Naturally ventilated buildings (NVB), as often used for dairy cattle housing, are particularly vulnerable to climate change since the microclimatic conditions inside strongly depend on the outdoor weather conditions. Without sound adaptation strategies, increased climate variability will result in a sub- optimal thermal environment impairing production and welfare of animals and increasing emission rates.
The objectives of OptiBarn are to:
- Assess the influence of outdoor climate on the indoor climate in NVB.
- Analyse region-specific risk on how often critical weather situations will occur under conditions of climate change.
- Assess cow-individual stress reactions in different climate zones.
- Assess engineering solutions to control indoor climate conditions.
- Assess environmental and economic effects of climate change on dairy cattle husbandry in NVB.
- Propose region-specific, sustainable adaptation strategies for dairy housing.
- Spatial variations of up to +/- 3°C, and up to +/- 20% relative humidity are observed inside a naturally ventilated building (NVB).
- Air speed inside NVB is increased in the first third and decreased in the last third of the main flow through the building compared to the inflow air speed; the inflow angle determines the orientation of the main flow and cows adapt their positions in the barn accordingly if possible. Modifications in the position and size of openings can reduce the local heat loads.
- Assessing climate related stress in cattle only by the temperature-humidity index (THI) based on point measurements results in an uncertainty in THI score of up to +/-4 corresponding to up to 8 kg difference in milk yield loss per cow.
- The amplitude of the responses to climatic stress (e.g. changes in body posture or rumination activity) varies during the day and has its maximum in the afternoon.
- With advancing climate change frequency and duration of heat stress events in European dairy cows will increase accompanied by additional pollutant emissions of up to about 16Gg ammonia and 0.1Gg methane.