If you have been using natural mating or conventional Artificial Insemination (AI) then you are aware of how frustrating it can be at times when you either wish to have a bull calf or a heifer.
Bulls are desired by those into beef production while heifers are a preference for dairy farmers. In Kenya; the pull towards milk production is greater, hence the desire for more heifers than bulls.
Wasting a year expecting a heifer only for a bull to emerge doesn’t come with a good feeling for a farmer struggling to increase a dairy herd.
But that is how nature works, it chooses for you; unless you do something to assist it pull your way. It is such frustration that pushed scientists to come up with a way of predetermining the sex of calves. The result is what is referred to as sexed semen technology. The technology greatly increases a farmer’s chances of getting the desired sex by over 90 per cent.
How does it work ?
Whether an offspring will be male or female is determined by genetic materials carried in chromosomes with the sex cells.
The male sex cell is called the sperm while the female sex cell is called ovum (singular) and ova (plural). There are two types of chromosomes namely X or Y; which determine the sex of an offspring. The female cell or the ovum has two X chromosomes while the sperm has X and Y. The male and female sex cells contain only half of the normal chromosomes; a reason the two fuse to complete the equation. These two come together during fertilisation and at this moment the sex of the offspring is determined. If the two Xs combine a female will be born but if X and Y combine, then a male is born.
This means it is the male and not the female that determine the sex of the offspring. The separation of X and Y chromosomes through a complex process which yields sexed semen.
This process has other advantages like sorting out dead, dying or damaged sperms thus making the remaining sperms more viable. The process is not foolproof, but has a 90 per cent chance of predetermining the sex of a calve at insemination.
If heifer herd expansion is the farmer’s goal, then sexed semen technology should be the tool of choice. With sexed semen, a farmer will reduce incidences of birth complications since females are born easily relative to bull calves thus lowering veterinary costs associated with difficult births. With this reproductive technology; there are no replacement headaches as all you need will be homegrown from your farm. The advantage of this is that you are able to control the occurrence and spread of various diseases predisposed by introduction of herds from other farms.
Nonetheless do note that sexed semen has its disadvantages; due to the rigorous preparation process sexed semen has a relatively low conception rates as compared to conventional AI. This will mean more repeat inseminations and thus a relatively higher cost in terms of the cost of the repeats and an extended rearing cost of heifers or more open days for lactating cows. Thus if you have been doing AI and wish to venture into sexed semen your success rate with AI must have been very high.
Downside
Sexed semen is expensive and a straw (single dose) will cost anything between Sh3,000 and Sh7,000 as compared to the ordinary semen which can go for about Sh250.
Note that on top of the cost of the semen you will still incur veterinary costs for administration. It is therefore good to sought for an experienced inseminator when dealing with sexed semen.
Nonetheless, this cannot compare with the cost you will incur and time you will waste on a bull calve if your eyes were set on a heifer and vice versa.
The one off payment may look costly as compared to the traditional semen but when you aren’t lucky it may be expensive in the long run. In Kenya; sexed semen is available from a number of distributors like Kenya Genetic Resources Centre (KAGRC), Worldwide Sires Company, Coopers, Bimeda, ABS, Semex and Highchem which have outlets in most parts of the country.
