Problems of pregnancy

Question 1

Superfecundation

Answer 1

Offspring from more than one sire conceived at the same oestrus, i.e. twins of different breeds are born.

It is seen in cows served by more than one bull, it also occurs following artificial insemination (AI) when semen of multiple sires is used in high fertility straws.

Question 2

Superfetation

Answer 2

The simultaneous occurrence of more than one stage of developing offspring in the same animal.

This does not occur in domestic cattle but may appear to occur and the veterinary surgeon may be consulted.

The usual scenario is a cow adopts a calf of a herd mate then its own calf is born a few days later.

Question 3

Ectopic pregnancy

Answer 3

The placentation of domestic species means that true ectopic pregnancy is extremely unlikely.

An apparent ectopic pregnancy may be seen in cases of ruptured uterus, or vaginal pregnancy where the foetus is sometimes found in the vagina following incomplete abortion.

Question 4

Fertilisation rates of domestic species

Answer 4

Very high, normally approximately 90% of ova that are shed are fertilised, however a proportion of these ova fail to develop to full-term offspring, e.g. in cattle there is 45-65% wastage and in sheep 20-30%.

Question 5

Adverse factors that affect the conceptus

Answer 5

Genetic abnormalities

Failure of hormonal support, especially progesterone

Failure of maternal recognition of the presence of the embryo

Environmental stress such as climate and housing

Nutritional factors

Infection affecting the conceptus, its placenta or the uterus

Chemical factors such as poisons and drugs

Immunological factors

Question 6

Foetal monsters

Answer 6

Achondroplasia

Anasarca

Co-joined foetuses

Foetal mole

Amputate (otter) calf

Schistosomus reflexus

Perosomus elumbis

Hydocephalus

Accessory front limbs

Arthrogryphosis

Question 7

Achondroplasia

Answer 7

Short-limbed ‘dwarf’ e.g. bulldog calves in the Dexter breed.

Question 8

Anasarca

Answer 8

Foetal skin and subcutis are oedematous.

Dystocia may be a problem.

Often with foetal abnormalities such as heart defects causing circulatory problems.

Question 9

Co-joined foetuses

Answer 9

(Siamese twins)

Monozygotic twins that have failed to separate.

The foetus may have two faces (diprosopus) or two heads (dicephalus).

Other partial divisions are also described.

These may cause dystocia.

Question 10

Foetal mole

Answer 10

(amorphous globusus)

Small structure of mixed foetal tissues surrounded by skin.

Usually an incidental finding at the birth of the co-twin.

Question 11

Schistosomus reflexus

Answer 11

The spinal cord is severely deviated so that the anterior and posterior ends are close together.

The foetus has an abnormal body wall and thoracic and abdominal contents may be uncovered.

Calves with this abnormality can survive during pregnancy but may cause dystocia and be non-viable at birth.

Question 12

Perosomus elumbis

Answer 12

means ‘loathsome loins’ in Latin.

Affected foetus has a shortened spinal cord which terminates in the thoracic region.

As a result, the hind limbs have no nerve supply and cannot be moved in utero and develop ankylosed joints.

The condition can cause dystocia and the foetus is not viable.

Question 13

Foetal mummification

Answer 13

the amnionic, allantoic and foetal fluids are resorbed and the foetus becomes mummified

Normally the corpus luteum (CL) remains and the dam does not return to oestrus.

Mummification is detected on rectal examination of a cow which is either past her expected calving date or does not look as heavily pregnant as her insemination date suggests.

The uterus feels tight and the foetus is easily felt through the uterine wall with an absence of the normal uterine fluids.

No cotyledons are felt, and fremitus is absent in the middle uterine artery.

Ultrasonography can confirm the diagnosis.

Occasionally spontaneous regression of the CL occurs and the mummified foetus may be expelled leading to an abortion.

Question 14

Treatment of foetal mummification

Answer 14

PGF2α causing luteolysis usually within 2 - 3 days, with the cow coming into oestrus and the cervix will become open and the foetus is expelled

Question 15

Foetal maceration

Answer 15

occurs if the foetal death is accompanied by entry of bacteria into the uterus.

