Livestock Comfort Index Tool Documentation

Introduction

Climate change modeling indicates that Nova Scotia will experience more extreme weather events, prolonged excessive heat and cold periods and overall, more variable conditions in temperature, relative humidity and wind conditions. The impact of extreme or prolonged weather conditions and events can cause significant stress in livestock, leading to welfare and comfort concerns, reduced productivity and increased susceptibility to negative health outcomes. It is important for producers and livestock managers to monitor weather conditions and their animals for signs of heat and cold stress particularly during these periods.

The Livestock Comfort Index tool provides producers and livestock managers with real-time, and forecasted, estimates of livestock comfort levels based on data from Perennia’s OnFarm Weather Station Network and Environment and Climate Change Canada weather forecasts. Users can obtain the Livestock Comfort Index information from a particular on-farm weather station, closest to their livestock and representative of their localized conditions.

The Livestock Comfort Index tool is accessible by utilizing an internet connected computer, tablet or smartphone.

Model

Perennia has developed the livestock comfort index tool based on the model developed and introduced as the Comprehensive Climate Index by Terry L. Mader and Leslie J. Johnson at the University of Nebraska and John B. Gaughan at the University of Queensland in Gatton, Australia Mader et al.(2014) (opens in a new tab). The model output produces an apparent or “feels-like” temperature for livestock based on the following weather parameters:

• Air Temperature • Relative Humidity • Wind Speed • Solar Radiation

Livestock Comfort Index values are reported in degrees Celsius, but these values do not represent actual air temperature. They do represent an estimated apparent temperature or “feels-like” temperature perceived by livestock.

Categories

Heat and cold stress level categories for the Livestock Comfort Index tool are:

The category stress ranges are for healthy animals that have developed a hair coat appropriate for the season and are receiving nutrient supplies compatible to the level of environmental exposure. Continuous moisture will increase the stress associated with cold temperatures. Mild cold stress could be experienced at temperatures above 5ºC for non-acclimated, very young and newborn animals. Thus, shifting the stress thresholds to 10 or 15ºC may be appropriate for those animals.

The Livestock Comfort Index tool should be used for reference and information purposes only. Livestock managers should monitor onsite weather conditions and livestock health and prepare a precautionary plan in advance of stress events.