Equine Repro Flashcards
What are some of the methods of artificial lighting?
Constant lighting (14-16 hr day), intermittent (1-2hrs during night) or gradual increase
What should the intensity of light be for artificial lighting?
You can just read a newspaper in the stable
List 2 dopamine antagonists and describe how they work
Sulpiride or domperidone. Increase prolactin secretion to increase LH receptors
Why would we choose to use a dopamine antagonist?
Used to induce oestrus in mares not undergoing ovulation
How else can we induce early onset of oestrus?
Give mare increasing amounts of artificial light and commence treatment with domperidine daily once follicles are 15mm. can also give progestins in the late transition period when follicle >25mm.
What do you need to keep in mind when managing a mare that has not yet ovulated this season?
It is best to confirm if the mare has ovulated at least once this season before treatment because anovulation may occur if the mare remains transitional
List some of the methods used to synchronize oestrus/ovulation in mares
Terminate luteal phase, lengthen the luteal phase, induce ovulation or inhibit follicular development
How many shots of prostaglandin injection is most effective in inducing oestrus?
2 shots 2 weeks apart
How can you lengthen the luteal phase?
Exogenous progestins: 10-15 days of Altrenogest, cue-mare or compound pharmacy, progesterone
What are some admin methods of progestins?
Orally, injectable or Cue-mare
How can you induce ovulation?
hCG (human chorionic gondaotropin) or deslorelin acetate
After what day post-partum is pregnancy conception survival significantly higher?
15
What are some of the approaches to breeding a foal heat?
Scan mares during early post-partum period, breed mares at foal heat if ovulation is >10 days and there is little/no fluid. If ovulation occurs before day 10 and/or fluid remains in the uterus, delay breeding and administerPGF2a 5-6 days post ovulation
How can you immunologically suppress oestrus?
GnRH vaccine called equity, 2 doses 30 days apart. Use in mares that are not intended for breeding. Induces anoetrus within 4 weeks. Duration of action is normally one year.
How else can you suppress oestrus?
Ovarectomy, theoretically aborting a 40 day pregnancy, glass marbles,
How can you induce oestrus in the mare?
Artificial lighting, dopamine antagonists, GnRH, progestins and combinations of methods
What method would you use to induce ovulation in the mare?
Administer hCG or deslorelin when a follicle 35mm in diameter is present
How could you delay breeding at foal heat?
Delay ovulation by administration of altrenogest (progestin) from the day of foaling until day 8, inject PGF2a on day 9
What are the advantages of AI in the mare?
Genetic gain, disease control, reduces mare contamination, safety, prevents overuse of stallions, enables semen to be regularly evaluated, less transport of horses
What are the disadvantages of AI in mare?
Restrictions of AI on certain breeds, need to be organized, transport may not arrive on time
Describe the process of collecting and preparing semen for transport or preservation
The stallion has a mare in sight teasing. The penis is washed to minimize contamination and he then approaches the phantom. Upon mounting the phantom the semen is collected with the AV. Once collected the warm water in the AV is removed and the semen is collected into the vial. A semen extender that may contain buffer, protein, energy and/or antibiotics is added to the fresh semen at a normal ration of 1:3 Semen:extender. You want 500 million progressively motile, normal semen per AI mare.
What is the management protocol for AI mares with either cooled or frozen semen
Open the package, check the instruction, check correct stallion and mare, aspirate into syringe and inseminate after checking mare is well. Can AI mare with fresh 5 days before ovulation. With frozen semen need to thaw and AI mare 12 hrs before and 6 hours after ovulation. Can use double insemination or single insemination for frozen. If only single insemination scan every 6 hours until ovulation and then AI when ovulation occurs. RE-examine mare less than 12 hrs post ovulation to confirm ovulation and to look for the presence of any fluid.
Describe the methods of equine embryo collection and transfer in mares
Synchronize ovulation between donor and recipient mares ? breed donor mare ? flush uterus of donor mare and retrieve embryo (usually day 6,7,8 post ovulation) ? wash and evaluate embryo ? load into transfer straw ? transfer to uterus of recipient. Transfer can be surgical or non-surgical
Describe how you would prepare embryo transfer recipients
Age 3 ? 10 yrs, ovulated 1 day before or 0-3 days after the donor mare, need to have had more than 2 cycles before transfer. Synchronize mares with PGs, progestins and progesterone
What are some abnormalities of the vagina?
