Comparing grass utilisation and herbage intake of elite New Zealand versus Irish ewes in the pre-weaning period

摘要

Pasture-based ruminant production systems are dependent upon the supply and utilisation of high quality swards to maximise animal performance within the grass based system. The aim of this study is to investigate the influence ofhigh genetic merit ewes from two origins: New Zealand (NZ) and Ireland, on grass utilisation and herbage intake, while further comparing this to ewe milk yield during the pre-weaning period over two production years. Two groups of ewes representing elite NZ (n = 60) and eliteIrish (n = 60) maternal genetics comprising of two main breeds (Texel and Suffolk) were assembled. Phenotypes collected from all ewes included live-weight and body condition score (BCS), while the milk production potential was estimated from a cohort ofanimals (n = 10 per genetic origin) on four occasions throughout lactation using the weigh-suckle-weigh method. Results indicate that irrespective of ewe genetic origin, grass utilisation and feed intake were similar (P > 0.05) in the pre-weaning period. Similarly, no difference in estimated milk yield of NZ versus Irish ewes were detected (2.01 ± 0.18 vs 1.92 ± 0.18 kg ewe~(-1), respectively; P > 0.05). This study demonstrates the capability ofhigh genetic merit ewes, irrespective of genetic origin,in maintaining BCS and achieving high levels of milk production in a grass based production system.