EVALUATION OF A COMMERCIAL ACCELEROMETER FOR REMOTE MONITORING OF LYING AND STANDING EVENTS IN DAIRY CALVES IN PUERTO RICO

Behavior monitoring provides important information about the impact of environment (Bonk et al., 2013), food (DeVries et al., 2003; González et al., 2008; Nielsen, 2013; RayasAmor et al., 2017) and water intake (Lukas et al., 2008; McDonald et al., 2019), welfare (Müller and Schrader, 2003), health (González et al., 2008; Lukas et al., 2008) and comfort status (Lomb et al., 2018) on dairy cattle. Thus, two methods have been commonly used to evaluate animal behavior for scientific research: direct visual observations and video footage analysis (Nielsen et al., 2010). However, both monitoring systems are time consuming (Ledgerwood et al., 2010; Bonk et al., 2013; Nielsen, 2013) and labor consuming (Ito et al., 2009; Ledgerwood et al., 2010), which limits considerably their feasibility. For these reasons livestock research has incorporated automated tools, such as data loggers, to remotely monitor animal behavior (Ledgerwood et al., 2010; Bonk et al., 2013). Even though multiple studies have confirmed the effectiveness of using data loggers as indicators for lying events in mature dairy cows (Ito et al., 2009; Ledgerwood et al., 2010; Swartz et al., 2016), to our knowledge there is only one study (Bonk et al., 2013) that has validated these sensors for the study of lying activity in Holstein calves. However, the Bonk et al. (2013) study was performed in Germany, a country with very different environmental conditions than Puerto Rico (temperate vs. tropical weather, respectively). Thus, although their data loggers’ validation may be highly useful as a guide when evaluating similar behavior in other countries, their results may not be directly extrapolated to Puerto Rico’s environmental conditions. Since Puerto Rico is located in the tropical region, the chronic nature of its high relative humidity and environmental temperature (Daly et al., 2003; PRCCC, 2013) can lead to heat stress in dairy cattle (West, 2003; Chen et al., 2013). This problem is exacerbated because Holstein cattle, the most common dairy breed on the island (Cortés et al., 2010), are highly adapted to temperate climates (Javed et al., 2004). This is important because heat stress has been reported to significantly affect cattle behavior, including their lying and standing patterns (Schütz et al., 2010; Chen et al., 2013; Polsky and von Keyser-