Animal performance and feed characteristics data used to estimate the IPCC Tier 2 enteric methane emissions for smallholder livestock systems in Nandi, Kenya

These datasets contains enteric methane emission factors derived using Intergovernmental Panel on Climate Change (IPCC) Tier 2 method. The activity data collected includes the live weight (LW) measurements of cattle in 126 smallholder farms from different agro-ecological zones collected between October November 2015 to October 2016 i.e. five LW and heart girth measurements at month 0, 3, 6, 9, 12, live weight flux (change) for different periods, body condition scoring and physiological status all referred here as "Activity data". The animal performance activity data coupled with feed quality data (dry matter digestibility (DMD) were used to predict the energy requirements of the animals. These energy requirements include for maintenance, LW gain or loss, locomotion and lactation (for lactating animals). The average of the LW per period was calculated and used to estimate the metabolizable energy requirement (MER) for maintenance and MER for locomotion (energy used when walking during grazing). The LW change was used to estimate the MER for LW gain or loss. The animals were grouped by age and sex; Adult females (>2 years), Adult males (>2years), Heifers (1-2years), Young Males (1-2years) and calves (both sexes, <1year). The MER for maintenance, gain or loss and locomotion applied to all animal classes. However, Adult females (>2years) had an additional energy requirement since most at this age group were lactating and therefore part of the energy was used for milk production. The MER for lactation was calculated using average daily milk yield plus predicted calf milk consumptions for dams with calves of 0 to 3.5 months of age, and milk energy derived from measured herd milk quality (butter fat and solid non fat content). It was assumed that calves were tethered around the homestead and therefore MER for locomotion is negligible and not included for calves. A sum of all the MERs was calculated then used together with feed DMD and Gross energy (GE) to estimate the dry matter intake (DMI) that was in turn used to predict the daily methane production (DMP). All calves of 0 to 3.5 months of age were excluded from DMP calculations as it was assumed that their rumen is not fully developed as hence negligible enteric methane was produced. The DMP was converted to emission factor (EF) by multiplying it with 365 days to get an annual enteric methane emission figure.
Feed basket Information for Nandi County Kenya contain information on feedstuffs available and their contribution to feed baskets per agro-ecological zones in Nandi county. In addition, we had acreage data for each fodder crop, pasture or food crop residue that were fed to the animals, pasture biomass yield for different periods, the feed nitrogen and acid detergent fibre (ADF) that were used to calculate the proportion of each feedstuff to the entire feed-basket and the DMD of the feed-baskets for the agro-ecological zones in Nandi county.

本数据集包含使用政府间气候变化专门委员会（IPCC）第二级方法推导的肠道甲烷排放系数。收集的活动数据包括来自不同农业生态区126个小农场的牲畜活重（LW）测量值，时间跨度为2015年10月至2016年10月，即0个月、3个月、6个月、9个月、12个月时的五个LW和胸围测量值，不同时期的活重变化（流量），体况评分和生理状态，统称为“活动数据”。将动物表现活动数据与饲料质量数据（干物质消化率（DMD））相结合，用于预测动物的能量需求。这些能量需求包括维持、活重增减、运动和泌乳（针对泌乳动物）。计算了每个时期的平均活重，并用于估算维持代谢能量需求（MER）和运动MER（放牧期间行走时的能量消耗）。活重变化用于估算活重增减的MER。动物按年龄和性别分组；成年雌性（>2岁）、成年雄性（>2岁）、母牛（1-2岁）、年轻雄性（1-2岁）和小牛（两种性别，<1岁）。所有动物类别均适用维持、增减和运动的MER。然而，成年雌性（>2岁）有额外的能量需求，因为大多数此年龄组的动物处于泌乳期，因此部分能量用于产奶。使用平均日奶产量和预测的小牛奶消耗量（针对0至3.5月龄的小牛），以及从测量的 herd 奶质量（黄油脂肪和非脂肪固体含量）中提取的奶能量，计算了泌乳MER。假定小牛被拴在宅邸周围，因此运动MER可以忽略不计，不包括在小牛中。计算了所有MER的总和，然后与饲料DMD和总能量（GE）一起用于估算干物质摄入量（DMI），随后用于预测每日甲烷产量（DMP）。所有0至3.5月龄的小牛均从DMP计算中排除，因为假定它们的瘤胃尚未完全发育，因此肠道甲烷产生可以忽略不计。将DMP转换为排放系数（EF），通过乘以365天以获得年度肠道甲烷排放量。关于肯尼亚Nandi县的饲料篮信息包含有关饲料原料及其在Nandi县农业生态区饲料篮中的贡献的信息。此外，我们还拥有每种饲料作物、牧场或粮食作物残渣的面积数据，这些数据被用于喂食动物，不同时期的牧场生物量产量，以及用于计算每种饲料原料在整个饲料篮中比例的饲料氮和酸性洗涤纤维（ADF），以及Nandi县农业生态区的饲料篮干物质消化率（DMD）。