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

Published: 24 August 2021| Version 2 | DOI: 10.17632/j5b9d7dd2b.2
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Description

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 131 smallholder farms from different agro-ecological zones collected between December 2016 to January 2018 i.e. five LW 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. Feedbasket Information_Bomet_Kenya_2016 to 2018 contain information on feedstuffs available and their contribution to feedbaskets per agro-ecological zones in Bomet 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, acid detergent fibre (ADF) and gross energy for the feedstuffs that were used to calculate the proportion of each feedstuff to the the entire feed-basket and the DMD, Nitrogen and GE of the feed-baskets for the agro-ecological zones in Bomet county.

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