Heterosis and Breed Effects for Milk Production, Udder Health and Fertility in Danish Herds applying Systematic Crossbreeding

Abstract Text: Use of systematic crossbreeding in dairy cattle has been increasing the last decades. The aim of this study was to estimate the effect of breed and heterosis on protein yield (PY), somatic cell score (SCS) and days from calving to first insemination (CFI) in first lactation crosses between Danish Holstein (DH), Danish Red (DR) and Danish Jersey (DJ). The effect of breed was estimated relatively to a pure DH. There was a significant difference in PY between DH and DJ, but no difference between DH and DR. For SCS, there was a significant difference between DH and the two other breeds. The difference in CFI was only significant between DH and DR. For all combination of breeds, heterosis for PY was significant. There was no significant heterosis for SCS. For CFI, only combinations of DH and DR showed significant heterosis. 

Keywords: crossbreeding, protein yield, functional traits