"Details on Artificial Insemination in Chicken Breeder Flock" By Dr. Sanjay Gapat

INTRODUCTION

Artificial insemination (AI) is the manual transfer of semen into the female’s vagina. Basically, it is a two-step procedure: first, collecting semen from the male and second, inseminating the semen into the female. Artificial insemination was first practiced in America during the 1920’s and then used widely in Australia with the introduction of laying cages during late 1950's. AI is the method of choice for the geneticist for maintaining the pedigreed mating. Broad breasted turkey was produced by genetic selection, which is physically incapable of natural mating so in such birds AI is the only way of mating. AI is done to minimize the size of male flock in guinea fowl as in guinea fowl one male is used for two-three female.

Some of the advantages of artificial insemination in the poultry are: 1. Increased mating ratio: Normally one cockerel can mated to six to ten hens. With artificial insemination this ratio could be increased fourfold. 2. Older males having outstanding performance can be used for several generations. Whereas under natural mating their useful life is limited. 3. Valuable male birds having the leg injury can still be used for artificial insemination. 4. Elimination of preferential mating: When there is poor fertility caused by preferential mating, it can be eliminated. 5. Successful cross breeding: Although cross breeding is very successful under natural conditions, but sometimes there is a kind of color discrimination as some hens will not mate with a male of a different color unless they have been reared together. In such condition AI helps in successful cross breeding.

ARTIFICIAL INSEMINATION

Day old male parent chicks are supplied dubbed and detoed. Males are reared separately from 0-21 weeks of age. Start with 12% males in case of natural mating and 8% in case of artificial insemination. At the beginning of the breeding season (22 weeks), introduce 8 males per 100 females. Replace weak, lame and sick males promptly. In case of A.I. maintain at least 5% males which can yield about 0.5 ml neat semen per ejaculate with not less than 60% motility. Inseminate females once in 5 days, with 0.03 – 0.05 ml of neat semen: within 30 minutes after collection.

Artificial Insemination (AI) is an important tool to improve the reproductive performance of birds especially broiler breeders where fertility is low due to heavy body weight. Even though AI is well developed technique in cattle, is not so well developed in poultry because no standard technique is available to store poultry semen for a long period. The techniques available at present permits to collect semen and use it for insemination immediately with or without dilution using semen diluent s at 1: 2 ratios.

Semen collected from one cock is sufficient for inseminating 5 to 10 hens depending upon the semen volume and sperm concentration. At farms, where AI is practiced the males are kept separately in individual cages where sufficient space is available for movement of the birds. There should be a team of workers to associate collection and insemination of semen. Frequent changes of personnel in the team may affect the normal behavior of birds. Rough handling should be avoided, if not it may develop fear reaction, which affects the semen volume during ejaculation.

Characteristics of poultry semen

Usually cock start producing semen from the age of 16 weeks but the fertilizing capacity of the semen is low. So, the cocks from 22 or 24 weeks of age are used for semen collection.

The natural color of poultry semen is white or pearly white. Heavy breed male can produce 0.75 to 1 ml semen and light breed male can produce 0.4 to 0.6 ml of semen.

A male can be used thrice in a week for semen collection with a gap of one day. Although everyday semen collection will not change the fertilizing capacity, but the volume of semen will be low.

Semen consists of spermatozoa and seminal plasma. Fowl semen is generally highly concentrated (3 to 8 billion spermatozoa per ml for broiler fowl). This is due to the presence of limited amount of seminal plasma since the accessory reproductive organs are absent in avian species. The seminal plasma is derived from the testes and excurrent ducts.

At the time of ejaculation, a lymph-like fluid (also known as transparent fluid) of cloacal origin may be added to the semen in varying amounts. The addition of transparent fluid to semen at the time of ejaculation act as an activating medium for the previously non-motile spermatozoa, thus ensuring their transport from the site of deposition to the sites of sperm storage tubules in the utero-vaginal junction of the hen's oviduct.

Equipment’s needed for A.I

·        Small glass funnel with stem plugged with wax.

·        Inseminating syringe

·        Wide mouthed glass vial.

·        Small pyrex semen cup

·        Large flask to hold water at 180 C to 200 C range for short time holding of semen.

Steps in Artificial Insemination

AI in poultry is a three-step procedure involving semen collection, semen dilution and insemination. The second step may be omitted if 'neat' semen (undiluted) is to be used for insemination within 30 minutes after collection.

Semen collection

The first step in AI program is manual collection (milking) of the semen. For semen collection, a team of two members are generally involved, one for restraining the male and the other for collecting semen.

The bird is held in a horizontal position by a person at a height convenient to the operator who is attempting to collect the semen. To collect semen the operator should place the thumb and index finger of the left hand on either side of the cloaca and massage gently.

By his right hand the operator should hold a collecting funnel and with the thumb and index finger massage the soft part of abdomen below the pelvic bones. Massage should be rapid and continuous until the cock protrudes the papilla from the cloaca.

Once the papilla is fully protruded, the previously positioned thumb and index finger of the left hand are used to squeeze out the semen into the collecting funnel. Avoid contamination of semen with faeces and feather.

Semen evaluation at the time of collection

Normal color of the semen in pearly white or cream colored. Yellow semen and semen contaminated with blood, urates, faeces, or other debris should be avoided. Do not allow semen to contact water.

If debris or contaminants are observed in pooled semen, carefully aspirate contaminates from the sample before mixing with additional diluent with the semen.

Place the diluted semen in a cooler or refrigerator (3 to 12-degree Celsius) to cool down.

Insemination

All equipment used for insemination should be thoroughly cleaned and dry before Use.

Insemination must be carried out when majority of the birds completed laying since a hard-shelled egg in the lower end of the oviduct obstructs insemination and lowers fertility.

In practice, inseminating chicken after 3 pm obtained better results.

It is difficult to inseminate non-laying hens.

Usually insemination is done when the flock reaches 25% egg production.

Hens are inseminated twice during first week. Then at weekly intervals.

Procedure

Bird is held by the legs with the left hand down and tail tucked back and against the operator chest.

The thumb of the right hand is placed against the upper lip of the vent then with a rounding motion press the abdomen muscle.

Do not squeeze with fingers but apply pressure evenly with the palm of the hand.

When the oviduct is everted, the second operator inserts the syringe into oviduct as far as it is going inside without exerting pressure.

The insemination apparatus is introduced into the vagina about 1 inch and semen is deposited at the junction of vagina and uterus.

Dose and frequency of insemination

Chicken: 0.05 ml, once in a week

It has been observed that the males produce more semen of good quality during morning and females produce more fertile eggs when inseminated around 9 p.m.

Conclusion:

The benefits of AI for broilers would include the following: the male: female ratio would be increased from 1:10 for natural mating to 1:25 with AI; with fewer males needed, there would be greater selection pressure on the male traits of economic importance and subsequently greater genetic advancement per generation. It may happen that sometime in the future, research addressing poultry sperm biology and the cellular and molecular basis of oviductal spermatozoa transport, selection, and storage will lead to the following innovations in poultry AI technology: insemination intervals increased to 10–14 days (versus 7-day) with fewer sperm per insemination; in vitro sperm storage for 24–36 h at ambient temperature with minimal loss of sperm viability.

References:

1. https://www.agritech.tnau.ac.in/

2. Kharayat NS, Chaudhary GR, Katiyar R et al. Significance of Artificial Insemination in    Poultry.Research & Reviews: Journal of Veterinary Science and Technology. 2016; 5(1):

3. Leeson S, Summer JD. 2009. Broiler Breeder Production. Chapter 2. Reproduction. Nottingham University Press, 22–49p