Group 3- set 3/3 - Pregnancy Complications - revision period COMPLETE **** Flashcards by Amelia Watson

State the 3 possible types of embryonic loss

early embryonic death
late embryonic death
abortion

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Early Embryonic Death: When does this occur?
- What does this mean?

pre-implantation
before maternal recognition of pregnancy

the life of the corpus luteum has not been extended

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Early Embryonic Death: What classes as early embryonic death in a cow?
- what percentage of loses are early embryonic in cows?

embryo loss before day 21

75%

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Late Embryonic Death: When can this occur? 2

peri-implantation
after the life of the corpus luteum has been extended

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Abortion: When does this occur? 2

post-implantation
after organogenesis

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When might pseudopregnancy occur following pregnancy loss?
- What happens as a result? 3
- Which species can this occur in?

if the pregnancy loss occurred after maternal recognition of pregnancy

the corpus luteum fails to regress
progesterone is secreted
leading to pseudopregnancy

mare, sow, goat, queen

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Pregnancy Loss in Mare: State the 2 types of pregnancy loss in the mare and give dates

type 1 is early embryonic death after maternal recognition of pregnancy so after day 15

type 2 is foetal death after endometrial cup formation at day 36

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Pregnancy Loss in Mare - Type 1: What happens after the pregnancy loss?
- How can you treat this?

the corpus luteum will persist, prolonging the luteal phase

prostaglandin

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Pregnancy Loss in Mare - Type 2: How long does the Pseudopregnancy last?
- Why can’t you treat this with prostaglandin?

until the demise of the endometrial cups between days 90-150

because the loss occurred after the formation of the endometrial cups which are secreting ECG to increase progesterone production

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Pregnancy Loss in Goat: Why might you get pseudopregnancy in the goat after pregnancy loss post maternal recognition of pregnancy? 2
- What phenomenon can happen in goats, making the goat look very pregnant?
- What is this called clinically?

because the corpus luteum will persist
so progesterone will still be produced

the accumulation of sterile secretions into the uterus in the absence of an embryo

hydrometra or cloudburst

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Pregnancy Loss in Goats: Why can you get Pseudopregnancy in cyclic non-mated does?

the corpus lutes persists for an unknown reasons
so progesterone will still be produced

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Give and explain some causes of embryonic and foetal loss 7

chromosome abnormalities
nutritional deficiencies
environmental factors - climate, stress, pollutants
infectious agents
trauma by rectal palpation during PD
insemination - poor semen quality or given in error during pregnancy
physiological factors like uterine environment or ovulation rate

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Why could insemination during pregnancy cause pregnancy loss?

semen contains prostaglandins which could induce luteolysis

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Which factor is the most common cause of abortion in Ruminants?

infectious agents

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Infectious Agents: What are the 3 main routes for entry of infectious agents during pregnancy?
- What about before pregnancy?

the cervix
the blood
pathogens affecting the corpus luteum

with the sperm

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Infectious Agents: Which cervixes can be affected by ascending infections?

both an incompetent cervix and competent cervix

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Infectious Agents: How can systemic (in the blood) infectious agents cause abortion?

could affect the endometrium
could affect the placenta
could cross the placenta and affect the foetus

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Infectious Agents: Give an example of a pathogen which can affect the corpus luteum

infectious bovine rhinotracheitis

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Infectious Agents: State the 4 most common ones

bacterial
viral
parasitic
fungal

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Manifestations of Pregnancy loss: What happens following -
- Early Embryonic death
- Death following infection

tissues are normally reabsorbed and animal returns to oestrus

pyometra may follow

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Why in cattle might a Pyometra occur following death by infection?

because the corpus luteum persists, so the cervix remains closed and pus can accumulate

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Manifestations of Pregnancy loss: What happens following -
- Later gestational loss

expulsion of aborted foetus or foetal mummification

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Why might expulsion of aborted foetuses occur following later gestational death, if not all the foetuses are dead?

death of some of the foetuses in the first half of pregnancy may cause lysis of the corpus luteum and immediate expulsion

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What is Papyraceous mummification? 3

where foetal fluids and reabsorbed
foetal membranes are shrivelled
and the uterus contracts

What happens with mummification of a foetus in polytocus species?

mummified foetus might be expelled at parturition with no harm to the live foetuses

Which species are more likely to expel aborted foetuses fresh? - Why? 4

species that are not dependent on the corpus luteum throughout pregnancy because foetal death leads to cessation of the foetal contribution to the placenta so placental progesterone declines and the foetus is expelled in a fresh state

Which species are more likely to expel an aborted foetus in a state of autolysis? - Why?

species that are dependent on the corpus luteum throughout pregnancy because there will be a delay between the time of death and lysis of the corpus luteum

Infectious Agents: Does the time of infection have an impact on the effect of the infection? - Give an example of such an infectious agent for- - Sow - Cow -Ewe

porcine parvovirus bovine viral diarrhoea virus border disease virus

What does SMEDI stand for? - What can it be used to do?

stillbirths mummification embryonic death infertility to characterise a number of viral infections in the sow

How does SMEDI work? 2

it reflects the different stages of development at the time of infection the stage at which the sow is infected determines which one of SMEDI will manifest

SMEDI: What is a classical sign of a SMEDI infection? 2 - What is often the cause?