Persistant hymen, laceration, adhesions, urine pooling, vaginal bleeding
Describe a persistent hymen
A vestibule vaginal junction just cranial to the urethral opening that can prevent intromission and may need to be incised if breeding is required. The caudal end of the paramesonephric duct fails to join the invagination of the vestibule.
Why do an endometrial biopsy?
To evaluate the endometrium and provide a diagnostic and prognostic aid
What are the two types of endometrial cysts?
Glandular and lymphatic lacunae
What is the clinical significance of cysts?
Large numbers have been associated with infertility and interfers with embryo migration. Can create confusion on pregnancy diagnosis
How do you diagnose and treat cysts?
Cysts on ultrasound are not spherical , may have an irregular outline and are consistent in position and do not increase in size. Ultrasound, uteroscopy and biopsy. Treat by cyst ablation for larger cysts using biopsy forceps, needle aspiration or laser forceps
What are the clinical signs of gonadal dysgenesis (chromosomal abnormalities)?
External genitalia are female, vulva may be smaller than normal and stature may be smaller. Persistent or irregular periods of anoestrus. Small ovaries, small uterus and a flaccid paled dilated cervix.
How do you diagnose gonadal dysgenesis?
Karyotyping
What is the most common neoplasia reproductive disease of mares?
Granulosa thecal cell tumor
What are the three main presentations of granulosa thecal cell tumors?
Anoestrus, prolonged oestrus behaviour or stallion like behaviour
What are the hormonal findings of GTCT?s?
Elevated inhibin, elevated testosterone and elevated anti-mullerian hormone
What are the other clinical findings of GTCT?s?
Slightly enlarged ovary and one small ovary, on ultrasound a honey comb appearance, needs to be differentiated from ovarian haemotoma (haemotomas appear quickly and regress over time). Treatment: ovariectomy and horse returns to normal usually within 8 months
What can cause irregular oestrus cycles?
Vernal transmission and age related cycle irregularities (getting too old for getting jiggy)
AT what age does fertility decline in mares and how so?
13 and then again at 20 drastically. This is due to abnormal oocytes which when fertilized experience a higher rate of early embryonic loss
What can be cause of anoestrus in mares?
Season, nutrition, disease, ovarian tumors, chromosomal abnormalities, lactational anoestrus
What are anovulatory follicles?
Follicles that reach ovulatory size during oestrus but fail to ovulate. And may stay that way for weeks ? intrafollicular haemorhhage can then occur. There is an increase in Echogenicity of antrum associated with haemorrhage into follicle.
What is metritis?
Inflammation of the myometrium
What are the mechanisms by which endometritis causes infertility?
Induces release of PGF2a and placentitis
What are the 5 main types of endometritis?
Post mating endometritis, chronic endometritis, transitional endometritis, pyometra, endometriosis
What are some conformational factors that can contribute to the development of endometritis?
Incompetent vulval seal, cranial sloping of the vagina, tears in vulval lips, rectovaginal fistula, incompetent vestibule-vaginal constriction
How can you treat transient endometritis?
Correct conformational abnormality
What is the definition of post mating-induced endometritis?
Retention of >2cm of fluid in the uterus > 18hrs after breeding
Why do mares get post mating endometritis?
Mares maintain an excessive amount of fluid and are unable to clear the fluid from the uterus. Provides for a favourable site for bacteria and retention of dead sperm.
What are the predisposing factors for post-mating endometritis?
Age, reduced myometrium activity, failure of cervix to relax in oestrus, insufficient reasorption into lymphatics,
How do you diagnose post- mating endometritis?
Ultrasound
How do you treat post-mating endometritis?
Sexual rest, minimum contaminating breeding technique, limiting breeding to one per round, uterine lavage, ecbolics, intrauterine antibiotics, exercise
What are ecbolics and what are they used for?
Cause contractions of the myometrium. Oxytocin and prostaglandins.
Would you give prostaglandin post ovulation?
NOOOOOOOO ? due to risk of decreasing plasma comcentration of progesterone
What are the pre-breeding strategies for avoiding post mating endometritis?
Use of oxytocin, digitally dilating cervix, lavage and single mating
What are the after mating strategies for avoiding post mating endometritis?
Oxytocin, lavage and oxytocin 24hrs after, low volume of non-irritant antibiotic, re-examine next day and repeat treatment if needed.
