BRIEF COMMUNICATION: Intake of ewe lambs is influenced by the dry matter percentage of the feed consumed

Introduction For most New Zealand farmed animals species energy is derived predominately from pasture but the plant species that comprise the pasture sward vary within and between properties. The ultimate energy obtained by an animal from the pasture it consumes is driven by several factors including the concentration of energy in the pasture, expressed most commonly as Metabolisable Energy per kilogram of dry-matter (MJ ME/kgDM); the drymatter (DM) percentage of the feed, which is an indication of the water content versus actual nutritive component of the pasture and the digestibility of the feed (Waghorn et al. 2007). The DM% of New Zealand pastures is influenced by the vast variety of climatic conditions that the pastures are exposed to including temperature, wind (speed and direction) and moisture as well as the pasture species and stage of growth of the plant. The DM% of a variety of fresh-cut pastures from different locations throughout New Zealand has been reported by a number of authors to range from 13% to 25% (John and Ulyatt 1987; Waghorn 2002; Piggott 2009). It is hypothesised that if production animals consume feed with a DM% less than 16% that the energy requirements of the animal may not be met due to water creating bulk which prevents the intake of sufficient dry matter (John & Ulyatt 1987; Waghorn et al. 2007). A pilot study set up to investigate feed efficiency in ewe lambs involved the feeding of fresh-cut ryegrass over several months. The data collected from this pilot study allows the relationship between feed intake and DM% to be investigated, and whether there is an influence on the ability of the animal to consume their energy requirements given varying DM%.