5. Breeding goals and traits of dairy cattle 젖소 품종 개량

B4. Breeding goals and characteristics (traits) of dairy cattle, milk properties

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• The estimation of the breeding value is one of the stations of the animal production’s cycle.

• On the course of the breeding value estimation we grade our candidate individuals according to their estimated value. Then, we designate the real future parents from this ordinal list of candidate individuals (in most of the cases from the top or from the bottom of it.

-The breeding value of an animal – is the deviation of the individual genetic merit from the mean genetic merit of a reference population. The individual breeding value is of altering degree, and changes according to the value (genetic merit) of the reference population or of mating partners.

-The aggregated breeding value (or breeding index; see selection) – is a complex type of breeding value established for more traits simultaneously, which is achieved upon the base of a linear combination of in the breeding goal declared valuable traits:​

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Breeding programs

Goal: Systematic production of breeding & commercial animals of defined pedigree & production traits

Involves breeding associations & organizations

Corner points & requirements for successful breeding programs:

• Breeding population
• Marking of animals & Identification
• Safety of descent & origin of animals
• Guaranteed by mating, parturition, bloodgroups, DNA analysys

Performance & progeny testing

• Reproduction techniques
• AI, embryo transfer, MOET (multiple ovulation embryo transfer), cloning
• Breeding goals: Breeding programs can lead to breed improvement
• Breeding value estimation​

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Most important performance traits used in dairy cattle selection (performance testing for breeding)

• Meat performance
• Reproductive performance
• Fertility
• Calving ease
• Health
• Milking ability
• Conformation
• Hereditary disorders

Milk performance (during first 305 days lactation)

• Average milk yield (kg)
• Max daily milk yield (kg)
• FCM – Fat corrected milk yield (kg)
• Fat yield (kg)
• Protein yield (kg)​

Chemical composition of milk

• Fat content (%)
• Protein content (%)
• PFR – Protein to fat ration
• FPD – Fat protein difference
• Lactose content (%)
• SCC (somatic cell count)

Primary traits:

• Milk producing-ability

1. Milk yield, Kg

2. Relative milk yield, Kg

3. Milk content, %, fat & protein yield

4. Milking-ability

5. Others: DM%, Ash%, urea%, fatty acids, cell count, vitamins, color

​Secondary traits:

• Conformation
• Reproduction
• Feed intake – conversion ratio
• Adaptation (e.g. industrialised Environment
• Health
• Resistance
• Others

​milk properties of cattle

• high water content
• low fat content