The development of an extreme cold warning system for livestock in northeastern Montana

The coldest temperature ever recorded at Glasgow, Montana, was -59°F on February 15, 1936. Arctic outbreaks with wind chills in the -30°F to -50°F range occur frequently during the winter months. These bitterly cold temperatures affect the agricultural community of northeast Montana as ranchers typically breed their livestock such that calving and lambing occur in February and March. During these critical weeks, ranchers require advanced warning of extreme cold to move susceptible livestock to shelter. Newborn animals (less than 24h old) are especially vulnerable to cold because they are not yet able to regulate their body temperature effectively (Stanko et al., 1991). For example, in one spring cold outbreak, a rancher in Big Sandy, Montana, lost more than 10% of his herd: 250 calves from his herd of 2000 head. This equated to a loss of approximately $110,000. Development of a warning system for dangerous events should allow producers to minimize mortality rates of newborn calves and lambs and the associated economic losses.

This study explores the development of such a cold warning system for northeastern Montana, the Cold Advisory for Newborn Livestock (CANL) system, with a focus on identifying weather conditions that result in livestock losses. System development was accomplished by two means: 1. a literature review identified studies which had been undertaken in other areas, or in climate chambers, to determine the effects of cold exposure on newborn animals; 2. livestock producers in the region were interviewed to identify specific weather events that had caused losses in the area in the past. This study defines meteorological thresholds for which a cold warning would be called, discusses the development of an operational warning system and sets the stage for the development of similar systems in other areas.