Pregnancy diagnosis Flashcards
Why is early pregnancy diagnosis important?
- Can identify problems in male and female fertility early
- Assist with production system e.g. rebred/cull, management changes such as feeding
- Satisfaction for breeder/keeper
What, other than pregnancy, may cause to a non-return to oestrus?
- Mis-timing of observations
- pathological conditions e.g. persistent CL, luteal cysts
- Short oestrus intervals
- Pregnancy loss after maternal recognition of pregnancy
How does pregnancy loss after maternal recognition of pregnancy lead to non-return to cyclicity?
- Luteolysis prevented
- No second luteolysis window/luteo-placental shift of progesterone production has occured
- Progesterone will remain elevated
- Often lasts longer than normal pregnancy as there is no stimulation of post-parturient lutolysis
Give some diferences in pseudopregnancies in different species
- Can be normal after every luteal phase )e.g. itch)
- Induced ovulators may occur in non-pregnant luteal phase (sterile mating)
- In some only after pregnancy lost (e.g. mare)
- In some spontaneously or following pregnancy loss
Describe pregnancy loss in the mare between days 1 and 5
- Lost while still in oviduct
- Returns to normal oestrus cycle as thorugh never pregnant
Describe pregnancy loss in mare between days 5 and 15
- No MRP
- Normal oestrus cycle resumes unless associated with uterine inflammation or short cycle
Describe type I pseudopregnancy in the mare
- Between days 15 and 36
- Maternal recognition has occured
- No return to oestrus
- Primary CL will persist for normal lifespan
- CL lysed by administration of prostaglandin (before luteo-placental shift)
Describe type II pseudopregnancy in the mare
- Failure between days 36 and 140
- Endometrial cups formed, producing eCG, maintains secondary CL
- No return to oestrus
- Secondary CLs persist nfor normal lifespan (~150 days)
- CL not lysed by administration of PG
- Mare pseudopregnant until cups naturally regress
What features of pregnancy can be used for pregnancy diagnosis?
- Protein/endocrinological changes in urine/blood
- Foetus or foetal membranes directly or indirectly
- Physical changes in dam associated with accomodation of foetus
- Maternal changes secondary to endocrinological changes
What techniques can be used to identify foetus or foetal membranes directly or indirectly?
- Ultrasound examination
- Rectal palpation
- Abdominal palpation
- Radiographic examination
What are some physical change in the dam associated with accomodation of a foetus that can be used for pregnancy diagnosis?
- Increased uterine size or uterine artery (fremitus)
- Increased appetite
- Weight gain
- Abdominal enlargement
- Relaxation of perineal tissue
- Auscultation of foetal heart beats
Describe maternal changes that occur secondary to endocrinological changes that can be used for pregnancy diagnosis
- Absence of oestrus
- Change in cervical mucus (elevated progesterone becomes dry and tacky)
- Vaginal wall thinning
- Teat and mammary gland enlargement
- Secretion of milk in late pregnancy
- Waxing up in mare in late pregnancy
How can abdominal palpation be used for pregnancy diagnosis?
- Detectio of enlargment of uterus
- Ballotment of foetus
- Abdominal distension
Describe the use of radiographic examination in pregnancy diagnosis
- Detection of uterine enlargment
- Mineralisation of foetal skeleton
- Can be done later in pregnancy
- Useful if obese as ultrasound can be difficult if transabdominal scanning
What can be used for early pregnancy diagnosis in the cow?
- Early conception factor
- Transrectal ultrasound for conceptus
- Failure to return to oestrus
What is most commonly used for pregnancy diagnosis in the cow?
- Transrectal ultrasound
- Transrectal palpation
- Transrectal detection of foetal membrane (membrane slip)
- Transrectal ballotment of foetus
- Transrectal palpationof caruncles/cotyledons
- Transrectal uterine artery fremitus
What can be used later in pregnancy for diagnosis in the cow?
- Oestrone sulphate in milk
- Transrectal palpation of foetus
What is commonly used for early pregnancy diagnosis in ewes?
- Failure to be raddled (i.e. non-return to oestrus, high fertility so good indicator of pregnancy)
- Transabdominal ultrasound
What other methods can be used for pregnancy diagnosis later inpregnancy in ewes?
- Foetal pulse detector with doppler ultrasound
- Palpation of caudal uterine artery
- Detection of pregnancy cergical mucus
- Enlargement of abdomen and udder
- Transabdominal ballotment of foetus
What method is most commonly used for pregnancy diagnosis in the sow?
