Development of selection tools

There are many statistical and technical tools on which the modern breeding plans depend in case of dairy cattle. The much oldest tool among these is the milk recording that was developed in 1997. In this tool of milk recording the concentration of fats and milk is recorded on monthly basis.

Later on when the computers developed than  the tool of milk recording was replaced. The animals that have been selected, their information like reproduction, birth date, pedigree etc is stored in computer so that this data can be used in future for the selection of animals.

A well defined breeding program contains data about reproduction, pedigree, calvings of animals. We can also include health information of animal. The method of artificial insemination was developed in 1960. At that time the artificial insemination was used to prevent animals from different diseases as they caused much harm to animals.

Later on artificial insemination was used as a selection tool when the tests of progeny were performed. When we look at the tool of milk recording in it just females are involved as the milk of female animals is recorded but in case of artificial insemination both male and female are involved as semen is collected from males and is introduced into females.

Freezing of semen:

As in case of artificial insemination we collect semen from male bulls and introduce them into female bulls that semen can be frozen and can be transferred to other countries to establish that phenomena at international level. We can collect 2000 doses of semen from a bull.

If the semen is not to be transferred we can store that semen for future use. In the previous times the heavy bulls were transported and that was a difficult task but with the advent of artificial insemination it has become possible to transfer semen. We can also store semen for longer periods of time.

Genetic evaluation methods:

In order to evaluate genetics we test the number of progeny on annual basis and the best animal is selected and further proceeded. The age of bulls should be 5 years old. In 1960s the selection programs were developed. One of the major advantage of freezing of semen is that we can check and evaluate progeny in different countries rather than testing in just one country.

Now a days new statistical tools has been developed in order to select superior animals. A new method BLUP was developed by Hendreson. The relationships that exist among the bulls can be utilized in order to improve breeding plans. The male and female bulls from different generations were added.

International genetic evaluations:

The method BLUP caused the evaluation of bulls on a common scale due to the transfer of frozen semen across different countries. In 1983 the “interbull” was formed and in 1997 the 35 countries became the member of this international body. The interbull was developed in order to improve the existing methods and to develop new methods for the betterment of breeding plans. In 1991 the center of this body was created.

Embryo transfer:

As the techniques for reproduction has been developed the reproduction efficiency has also been improved. One of the new technique is embryo transfer in which we transfer embryos into another female rather than transferring the heavier animals. In Europe this technique has been greatly employed.

Factors:

There are different factors that affect genetic gain. These factors are selection intensity that is how we have selected animals. We evaluate the performance and then select the animals. Another factor is accuracy of selection which means that how accurately we have selected animals either on the basis of their own performance or on the basis of performance of their relatives. Another factor is genetic variation, those animals that have genetic variation are best rather than those animals that don’t have genetic variation.