or poor blood and nutrient supply
- genetic mutation - chromosomal abnormalities, equine turner syndrome = mare only has one X chromosome
- timing of breeding/AI and success of fertilisation
12
Q
Non-infectious factors that impact fertility - Internal - Maternal
A
- Age
- silent heat = develop follicles and ovulate but without behavioural signs
- tumours
- low egg count
- hormones (low = decrese quality, high = cant get preg)
- cysts on ovaries = prob with ovulation, hormone levels, genetic issue
- cysts in uterus = cant hold preg, embryo cant implant
- haematomas = collection of blood outside vessels
- hypoplastic glands
- endometritis
- only born with one ovary
- infected pyometra (pus)
13
Q
Non-infectious factors that impact fertility - External - Nutrition
A
- Amino acids - low = increase risk failure to ovulate and embryonic loss
- fatty acids - help inhibit prostaglandin production and maintains CL
- carbohydrates - high = gut overload, toxins enter blood stream, infection, metritis, abortion
- vitamin A helps optimise efficiency
- low BCS = low energy, more likley suffer from irregular ovulation, decreased conception rate, embryonic death, eventually anovulatory
- high BCS = longer oestruc cycle, persistant CL, increase abnormal follicle maturation
14
Q
Non-infectious factors that impact fertility - External - Environment
A
- light and season
- wamth
- mating enviro (floor, height of horse/dummy, space for mounting)
- ventilation (resp issues)
15
Q
Non-infectious factors that impact fertility - External - Management
A
- clenliness - increase hygine = decrease chance of infection
- stress
~ human handling (need to know what they are doing/confident)
~ isolation or change in group enviro
~ conflict in group of mares - age - decide what age mare and stallion should be
- timing of breeding/AI
- presence of chemicals - could lead to poor development of foetus
- change of location and feeding time
- exogenous hormones = any hormones entering the horse that are not produced by horse own endocrine glands. Help with mare behaviour, growth and performance but compromise with breeding as exposed to hormones which are not compatible with reproduction. Can decrease size of ovaries and lower quality ova
