RPM: practice questions (week 3)

male infertility cont., induction parturition/termination of pregnancy, mammary conditions, neonatal PA + equine, foal medicine, dummy foals

A 5yo Holstein dairy cow at day 272 of gestation has developed severe, treatment-refractory laminitis. The owner wants to induce parturition to reduce maternal stress while maximizing the likelihood of delivering a viable calf. What is the most appropriate method to induce parturition in this cow? 

Dexamethasone →mimics the fetal cortisol signal that initiates the endocrine cascade leading to parturition

A 4yo mixed-breed queen is brought to the clinic at approximately day 35 of an unwanted pregnancy following an unobserved mating. PE reveals the queen is healthy with no abnormalities detected. The owner requests pregnancy termination while maintaining future breeding potential. What is the safest method for pregnancy termination in this case? 

Aglepristone → progesterone-receptor antagonist

When performing a routine spay procedure, what anatomical structure is grasped using Halsted hemostats to allow for easy manipulation of the ovarian pedicle?

Proper ligament

Before closing the abdomen, it’s important to check the abdominal gutters for any pooling of blood. This is made easy by using the anatomical retractors to increase visibility of the gutters?

Mesocolon (left side) & Mesoduodenum (right side)

In preparation for a midline abdominal wall incision closure, it is important to identify the holding layer for the abdomen to ensure a secure closure. What is the holding layer for the body wall?

External rectus sheath

During the subcutaneous tissue closure, it is important to ‘tack’ it down to the body wall, doing this ensures that there is no potential dead space. What post op complication is most likely to occur if ‘tacking’ is not performed?

Seroma

While monitoring a patient under general anesthesia using a rebreathing system, the capnograph shows an inspired carbon dioxide concentration (FiCO₂) of 7 mmHg. Which of the following is the most likely cause?

Exhausted CO₂ absorbent in the anesthesia breathing circuit 

Which components of a circle (rebreathing) anesthesia system is absent in a non-rebreathing anesthesia system?

CO₂ absorbent canister, unidirectional valves

Which of the following drugs is most likely to cause an initial increase in blood pressure due to peripheral vasoconstriction, accompanied by reflex bradycardia?

Dexmedetomidine

A 3yo Jersey dairy cow has just calved following an uncomplicated full-term pregnancy. Within 24-48 hours, the farmer notes a marked increase in milk production compared to prepartum colostrum secretions. 

What physiological event is primarily responsible for initiating milk production in this cow?

Reduction in progesterone following parturition

What are some examples of the mammary glands’ anatomic defense?

-Tight junctions between epithelial cells

-Keratin lining of the teat canal

-Post-milking teat dip (reducing bacterial load)

-Teat sphincter closure

What are some examples of the mammary glands’ innate immune defense?

-Lactoferrin binding iron

-Neutrophil infiltration during infection

-Macrophages in healthy mammary gland

What is an example of the mammary glands’ adaptive immune defense?

Immunoglobulins in milk

A 4yo Holstein dairy cow presents with decreased milk production in the right rear quarter. On exam, the quarter is mildly swollen + produces milk with small clumps when stripped into a strip cup.  A California Mastitis Test (CMT) is performed during the PE, which yields a score of 1 in the affected quarter.  What is the most appropriate next diagnostic step to confirm the presence of an intramammary infection & identify the causative pathogen to guide treatment + herd management decisions?

Submit an aseptically collected milk sample from the affected quarter for C/S or PCR

What 2 factors are most important in determining if a calf is going to ingest sufficient colostrum?

Dystocia + having a suckle reflex

At what stage, post-birth, should calves receive their colostrum?

0-6 hrs post birth

What is the optimum method to supplement colostrum in beef cattle?

Bottle feed

Why should colostrum be pasteurized before being given to a calf?

To reduce the bacterial load of the colostrum due to a raised abomasal pH

How often must a calf be fed so the animal does not enter a negative energy balance?

Every 12- 18 hrs

How can we treat a stallion with penile trauma?

-Stall + sexual rest

-Elevate! → replace penis in sheath + put in retention stitches or sling/belly wrap

-Lubricate

-Cold water hydrotherapy 2-3x/day

-NSAIDs, corticosteroids, antibiotics

What is the inability to retract the penis back into the prepuce called?

Paraphimosis

What drug can cause priapism (persistent erection without sexual stimulation) leading to paraphimosis & penile paralysis in breeding males?

Acepromazine

How can you diagnose cryptorchidism via transrectal exam if unable to feel the testes in the scrotum of a stallion?

Find inguinal ring & feel for the spermatic cord running through it

What is the most reliable hormone assay that you can use to aid in diagnosis of cryptorchidism in a stallion & how does it work?

hCG stimulation test

-take blood sample → admin hCG (10,000IU IV or IM) → take blood samples @ 30 min intervals for up to 3hrs (or just one sample @ 3hrs post-hCG) → should see marked increase in testosterone after hCG admin in intact stallions

What two hormone assays are used most often to diagnose cryptorchidism in stallions?

hCG stimulation test + Antimullerian hormone (AMH)

What are some of the differentials that may cause a swollen scrotum?

Inguinal hernia, Hydrocele, Torsion of spermatic cord, Orchitis, Trauma

What treatment for long-standing torsion of the spermatic cord can be performed if you want to protect spermatogenesis in the contralateral testis?

