What are the critical points in the chain of events that has to take place after parturition to breeding?
Parturition, cycle again, ovulate/ breed, maintain pregnancy, neonatal mortality
Rectum, prostrate, and bladder location in a dog
What are the four possible anatomical locations for the retained testicle?
1. External to the inguinal canal
2. Within the inguinal canal
3. Incomplete abdominal cryptorchid- epididymus protrudes into the inguinal canal but the testicle remains in the abdominal cavity.
4. Complete abdominal cryptorchid- all structures are retained within the abdominal cavity
Ampullary and vesicular gland
What test would you perform to a potential cryptorchid?
Which stage does meiosis occur?
When does meiosis occur in spermatogenesis?
What is canine pyometra?
Accumulation of purulent secretions in the uterine lumen of sexually intact bitches, with an open or closed cervix (open or closed pyometra)
** endogenous and exogenous gestagens seem to play a role over an extended period
* a canine uterus under the influence of progesterone is susceptible to bacterial infections as progesterone stimulates the growth of the endometrial glands and their secretory activity, along with cervical closeure and suppression of myometrial contractions
*Most bitches with pyometra are presented during the luteal phase of the cycle with purulent vaginal discharge in cases of open pyometer and PU/PD (closed pyometra- often presented at a later stage of disease when endotoxins absorbed from the uterine lumen already resulted in a generalized isllness-- elevated WBC count, prerenal azotemia, hyperproteinaemia, and hyperglobulinaemia)
** treated surgically-- ovariohysterectomy OR prostaglandins or anti-progesterone
How do uterine infections vary between cows and mares?
In cows it usually occurs post parturition, while in mares it is usually post mating
What do uterine infections typically occur in cows, dogs, and mares?
What does this mean?
Likely a uterine infection
What does progesterone actually do?
Progesterone induces oestrogen receptors, remove progesterone block on the hypothalamus (FSH & LH)
What would you find on a cow's ovary to be sure she is cycling?
Dominant follicle. Bigger vs. an anoestrous cow.
Could potentially have a "cystic cow"- follicles can become cystic "follicular cysts" or "luteal cycts"- cysts with luteal tissue-- follicular cysts can turn into luteal cysts (could give GnRH (other species hcg)--to cause luteinization which would turn it into a luteal cyst-- then give PGF2alpha a week later)
What species do and don't get follicular cysts?
* Horses do not have follicular cysts
* Dogs and cows can get follicular cysts
Why is it better to inseminate 48 hours before a horse ovulates? What is the absolute latest?
* must inseminate before indogenous LH surge, otherwise you've missed your window for AI
* give hcg (ovulation would occur 36-42 hours after--cheaper and easier to place) or GnRH agonist (ovulplant- more expensive) (42-48 hours after)
* At that stage oestrogen is high which is a natural anti-inflammatory (responding to the immediate physiologic inflammatory response) to get rid of everything in the uterus except for a few sperm before the oestrogen drops off and the cervix closes
* What is the absolute latest? 6 days when the embryo enters the uterus, but not a good idea as cervix is closed and much more likely to induce an infection
** always a trade off between semen longevity and giving the mare time
Why is it important for the cervix to stretch? Difficulty with an old maiden? What is one advantage of natural breeding?
So it can drain. Difficulty in an old maiden- tight cervix.
Stallion stretches cervix. So you manually stretch cervix with up to 4 fingers.
What is more likely to introduce infection, natural breeding or AI with a mare?
natural has a higher chance of introducing bacteria and debris from stallion's penis... AI done properly would probably be better because it is sterile (antibiotics) and you are only putting in as much as needed for optimal dose, not overloading the system and stretching the cervix up to 4 fingers. But you have to stretch the cervix, if you don't then the stallion would be better.
When does oxytocin work in mares, cows, and dogs? Why would it be bad to give oxytocin too late?
Mares always respond to oxytocin.
Dogs and cows- when oestrogen levels are high (because oxytocin receptors are present)
**Bad to give oxytocin too late because you could impair the CL... positive feedback between PGF2alpha and oxytocin-- PGF2alpha only acts on the CL after 5 days-- but if you have high levels of oxytocin you can impair the CL earlier potentially
Diagnosing pyometra in a dog, what is your first advice? How do you treat if they want to treat with drugs?
