Small Ruminant Repro Flashcards
Goals of small ruminant repro
Commercial, pets/ acreage sustainability, purebred/show
Ewe and doe anatomy
Bicornuate uterus, ringed cervix, caruncular pigment in black-faced sheep
Placenta of the ewe and doe
Epitheliochorial cotydedonary placenta
No commingling of fetal blood supply
Concave placentomes
Puberty and breeding of the ewe
Puberty: 6-8mo
Breeding age: 8-10mo and 60-70% mature wt
Breeding season: August- January (↑ darkness)
Estrous cycle in the ewe
Cycle: 14-19d (ave 17)
Estrus: 15-45 hrs (ave 30) with ovulation at the end of or after behavioral heat
Gestation length for the ewe
145-150 days or 5m
Puberty and breeding of the doe
Puberty: 6-8mo (3m for Nigerian or pygmy)
Breeding age: 6-10mo and 70% mature wt
Breeding season: August- March (↑ darkness)
Estrous cycle in the doe
Cycle: 18-22d (ave 21)
Estrus: 24-72 hrs (ave 36) with ovulation 12-36 hrs after behavioral heat
Gestation length of the doe
147-155 d (5m)
Estrus behavior
Seek out the male: fence line, vasectomized male, marking harness (sheep), buck rag (goat)
Vocalization ↑ and rapid tail wagging in the doe
Vulva area pinker
Estrual discharge in the doe
Clear mucous discharge at the start of estrus
Cloudy as estrus ends
Thick and caseous (normal)
Physiology of short-day breeders
Longer dark pds: less inhibition of the pineal gland
↑ melatonin secretion
Stimulate GnRH, FSH and LH produced
__________ during transition can ↑ OV rates
Flushing
Ram/Buck effect
Pheromones of the male induce cycling in females
Isolate males from females for 30-60d prior
LH surge and OV within 6d of intro of male
What is the Ram/Buck effect for?
Used to synchronize estrus
CIDR for breeding manipulation
CIDR used alone or with hormones (PG600, GnRH)
Light duration for breeding manipulation
18-20hrs for 60d then slowly ↓ to 8-10hrs
House male and female separately
Does that exhibit estrus every _________ are potentially _________. What do you treat it with?
5-7d
Cystic
Tx with GnRH and CIDR
Pregnancy Dx
US: rectal- early or abdominally- 45 -70d of gestation
Blood: pregnancy associated glycoprotein (PAG)
Urine: P test- estrone sulfate
Sheep pregnancy maintenance
CL only required until 50-60d of gestation
Goat pregnancy maintenance
CL required throughout pregnancy
Parturition
3-6hrs
Stage 1: 1-4 hrs
Stage 2: up to 2 hrs, multiple kids within 30-45min
Stage 3: 1-4 hrs, longer for first fresheners
Causes of dystocia in the ewe/doe
Fetal postural abnormalities*
Incomplete dilation, fetal monster, simultaneous presentation during delivery of multiple kids/ lambs, fetal-maternal disproportion
Induction of parturition of ewes
After 142d gestation
Dexamethasome
Lambs within 48 hrs
Induction of parturition in does
After 144d gestation
PGF2a (cloprostenol), dexamethasone if pregnancy toxemia
Kidding within 30 hrs
Vaginal prolapse
Prepartum (3w before lambing)
Caused by genetics, tail docked too short, too fat, resp. dz
Tx of vaginal prolapse
Cleanse with mild soap
Gently replace +/- lidocaine epidural
Maintaining cervix (harness, sutures, paddle)
T/F: cull ewe/doe post-weaning of her lamb and kid if she has a vaginal prolapse
TRUE
don’t keep offspring
Uterine prolapse
Postpartum random occurrence (dystocia)
Emergency
Tx of uterine prolapse
Cleanse with mild soap and water
Gently replace +/- caudal epidural (lidocaine)
Suture/harness
NSAIDs, broad spectrum antimicrobials
+/- calcium
Pseudopregnancy in goats
Hydrometra or “cloudburst”
Prolonged luteal phase
Sheep/goat hybrids, out of season breeding, last estrus of breeding season, EED or abortion with retained CL
Signs of pseudopregnancy in goats
Anestrus
↑ abdominal signs
Behavioral signs of pregnancy
Udder development
Tx and Dx pseudopregnancy in goats
US and tx with PGF2a
Infectious abortion
Most common cause of abortion: infectious cause
Chlamydophilia/ Chlamydia abortus, toxoplasma gondii, campylobacter
Abortion in sheep and goats
Later term
Submit placenta for dx
Abortion causing organisms are zoonotic: coxiella, listeria, toxoplasmosis, campylobacter/vibrio
Campylobacter Abortion
C. fetus fetus: abortion storms
C. jejuni: sporadic cases of abortion
Oral transmission
CS of campylobacter
Stillbirths, weak lambs
Focal areas of necrosis in liver (target lesions)
Tx campylobacter abortion
Antimicrobials with penicillin or tetracycline (resistance common now)
Chlamydophilia/ Chlamydia abortus
Transmitted via oronasal exposure
Abortions in last 2-3w of gestation (necrotizing placentitis)
Infection maintained in chronic carriers
Control of C. abortus
Vx: 8w and 4w pre-breeding (repeat annually, don’t eliminate infection, prevents abortion)
Remove aborting females for 3w
Tx of C. abortus
Oxytetracycline in the last 4-6w of gestation
Q fever abortion
Coxiella burnetti
3rd semester abortions
Necrotic placentitis with abortion storms in cattle, sheep and goats
Transmission of Q fever
Contact with contaminated tissues or fluid
Spread by wind in dry dusty conditions
Ticks minor source
Brucellosis and abortion
B. ovis: ram dz
B. melitensis: rare in US but zoonotic
