Abstract

Most of New Zealand’s methane is generated as a by-product of feed fermentation in the rumen of livestock and is released through the mouth and nose. An experiment conducted in late summer using Friesian and Jersey dairy cows investigated whether feeding sulla (Hedysarum coronarium), a condensed tannin (CT)-containing legume, reduced methane emissions without compromising milksolids production. Cows grazing sulla had higher intake (DMI; 13.1 vs. 10.7 kg DM/cow/d, P<0.001) and milksolids production (1.07 vs. 0.81 kg MS/cow/d, P<0.001) than cows grazing perennial ryegrass pasture. Total daily methane emissions were similar (253.9 vs. 260.0 g CH4 /cow/d, ns). However, cows fed sulla produced less methane production per unit DMI (19.5 vs. 24.6 g CH4 /kg DM, P<0.05) and per unit milksolids yield (243.3 vs. 327.8 g CH4 /kg MS, P<0.01) than those fed ryegrass due to the higher nutritive value of sulla compared with the ryegrass, and possibly the presence of CT. Further research will determine whether feeding alternative, high quality forages is a viable methane mitigation option for New Zealand dairy farm systems, but results of this study clearly indicate that CT-containing legumes, such as sulla, do effectively reduce methane emissions from dairy cows without compromising milksolids production.

SL, Woodward, GC Waghorn, KR Lassey, and PG Laboyrie

Proceedings of the New Zealand Society of Animal Production, Volume 62, Palmerston North, 227-230, 2002