Table 2 Studies analysing effects of bromoform/halogenated compounds on CH4 emissions in vitro and in vivo
Compound | Type of study | Animal | Basal diet | Dosage | Impact on CH4 emissions | References |
|---|---|---|---|---|---|---|
Bromoform | In vitro (batch fermentation) | Brahman steers cattle | Rhodes grass | 2 concentrations tested: 1 µmol/L and 5 µmol/L | Addition of 1 µmol/L reduced CH4 by 77% and 5 µmol/L reduced CH4 by > 99% compared to basal substrate-only control | [13] |
Bromoform | In vitro (gas production recorder) | Lactating Swedish Red cows | Timothy grass, rolled barley, rapeseed in ratio 545:363:92Â g/kg diet dry matter | 2 dosage rates: 1.5Â mg/g dry matter, and 3Â mg/g dry matter | 95% reduction in CH4 | [39] |
Bromoform Dibromochloromethane Bromochloroacetic acid Dibromoacetic acid | In vitro (Ankom system) | Brahman steers cattle | Rhodes grass hay | 4 concentrations tested: 1 µmol/L, 5 µmol/L, 10 µmol/L, and 25 µmol/L | In the case of bromoform and dibromochloromethane, CH4 production completely inhibited at concentrations ≥ 5 µmol/L In the case of bromochloroacetic acid and dibromoacetic acid, no effect on CH4 production observed | [71] |
Bromochloromethane | In vivo | Murciano-Granadina lactating goats | Alfalfa hay with 600Â g/d concentrates | 0.3Â g of BCM/100 kg body weight BCM administered 2 equal doses per day from parturition to 2 weeks postweaning | 33% reduction in CH4 | [29] |
Bromochloromethane | In vivo | Brahman-crossbred steers | Rhodes grass and 1Â kg/d proprietary grain pellets | 0.3Â g of BCM/100 kg body weight | 30% reduction in CH4 | [31] |
Bromochloromethane | In vitro (batch and continuous fermentation) | Non-lactating Friesian-Holstein cattle | Batch: hay Continuous: 20 g/d hay | Batch: 5 µmol/L and 10 µmol/L tested Continuous: 5 µmol/L | Batch: 89%–94% reduction of CH4 at both concentrations tested Continuous fermentation resulted in 85%–90% CH4 reduction | [75] |
Bromochloromethane | In vivo | Japanese native (Shiba) goats | 50% timothy gras 50% concentrates | Animals sequentially adapted to low, medium, and high doses of BCM. Low dose: 0.5Â g/100 kg live weight Medium dose: 2Â g/100 kg live weight High dose: 5Â g/100Â kg live weight | Low dose: 5% reduction in CH4 Medium dose: 71% reduction in CH4 High dose: 91% reduction in CH4 | [76] |