Beef production from the dairy herd: I. Calving records from Friesian cows mated to Friesian and beef breed bulls

The involvement of New Zealand dairy farmers in beef production is outlined as a perspective for this series of papers. Objectives of the experiment reported in this series are described. Data are reported on calving difficulties, cow and calf mortalities, birth weights, and gestation lengths of 2188 single-born calves out of Friesian (F) cows sired by Friesian, Hereford (H), Simmental (S), Angus (A), Limousin (L), South Devon (SD), Blonde d'Aquitaine (BA), Red Devon (RD), and Charolais (C) bulls, born on 21, 18, 16, and 19 South Auckland dairy farms in the spring seasons of 1973–76 respectively. First-calving heifers, 2 years old at calving, were not used. In each year 10 F bulls were used, together with 10 from each of 2 of the other sire breeds listed. Relative to the F in each year, cows in-calf to C, BA, SD, or S bulls required more frequent assistance at calving than those in-calf to L, A, or H bulls in the descending order given. Dystocia was positively associated with sire breed mean birt...