Family Selection and Sib selection

• Family selection: here the selection is based on the mean phenotypic value of the family. If the records of the individual are included in arriving in the family average and used as a criterion for selection, then it is known as family selection.
• Here the whole families are selected or rejected as units according to the mean phenotypic value of the family.
• The efficiency of family selection rests on the fact that environmental deviations of the individuals tend to cancel each other out in the mean value of the family.
• Sib-selection: some characters cannot be measured on the individual that are to be used as parents i.e. the individual’s records are not included in arriving at the family average and selection can only be based on the value of relatives and this method of selection is called Sib-selection.
• This is also a family selection but the selected individual has not contributed to the estimate of their family mean.

Family selection/SIB selection is recommended

1. When the character has low heritability
2. When the character is sex-limited
3. When the characters are carcass traits and threshold traits like twinning in cattle, disease resistance, survival or death, etc.