1. therio- small ruminant breeding soundness and male infertility

why are BSEs in rams performed?

the goal is to impregnate all available females in early breeding season:

-up to 10-15% of rams are unsatisfactory breeding quality

-->doing the BSE eliminates males with reduced potential fertility prior to breeding season, which can improve economic returns

what does the BSE evaluate in bucks/rams?

evaluates male potential reproductive performance

-PE w/ emphasis on repro tract

-assessment of semen quality

- +/- assessment of libido and social behavior

what are the benefits of using superior/excellent rams?

increases lamb crop

-more ewes pregnant

-more multiple births

-earlier puberty in female offspring

what is evaluated in the physical exam portion of the BSE?

-structural soundness (feet, legs, teeth)

-BCS: should be 3.5-4/5 at start of season

what is scrotal circumference associated with?

associated with reproductive efficiency

- positive correlation with sperm output

- younger age at puberty of female offspring

-ovulation rate of daughters (multiple births)

how is scrotal circumference different in rams vs bulls?

in rams/bucks, SC varies by season and BCS (this is different than in bulls)

is scrotal circumference in rams heritable?

yes, highly heritable (35%)

how does the scrotal circumference/turgidity vary during the breeding season in rams?

during the breeding season, the scrotal circumference is larger and more turgid (~2cm larger at start of breeding season)

how are the testes examined during a BSE?

-palpable lesions

-tone

-asymmetry

how are the epididymides examined during a BSE?

check for enlargement due to inflammation or fibrosis

how does the cause of epididymitis differ in young lambs and mature rams?

young (lamb) rams: caused by histophilus or actinobacillus

mature rams: caused by B. ovis

how is the penis examined during a BSE?

-should be extended and examined

-examine glans and urethral process

-check for raw or ulcerated lesions at orifice

what are differentials for raw/ulcerated lesions at the orifice of the penis in small ruminants?

-ulcerative balanoposthitis/ pizzle rot (c. renale--> ammonia)

-ulcerative dermatosis (similar to contagious ecthyma virus)

-phimosis (cant extend penis)

what is the pathogenesis of pizzle rot?

high protein diet --> increased urea in urine--> increased alkaline urine--> bacterial urease breaks down urea to release excess NH3--> increased NH3 causes irritation and ulceration --> corynebacterium renale infection--> blocked preputial opening (scars and strictures)

how long is spermatogenesis in rams/bucks?

49 days plus 10-14 days in epididymis

ie sperm collected today began development 59-63 days ago

how is semen collected in rams/bucks?

collected by electroejaculation

- +/- sedation

-extend and secure penis with gauze

-message seminal vesicle area with probe

-apply electrical stimulus for 6-8 seconds

-massage again

-repeat stimulus

or just use bull 'program'

how is sperm motility evaluated in rams/bucks?

-dilute semen with warm saline, LRS, or 2.9% buffered sodium citrate

-place on warm slide and apply coverslip

-examine under 200x

-estimate % progressively motile

what reduces sperm motility?

urine contamination, cold shock

how is sperm morphology evaluated?

-mix semen with warm eosin-nigrosin stain

-dry on slide warmer

-examine under oil immersion

-evaluate at least 100 cells

-observe presence of cells other than sperm (WBCs best seen with phase contrast)

what does presence of WBCs in semen indicate?

usually indicates inflammation

what are the ram BSE classifications?

-unsatisfactory

-questionable

-superior (excellent)

-satisfactory

what classifies a ram as unsatisfactory?

any unsatisfactory rating in any part of BSE

what classifies a ram as questionable?

any questionable rating in any part of BSE

what classifies a ram as superior (excellent)?

exceptional in all categories of BSE

what should be done with rams that are classified as unsatisfactory?

cull or treat/retest

what is the expected reproductive performance of a ram classified as 'questionable'?

may breed a limited number of ewes or treat/retest

how many ewes should a satisfactory ram breed in 60 days?

will be able to breed at least 50 ewes in 60 days

how many ewes should a excellent (superior) ram breed in 60 days?

will be able to breed at least 100 ewes in 60 days

how is libido in rams evaluated?

evaluation based on observation at beginning of breeding season

10-15% of rams have no interest in breeding ewes- this can interfere with working rams

what should be done for rams with poor libido?

cull them

what is included in the BSE for bucks?

-physical exam (BCS, structurally sound)

-collect semen (similar to ram)

what does body scrotal circumference in bucks correlate with?

bodyweight and total sperm/ejaculation

what is ram epididymitis?

caused by brucella ovis

-a contagious venereal disease of mature rams

-major cause of reduced fertility in multi-sire breeding systems in western US

how is ram epididymitis (b. ovis) transmitted?

by homosexual activity of rams or via ewe

-venereal and oro-nasal transmission (penetrates mucus membranes)

t or f: ewes are not permanently infected with b. ovis but serve as mechanical vectors for disease spread

true

what is the pathogenesis of ram epididymitis?

enters blood via mucus membranes, causes bacteremia, then infects the reproductive tract

localizes in epididymis and secondary sex organs

what pathology does ram epididymitis cause?

-enlargement and fibrosis of epididymides (obstruction)

-degeneration of testicular tissue

-can involve just secondary sex organs

how is ram epididymitis diagnosed?

semen culture or serology (ELISA)

b. ovis serology should be considered part of a routine BSE

what is the treatment for ram epididymitis?

cull infected rams

what is ram-lamb epididymitis?

caused by histophilus, actinobacillus, haemophilus, corynebacterium pseudotuberculosis

affects rams less than 1 year of age

how is ram-lamb epididymitis transmitted?

via oral or nasal spread

how is ram-lamb epididymitis diagnosed?

by palpation

many PMNs and abnormal sperm in semen

r/o brucella ovis by serology

how is ram-lamb epididymitis treated?

long acting tetracycline if caught early

otherwise cull

what is a varicocoele?

localized dilation and thrombosis of internal spermatic vein/pampiniform

-causes swelling in spermatic cord

-rear leg lameness

what causes sperm granulomas? which animals is this more common in?

more in goats

caused by blockage of tubules draining into epididymis

what are causes of testicular hypoplasia/degeneration?

zinc deficiency

hypothyroidism

starvation

temperature stress

what is a spermatocoele?

obstructtion of the epididymis

what are penile abnormalities that can cause male infertility in small ruminants?

-hypospadias

-short penis

-phimosis/paraphimosis (hair ring)

what is cryptorchidism?

failure of one or both testes to descend into scrotum

heritable

if a ram has 2 retained testes will he be fertile? only 1 retained?

if 2 retained (bilateral crypt): the ram will be infertile

if 1 retained: may be fertile, but will pass trait onto his offspring

what is a 'short scrotum' ram?

ram whose testicles have been elevated to the body cavity using a rubber ring

short-scrotum rams have growth performance advantages over wether lambs