The foetus will decay in-utero. Initially no symptoms will be present but after a period of time a foul vaginal discharge will be present.

Foetal bones are often too large to pass through the cervix and they will stay in the uterus.

Question 16

Diagnosis of foetal maceration

Answer 16

On rectal examination the uterus feels full of sharp bones and sharp fragments may be detected protruding from cervix into the vagina.

Ultrasonography can be useful to help confirm the diagnosis.

In small ruminants calcified bony fragments can be detected by radiography.

Question 17

Treatment of foetal maceration

Answer 17

In larger species the debris may be removed if fingers can be passed through the cervix (followed by uterine lavage).

In sheep hysterotomy may be attempted.

Question 18

Emphysematous foetus

Answer 18

Death of the foetus at a later stage of gestation can lead to an emphysematous foetus.

The decomposing process will produce gases and lead to emphysema of foetal tissues.

In most case the uterus will also be affected and metritis will be present.

Question 19

Treatment of emphysematous foetus

Answer 19

Unless the cervix opens and the foetus is expelled the prognosis is very poor and death of the dam can occur due to septicaemia and/or toxaemia.

Because the foetus is quite often quite dry and swollen extraction can be difficult.

Euthanasia might be the best solution in some cases.

At vaginal examination the emphysema will be easily diagnosed.

Question 20

Hydrops uteri

Answer 20

Estimated to occur in 1 in 7,500 bovine pregnancies.

Excessive amounts of foetal fluids within the pregnant uterus.

The foetus may or may not be oedematous and may show anasarca, hydrothorax or ascites.

Two forms have been described, depending on the site of the excessive fluid, either hydrops amnion (hydramnion) and hydrops allantois (hydrallantois).

Question 21

Hydrops amnion

Answer 21

Less common than hydrops allantois

Insidious onset

at 5-6 months gestation

Abnormal calf, normal placenta

Guarded prognosis

Mucoidal fluid

Question 22

Hydrops allantois

Answer 22

15x more common than hydrops amnion

Rapid onset

at 7-8 months gestation

normal calf, abnormal placenta

poor prognosis

watery fluid

Question 23

Incidence of hydrops amnion

Answer 23

Mostly sporadic, but there have been reports of several cases within a herd

Question 24

Aetiology of hydrops amnion

Answer 24

Associated with abnormalities of the foetus, especially cleft palate (leading to failure of the calf to swallow amniotic fluid, leading to its accumulation).

Other coincidental abnormalities include pituitary hypoplasia (Guernseys) and bulldog calves (Dexters).

Question 25

Clinical signs of hydrops amnion

Answer 25

Nothing may be seen until calving, when there appears to be more amniotic fluid (syrupy consistency) than normal.

If the uterus is distended contractions may be weak and assistance with delivery is required.

Other cases may have excessive abdominal distension and the farmer may suspect twins.

The cow may show difficulty getting up due to increasing weight as its pregnancy progresses.

Question 26

Diagnosis of hydrops amnion

Answer 26

Rectal examination may assist.

The uterus is large and it may be possible to palpate the foetus and cotyledons.

Ultrasonography may indicate the relatively large amounts of amniotic fluid that is present, but this may be difficult to visualise or interpret with certainty at the stage of pregnancy at which hydrops amnion is generally seen.

Excessive quantities of amniotic fluid may be noted at birth.

The calf may be deformed and the placenta is retained.

Question 27

Treatment of hydrops amnion

Answer 27

If cow bright and active there is no specific treatment, but assistance may be required at calving.

If the cow is distressed, then it may be necessary to terminate the pregnancy using corticosteroids and PGF2α.

Question 28

Incidence of hydrops allantois

Answer 28

Mostly sporadic.

There are reports of the condition affecting the same cow more than once.

Question 29

Aetiology of hydrops allantois

Answer 29

Not clear.

Placental abnormalities have been blamed and there is possible interference with sodium metabolism at cell level.

Question 30

Clinical signs of hydrops allantois

Answer 30

The onset is rapid and the condition may be life-threatening.