What are the signs of chronic endometritis?
History of infertility, matting of tail hairs, exudate, ultrasound there is fluid accumulation, urine pooling and faecel debri in vulva
What are the most common infectious causes (agents) of chronic endometritis?
Strep. Equi zooepidemicus, E.coli,
How do you diagnose endometritis?
Cytology, culture and biopsy
When should you do the testing for endometritis?
In oestrus the uterus is more resistant to human introduced bugs but may give contamination to our sample. In dioestrus culture better but we will probably introduce bugs to the sterile uterus.
How should you interpret your diagnostic tests?
You need to find more than one line of evidence to indicate a clinically significant infection is present.
How do you treat chronic endometritis?
Correct conformational abnormalities, check cervix, lavage, ecbolics, antimicrobial therapy
How do you try to prevent chronic endometritis?
Use minimum contamination breeding techniques: wash the horse genitalia, use AI, pre-treat mares uterus with antibiotics with extender (must be non-spermocidal), post breeding uterine lavage and ecbolic treatment. Sexual rest, immune stimulants, immune stimulants and mucolytics.
How would you treat fungal induced endometritis?
Uterine lavage and antifungals
How do you diagnose Taylorella Equigenitalis?
Swab and culture of clitoral surfaces and urethral surfaces.
How do you treat Taylorella Equigenitalis?
Intrauterine infusion and topical treatment. Local clitoral treatment and interuterine treatment (penicillin), clitoral sinusectomy
How do you treat pyometra?
Induce luteolysis, establish drainage, lavage, intrauterine antibiotic therapy
What is endometriosis?
Chronic degenerative changes within the endometrium associated with age and increase of births.
How do you diagnose endometriosis?
Endometrial biopsy
How do you treat endometriosis?
Correct conformational abnormalities, saline lavage,
What are the ultrasonic signs of early embryonic loss?
Irregular shape of embryonic vesicle, prolonged mobility of vesicle, fluid in uterine lumen, loss of heartbeat, undersized embryo for age, excessive endometrial oedema
How do you manage early embryonic loss?
Serial exams day 12-60. Progesterone, nutrition, NSAID, re-breeding, terminate pregnancy
What can cause uterine insufficiency?
Aging and fibrosis
What is a uterine body pregnancy?
When the embryo fixes in the uterine body rather than the base of the horn ? placental insufficiency, retarded foetal growth
What is hydrops of the foetal membranes?
Excessive accumulation of foetal fluids within the fluid membranes
What are the two types of hydrops?
Hydrops amnion and hydrops allantois (most common one)
What are the clinical signs of hydrops?
Enlarged abdomen, on rectal palpation feel enlarged uterus and maybe foetus not palpable, upon ultrasound there is excessive allantoic or amniotic fluid. Depression, anorexia, abdominal pain, tachypnoea
What is the treatment of hydrops?
Induction of abortion (foetus usually non-viable), pretreat mare with IV fluids and assit birth to avoid dystocia, supplementary treatment for maybe months
What are some complications of hydrops?
Rupture of prepubic tendon or abdominal musculature, inguinal herniation, uterine rupture, abortion
What are the pre-disposing factors of ventral abdominal ruptures?
Older mares, mares with twins, hydrops allantois, trauma
What are the signs and cause of ventral abdominal ruptures?
Ventral swelling, oedema, abdominal pain, swellin of udder, ?sawhorse?, subcutaneous haemorrhage and cold abdominal skin
What is the treatment of ventral abdominal ruptures?
Save mare: induce parturition. Save foal: apply support wraps and nursing until parturition, euthanasia is medical treatment not warranted
What is luteal insufficiency?
Luteolysis or inadequate production of P4 concentrations up to days 80-120
What are the treatment options for luteal insufficiency?
Treat with altrenogest until day 60 check p4, check until day 120, treat until 2 weeks before parturition and gradually decrease dose when ending treatment
What are the clinical indications for progesterone supplementation?
History of early embryonic loss, mares induced to ovulate that likely to be compromised, placentitis, evidence of uterine oedema, small for age vesicles, plasma concentrations of P4 low, non-ovulatory mares that are used as recipients for ET
What is a contraindication of progesterone supplementation?
Endometritis
What should you tell the client who has a twin pregnancy?
Describe the origin of twins in mares
Dizygotic twins that can be uni or bilateral (monozygotic twins rare)