Artificial Insemination

• Artificial insemination is the deliberate introduction of semen into a female's vagina or oviduct
• The goal of artificial insemination is to achieve pregnancy through fertilization, using an insemination tool
• Artificial insemination is a medical alternative to sexual intercourse or natural insemination.

Benefits of Artificial Insemination

• Increased efficiency is a benefit, where collected semen is diluted and extended to create hundreds of doses from a single ejaculate
• This allows for a wide use and distribution of bulls' high genetic value
• Speeds up genetic progress
• Eliminates the need to purchase and maintain bulls
• Reduces the risk of disease transmission
• The acceptance of artificial insemination technology worldwide has spurred the development of other technologies
• These technologies include cryopreservation and sexing of sperm, estrous cycle regulation, embryo harvesting, freezing, culture, transfer, and cloning

Semen Collection

• Artificial vagina is assembled and held at a 45° angle from the penis's direction
• The artificial vagina is held with the left hand
• When the bull mounts the cow, the operator inserts the bull's sheath, directing the gland penis into the artificial vagina, allowing the bull to ejaculate forcefully

Semen Storage

• Semen is stored in dry ice and alcohol at -73.3°C (-100°F)
• Semen can also be stored in liquid nitrogen at -195.6°C (-320°F) for extended periods
• Fresh, liquid semen can be stored successfully for 1 to 4 days at 4.4°C (40°F)
• Liquid nitrogen is preferred for storage as there is no evidence of fertility deterioration with age
• Fertility gradually declines in semen stored in dry ice-alcohol

Thawing

• Thawing is the process of a frozen substance becoming liquid or soft as it warms up
• Thawing needs to occur rapidly and at the correct temperature
• The National Association of Animal Breeders recommends using 30 – 35º C (90 – 95º F) for at least 30 seconds
• Use a water bath or wide-mouth thaw thermos with a thermometer for accurate temperature monitoring
• Use a timer to count 30 - 60 seconds before removing the straw from the thaw unit
• Once thawed, semen should be deposited into the uterus within 15 minutes

Incorrect Timing

• On average, oestrus/estrus lasts for 18 hours, but it can be as short as six hours for some cows
• Ovulation occurs approximately 12 hours following standing oestrus, necessitating insemination before ovulation, using an "am/pm rule"
• Cows seen at the onset of heat in the morning should be served in the afternoon

Causes of Low Conception Rate

• Low conception rates can result from semen straws that are kept in the water bath too long
• Low conception rates can result from extended exposure to the environment before being deposited in the uterus
• It is recommended to thaw only one or two straws at a time
• Serving cows that are already pregnant
• Serving pregnant cows can break the cervical seal and can lead to a loss of calves
• This can be caused by a failure to properly coordinate the timing of the breeding strategy

Insemination Procedure

• Locate and manipulate the tract with your left hand
• The opening into the cervix protrudes back into the vagina
• The cervix is located on the floor of the pelvic cavity near the anterior end of the pelvic bone
• As inserting the insemination rod/gun into the vagina, keep your left gloved hand even with the gun tip
• Keep your open left hand flat against the floor of the rectum

Relaxing Rectal Rings

• Insert two fingers through the center of the ring, and then massage back and forth
• Grasp the cervix and push the insemination rod forward to straighten vaginal folds
• For proper cervical placement, grasp the external opening to the cervix with the thumb on top.
• Move the forefingers underneath to close the fornix and guide the gun tip into the cervix
• Twist and bend the cervix until you feel the second ring slide over the gun tip
• Use your index finger to check rod/gun placement (0.64 cm (1/4 inch) past the end of the cervix) before depositing semen
• Push the plunger slowly so drops of semen fall directly into the uterine body

Considerations

• With correct insemination technique and placement, semen is deposited in the uterine body
• Contractions will transport spermatozoa forward to the horns and oviducts
• If the gun is more than 2.54cm (1 inch) through the cervix, the semen will be deposited into only one horn
• If encountering cervical mucous that is thick and sticky on the gun in a cow that has been previously inseminated, she may be pregnant
• When this occurs, deposit the semen halfway through the cervix
• Push in with the plunger do not pull back on the gun, because Doing so may result in much of the semen dose being deposited in the cervix and vagina
• Correct insemination procedures will result in better breeding efficiencies