Comparison of growth and reproduction performance of dairy (Holstein-Friesian) and beef (Belgian Blue) replacement heifers in farms with both types of cattle

Abstract

In Belgium, both dairy and beef cattle are managed intensively. Three commercial farms owning both a Belgian Blue —double muscled type- suckler beef herd and a Holstein-Friesian dairy herd were surveyed between 1994 and 1998. The aim of the study was to compare growth and reproduction performances of both breeds in a similar farm environment. The replacement heifers of both breeds were kept together until advanced pregnancy. Reproduction data were collected monthly from heifers older than fourteen months. The live weight of the replacement heifers was recorded quarterly until 20 months of age. Breed influenced the growth of replacement heifers at 6, 9 and 12 months (P < 0.001). The growth rate of Belgian Blue heifers was reduced after the age of one year and the live weight difference between breeds was not significant anymore. Belgian Blue heifers were always heavier than Holstein-Friesian heifers. Successfully bred heifers had a greater growth rate than non successfully bred heifers within the Belgian Blue breed. This was significant for the weight at 6 months (P < 0.05) and at 12 months (P < 0.05). Such an effect was not detected for the Holstein-Friesian breed (P > 0.05). Weight was not a limiting factor for fecundity of the Holstein-Friesian heifers. Management policies other than growth performance explained the difference between optimal fecundity and the fecundity index met in this study. Non successfully bred Belgian Blue heifers were lighter than successfully bred animals. Unsufficient weight performance had an impact on fecundity in that breed.