a full term litter consisting of small mummified foetuses ranging up to full grown still born or live weak piglets it reflects a progressive infection in utero porcine parvovirus

What type of causes is responsible for the most equine abortion?

non-infectious causes

What is the impact of twins on - - Mares - Cows 2

it reduces the surface area for nutrient exchange it reduces foetal growth and calf birth rate causes freemartinism in mixed sex pregnancies

Equine Twinning and Pregnancy Failure: Why is it so important that we dont get twins? - What happens if we do get twins that causes loss?

because the placenta is epitheliochorial so the conceptus is reliant on nutrition from the entire surface area of the endometrium as the placentas grow they abut each other and the placental interface cannot absorb sufficient nutrients

Equine Twinning: What are the potential outcomes that can happen if twins occur? 3

one foetus may be resorbed at an early stage or one foetus may be mummified at an early stage or both twins are aborted in mid to late gestation

Freemartinism: Why does this occur?

placental fusion permits the exchange of foetal cells and foetal hormones between foetuses the male hormones androgenise the female foetus producing a sterile XX/XY chimeric female

Define Intra-uterine growth restriction

impaired growth and development of the mammalian embryo or its organs during pregnancy

What can cause IUGR?

it can be naturally occurring or it can be environmentally induced

Give a few examples of environmental factors causing IUGR 4

temperature and stress insufficiency of the uterus endometrium or placenta ingestion of toxic substances maternal nutrient deficiencies

IUGR: A placental insufficiency can be the cause of IUGR. - What are the different causes of placental insufficiency and how do they lead to placental insufficiency? 4

multiple foetuses causing reduced placental blood flow in ruminants impaired by uteroplacental blood flow, placental size or surface area poor placental growth due to over or under nutrition gynaecological immaturity where the mother and foetus compete for nutrition

Schmallenberg Virus: What are its possible effects? 2 - How is it transmitted?

late abortion birth defects in newborn sheep, cattle and goats insect vectors

Schmallenberg Virus: Does it cause the same types of deformities in all infected animals?

no the foetal deformities vary depending on when in the pregnancy the infection occurred

Schmallenberg Virus: Mid-gestation Infection - What does the virus affect at this stage? - How would this manifest in the offspring? 3

CNS development very minimal brain development permanently flexed joints surviving animals would have major mobility issues

Schmallenberg Virus: Mass immunity was achieved due to widespread infection in recent years. - However, why are we expecting to see it re-emerge every 3-5 years?

because ewes are being replaced at a rate of 20-25% per year, so naive flocks are generated every 4 years

Schmallenberg Virus: What other disease should be considered in malformed calves and lambs?

blue tongue

Chlamydial Abortion: This is the main cause of Ovine abortion in UK - When in the pregnancy would the abortion occur? - Why is this?

in the last 3 weeks of pregnancy due to placental damage from day 90 from colonised bacteria and inflammation

Chlamydial Abortion: Describe some of the pathological features 2

thickened areas of tissue between the cotyledons on the placenta brown exudate over the surface of the placenta

Chlamydial Abortion: Why is it important to isolate infected animals?

because the organisms are present in large numbers in abortion products so must prevent contamination of the environment and other ewes

Toxoplasma Gondii: Which species does this cause pregnancy loss in? - What type of pathogen is it? - What type of host are the sheep? - How do sheep become infected?

sheep intracellular protozoan intermediate hosts ingestion of oocysts in food and water

Toxoplasma Gondii: How is it similar to schmallenberg? - What effect would it have in early pregnancy compared to late pregnancy? - What pathology does it cause?

the time of infection determines its impact on the foetus much greater impact in early pregnancy than late pregnancy lesions in the brain, liver and kidneys of aborted foetuses

Toxoplasma Gondii: Describe some of the pathological features that allow you to identify this as the infective agent

dark red placental cotyledons with white speckles of necrosis

Campylobacter: When would abortion occur? - What would the birth of a live infected lamb look like? - Why can it spread so rapidly between animals?

in the last 6 weeks of gestation weak lamb large number of organisms in the aborted materials

Non-infectious Pregnancy Loss in Cow: State 4 possible causes

nutrition stress timing of insemination conception too soon after calving

Non-infectious Pregnancy Loss in Cow: - Give examples of different nutritional problems leading to pregnancy loss 3 - Give examples of causes of stress 2

vitamin A deficiency negative energy balance high intake of rumen degradable protein high temperature high humidity

Non-infectious Pregnancy Loss in Cow: - How can timing of insemination cause pregnancy loss? - Why can conception too soon after calving result in pregnancy loss?

if it is performed too late in the oestrus period the ovum may have aged causing embryonic death due to the poor uterine environment

Non-infectious Pregnancy Loss in Ewe: - give one risk factor for embryonic death

multiple conceptions

Non-infectious Pregnancy Loss in Sow: - What are the possible types of reasons for pregnancy loss in sow? 2 - Why might a sow fail to establish a pregnancy? - What is the most common reason for failure of an established pregnancy?

failure to establish a pregnancy failure of an established pregnancy unattached conceptus is susceptible to damage due to long pre-implantation period break down in maternal recognition infection

Risk factors of pregnancy loss in Sow: - Give and describe them

ovulation rate - the higher the ovulation rate the lower the chance of embryo survival competition for uterine space when there are more than 5 foetuses nutrition - high energy levels post service reduces embryo survival stress due to temperature or management