Oestrus and oestrus detection Flashcards
Describe the signs of a oestrus in the cow
- Swelling of vulva, mucus discharge (may be bloody)
- Chin pressing
- Brawling, restless
- Reduced milk yield
- Mounts other cows
- stands to be mounted
Describe the signs of oestrus in the mare
- Vulval oedema and mucoid discharge
- Elevated tail and lean hindquarters towards stallion
- Winking of clitoris
- Flehmen response in stallion
Describe the signs of oestrus in the bitch
- Standing to be mated
- Deviationof tail
- Discharge paler in colour
- Reduction in vulval oedema
Describe the signs of oestrus in the queen
- Increased vocalisation, rubbing and rolling
- Increased activity and will seek tom
- Possible slight mucoid vulval discharge
- Standing to be mated, lordosis
- Tail erect and deviated to side
In all species, what is the main challenge in management of inseminatio/mating?
If oocyte not fertilised within 24 hours of ovulation, will age and will no longer be able to be fertilised
What is the main challenge with timing of insemination/mating in cows?
- Oestrus short and tightly regulated to time of ovulation so can inseminate/mate at oestrus onset
- However, oestrus detection can be difficult (often middle of the night)
What is the main challenge with insemination/mating in sheep?
- Are mated throughout oestrus by ram usually (runs with flock)
- But need to ensure ratio is correct
- Insemination requires laparoscopy so is uncommon
What is the main challenge with insemination/mating in pigs?
- Housed separately, presented for mating
- Oestrus detection important, tight window of ovulation
- Not well defined when ovulation occurs following onset of oestrus (2/3rds of way through)
What is the main challenge with insemination/mating in mares?
- Problematic as ovulation occurs 1-2 days before end of oestrus, but oestrus length is variable
- Return to oestrus also variable
What is the main challenge with insemination/mating in bitches?
Oestrus variable, signs relate poorly to time of ovulation
List the main methods for oestrus detection in the cow
- Examine/observe >4 times a day to see behaviour
- Detection aids: Kamars, pedometers, Estrotect, GPS, elctronic noses
- Use van Eerdenburg’s scoring
- Low plasma/milk progesterone
- Detection of large follicle
- Fall in body temp, reduction in vaginal pH, crystalisation patterns in vaginal mucus
What is van Eerdenburg’s scoring?
Method of adding up behavioural signs to decide when to serve (serve when signs add up to more than 50)
What factors may inhibit oestrus activity in the cow?
- Hard, non-supportive floor
- Concrete reduces oestrus behaviour
- High environmental temperature
- Overcrowding
- Recent mixing/stress
- Feeding (food distracts)
- Lameness
What is the benefit of ovulation synchronisation in the cow?
No need for oestrus detection
Describe ewe oestrus signs
- Restless
- Stands for ram
- Vulva swollen, mucoid discharge
- Induces flehmen in the ram
Describe signs of oestrus in the sow
- Vulva swollen and congested prior to oestrus
- Seeks boar
- Stands firmly to be mounted
- Restless with repetitive grunts
- Pacing and searching
- Lowered feed intake and loss of appetite
- Male-like sexual behaviour
- Increase in vaginal mucus
- Response to boar pheromones
Describe prooestrus in the bitch
- Very long (9 days)
- attactive to male but no mating
- Vulval swelling
- Presence of serosanguinous discharge
How is oestrus detected in the bitch?
- Clinical assessment
- Assessment of vaginal epithelial cells (cytology)
- Assessment of vulval softening
- Examination of the appearance of the vaginal wall
- Plasma progesterone concentrations
Describe the most defining characteristic of cytological oestrus in the bitch
- Predominance of superficial cells
- Most but not all bitches undergo full cornification
- Smear reveals monotonous pattern composed almost excusively of anucleat superficial cells
What effect does progesterone have on oestrus behaviour and during met/dioestrus?
- Inhibits oestrus behaviour
- Prepares uterus for pregnancy
- Closes cervix
- Blocks LH surge
What effect does the wave of FSH have on in dioestrus?