Transabdominal B-mode utrasound at day 20 (fluid filled uterine horn, detection of embryo later)
What method is most commonly used for pregnancy diagnosis in the mare?
Transrectal ultrasound (day 12-15) - Detection of migrating conceptuses and to ensure single pregnancy
How is pregnancy diagnosis confirmed later in the mare?
- Transrectal palpation (day 21)
- Plasma eCG (day 60-120)
- Transrectal foetal ballottement (day 80)
What methods are most commonly used for pregnancy detection in the bitch?
- Transabdominal ultrasound
- Plasma relaxin (only produced by placenta)
What methods can be used for confirmation of pregnancy diagnosis in teh bitch?
- Plasma acute phase proteins
- Abdominal palpation for discrete swellings
- Radiographic examination
- Transabdominal foetal ballottement
What methods can be used for pregnancy diagnosis in the queen?
- Transabdominal ultrasound and plasma relaxins from day 25
- Abdominal palpation for discrete swellings from day 28
- Radiographic examination from day 45
- Transabdominal foetal ballottment from day 50
Give examples of protein/endocrinological changes associated with pregnancy in the urine/blood
- No decline in progesterone
- Species-specific pregnancy specific factors e.g. hCG, PAG, placetnal oestrogens, relaxin
Outline early conception factor detection in pregnancy diagnosis
- Produced within 48 hours of conception, immunosuppressive
- Dipstick of serum/milk
- Cattle and horse
- Low accuracy
- Indicates conception rathre than pregnancy establishment
- High incidence of embryo mortality
Outline a non-decline in progesterone in pregnancy diagnosis
- Elevated progesteorne in blood/milk approx 22 days from mating
- Can be false positives (persistent CL)
- False negatives possible
- Non-return to oestrus also means no decline in progesterone
- Repeat sample to confirm result
Outline the use of maternal recognition of pregnancy factors in pregnancy diagnosis
- Specieis for species
- Most cannot be detected
- Either unknown or do not enter circulation so cannot be measured in blood
- hCH can be measured in urine
- eCG can be measured from day 35 onwards
Outline the use of foeto-placental oestrogens in pregnancy diagnosis
- Produces progesterone and oestrogens
- Oestrogen found from mid-pregnancy onwards in plasma and urine (later detection)
- Higher oestrogen in mid pregnancy than in oestrus
- No false positives
- Prengnacy specific oestrogens measured e.g. oestrone sulfate in cow
Outline the use of relaxin in pregnancy diagnosis
- Produced by CL in some species
- Produced in placenta (e.g. bitch/mare)
- Used for PD in bitch as only produced by placenta so definitive for pregnancy
Outline the use of palcental lactogens in pregnancy diagnosis
- e.g. PAG (pregnancy associated glycoprotein)
- Produced by placenta in several species
- Luteotrophic
- Commercial tests available
What ultrasound types can be used for pregnancy diagnosis
- Simple doppler transabdominally
- B-mode real time (transrectal or transabdominal)
Describe the transducer postioning for transabdominal ultrasound
Just behind udder, pointing back towards pelvis
Describe the appearance of the early conceptus
- Anechoic (fluid-filled) structure
- Represents yolk sac
Explain the significance of the migration of the equine conceptus in pregnancy detection via ultrasound
- Careful examination to ensure detection of twins if present
- Early detection important
- Need to scan whole uterus, may be on opposite side to CL
What may be seen later on ultrasound for pregnancy diagnosis?
- Flickering heartbeat of embryo
- Foetal structure i.e. ribs, head, abdomen, spine
What maternal features can be identified on ultrasound that may aid pregnancy diagnosis?
CL - no CL means pregnancy is impossible to have occured
What is detected in rectal palpation for pregnancy diagnosis?
- Uterine enlargement (usually one horn will enlarge where pregnancy forms)
- May be both horns if twins
- Foetal membranes detected
- Foetus itself
- CL in ovary
What may also cause uterine enlargment other that prengnacy?
- Pyometra
- Endometritis
How are foetal membranes detected on rectal palpation
- Membrane slip
- Can feel membranes move over each other
- Roll fingers over endometrium and feel for foetal membranes slipping past
Describe transrectal ballottement of the foetus
- Easier in mid pregnancy
- Later starts to move further into abdomen