Hemi-orchidectomy

Orchitis + epididymitis are more commonly seen in which species?

Small ruminants

What may occur due to chronic changes of the scrotum from a scrotal trauma?

Exposure of the body to sperm results in anti-sperm antibody formation

-also sperm granuloma, testicular degeneration/atrophy, infertility

What is the treatment of choice for a unilateral hydrocele in a valuable breeding stallion?

Removal of the affected testis

A stallion presents at the beginning of a new breeding season for history of mares not getting pregnant after covering. You evaluate the semen & find azoospermia/oligospermia as well as low alkaline phosphatase (ALP) concentration in the stallion’s ejaculate. What is your top differential diagnosis?

Blocked ampulla

How can we treat a blocked ampulla in a stallion?

Repeated semen collection, PGF2a, Oxytocin, Manual massage per rectum

A 4yo Standardbred stallion is presented to you in the US in November for a BSE. The stallion appears normal on physical, external, & internal reproductive exams. Semen is collected using an AV & on evaluation you find that the semen is watery to slightly milky in color with about 20% progressively motile + 10% morphologically normal spermatozoa. What is the best evaluation of the stallion’s breeding potential?

Questionable breeder; re-examine after multiple semen collections

A stallion presents with blood in the ejaculate but no other clinical signs. What is your top differential based off this information alone?

Tear in the pelvic urethra

What venereal disease in stallions shows up as an external genital infection that may cause pain during coitus, but becomes non-infectious once the ulcers have healed (although chance for reinfection is high)?

Coital exanthema → EHV-3

What is the abnormal termination of the penile urethra along the ventral surface of the penis due to incomplete fusion of the median raphe of the penis/prepuce/scrotum in the dog, most commonly presenting with urinary incontinence + associated dermatitis?

Hypospadia

Balanoposthitis is inflammation of the ____ ____ as well as the _______.

Glans penis, Prepuce

What dog breeds most commonly present with urethral prolapse secondary to sexual excitement or urethral infection?

Brachycephalic breeds (especially English Bulldogs) or Toy breeds

An English Bulldog presents with a red “pea” appearance at the tip of the penis, frequent urination, & intermittent bleeding from the preputial opening. What is your top differential diagnosis?

Urethral prolapse

How do we typically treat urethral prolapse in dogs?

Surgical replacement of prolapsed tissue with urethropexy

What are some of the potential differentials for a dog that presents with a “bloody” penis?

-Penile laceration

-Fracture of os penis

-Urethral prolapse

-TVT

-Prostate disorders

What are some of the potential differentials for a stallion with azoospermia (complete absence of sperm in ejaculate)?

-Plugged ampulla

-Incomplete ejaculation

-Testicular degeneration

-Retrograde ejaculation

-Congenital hypoplasia of epididymides

-Genetic abnormalities (trisomy)

How does scrotal dermatitis affect fertility of breeding males?

Inflammation of scrotum = increased intrascrotal temp. = decreased fertility

What is described as the collection of fluid in the vaginal cavity of a breeding male, commonly due to trauma to the testes?

Hydrocele

In the dog, how long after birth do we give the testes to drop into the scrotum before we can call them cryptorchid?

6 months

Retained testes are capable of _______ but not ________.

Steroidogenesis, Spermatogenesis

An owner presents a 3yo apparently neutered male dog she adopted from a shelter a year ago. The dog has been showing mounting behavior making the owner suspicious about its neuter status. On visual exam, palpation, & U/S, there is no evidence of testes being present. Serum LH test is positive (high LH) + serum AMH test is negative (undetectable AMH). What is the correct interpretation of these results?

The dog is neutered

-high LH + negative AMH both indicators for neutered dog

What should all dogs with scrotal enlargement (orchitis) also be tested for?

Brucella canis

A client presents a 2yo male dog that she adopted from a shelter. The client wants to know if the dog has been neutered. Visual exam + palpation of the scrotal & inguinal areas does not indicate the presence of testes. What test would be most likely to give you a confirmatory diagnosis?

GnRH/hCG stimulation test

When do tomcats lose the spines on their penis post-castration?

6 weeks

A 2yo male cat recently adopted from a shelter is presented to determine if he is neutered. On visual exam & palpation of the scrotal + inguinal areas, testes cannot be found. What is the best next diagnostic step?

Exam of the penis (for spines)

A 2yo male cat recently adopted from a shelter is presented to determine if he is neutered. On visual exam & palpation of the scrotal + inguinal areas, testes cannot be found. Exam of the penis indicates absence of spines. What is the best interpretation of the findings?

The cat is definitely neutered

What can we use to terminate pregnancy in the cow up to day 150 of gestation, where the corpus luteum is the major source of progesterone?

PGF2a alone

What can we use to terminate pregnancy in the cow from day 150-250 of gestation, where the placenta is the major source & the corpus luteum is the minor source of progesterone?

Combo of PGF2a + Dexamethasone

What can we use to terminate pregnancy in the cow from day 250 of gestation until full term, where the corpus luteum is the major source of progesterone?

Either PGF2a alone, Dexamethasone alone, OR a combo of both

What drug would work best to terminate pregnancy in an ewe at 4 months of gestation (