**1. Introduction**

Selling cattle through livestock markets is still common in many South American countries [1,2]. At livestock markets, animals are handled by anonymous, and generally untrained, handlers [3], and are exposed to at least twice as many physical and psychological stressors than calves sold directly from farm to farm [4]. In Chile, approximately one million cattle go through livestock markets annually and over 30% of them, being the main category sold, are calves. Preliminary results [5] show that the mean transport time of calves from origin (farm) to the market is only 75 min (although it ranged between 5 min and 13 h) and from the market to the final destination (usually another farm where calves are fattened) is only 45 min (5 min–40.5 h). However, including the time spent in the holding pens (without any food or water), calves generally underwent at least 12 h of fasting, and frequently up to 24 h of fasting, which is the maximum time allowed by Chilean legislation [6,7].

Although in many countries there are now regulations regarding the transport and slaughter of livestock [1], fasting times remain long in many South American countries for diverse reasons [2]. The short- and long-term effects of transport and fasting on welfare and production indicators in calves have not attracted as much attention as they have in slaughter weight cattle, and they are also more difficult to measure. Werner et al. [8] described body weight changes and some blood constituent changes related to the stress response during a 63-h transport of recently weaned calves (approximately 240 kg) in the Chilean Patagonia. The high cortisol concentration values before transport, found by Werner et al. [8], sugges<sup>t</sup> that the handling processes before transport (herding from distant fields and regrouping in pens before loading and weaning), which are common practice in extensive systems in the Patagonia, were already stressful for the calves, and represented the highest mean value found throughout all sampling stages. In the same study [8], there was significant body weight loss in the calves after the 63-h period (14% of LW, live weight). A recovery period of 30 days was required, probably because the calves ate and drank less than usual in the new environment but continued to mobilize body reserves. These results show that the long-distance transport of calves not only has an effect on animal welfare, but also creates economic losses for producers.

The marketing process is inherently stressful for calves because they are taken away from their environment, often weaned just before loading, loaded, unloaded, and transported. When selling through a livestock market additional stress can be caused because: the events associated to transport happen more than once, as they go to and from the market; animals are kept confined in an unknown environment and are often mixed with unfamiliar animals; and time without food and water increases. Physiological indicators commonly used to measure stress in animals have been reviewed by Knowles et al. [9]. Blood variables as indicators of stress have some limitations given that the handling and restraining of animals is required during sampling, which in turn produces a stress response [10].

When an animal becomes stressed, the hypothalamic–pituitary–adrenocortical (HPA) axis is activated because of the increase in catecholamines and cortisol concentrations, in addition to blood flow responses, and will produce changes in heat production and heat loss from the animal [11]. During a physical attack, or in response to a painful stimulus, blood can be diverted from the cutaneous bed and redirected to bodily organs with more urgen<sup>t</sup> metabolic requirements [12]. The effect of this vasoconstriction is a decrease in skin temperature, which can be detected by infrared thermography (IRT). IRT measures the superficial temperature of objects in a non-invasive manner and has been widely used to measure the superficial body temperature in animals [13–16]. Eye temperature has been shown to be a more consistent measure of temperature change than other anatomical areas, particularly in response to stress, and is not interfered with by fur or hair [17–23].

This is a preliminary study with the aim of determining the consequences for beef calves of a short transportation time followed by a prolonged time without food and water on their tympanic temperature (TT), maximum eye temperature (MET) measured using IRT, blood variables related to stress, and live weight.

## **2. Materials and Methods**

The Bioethics Committee "Use of animals in research" of the Universidad Austral de Chile, approved the present study (Application N◦325/2018).

Ten black and red Angus calves, mixed male and female, with a mean live weight of 146.1 ± 19.1 kg, weaned a month before the experiment, and clinically healthy were used. All calves had been bred on the same farm where the experiment was performed; they were kept on pasture during the day, with water *ad libitum*, and were put in a barn overnight, receiving 1 kg/head of sugar beet pulp and hay.

The study was carried out in Lanco, Chile, during winter. The study started at 9 a.m. and the calves were calmly moved approximately 50 m from the barn to a pen, and then to a race and chute that had a head-holder for immobilization, blood sampling, and measurement of other variables. Sampling took place before loading, after transport and unloading, and again after 24 h without food and water in an outdoor pen, to simulate the conditions during commercial movement of calves for livestock markets. The transport journey had a duration of 3 h with a space allowance of 1 m<sup>2</sup> per 270 kg and started approximately 2 h after the first sampling. Table 1 summarizes the environmental data present at the time the study was carried out [24].

**Table 1.** Values for climatic variables during the study period.


AT: Air temperature (◦C); RH: Relative humidity (%).
