Chapter 17 Insemination techniques

Object of insemnation technique: To place semen in the part of reproductive tract that will give the best chances for conception

17-1 Insemination of the cow

17-1-1 Vaginal insemination

Semen deposition: At the mouth of cervix: not usable in artificial insemination because of its low CR; Require much motile sperm/ insemination

17-1-2 Cervical insemination: See FIGURE 17-1

Figure 17-1 Speculum method for insemination the cow. Similar method is used for the ewe. 

A. Semen deposition: At 2.5 cm of cervix by use of speculum ¡æ 10% lower CR compared with recto-vaginal insemination

B. Speculum: Size: 2 to 3 cm in diameter and 35 to 40 cm long; Made of metal, glass and plastic materials with pen light or head lamp

17-1-3 Recto-vaginal insemination

* More difficult to learn, but its superior CR makes it the method of choice. Conception rates are lower for the beginner, but as the technique is mastered CR improves.

A. Grasp cervix with left hand through rectum: FUGURE 17-2

Figure 17-2 Recto-vaginal method for inseminating the cow. 

B. Insert inseminating instrument through vagina

C. Hold cervix by its posterior end with index and middle fingers and thumb, leaving the other two fingers free to help guide the inseminating instrument: FIGURE 17-3

D. Guide the instrument into the opening of cervix and manipulate the cervix in all directions to pass theinstrument through cervix

E. Move the fingers and thumb foward so that the manipulation is taking place just forward to the end of the instrument

F. Stop the instrument as soon as it reaches the anterior end of the cervix, and do not withdraw the instrument, especially when the cow urinates

G. Deposit semen slowly for 5 seconds

H. Some problem situations to beginners:

a. Insert the instrument into vagina not to enter suburethral diverticulum or external urethral orifice.

b. When muscular contractions force the reproductive tract toward anus and cause vagina to become folded, grasp the cervix with left hand and push it forward to straighten the vagina.

c. When cow attempt to expel left hand for rectum with peristaltic muscular contractions, wait until the rectum will be relaxed.

d. When the cervix cannot be felt or manipulated through contractions of rectal muscles, cup the fingers over the hardened rectal wall and pull the hand toward tha anus to cause the contracted rectal muscle to be relaxed and softened.

e. When the vagina fills with air, dispel the air by firm pressure with the hand toward the vulva.

f. When the bladder is extremely full, manipulate the clitoris to cause urination.

17-1-4 Inseminating equipment: See FIGURE 17-4

A. For using semen in ampolues:

a. A plastic inseminating catheter fitted with a polypropylene bulb
b. A plastic inseminating catheter attached to a 2 ml syringe with a short rubber connecting tube

B. For using semen packaged in straws:

A "straw gun": 1) stainless steel tube, 2) stainless steel rod as a plunger, and 3) plastic sheath designed to fit tightly against the end of straw, which forms seal to prevent semen from being trapped between straw and sheath

17-1-5 Thawing frozen bull semen

A. Thawing ampoules In ice water bath of polystyrene thaw box or soft plastic container as in FIGURE 17-5

B. Thawing straws
Straws should be thawed in a 32 to 35¡É water bath: See FIGURE 17-6

Reached 5¡É in 12 to 15 seconds, but leave straws for 45 to 60 seconds.

75-day NR rate: 66.3% vs. 64.4% for straws thawed for 40 vs. 9 seconds

C. Handling semen after thawing

a. Raise semen temperature to 35¡É and then protect sperm from cold shock
b. Insert the straw in warm starw-gun
c. Keep inseminating instrument warm by wrapping with paper towel and tucking inside the inseminator's clothing

17-1-6 Site of semen deposition

A. Vaginal and posterior cervical deposition: definitely inferior CR

B. Semen deposition at midcervix and body of uterus:

a. Little different CR; but no experiments have favored midcervical.
b. Cervix provides viable sperm at fertilization site for longer period as sperm pool, but there is little difference in sperm transport time to fertilization site between both semen deposition sites
c. Advantages of midcervical deposition assuming no difference in CR:

1) Reduced danger of damaging uterine wall
2) Utilization of antibacterial action of cervical secretions
3) Decreased danger of interrupting pregnancy with repeat breeders

d. When semen was deposited at midcervix because inseminator was unable to pass the instrument beyond that point, CR was found 15% lower: due to irritation and swelling of cervical mucosa or other factors which prevented semen from traversing the cervix

C. Deep uterine horn deposition: not recommended because of possible trauma and/or infection

17-1-7 Restraining facilities

A. Require more elaborate facilities for dairy and beef heifers and beef cows grazing on pastures: To protect inseminator and allow proper placement of semen wiht a minimum of excitement and trauma of the cow

B. An end of narrow chute, enclosed with plywood, with solid gate to swing out to open: Dark confinement area: Drive cow in and hold her in place with a piece of pipe: Allow her to stand quietly for a few minutes before being inseminated.

17-2 Insemination of the ewe and doe

A. Small stainless steel spreading speculum is used with aid of head light for cervical semen deposition: See FIGURE 17-7

B. For ewe: intrauterine insemination with 10 cm long, ball-tipped17 guage needle: 50 to 60% successful passage and 70% CR with frozen semen

C. For doe: A dorsal flap must be lifted and then 0.25 ml straw gun can be used for intrauterine isemination

17-3 Insemination of the sow

Use a plastic insemination catheter and squeeze bottle or large syringe as in FIGURE 17-8

17-4 Insemination of the mare: See FIGURE 17-9

Figure 17-9 Method used to inseminate the mare. 

A. Special emphasis on cleanlinesss is required because the gloved hand is place in vagina with a finger through cervix.

B. A 50 ml syringe with a volume of semen containing 500 million motile sperm is connected to a plastic inseminating catheter