The following analysis is by Egerton University researcher Sophie Miyumo.

Poultry farmer Stephen Mune has been trying for the past one year to better his breed with little success.

Mune keeps layers, and he wanted to crossbreed the exotic birds to improve his yields.

He was advised by another farmer to get a good cock and let it mate with a few birds from his brood. The birds would later lay eggs that would hatch to get the crossbreed he wants.

“Things have not worked as I expected despite buying several indigenous cocks from an agricultural institutions and following their advice,” he says. Like many other poultry farmers countrywide, Mune has not heard about artificial insemination (AI) in chicken.

However, researchers are now upbeat that a breakthrough in this technology, currently restricted to research and breeding centres, could change poultry farming in Kenya as we know it.

The technology requires one to understand the basic anatomy and physiology of the hen and cock’s reproductive tract. One must also be technically competent in semen collection and deposition procedures to achieve effectiveness in producing fertilised eggs.

MINIMAL STRESS

Prior to semen collection, cocks must be trained. This is done by massaging the bird’s abdomen and back for about a minute for three consecutively days.

This is the most commonly used method since it is non-invasive and has minimal stress on the cock.

The procedure involves restraining the cock followed by gentle but rapid stroking of the abdomen and back region towards the tail (testes are located in this region).

Doing this stimulates the copulatory organ making it to protrude.

At this point, the handler should quickly push the tail of the cock up with one hand and at the same time, using the thumb and forefinger, gently squeeze the region surrounding the sides of the cloaca to “milk” semen from the ducts of the copulatory organ.

Semen should then be collected in a small tube or any cup-like container. This procedure is repeated twice once a day; an additional round may cause damage to the testes and cloacal region. The volume of semen that can be collected from a single cock ranges from about 0.7 to one millilitre, with a sperm concentration of three to four billion per ml.

However, the quantity of semen depends on genetics and environmental factors such as age, bodyweight, season and nutrition.

The degree to which the male will respond to the abdominal massage technique and the pressure applied on the ejaculatory ducts will also influence the quantity of semen produced.

Chicken semen begins to lose fertilising ability when stored for more than an hour. Therefore, it must be deposited in the hen within an hour of collection. In the case of short-term storage and transportation of the semen, it is necessary to use liquid cold (four degrees celcius) storage to maintain spermatozoa viability for up to 24 hours.

Vaginal insemination is commonly used for semen deposition as there are less risks of injury to the hen.

Preliminary stroking and massaging of the back and abdomen is required to stimulate the hen. This is followed by applying pressure to the left side of its abdomen around the vent causing evertion of the cloaca hence protrusion of the vaginal orifice.

An inseminator containing the semen is inserted 2.5cm deep into this opening for semen to be deposited. As the semen is expelled by the inseminator, pressure around the vent is released so that the oviduct can return to its normal position and draw the semen inwards to the utero-vaginal junction.

LATE AFTERNOON

Inseminators such as straws, syringes or plastic tubes may be used. During insemination, the volume of semen required per hen is about 0.1ml, which contains about 100 to 200 million sperms. It is best to inseminate hens in the late afternoon between 2pm and 4pm since in the morning, hens may have an egg in the oviduct, making it difficult for the sperm to swim up to the ovary.

A significant feature of the reproductive physiology of the hen is the ability to store fertile spermatozoa for up to 14 days in the sperm storage tubules located at the utero-vaginal junction.

The tubules release the semen, slowly over time, which swim to the fertilisation site and allows hens to be inseminated consecutively for two days for the first time, and thereafter at regular intervals of 14 days.

Twenty-four hours after insemination, egg-breakout analysis is carried out to determine egg fertility.