Keywords: Livestock population | extrapolation | expert judgement
What data needs were addressed? To construct a time series for livestock populations.
Why was the data needed? Croatia has used a Tier 2 approach for cattle emissions since 2009. Cattle are categorized as mature dairy cows, mature non-dairy animals and calves. The challenges were to reconstruct time series for each of the cattle sub-categories when national official statistics were not available for all years, and the sub-categorizations in national statistics changed over time.
Methods used: extrapolation, expert judgement.
How was the data need addressed? The Croatian Bureau of Statistics (CBS) holds data on other cattle since 1990. Numbers of dairy cattle were provided by the Croatian Agricultural Agency (CAA) for the years 2008-2015. For 1990 to 2007, dairy cattle numbers were extrapolated based on the 2008-2015 numbers using expert opinion from the Croatian Agency for the Environment and Nature. For non-dairy cattle, the sub-categories reported by the CBS has changed over time. The table below shows how different categories were mapped onto the IPCC categories over time.
Table 1: Changing classifications of non-dairy cattle in Croatia