Infertility workshops Flashcards
What does BAR DUDE stand for
Bright
Alert
Responsive
Defecating
urinating
Drinking
Eating
What do you see in a mares ovary immediately after ovulation
corpus haemorrhagicum- large blood filled structure
Large anechoic structure
What does free fluid in the body of the uterus indicate
always abnormal unless immediately after mating-> may suggest endometritis
What happens to vulval confirmation when a horse looses muscle and fat
anus becomes sunken
Faecal contamination of vestibule and ascending infection into the uterus more likely
Mare is more likely to loose a pregnancy if she gets pregnant
What is the most common cause of infertility in the mare and what factors predispose to this
Post-breeding or breeding/ mating induced endometritis
Increased bacterial load or reduced drainage (due to poor uterine contractions, abnormal cervix, dependant uterus)
How to treat/reduce risk of post-breeding endometritis
Early treatment (removal of fluid post mating, use of antimicrobials) may allow the mare to get pregnant
Surgery to improve poor conformation reduces the risk of the problem
When does the natural and thoroughbred breeding seasons start
Natural- April-July
Thoroughbred- February (11 month gestation, age of foals counted from 1st Jan so want them to be born as close to but after then
Why are pregnant mares also put in artificial light
when they foal they think it is already spring time and start cycling again straight away
Why might exogenous progesterone be given to a mare
Exogenous progestogens (altrenogest [Regumate]) causes suppression, storage of gonadotrophins and surge release when stop progestogen
Used as method of inducing/synchronising oestrus by administration and withdrawal of the product
when its given it negatively feeds back to the hypothalamus but when it is withdrawn there is a big surge of GnRh from hypothalamus which can help a mare to reach high levels of FSH adn LH needed to ovulate
Why wouldn’t you give exogenous progesterone to a mare in anoestrus
There is no GnRH to suppress with the progesterone in the first place -> they just need light
Why are mares put under artificla light
The imposed breeding season and the natural breeding season do not coincide at least for thoroughbreds (we often try to breed when mares should not be expected to be cycling)
Supplementary light can advance the transitional phase, and then suppression with progestogens and their subsequent removal may allow onset of an ovulatory cycle
Additional drugs may be required to force ovulation after progestogen withdrawal
What is dioestrus ovulation and why does it occur in mares
Normally in the luteal phase waves of follicles grow but regress due to high levels of progesterone
Sometimes the luteal phase follicle ovulates – this seems strange because the oocyte is released at a time when progesterone is high and the mare is not in oestrus. These are called dioestrus ovulations and they result in the formation of a new CL
The mare still produces PG from her uterus at the normal time (day 16) and this PG lyses the first (primary CL) as expected
If the new CL is young when the PG is released it may not be lysed (remember CLs are resistant to PG for the first 5d)
There is no new production of PG so the new CL persists
How common is a dioestrus ovulation in the mare and what does it result in and what is the treatment
Common- around 24% of cycles
Results in prolonged dioestrus
Treatment is a single does of PG
What is the most common cyclic abnormality in the mare
Prolonged dioestrus- persistence of a secondary CL, which is the result of a dioestrus ovulation
What is a granulosal cell tumour
Most common ovarian tumour in the mare
They can affect mares of many ages
They are usually endocrinologically active, so often the contra-lateral ovary is supressed and is small
Many are asymptomatic and are incidental findings (possibly in the early course of the disease)
They may secrete
Oestrogen – resulting in persistent oestrus
Progesterone – resulting in failure to cycle
Androgen – resulting in virilisation
Why are mares put under artificial light- what phase does it advance
The imposed breeding season and the natural breeding season do not coincide at least for thoroughbreds (we often try to breed when mares should not be expected to be cycling)
Supplementary light can advance the transitional phase, and then suppression with progestogens and their subsequent removal may allow onset of an ovulatory cycle
Additional drugs may be required to force ovulation after progestogen withdrawal
Effect of light on cycling mare, what is done to light and from when
Would need melatonin antagonist (not available) to stimulate oestrus
Daylight is effective if day-length is extended from December onwards
Effect of exogenous hCG on a mare
LH like activeity!
Endogenous LH (hCG [Chorulon]) causes final maturation of follicles
Attempts to induce ovulation in animals that are in oestrus
To hasten ovulation in AI regimes (i.e. ensure ovulation occurs when expected)
Effect of GnRh agonist in mare
Short-term in action (e.g. buserelin [Receptal] injection or deslorelin [Ovuplant] implant) causes stimulation of LH and FSH release
Hastening of ovulation within normal oestrus
Hastening ovulation as part of synchonisation / induction regimes
Effect of exogenous prostaglandin on mare
Exogenous prostaglandins causes lysis of the corpora lutea although early CLs are usually not responsive
Return to oestrus (synchronisation?)
Ecbolic effect
Should you swab a dog for a bacterial veneral pathogen
no
There are currently no bacterial venereal pathogens affecting dogs in the UK so screening is pointless
Brucella canis may come from Europe
What is the most common cause of infertility in bitches
incorrect mating time
Normal bitches may ovulate much earlier or later than expected- normally compared to onset of proestrus
3 conditions of ovulation in queen
Stimulation of the female (perineal/vaginal)
Frequent mating occurs within a short period of time (three matings within 12 hours)
Matings occur on the second or third day of oestrus
3 common problems affecting ovulation in queen
Queens are mated on day 1 of oestrus
Mating is not confirmed
A single mating is allowed
What is the most common cause of infertility in the queen
what is given to induce ovulation
Insufficient number of matings and mating too early in oestrus
This results in failure of ovulation which can be easily detected because of a return to oestrus after 2-3 weeks (ie there has been no luteal phase)
Alternatively detecting no rise in progesterone will also confirm lack of ovulation
Ovulation can be induced in oestrus queens either by administration of hCG (which is LH-like in activity) or short acting GnRH
After ovulation the return to oestrus is delayed
Cystic endometrial hyperplasia
Hyperplasia occurs in each luteal phase as part of preparation for pregnancy
In older bitches hyperplasia does not fully regress at the end of the luteal phase
Cysts and thickening of the endometrium may persist
This can affect establishment of pregnancy and cause pregnancy loss (usually resorption)
uterine disease is one of the most common causes of infertility especially in older bitches (probably inappropriate mating time and male factor infertility or higher on the list of causes
When do bitches normally reach puberty
between 6-23 months of age
small breeds normally earlier than larger breeds
Common problems at puberty in the bitch
It is common for the pubertal oestrus to be abnormal
Prolonged proestrus
Prolonged oestrus
Lack of ovulation = split oestrus
Silent oestrus (rare)
What is virilization
development of male characteristics
