AI in Cattle

Question 1

How is semen frozen?

Answer 1

At a concentration of 15-20 x 10^6 sperm

Stored in liquid nitrogen

Question 2

How is semen thawed?

Answer 2

Thaw in 95-98 degree water bath for 40 seconds

Question 3

How is thawed semen inserted?

Answer 3

Insert AI gun through vaginal vault up to the external os of cervix –> use rectal palpation to guide the gun through the cervix –> advance until the tip of the gun reaches the uterine body –> deposit semen in the uterine body

*dec preg rates occur when semen is deposited in cervix or one horn only

Question 4

How is semen sexing done?

Answer 4

Flow cytometry used to sort semen using fluorescent dye

Question 5

Advantages of sexed semen?

Answer 5

select primarily for females
more replacements, avoid purchasing outside animals
fewer dystocias
accelerate genetic improvements
cows carrying female calves give more milk

Question 6

Factors limiting success of AI

Answer 6

heat (estrus) detection can be difficult (limited staff or knowledge)

• keep good records to anticipate heat
• know behavioral signs
• use heat detection aids

Question 7

Estrous synchronization

Answer 7

Use of sync protocols allows for timed AI

e.g. prostaglandins to lyse CL