Abstract

Perennial ryegrass (Lolium perenne L.) with a higher concentration of water-soluble carbohydrates (WSC) has been bred by plant breeders (Humphreys 1989). Ryegrass with a higher WSC can potentially alter rumen microbial fermentation, synchrony of energy and protein in the rumen, total energy supply to the animal and consequently productivity (Edwards et al. 2007). Methane originates mainly from rumen fermentation and is the main greenhouse-gas produced by New Zealand (NZ) agriculture (MfE 2013). The higher concentration of WSC in high sugar ryegrass (HSG) can change rumen fermentation patterns (Lee et al. 2003) and may consequently affect methane emissions. Methane emissions are largely driven by dry matter intake (DMI) (Hammond et al. 2013) and methane mitigation strategies are often more effective at a high DMI (Moe & Tyrrell 1979). However, a true methane mitigation strategy should be effective at any DMI level. The objective of this study was to determine methane emissions from sheep fed freshly cut diploid HSG, conventional diploid ryegrass (CRG) and tetraploid ryegrass (TRG) offered at two levels of metabolisable energy for maintenance (MEm).

A, Jonker, G Molano, E Sandoval, PS Taylor, C Antwi, and GP Cosgrove

Proceedings of the New Zealand Society of Animal Production, Volume 74, Napier, 145-147, 2014