Izlaganje sa skupa
INCORPORATION OF MILK CONTENT TRAITS INTO A BREEDING PROGRAM
E.A. Mäntysaari
; Agricultural Research Center, Institute of Animal Production, Jokioinen,Finland
Sažetak
Although it is commonly agreed that the breeding goal in milk composition should be towards increased (or unaltered) protein-% and decreased fat-%, in most breeding programs high fat percentage is favored either directly or indirectly via selection for high protein-%. Even in single trait selection for protein-%, due to high correlation between content traits and a bigger variability in fat-% the correlated response in fat-% can be larger than direct inprovement in protein-%. In Finland the percentage traits have been considered in the national breeding since 1988. The goal to decrease fat-% has been adopted, and as a result bulls born after 1990 have about -.25% -units lower fat content of milk than bulls born 1985-87. In 1990 an open nucleus embryo transfer breeding program was established that employed alternative breeding goal in milk composition. The aim was to raise the protein to fat ration in milk by increasing the protein content while the same time keeping the fat-% unaltered. Relative weights for traits were chosen that gave equal importance to protein yield and percentage, with simultaneous negative weight on fat-%. During the four years of operation 291 cows have been flushed, and 1607 embryos have been transferred. Till now 766 calves have been born. In 1995 first 95 ET-daughters were evaluated with national animal model program. Their protein-% BLUPs were +. 14 above the group of heifers born same year, and the protein yield BLUPs were 12 kg above analogous group mean. The fat-% breeding values were in same level as in the year class.
Ključne riječi
Hrčak ID:
164422
URI
Datum izdavanja:
23.4.1996.
Posjeta: 408 *