Measurements of methane emissions and energy and nitrogen utilisation for quantifying the carbon footprint of young Holstein cattle

• Main Author: Jiao, Haopeng
• Published: University of Ulster 2013
• Subjects: 636.2
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601201

The desire to develop national greenhouse gas (OHO) emission inventories and mitigation strategies to reduce carbon footprint of cattle production systems, has prompted interest to fill the knowledge gap of OHO emission from young cattle in the UK. The current UK government funded study was undertaken over a two-year period to evaluate the effects of gender (steers vs. heifers) of growing Holstein cattle (6 to 22 months of age) on enteric methane emissions and energy and nitrogen utilisation and then to use these data to develop prediction models for quantification of carbon footprint of the dairy production sector. Twenty 5-month old Holstein cattle (10 steers and 10 heifers) were used in successive 28 d feeding period, with measurements undertaken at age of 6, 12, 18 and 22 months, to investigate the effects on feed intake, live weight gain, energy and nitrogen (N) utilisation and enteric methane (CH4) emission. Throughout the study, cattle were offered a diet for ad libitum intake containing a single perennial ryegrass silage mixed with concentrates. In the first period, the concentrate supplement was offered at a ratio of 550 g/kg of dry matter (DM), while it was given at a fixed rate of 2 kg DM daily in other 3 periods. During each measurement period, the cattle were housed as a single group in cubicle accommodation for the first 20 d, then individually in metabolism units for the next 3 d, and then in indirect open-circuit respiration calorimeter chambers for the final 5 d with feed intake, faeces and urine outputs and gaseous exchange measured during the last 4 d.