Keywords: Expert judgement | digestibility
What data needs were addressed? Estimation of a time series since 1990 for feed digestibility when digestibility data for previous years is missing.
Why was the data needed? When adopting a Tier 2 approach, the approach should be applied to the whole time series back to the base year (1990), but historical data on feed digestibility was missing, so alternative methods were needed.
Over recent decades, fodder and feed production in the Republic of Moldova has been affected by both general socio-economic conditions and natural conditions. Prior to the early 1990s, cattle production was organised in collective farms and fodder production was carefully managed. With reforms in the 1990s, the collective farms collapsed and livestock concentrated in the smallholder private sector. The average productivity of dairy cows decreased significantly as a consequence of poor organization of fodder production and inappropriate animal feeding and maintenance conditions. Since the early 2000’s, fodder and feed production and dairy cow productivity have improved. Fodder and feed production have also been affected by annual variability in growing conditions, such as droughts or other weather conditions in some years.
Methods used: expert opinion.
How was the data gap addressed? The IPCC 1996 Guidelines (Reference Manual, Ch 4, 4.16) provides representative feed digestibility values for different types of livestock: 50-60% for crop by-products and range lands, 60-75% for good pastures, good preserved forages, and grain supplemented forage-based diets and 75-85% for grain-based diets fed in feedlots. Expert judgement was used to estimate the feed digestibility value for cattle in different historical periods. The approach used assumed that when livestock maintenance conditions, fodder and feed production conditions were optimal, the digestibility value would be 67%. Based on changes affecting fodder and feed production and cattle raising in the country, a time series for digestibility was estimated (Table 1).
Table 1: Cattle feed digestibility values for Republic of Moldova 1991-2013