Thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road
Even under favourable conditions, livestock are exposed to a range of potential stressors which may compromise their welfare, health and performance due to changes in the thermal micro‐environment, weather conditions, social mixing, handling, withdrawal of feed and water, vibration and acceleration and associated fatigue, loading and unloading stress and injury, noise and environmental pollutants (Mitchell and Kettlewell, 2008; Miranda‐de la Lama et al., 2014). Stressors are known to cause a short‐lived increase in core body temperature or hyperthermia in ruminants (Proctor and Carder, 2015). They stimulate the sympathetic pathway of the autonomic nervous system and may alter the thermoregulatory set point (Pedernera‐Romano et al., 2010), which can be a potential welfare indicator (Ingram et al., 2002). Rectal temperature has traditionally been used to measure the core temperature of animals, although miniature temperature data loggers have recently been employed to measure core temperature, while avoiding the potential stress of rectal measurement (which itself could induce a rise in body temperature; Piccione et al., 2014).
Recently, iButtons have been used to record body temperatures, especially in animals of all sizes, through surgical implantations, insertions into the gastrointestinal tract, ear canal or attachment to the animal's outer surface (Roznik and Alford, 2012). Thus, the impact of various stressors such as transportation can be determined by monitoring body temperature dynamics. However, little is known about the possible impacts of transport on the thermophysiological stress response in general in farm animals, and especially in sheep using miniature data loggers as non‐invasive welfare indicator during transport. The authors of this study propose the application of the IBUTTON THERMOCHRON® as tool for measurement of intravaginal temperature in ewes to study the stress response during road transport. Additionally, numerous studies have investigated the effects of transport on sheep destined to slaughterhouses, but to our knowledge there are no reports concerning live journeys for productive reasons. The hypothesis of the current study is that the thermophysiological, haematological, biochemical and behavioural responses of transported sheep provide a sensitive indication of transport‐level stress. As a result, basic information on ewes during road transport could contribute to improving the welfare and health aspects of transportation in live journeys. Therefore, the aim of this study was to evaluate the thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road.