Environmental assessment of meat and milk production of sedentary dual-purpose cattle farms in two vegetation zones in Benin using the GLEAM-i model

To cope with the new regulations on pastoralism in Benin, herders shifted from mobile livestock herding towards a more sedentary lifestyle. However, sedentary livestock keeping may lead to severe challenges if feeding and animal health, as well as environmental health, are poorly managed. To provide appropriate recommendations for the sustainability of this land-use system, this study assessed the environmental impact of sedentary cattle farms by estimating their greenhouse gas emissions using the Global Livestock Environmental Assessment Model-interactive (GLEAM-i, Online version). Therefore, three sedentary cattle farm types, namely sedentary zebu (SZF), taurine (STF) and crossbreed (SCF), were selected in two vegetation zones (Sudanian in the North (SZ) and Guineo-Congolian (GCZ) in the South of Benin). Irrespective of the farm type, the animals were exclusively fed on natural pasture. A total of 12 cattle herds were surveyed to collect input data (herd structure, demographic parameters, milk production and composition, and weight data) for the GLEAM-i. The fat and protein content of the milk (determined using a milkotester device), live weight and weight at slaughter of animals were entered into GLEAM-i, which automatically determines the emission intensity values per kg of protein produced. The results revealed that CH₄ was the main GHG emitted (88%) followed by CO₂ (6-7%) and N₂O (6%). The highest and lowest total GHG emissions (kgCO₂-eq/year) were recorded in SZF (188,497) and STF (52,003) farms, respectively. With regard to emissions intensity (kgCO₂-eq/kg Protein), emissions varied from 506.59 to 3043.73 for meat and from 588.86 to 3043.73 for milk. Overall, preliminary trends suggest lower intensities for taurine in the GCZ and for zebu in the SZ. However, these results would be more meaningful with larger studies with production conditions, zone effects, and controlled allocation. These would allow for drawing firm recommendations for breeding strategies to reduce GHG emissions in Benin.