- Stimulates development of antral follicles and selection of dominant/ovulatory follicles
- Increased oestradiol and inhibin leading to decreased FSH and degeneration of subordinate follicles
What hormonal changes occur at the end of dioestrus in the non-pregnant animal and what is the effect?
- Release of uterine PGF2a
- Causes luteolysis
- Decreases progesterone
- Increased oestradiol from ovulatory follicle-
- Stimulates LH surge allowing next ovulation to occur
Define anoestrus
Without cyclcicity
- Can be normal (dog) and is not the same as silent heat
What may cause anoestrus?
- Gestation
- Lactation/presence of offspring
- Seasonality
- Ovarian pathologies
- Normal in monoestrus breeders
What is silent heat?
Ovulation with limited signs of oestrus
When and why does silent heat often occur?
- Often at first oestrus after seasonal anoestrus/parturition
- No progesterone prining, no progesterone fall and no sudden release of oestrogen or LH suppression
- In cows may be due to negative energy balance or breed
Describe vaginal cytology of the bitch in anoestrus
- few layers of cell lining vagina
- Small number of epithelial cells on smear
- Mostly parabasal or small intermediate cells
- Other cells may also be present as remnants of previous monoestrus phase
- Number of cells increases prior to prooestrus
Describe vaginal cytology of the bitch in prooestrus
- INcreased number of cell layers of vaginal epithelium
- Overal thickening of vaginal mucosa
- Cells present on surface of vagina change in shape and size
- Variation in staining characteristics
- Cells larger and more irregular in shape
Describe the vaginal cytology of the bitch in oestrus
- Increase in dead cornified cells
- Easily removed as smear sample taken
- Mucosa changes from cuboidal to keratinised squamous epithelium
What is the cornification index?
A quantitative assessment for determining the stage of oestrus cycle a bitch is in based on proportion of keratinised cells in vaginal smea
Describe the vaginal cytology of the bitch in metoestrus
- Sloughing of vaginal epithelium
- Number of cell layers decreases, deeper cells uncovered
- %age of large, irregularly shaped, anuclear cells decreases
- Polymorphonuclear leucocytes absent in fertile period but reappear at end of fertilisation period
- In fertilisation period, vaginal smear dominated by small intermediate cells, cellular debris, bacteria and polymorphonuclear leucocytes
What stage of the oestrus cycle will the bitch be in 3 months after the end of oetrus?
Anoestrus
What stage of the oestrus cycle will a non-mated cow 10 days from last oestrus be in?
Dioestrus (luteal phase)
What stage of oestrus will the mare in November be in?
Seasonal anoestrus
What stage of the oestrus cycle will the ewe in September be in after exposure for several weeks to vasectomised ram?
- Onset of cyclicity (could be anywhere in cycle)
What is the effect of administration of exogenous PGs to a bitch in anoestrus?
NO effect, no CL to act on
What is the effect of administration of exogenous PGs to a cow in dioestrus
- Come into oestrus
- Due to luteolysis
- Can be used to synchronise herd
What is the effect of administration of exogenous PGs to a mare in seasonal anoestrus?
No effect, no CL to act on
What is the effect of administration of exogenous PGs to a ewe in early luteal, mid luteal and late luteal phase?
- Early: no effect, first 5 days in luteal CL not responsive to PGF2a
- Mid: luteolysis and return to oestrus
- Late: little effect, already producing endogenous PGs
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the anoestrus bitch?
- No effect
- Nothing for progesterone to act on (no active HPG acis to inhibit)
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the dioestrus cow?
- Extension of luteal phase
- If primary Cl regressed when progesterone removed then will be rapid return to oestrus
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the mare in seasonal anoestrus
No effect, no gonadotrophins to influence
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the ewe in follicular phase?
Delay ovulation, withdrawal leads to ovulation and return to oestrus
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the ewe in early, mid luteal phase?
- Early: already progesterone in system, coincides with withdrawal of endogenous
- mid: extension of luteal phase, primary CL likely to regress but may persist after withdrawal
- Can be used to synchronise the flock
What is the effect of administration of exogenous progesterone for 10 days, then withdrawal in the anoestrus ewe?
Bring back to cyclicity
