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MEKARN Workshop 2009: Livestock, Climate Change and the Environment |
The biochemical changes when nitrate is converted to ammonia in the rumen of cattle and sheep is known to lower methane production. The present study aimed to demonstrate that nitrate salts could inhibit methane production on cattle. Three rumen fistulated cattle were allocated in a 3 x 3 Latin square with three treatments, sodium nitrate (SN), ammonium nitrate (AM) and urea (U) and housed in individual cages. They were fed a mixed diet consisting of NaOH-treated rice straw, para grass, cotton seed meal and molasses and one of the three sources of N.. Each period consist of 4 weeks: adaptation of 2 weeks to reach nitrate/urea levels of (SN= 6.6%, AM= 3%, U= 2.2%); one week more on these levels and one week for collecting data. At one hour before feeding, percent of methane in rumen gas in the SN treatment was lower compared with AM and U (9.27, 10.46, and 13.76); CO2 levels were: 25.33, 27.86 and 37.83). At 2 h after feeding methane levels were: 3.13, 4.13 and 7.37% for SN, AM and U, respectively. Levels of CO2 were: 11.6, 17.6 and 25.6%. Feed intakes (kg DM/day/head) were 5.57 (SN); 5.52 (AM) and 5.43 (U)). Daily weigh gains (kg/day) were 0.47 (SN); 0. 45 (AM) and 0.43 (U).