Methane Emission from Sheep Respiration and Sheepfolds During the Grazing Season in a Desert Grassland

Methane (CH4) emissions from ruminants should be accounted for the natural grazed rangeland ecosystems when devising greenhouse gas budget inventory, in particular, their contribution to global warming. In this study, CH4 emission from sheep respiration at different grazing intensities (light grazing, 0.75 sheep/ha, LG; moderate grazing, 1.50 sheep/ha, MG; and heavy grazing, 2.25 sheep/ha, HG) and in sheepfolds were evaluated in a desert grassland of Inner Mongolia. Results indicated that daily CH4 emission from sheep was not significantly different between treatments. When CH4 emission was expressed emission per 100g daily, there was a significant difference of LG vs HG and MG vs HG, with the values of 15.64g, 20.00g and 28.63g for LG, MG and HG, respectively, during the grazing season. There was no significant difference among CH4 fluxes in sheepfolds (mean 39.0 ug m-1 h-1). Considering CH4 emissions from the grazing ecosystem, net CH4 emissions from LG, MG and HG plots were -18.33, -1.91 and 21.19 g/ha/day, respectively. The digestibility of forage had a positive correlation with CH emission expressed on daily and metabolic body weight basis. It is concluded that MG will improve the balance between CH emission from grassland and grazing livestock in the desert grasslands of Inner Mongolia.

Consequences of nutrition during gestation, and the challenge to better understand and enhance livestock productivity and efficiency in pastoral ecosystems

The major economic costs to ruminant livestock producers of meat are associated with the breeding herd, which is an important target for improving productivity and efficiency at pasture. There is increasing interest in how to manage breeding females and their offspring to either minimise the consequences of adverse environmental effects or to enhance productivity and efficiency of offspring. This paper briefly reviews influences on fetal growth including the placenta, and reports results of our studies on factors including chronic, severe nutritional restriction during pregnancy and/or lactation within pasture-based systems on postnatal productivity of beef cattle. Cattle severely growth restricted early in life can have reduced weight for age to market weight, but with little or no alteration to normal allometric growth patterns of carcass tissues or beef quality, at least within pasture-based systems. The extent to which Bill McClymont’s vision of improving productivity and efficiency through improved understanding of the interactions between livestock, plants and soils can be realised is limited by our capacity to generate, in a timely manner, objective data on animal performance including intake and feed use efficiency within pastoral ecosystems. The capacity to improve productivity and efficiency, most notably for the breeding herd, within pastoral ecosystems will be enhanced by the development of wireless sensor networks and methods to manage and develop applications from ‘big data’. These applications of wireless sensor networks will include measurement of pasture intake, which is the input trait that underpins livestock production efficiency. Consistent with Bill McClymont’s vision, consumption of pasture by ruminants represents the point in the grazing ecosystem where livestock interface with plants and soils, and thus measurement of pasture intake should be a high priority for future research on productivity and efficiency.