Breeder Bull Selection
• The animals that have breeder documents or pure race certificate, are free of diseases, have a high yield and display the distinct characteristics of its breed in the country or region that they are bred in are called breeder animals.
• Breeder selection includes works focused on
determining improvement methods by
scientific means to obtain better yields from
animals.
The advantages of breeder selection from males ;
• The number of male gonad cells – spermatozoa- being distinctly more than female gonad cells
• Because male gonad cells are higher in number; chance of elimination is higher, manipulation is easier, experiments, studies, transfer and freezing of semen is less risky
• While spermatogenezis continues all year, in most females ovulation occurs in restricted time periods
• Maintenance, nutrition and elimination of diseases of one male is easier and it can be used to fertilize many females
• Being negatively affected by selection is less in males
Breeder Bull Selection
To decide on a bull to be chosen as a breeder;
• Phenotype values
• Pedigree
• Family averages
• Offspring averages (Progeny Test and Genomic Test)
Breeder Bull Selection
Selection According to Phenotype Values
• Whatever the chosen yield is, to be able to do selection according to physical appereances, animals should display the characteristic properties of their breed, have the main structural properties appropriate for its yield and have solid constitution.
• The principle of the method is that animals that have high a yield will have offspring that will have high yield.
• However, since most of the characters that have economic importance have a low heritage, success in selection according to personal data is not high.
Breeder Bull Selection
Selection According to Pedigree
• The document that introduces an animal descendants yield properties is called pedigree.
• This application depends on the information that an animal takes half of its genotype from the mother and the other half from the father.
• The success assurance in selection with pedigree is hereditary degree. However hereditary degrees are usually low, so if there are better methods, it is recommended that other means should be used.
Breeder Bull Selection
Selection Depending on Family
• The groups that are constituted of beings related in some degree are called family.
• In this method, selection is done by choosing the families that have the highest yield, or choosing beings with highest yields or choosing depending on phenotypic averages of siblings.
Breeder Bull Selection
Progeny Test
• Determination of a bulls daughters yield averages and the revealing the difference of these values from all other bulls daughters averages, offspring or generation control is called progeny test.
• Progeny test is a way of determining if an animal is pure breed.
• The main aim of progeny test is to choose the healthiest, who have the highest yield capasity and ones which are able to maintain these properties for a longer time; and to make sure these animals maintain their genetic properties.
• It takes 5-7 years for all stages of progeny test to finish.
Breeder Bull Selection
Progeny Test
• Genetic advance: The advance obtained in a character after selection is called genetic advance. In a rapid genetic advance, bulls participation is around 75%.
• Breeder bull candidate selection: Breeder bull candidates for dairy, beef or combined yield selection is made from offsprings of cows with at least 70% milk yield average. Candidates should also be evaluated acoording to their mother, father, grandmothers’ milk yield, live weight, endurance to diseases, frequency of distocia.
Breeder Bull Selection
Progeny Test
• Examination of male reproductive organs: is done according to the andrological evaluation examination protocol.
• Selection criteria:
– The contribution of the selected bull to the establishment should be investigated depending on the bull selection reason of the enterprise.
– Bulls usability in heifers, cows or in both should be known.
– The purpose of offsprings produced from the herd should be known.
– Work load abilities, nutrition resources, situation of environmental conditions should be taken into consideration.
