Artificial Insemination (AI) in Animals

Artificial insemination (AI) is a reproductive technique in which semen is collected from a male animal and manually inserted into the reproductive tract of a female animal using specialized tools, without natural mating.

The object of insemination technique is to place good quality semen in the accurate place which will give best chance of conception.

There are different types of insemination techniques are available. These insemination techniques depend upon the size of the female animals of different species and difference in their anatomy.

Points to be considered before inseminating the animals:

• The animal should have appropriate body weight to carry the pregnancy-minimum of 250 kg in cattle heifers and 300 kg in buffalo heifers.
• Animal should be in estrum.
• The reproductive tract should be free of infection.
• Discharge should be clear.
• Congenital or hereditary anatomical defects of reproductive tract should not be there.
• Animal should not be pregnant. Before performing AI rule out pregnancy.
• If it is post partum animal, there should be gap of 60 days from the time of parturition.
• If there was abnormal calving in previous parturition, the time gap of 90 days is preferable.
• The type of semen-breed, bull no should be decided well in advance.

Vaginal Insemination

Here a pipette is inserted in to vagina and the semen is deposited in anterior vagina or near to cervix.

The major disadvantages of this method are:

• The vaginal environment is not conducive for the longer life of the sperm
• Deposition of more number of sperms is necessary to get moderate result

Cervical Insemination Using Vaginal Speculum

In this method a sterilized vaginal speculum is inserted into the vagina which will help to see the cervix from outside.

With the help of light source a long inseminating pipette is inserted into the cervix and the semen is deposited in cervix.

The disadvantage of this method are:

• When large number of cows are inseminated the sterilization of speculum sometimes will become problem.
• Chances of injury and infection of vagina and cervix will lower the fertility.
• In some cows it is difficult to introduce the semen into cervical lumen and it is deposited in external os which will lower the conception rate.

Recto-vaginal Method

Recto-vaginal method was introduced by Larson in 1938 at Denmark. The operator or inseminator should have good knowledge about the anatomy and physiopathology of the reproductive tract to get higher conception rate.

• This recto-vaginal method is performed in animals in standing position.
• The animal should be restrained in a service crate.
• The perineal region of the animal should be washed with running tap water to remove the dung and dirt. The water should be wiped off.
• The inseminators hand is covered with disposable rubber sleeve.
• The lubrication is done with non-irritant soap and the hand is passed into the rectum.
• The excessive dung inside the rectum is removed. But complete removal is not advisable because a minimum level of dung is essential for better operation.
• Frequent removal of hand from the rectum while removing dung also should be avoided because it will lead to ballooning of the rectum.
• The vulval lips are carefully wiped with cotton to remove all the dung
• The cervix is grasped with gloved hand and the external os is located
• The vulval lips are widened apart by an attendant and the insemination catheter/gun is passed inside the vulval lips at it is carried forward towards cervix. If the vaginal folds are interfering in taking the catheter the cervix is pushed forward to clear the passage.
• The catheter/gun is placed on the external os of cervix and it is passed into the cervix.
• The cervix will have annular rings which will cause the cervix somewhat spiral in nature.
• The catheter is taken through annular rings by gently manipulating cervix and catheter.
• The semen is deposited in the internal os of cervix or in body of uterus.

Advantages of Recto-vaginal Technique

• Deposition of semen at proper site is ensured without loss of semen.
• Chance of infection is minimized and fertility rate is high compared to speculum method.
• Injury/bleeding caused while using speculum is avoided in this method.
• Estrum is confirmed while examining the animal per rectum.
• Inseminating pregnant animal is also avoided because the rectal palpation of genital organs rules out pregnancy.