Third trimester abortion from placentitis, causes malta fever in humans, goat-specific, abortion in sheep
Parasitic causes of abortion
Toxoplasmosis
Stillbirths, necrotic foci on cotyledons (pepperoni lesions)
Viral causes of abortion
Bluetongue: skeletal deformities, hydrocephalus
Border Dz: hairy shaker, skeletal deformities, neuro deficits
Artificial insemination
Vaginal in goats and laparoscopic in sheep
Male not needed on farms
AI equipment
Semen tank (liquid nitrogen)
Goat AI gun
Vaginal speculums
Light source
Thermometer, straw cutter, thawing jaw and sterile lubricant
Significance of the male reproductive tract
Urethral process (urinary canniculi common @ the end)
Physiology of the Ram
Puberty: 6m
Breeding age: 8-10m
Breeding season Aug- Jan (↑ darkness)
Ram breeding ratio
3-3.5 mature rams / 100 ewes
4-7 rams/ 100 ewes
Physiology of the Buck
Puberty: 4m (2m in pygmy and nigerians)
Breeding age: 6-10m
Breeding season: peaks with ↑ darkness
Buck breeding ratio
3-4 mature bucks / 100 does
4-7 rams/ 100 does if <1yr
Ram selection
Select male offspring of high producing ewes for optimal fertility: #of lambs born, wt. of lambs weaned, ewes lambing early in the season
Co-twin to a male
Structural soundness and libido
Buck selection
Progeny testing for traits: dairy, fiber, meat
Testicular size: large testicles and high quality semen
Avoid phenotypically polled bucks
Reasons for poor reproductive performance
Poor leg conformation
Arthritis
Splay toes
Buck rut behavior
Urinate on front legs and face
Blubbering
Challenging behavior (lowering head, rearing, shoving)
Guarding behavior (keeping you away from does)
Body condition
BCS 3.5 to 4/5 @ the start of breeding season
Causes of male infertility
Epididymitis
Ulcerative posthitis
Sperm Granulomas
Varicocoele
Caprine Intersex Syndrome
Epididymitis
Impt. dz in rams (reportable)
Brucella ovis most common, esp. in mature rams
Exposure via mm
Epididymitis transmission
Passive venereal infection: infected ram breeds ewe, or clean ram breeds ewe
Ram to ram: group-housed rams
Infected rams excrete B. ovis in ______
semen
B. ovis infection in ewes
More resistant
15-30% ↓ in lambing rates with chronic infection
Conception failure, embryonic death, abortions, stillbirths, weak lambs
Pathogenesis of B. ovis infection
Exposure via mm → Bacteremia → epididymitis/ seminal vesculitis → spem granuloma → reduced fertility
CS of epididymitis
↓ semen quality + WBC in semen
Scrotal swelling
Infection in seminal vesicles
Chronic infection → obstruction of epididymal ducts
Epididymitis dx
ELISA (97% sensitivity, 100% specificity)
Epididymitis prevetion
Segregate rams by age
Perform yearly BSE of all rams
Newly purchased animals: 2 - ELISA tests, Purchase from B. ovis free flock, 30d quarantine
Epididymitis in young rams
<2yrs
Actinobacillus seminis, histophilus, corynebacterium pseudotuberculosis (caseous lymphadenitis)
Cx from prepuce, penis, oral and nasal cavities
Transmission of lamb epididymitis
Shed organism in preputial secretions and semen @ puberty
Ram to ram via oral or nasal route (blood)
Retrograde migrattion via urethra
CS of acute lamb epididymitis
Enlarged epididymus and swollen testes
+/- fever, anorexia and depression
Lame from pain
Semen with leukos and bacteria
CS of chronic lamb epididymitis
Obstruction of ductus deferens, granulomas or abscesses
Testicular atrophy
Bacteria clear by 12-15m
Prognosis of lamb epididymitis
Some individuals may recover and be fertile breeders
Prognosis depends on severity
Tx of lamb epididymitis
Oxytetracycline
Segregate infected lambs/ cull
Use low chlortetracycline in feed
Ulcerative Posthitis (Pizzle Rot)
Corynebacterium renale in sheep, goats and camelids
Pathogenesis of Ulcerative Posthitis
High protein ration (16-18%) → ↑ concentration of urea in urine → hydrolysis of urea → ammonia by C. renale→ ulceration of skin at muco-cutaneous junction of prepuce
Tx of Ulcerative Posthitis
Clean and debride wound
Apply abx ointment
Reduce dietary protein to 12-13%
Sexual rest for 1m
Ulcerative Posthitis complications
Fibrosis of preputial orifice can cause phimosis (inability to extend penis)
Varicocoeles
Dilation and thrombosis of internal spermatic vein
No tx, don’t use for breeding
Varicocoeles CS
Fluctant to firm swelling in spermatic cord
Ram lame or awkward gait
Poor thermoregulation affects semen quality
Sperm Granuloma
More common in goats and sheep
Caused by blockage of efferent ducts draining into epididymus (duct distention and rupture)
No tx
Sperm granuloma palpation findings
Acute: swollen, edematous testes, enlarged epididymus
Chronic: small, firm
US: hyperechoic (mineralization)
Caprine Intersex Condition
More prevalent in polled dairy goats
XX sex reversal due to loss of ovary determining genes that are linked to the polled trait
Genetically female and appears female @ birth
CS of Caprine Intersex Condition
Enlarged clitorus, ↑ or ↓ anogenital distance
Bilateral cryptorchidism or partially descended testes
Hypospadia, sperm granulomas, hypoplastic testes
Avoid breeding _______________-
Phenotypically polled bucks
