SELECTION & CULLING

• Breeding Soundness Evaluation - predicts potential fertility.
• Breeding Soundness Evaluation - more than just a semen exam.
• BSE Evaluation:

  Mobility and athleticism in the pasture

  Structural soundness

  Overall reproductive development

  Testicular size and health

  Semen quality
• To observe in bulls while servicing a cow/heifer:

  Assessment of libido

  Desire to breed

  Ease of mounting

  Ability to achieve erection and extend the penis

  Presence of penile deviation or any abnormalities
• Breeding Soundness Evaluation:

  Restrained in the chute.
• Breeding Soundness Evaluation:

  Conduct BCS.
• Breeding Soundness Evaluation:

  General physical examination - feet, legs, eyes, sheath.
• Breeding Soundness Evaluation:

  Palpation of inguinal rings and internal genitalia per rectum to detect abnormalities.
• Breeding Soundness Evaluation:

  Testes should be symmetrical in size, smooth, resilient, and freely movable within the scrotum.
• Breeding Soundness Evaluation:

  Palpate the scrotum to evaluate testes, epididymides, spermatic cords, and scrotal skin.
• Cryptorchidism - is considered an undesirable heritable trait and renders a bull unsatisfactory for breeding even though semen quality might be acceptable.
• Testes should be cooler than the core body temperature for optimal sperm production.
• Testes temperature: 2–6 C or 35.6–42.8 F
• Epididymis - should have no palpable masses.
• Scrotal circumference – a measurement considered as a reliable predictor of paired testis weight.
• Scrotal circumference - provides an accurate estimate of daily sperm production and quality.
• Scrotal circumference - should be measured at its maximal diameter, and size depends greatly on bull age and breed.
• Scrotum circumference:

  ≥30 cm = < 15 months old
• Scrotum circumference:

  31 cm = 16–18 months old
• Scrotum circumference:

  32 cm = 19–21 months old
• Scrotum circumference:

  33 cm = 22–23 months old
• Scrotum circumference:

  34 cm = ≥2 year old
• Testicular size - is directly related to the volume of sperm production and to the onset of puberty in the offspring.
• Asymmetrical scrotum - the other testicle is smaller but both has normal tone.
• Asymmetrical testes - different lengths but both has normal tone.
• Unilateral scrotal enlargement - the other testis is enlarged due to a hydrocele.
• Inguinal hernias - most common on the left side.
• Inguinal hernia - contents can generally be reduced.
• Penis - examined at full erection for abnormalities.
• Preputial washing - isolation and culture of Campylobacter fetus venerialis, or Tritrichomonas foetus.
• Semen collection via AV - 40.5–42 C
• Semen collection via AV - is a critical factor in stimulating ejaculation.
• Semen evaluation:

  Concentration

  Volume

  Count

  Motility

  Morphology
• Presence of cells other than spermatozoa in the sample should be investigated while estimating motility (RBCs, WBCs, immature sperm).
• Satisfactory Potential Breeders – bulls that have no physical abnormalities that would prevent breeding, meet minimal qualifications for SC, motility, morphology.
• Rams - BSE is performed using an electroejaculator.
• Rams BCS:

  1–2 questionable (underconditioned)

  3–4 satisfactory

  5 questionable (overconditioned)
• Brucella ovis - common cause of epididymal masses (sperm granulomas), also associated with testicular atrophy.
• Ram scrotal circumference:

  ≥28 cm = 8–14 months old

  >36 cm is exceptional
• Ram scrotal circumference:

  ≥32 cm = >14 months old

  >40 cm is exceptional