The abdomen is enlarged and tense, the cow looks ill and is often in poor body condition.

The uterus is massively enlarged and may contain more than 200 litres of fluid (the normal volume of allantoic fluid near to term is 8-15 litres).

Abdominal pressure is greatly increased, breathing may be laboured, appetite depressed and complications such as rectal or vaginal prolapse, hip dislocations, rupture of prepubic tendon and recumbency may follow.

On rectal examination the uterus is grossly enlarged and apparently filling the entire abdomen and pushing backwards and upwards into the pelvic cavity.

Numerous very small accessory cotyledons are palpable and the foetus is mostly inaccessible to touch.

Ultrasonography of the uterus reveals excessive quantities of allantoic fluid and numerous small cotyledons which are features of the disease.

Question 31

Diagnosis of hydrops allantois

Answer 31

Based on clinical signs, a sudden severe onset and specific rectal findings give the diagnosis.

Differential diagnoses include normal twin pregnancy, rumen tympany, abomasal disorders, peritonitis and ascites.

Abdominal paracentesis may be useful and aspiration of fluid can be identified as allantoic.

Question 32

Prognosis of hydrops allantois

Answer 32

Extremely guarded

Question 33

Treatment of hydrops allantois

Answer 33

Considerations needs to be given to the expected calving date, the condition of the dam (especially its ability to rise and eat), viability of the calf (if known), the relative value of cow and calf and the facilities available.

The treatments available include:

1. Conservative – possibly the best course if the cow is in reasonable health and near to calving
2. Uterine drainage – temporary relief but rapidly refills and there is a risk of infection
3. Induction of birth – risk of losing a premature calf, there will be uterine inertia so it is likely there will be a need to assist at calving
4. Elective caesarean possibly with partial drainage of the uterus before surgery due to the risk of shock when the uterus is emptied, this is not a serious problem because the fluid is extra-circulatory, although loss of abdominal pressure could lead to splanchnic complications. The foetus is usually small and poorly developed but sometimes survives.

Question 34

Abnormal offspring syndrome (OAS)

Answer 34

Hydrops allantois can be part of AOS a negative consequence of in-vitro fertilisation (IVF) and embryo transfer procedures.

Also embryo, foetus, placenta and offspring can differ in morphology and developmental competence compared with natural embryos.

Question 35

How to terminate a pregnancy between 4-100 days

Answer 35

PGF2a analogue

At this stage the pregnancy is maintained by P4 from the CL

Question 36

How to terminate a pregnancy from 150-270 days

Answer 36

PGF2α alone will not be effective
Need long acting corticosteroids (dexamethosone) as the placenta forms additional P4

Question 37

Predisposing factors for vaginal prolapse

Answer 37

breed: higher incidence in Hereford cows,

high levels of oestrogens in the diet (some clovers),

high endogenous production of oestrogens,

sloping environment,

ruminal tympany,

overfeeding with bulky food,

age of animal (pelvic muscles and ligaments become less elastic with successive pregnancies).

Question 38

Treatment of vaginal prolapse

Answer 38

Consideration needs to be given to the severity of the prolapse, the proximity of parturition and any damage to the vagina and/or cervix.

Correction involves preventing further damage to the vagina and replacing the prolapse following cleaning.

Supervision of the birth.

If the prolapse is intermittent or slight, then conservative treatment involving replacement when necessary and supervision until parturition may be all that is necessary.

In other cases, replacement under epidural anaesthesia is necessary and sutures or trusses may be used.

Numerous suturing patterns are described including simple mattress suture and Buhner’s purse string suture.

In sheep a plastic vaginal truss or prolapse replacer (Moffat replacer) is effective.

Surgical techniques may be used for chronic or difficult cases where parturition is a long way ahead.

These include Caslick’s operation in which the upper portion of the vulva are sutured, Farquarson’s operation which is a submucous resection of the prolapsed part of the vagina and Winkler’s operation in which the cervix is fixed to the prepubic tendon to prevent the genital tract from slipping backwards.