Comparative performance in Holstein-Friesian, Jersey and crossbred cows milked once daily under a pasture-based system in New Zealand

摘要

ABSTRACT Production and efficiency of Holstein-Friesian (F), Jersey (J) and crossbred F?×?J milked once-a-day (OAD) were studied at Massey University dairy farm No. 1. Herd test records of milk yields, somatic cell score (SCS), live weight (LW) and body condition score (BCS) were used to model the lactation curves using a third-order orthogonal polynomial. Total lactation yields of milk (MY), fat (FY), protein (PY) and milk solids (MS?=?FY?+?PY) were calculated based on predicted daily yields. Predicted efficiencies were feed conversion efficiency (FCE; total lactation MS per kg of predicted total lactation dry matter intake [DMI]); biological efficiency (BE; total lactation MS per 100?kg of LW) and DMI capacity (DMIC; total lactation DMI per 100?kg of LW). Holstein-Friesian cows yielded 376?kg milk more than F?×?J cows and 1101?kg milk more than J cows per lactation. Holstein-Friesian and F?×?J produced similar total lactation MSY (366 and 369?kg, respectively). Jersey cows were more efficient than cows of the other breeds: FCE was 78.2, 82.3 and 86.3; BE was 69.7, 74.1 and 77.8; and DMIC was 887.9, 896.8 and 897.7 for F, F?×?J and J cows, respectively. There were significant differences in production and efficiency among the breeds, with J cows being more efficient per 100?kg of LW than F or F?×?J cows. Further research is required to compare breed profit per ha in order to conclude the best breed for OAD systems.