Type of indicator
Quantitative
Relative dimension and aggregated criteria
Environmental sustainability: Herd management practices: feed efficiency
Description
This indicator calculates the percentage of total N inputs recovered in the milk production process, i.e., the percentage of ‘total N ingested’ to ‘total N fixed’. N fixed represents the total N content of the milk produced, while N ingested refers to the total N content of dairy cow diets. This percentage evaluates aspects of the environmental impacts of feed management, largely influenced by N emissions of dairy production (Dulphy and Grenet, 2001; INRA, 2007).
Indicator calculation
𝑇𝑜𝑡𝑎𝑙 𝑁 𝑖𝑛𝑔𝑒𝑠𝑡𝑒𝑑 / 𝑇𝑜𝑡𝑎𝑙 𝑁 𝑓𝑖𝑥𝑒𝑑 ∗ 100
𝑇𝑜𝑡𝑎𝑙 𝑁 𝑖𝑛𝑔𝑒𝑠𝑡𝑒𝑑=(Σi=1 (𝐹𝑀𝑖∗(100/𝐷𝑀𝑖)∗𝑁 𝑐𝑜𝑛𝑡𝑒𝑛𝑡𝑖)∗ 𝑃𝑖 ∗ 𝑁)∗1000
Where:
n = Number of feed type
i = Type of feed
𝐹𝑀𝑖 = Fresh matter of feed i in grams (g)/day/head
𝐷𝑀𝑖 = Dry matter (DM) of feed i in g/day/head
𝑁 𝑐𝑜𝑛𝑡𝑒𝑛𝑡𝑖 = N content of feed i in percentage (%)
𝑃𝑖 = Distribution period of feed i in days
𝑁 = Average dairy herd size
𝑇𝑜𝑡𝑎𝑙 𝑁 𝑓𝑖𝑥𝑒𝑑 = 𝑇𝑜𝑡𝑎𝑙 𝑚𝑖𝑙𝑘 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑∗𝑁 𝑓𝑖𝑥𝑒𝑑 𝑝𝑒𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 𝑔𝑎𝑖𝑛 ∗(𝑀𝑖𝑙𝑘 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 / 1000 )
𝑇𝑜𝑡𝑎𝑙 𝑚𝑖𝑙𝑘 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑 = Total raw milk produced in litres (L)
𝑁 𝑓𝑖𝑥𝑒𝑑 𝑝𝑒𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 𝑔𝑎𝑖𝑛 = Total N fixed in g, divided by dairy cow weight gain in kg
𝑀𝑖𝑙𝑘 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 = 1.032 kg/L
Unit
Percentage
Indicator interpretation
Higher values are associated with better environmental management practices and are thus expected to lead to enhanced environmental sustainability.
Scale definition
| Reference values
(%) |
Scalings | Dexi interpretations | References | |
| 20 min | >=30 | High | + | (Aguirre-Villegas et al., 2017). Scale built in a participative approach by scientists and experts |
| 45 theoretical max | [25 ; 30] | Medium to high | ||
| [20 ; 25] | Medium to low | |||
| <20 | Low | – | ||
References
Dulphy, J.P., Grenet, N., 2001. Estimation des flux d’azote, de phosphore et de potassium associés aux bovins allaitants et aux bovins en croissance ou à l’engrais, issus des troupeaux allaitants et laitiers, et à leur système fourrager, in: ABioDoc (Ed.). CORPEN, p. 34p.
INRA, 2007. Alimentation des bovins, ovins et caprins. Quae, p. 309p.