Entry Points for Reduction of Greenhouse Gas Emissions in Small-Scale Dairy Farms: Looking Beyond Milk Yield Increase

Abstract

Increasing milk yield per cow is considered a promising climate change mitigation strategy for small-scale dairy farms in developing countries. As it can be difficult to increase cow productivity, mitigation options beyond this production strategy need to be identified. The aim of this study was to identify entry points for mitigation of GHG emissions in small-scale dairy farms in Lembang Sub-district, West Java, Indonesia. Data on herd composition, productivity, feeding, and manure management were collected in a survey of 300 randomly selected dairy farms. Characteristics of farms with the 25% lowest (<3291 kg milk/cow/y), medium 50% (3291-4975 kg milk/cow/y), and 25% highest milk yields (≥4976 kg milk/cow/y) were compared. Life cycle assessment was then performed to estimate the cradle-to-farm gate GHG emission intensity (EI) of farms. The relationship between EI and milk yield per cow for all farms was modeled and farms with an EI below and above their predicted EI were compared ("low" and "high" EI farms). Results showed that milk yield explained 57% of the variance in EI among farms. Farms with medium and high milk yields were more often specialized farms, fed more tofu waste and compound feed, and had higher feed costs than farms with low milk yields (P < 0.05). Farms with high milk yields also applied less manure on farm land than farms with low milk yields (P < 0.05). Low EI farms had fewer cows, and fed less rice straw, more cassava waste, and more compound concentrate feed (particularly the type of concentrates consisting largely of by-products from milling industries) than high EI farms (P < 0.05). In addition, low EI farms discharged more manure, stored less solid manure, used less manure for anaerobic digestion followed by daily spreading, and applied less manure N on farmland than high EI farms (P < 0.05). Some associations were affected by confounding factors. Farm management factors associated with milk yield and the residual variation in EI were considered potential entry points for GHG mitigation. Feeding less rice straw and discharging manure, however, were considered unsuitable mitigation strategies because of expected trade-offs with other environmental issues or negative impacts on food-feed competition.

Understanding variability in greenhouse gas emission estimates of smallholder dairy farms in Indonesia

“…For discharged urine, also the emission factor of the category daily spread was used. The fraction of N losses in the form of NO 3 − leaching for specific manure management systems were based on personal communication with experts (De Vries et al 2019). To estimate leaching of NO 3 − from manure storage, a leaching fraction of 18% was used.…”

“…Depending on Indonesia's strategy taken to increase domestic milk production, greenhouse gas emissions (GHGE) from dairy production may further increase, particularly if the numbers of cattle are to be increased (Tubiello et al 2014;De Vries et al 2019). Life cycle assessment (LCA) is a well-known method to assess GHGE along the production chain of milk and is mainly used to identify emission hotspots and potential mitigation options.…”

“…To address variation in farm management practices over time, researchers often ask farmers to recall the situation over a particular year or season (e.g. De Vries et al 2019). However, both cross-sectional observations and farmer recall could hamper an accurate assessment of the exact situation on a farm.…”

“…For example, a study by Migose et al (2020) showed that assessment of milk yield based on farmers recall was less accurate than those based on recordings, while milk yield explains a significant part of the variation in GHG emission intensity (e.g. De Vries et al 2019;Wilkes et al 2020). As the climate of Indonesia is characterised by a dry and a rainy season, dairy farmers adapt their practices to these seasons, mainly with regard to the amount and type of feed offered to dairy cattle (De Vries and Wouters 2017).…”

Sustainability of Four Dairy Farming Scenarios in an Alpine Environment: The Case Study of Toma di Lanzo Cheese

“…In literature, several researches have focused on the assessment of the environmental and economic impacts of the Italian dairy chain by using the Life Cycle Thinking (LCT) approach. Within the LCT approach, many different methodologies are useful to evaluate the environmental and economic impacts of a life cycle, and the commonly used methodologies are Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) (18)(19)(20)(21).…”