Performance of beef suckler cows and their progeny to slaughter on intensive and extensive grassland systems

摘要

The performance of rotationally grazed, beef suckler cows and their progeny to slaughter on two lowland grassland Systems differing in stocking rate (SR) and fertilizer nitrogen (N) level was compared over eight years. The two Systems were 1) Intensive (INT): 0.58 or 0.72 ha cow~(-1) unit, 211 kg fertilizer N ha~(-1), two silage harvests; and 2) Extensive (EXT) compatible with the EU, Rural Environmental Protection Scheme (REPS): 0.72 or 0.89 ha cow~(-1) unit, 97 kg fertilizer N ha~(-1) and one staggered silage harvest. Herbage dry matter digestibility both pre-and post-grazing was similar (P > 0.05) for the two Systems, whereas herbage crude protein concentrations were generally lower for the EXT System. There was no difference (P > 0.05) between the Systems in cow live-weight, body condition score or their changes, in calf live-weight gain pre- or post-weaning or in slaughter or carcass weight, kill-out proportion, estimated carcass gain, carcass conformation or fat score of the progeny. Efficiency of N use ha~(-1) was higher on the EXT than INT System. In conclusion, similar individual animal performance can be expected in an extensive, lowland, grassland-based, suckler calf-to-beef System compatible with the EU, REPS as that attained in a moreintensive System.