Untersuchungen an den Ergebnissen der Zuchtwertschätzung von Holstein Bullen und Kühen in Deutschland

Abstract. Title of the paper: Examinations using the results of breeding value estimation for Holstein sires and cows in Germany
Besides for selection purposes, estimated breeding values can be used to analyze genetic trends and structures in populations. Using data of 2,440,261 cows from four regions in Germany, genetic trends for all cows under test (registered and grade) were calculated for the period of birth years 1992 to 1999. For milk, fat, and protein yield annual trends on average were 111 kg, 3.2 kg, and 3.3 kg, respectively. An analysis of the use of proven sires revealed that a relatively large proportion of bulls get second crop daughters. Most of them, however, are used in a very limited way. The differential use of sires by breeders besides production is highly influenced by type proofs although in this respect clear differences exist between regions. An analysis comparing first proofs of young bulls with their later proofs based on additional second crop daughters for all German Holstein breeding organisations showed a high degree of agreement between the two proofs. However, this analysis was based on only 127 sires that were used more widely (plus > 500 second crop daughters).