Spay. (side note: Closed pyometra is treatable)
Treat with PGF2alpha-- open the cervix and antibiotic
What is the difference between endometritis? Metritis? And pyometra?
Do not get endometritis with systemic signs. Metritis has systemic signs as well. Pyometra is really a descriptive term- pus in the uterus.
What is the normal average gestation period for a sheep?
When are sheep often due to start lambing?
What type of placenta does a sheep have?
Foetal liver of aborted foetus
Campylobacter spp. either subsp fetus or C. jejuni
Some organisms that cause abortion in sheep are zoonotic, can they cause abortion in humans?
Toxoplasma gondii, Campylobacter jejuni, Listeria monocytogenes, Clostridium perfringens, Brucella ovis
Which of these is most likely to cause a mummified foetus?
Toxoplasma gondii, Campylobacter jejuni, Listeria monocytogenes, Clostridium perfringens, Brucella ovis
True or false. Compared to the epitheliochorial placental structure in sheep, dogs have an endotheliochorial placental structure. This means that of the maternal cell layers, none remain and teh maternal blood is in direct contact with the outermost foetal membrane layer (the chorionic epithelium).
Which of these are zoonotic?
ALL of them
Which of these organisms is least likely to cause abortion in sheep? Toxoplasma gondii, Campylobacter jejuni, Listeria monocytogenes, Clostridium perfringens, Brucella ovis
Ewes that abort due to Campylobacter infection are unlikely to have problems with Campylobacter abortion in the future because they develop immunity to infection. Is there a vaccine available against C. fetus supsp. fetus?
True or false. Campylobacter fetus supsp. fetus infection in sheep does not result in infertility in either ewes or rams. In comparison, infection of cattle with Campylobacter fetus subsp. venerearlis can result in infertility.
Most common Campylobacter spp. isolated from human infections
Campylobacter infection usually results in abortion at what term of gestation? Or what else could result?
Can you tell the ewe is sick?
Late term abortions & Weak, full term lambs.
Ewes usually appear clinically well. Some may have a slight vaginal discharge. Ewes can develop metritis following abortion, but death of ewe is uncommon.
What diseases does Guardian 6 in 1 protect sheep against?
Corynebacterium pseudotuberculosis, Clostridium perfringens, Clostridium chauvoei, Clostridium septicum, Clostridium novyi, Clostridium tetani
With infectious agents in a foetus, what organs to sample? What else?
Liver, lungs, spleen, thymus
* 2 Cotyledons with tissue in between
What is the optimum time and duration for observation of oestrus in cows?
* Two 15 minute periods a day after the morning milking and prior to the afternoon milking
At the end of 6 weeks, Laurie has 60 cows that have not been inseminated. How many bulls would you advise him to run with his herd in order to successfully breed with these cows and cows that return to oestrus after AI?
What is the medication of choice for inducing calving?
Dexamethasone trimethylacetate (Opticortenol)- a long acting corticosteroid
** Another option is Cloprostenol (Estrumate)-- you administer this for the remaining cows that have not been induced-- Cloprostenol is a synthetic prostaglandin F2alpha analogue
What are some of the risks of early induction?
Retained fetal membranes, hypocalcaemia (milk fever), post partum septicaemia, calves born as "slinky calves" (smooth silky coats)-- premature calves with low birth weight-- cannot stand
** Most importantly: calves that are induced at around 8 months or less are generally euthanized shortly after birth
When is induction of parturition for cows a good idea?
