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Dairy heat stess under climate change

Description

The Thermal Heat Index (THI) is a model of the level of heat stress experienced by dairy cows as described by Bryant et al (2007). This data set estimates the number of days annually (starting in July) that the THI exceeds a threshold - in this case the threshold of 72 units.
The ensemble annual means across six Global Climate Models (GCMs) are provided for:

  • the historical baseline (1981-2000),
  • mid-century (2041-2060) and
  • end of century (2081-2100)

for four Representive Concentration Pathways (RCP) of future anthropogenic emissions.

This representation of heatstress may only be applicable to indoor animals.

 

Date: December 2023 Version: v1

Owner: NIWA

Contact: Dr Abha Sood, NIWA

 

Link to report / paper

Bryant JR, Lopez-Villalobos N, Pryce JE, Holmes CW, Johnson DL 2007. Quantifying the effect of thermal environment on production traits in three breeds of dairy cattle in New Zealand. New Zealand Journal of Agricultural Research 50(3): 327-338, 10.1080/00288230709510301.

Davis MS, Mader TL, Holt SM, Parkhurst AM 2003. Strategies to reduce feedlot cattle heat stress: effects on tympanic temperature. Journal of Animal Science 81: 649-661.

 

Preview Image

 

Dataset attributes

Spatial extent New Zealand
Spatial resolution 5km climate grid
Temporal extent Three time periods: historical baseline (1981-2000), mid-century (2041-2060) and end of century (2081-2100)
Temporal resolution
Evaluation method (Validation) None
Evaluation result (Numeric)
Evaluation result (Categorical)
Uncertainty method Not supplied but an estimate of uncertainty can be generated by assessing the variability of estimates between years and GCMs
Uncertainty data format (Numeric)
Uncertainty data format (Categorical)

 

Methodology

The THI as per Davis et al (2003) from Bryant et al. (2007) was applied to the NIWA VCSN, under the past and future climate scenarios from IPCC.
The annual estimates of the number of days of heat stress were averaged across the six Global Climate Models and the relevant time period (historical baseline (1981-2000), mid-century (2041-2060) and end of century (2081-2100)) for each of four Representative Concentration Pathways (RCP) of future anthropogenic emissions (2.6, 4.5, 6.0, 8.5).

 

Fitness for purpose / limitations

This table indicates whether the dataset is suitable for different types of questions at different scales.

Note: Users should carefully consider their purpose as this dataset may not be suitable.

Operational Absolute Relative Screening/scoping
Block/farm No No No Maybe
Multi-farms(5+) Maybe Maybe Maybe Yes
Catchment Yes Yes Yes Yes
National/regional Yes Yes Yes Yes
Caveat(s) The climate information is too coarse for use at finer scales.

Data and Resources