Calving traits
Calf survival and calving ease based on cows in 1st and later lactations, respectively. Pure direct effect – the bull is father of the calf and the measure describes his direct effect on the calf’s ability to be born easily and alive.
All four breeding values can be published if the bull has a minimum reliability of 50 % for breeding value for either calf survival or calving ease in later lactations. Information of calf size is used as an indicator trait in the evaluation (only available from Denmark).
Birth index includes breeding values for calf survival and calving ease in later lactations. Birth is included in NBDI.
Youngstock survival
Youngstock survival describes survival of calves from day one after birth until 200 days of age. The index Youngstock survival is composed of the two breeding values for early period and late period. Breeding value for early period is based on the survival rate in the period from day 1 to day 30 and the late period is based on the survival rate in the period from day 31 to day 200.
All three breeding values are published when bull’s reliability for late period is 50 % or it has at least 500 offspring or published breeding values for calving and growth traits.
Youngstock survival index is included in NBDI.
Gestation length
Gestation length cow describes bull’s calves gestation length when the dam is calved at least once. Breeding values for gestation length are expressed in days and as a deviation from a standard dairy gestation length mean fixed at 280 days. Breeding values for gestation length, cow are published if the beef bull has got official breeding values for calving traits and reliability for gestation length is higher than 50%.
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