* useful tool for treatment of medical conditions to save the life of the fetus or the cow- the fetus will gain about 0.5 kg/day in the final weeks of normal gestation and 1 kg/day when gestation has progressed beyond the normal due date-- may be used to prevent dystocia from an oversized fetus
** As well as used to schedule calving to occur during daylight hours or known dates for personnel
** allow the cow extra time to resume cycling for rebreeding when gestation is prolonged
Describe the hormonal changes that occur during the bovine oestrus cycle
* Progesterone from the CL through gestation-- luteal regression is necessary for parturition to occur-- after 120 days of gestation, the placenta begins to secrete progesterone and this source alone is sufficient to maintain pregnancy until approximately 240 days
* rising fetal cortisol in the last 4 to 6 weeks of gestation gradually reduces the uteroplacental synthesis of progresterone, therefore near the end of pregnancy, maintenance of pregnancy will again become dependent on the CL-- if luteolysis occurs before the 8th month of gestation pregnancy would be maintained for a time, but parturition would likely occur several weeks before the normal due date
What maintains uterine quiescence?
High concentrations of progesterone maintain uterine quiescence by hyperpolarizing the myometrial cells. At the end of gestation, falling progesterone and increasing estrogen produce depolarization of the myometrial cells and stimulate the formation of the myometrial cell gap junctions that enhance the sensitivity of the myometrium to stimulatory agonists
Explain the hormonal basis for the maintenance of pregnancy in cattle and how drugs may be used to interfere with this mechanism to allow induction of parturition.
* corticosteroids (most commonly Dexamethasone- 80-90% success about 48 hours later when given within 2 weeks of normal term) or prostaglandins in combination with various estrogen preparation and oxytocin.
* when corticosteroids fail, it is likely because we aren't removing the ovarian source of progesterone-- whereas prostaglandin injections efficiently remove the ovarian source of progesterone but may fail because of the remaining placental progesterone-- a combination of prostaglandin and corticosteroids would remove both sources of progerstone
** Dimenhydrate and relaxin WITH dexamethasone have been reported to reduce placental retention
* Long acting corticosteroids (such as Dexamethasone trimethyl acetate or triamcinolone acetonide) are given when calf viability is not of primary importance but for synchronization (long acting corticosteroids retention of fetal membranes is low, but calf mortality is high)
Normal range of duration for stage one of parturition of a bitch is? Is there evidence of straining in stage one?
6 to 12 hours
No evidence of straining in stage 1
What is the normal interval between pups in stage 2 or parturition in the bitch?
15 minutes to 2 hours
Is a green to black vulval discharge normal in a bitch during parturiton? Ewe?
Bitch- yes ; ewe- no
Average gestational length in a cat? Rabbit?
Cat- 65 days; Rabbit- 30 days
What does it mean for a newborn to be altricious? What is an example of a species that is?
Their skin is without pigment or hair at birth. Rabbit.
Where does the green-black discharge come from in the bitch?
Part of the chorion
What are the stimuli to the straining reflex in an animal during parturition?
* Stretching of the vagina, stretching of the cervix, suckling of the puppies already born.
Acepromazine is a sedative, it is not an analgesic. What is it likely to cause in a bitch?
* Hypotension with an associated reflex tachycardia
What is ventricular tachycardia?
* A rapid and irregular heart rate associated with premature contractions (VPC's) identified on an ECG trace
Will morphine cross the placenta to enter the unborn puppy?
What is a possible consequence to puppies of morphine administration during whelping?
Depressed post natal respiratory drive
With a bitch during parturition with generalized skeletal muscle twitching, abscence of straining when vagina is distended with speculum, and failure to deliver a pup after two or more hours-- what might you think is one of the problems?
What hormones deal with mobilizing stored calcium?
* Parathyroid hormone
What could the vet have done better in the case of two dead pups and dead mom?
* Correction of hypocalcaemia with IV calcium gluconate prior to surgery
*Aggressive fluid therapy piror to surgery for correction of fluid balance and any acid/ base anomalies was indicated
* if pre medication is required (though commonly not required) then a low dose or partial mixed opioid would be more appropriate (butorphanol or bprenorphine). Acepromazine provides excellent sedation but is profoundly hypotensive. Morphine provides excellent analgesia but causes marked cardiovascular depression
* clip prior to anathesia so she doesn't have to be under as long
* pre-oxygenating the bitch is a good idea since all induction agents, and inhaled gaseous anaesthetics are cardio-respiratory depressive
* Isoflurane inhalation should be kept to a minimum to reduce cardio respiratory depression and resulting hypotension
* prior preparation is important- a warm dry area should already be prepared for the puppies