1 tropical beef cattle 2 Effect of slaughter on carcass characteristics and meat quality in tropical 3 cattle 4 5 Running title: Effects of stress on carcass and meat quality 6 7

Animal training is meant to teach specific behavioral responses to specific cues. Clicker training (CT) is a popular training method based on the use of a device that emits a sound of double-click to be associated as a first-order conditioned stimulus in contingency with positive reinforcements. After some repetitions, the clicker sound gains some incentive value and can be paired with the desired behavior. Animal trainers believed that CT can decrease training time compared to other types of training. Herein, we used two-month old miniature piglets to evaluate whether CT decreased the number of repetitions required to learn complex behaviors as compared with animals trained with voice instead of the clicker. In addition, we compared the number of correct choices of animals from both groups when exposed to object discriminative tests. Results indicated that CT decreased the number of repetitions required for pigs to learn to fetch an object but reduced the ability of animals to make correct choices during the discriminate trials. This suggests that CT is more efficient than voice to teach complex behaviors but reduces the ability of animals to use cognitive processes required to discriminate and select objects associated with reward.

The study evaluated the concentrations of faecal cortisol metabolites (FCM) in intensively fattened beef cattle from a feedlot in a humid tropical environment. A total of 360 bulls weighing 271-371 kg were kept confined in pens from the start to the end of the fattening period (FP). At 24 h after arriving at the feedlot, cattle were distributed into the pens according to their live weight: 271-320 kg, 321-370 kg, and >370 kg. At the start of the FP, four pens of each weight group were randomly selected, and in each of them 10 faecal samples were obtained from 10 randomly selected bulls; this sampling was repeated in the same pens and in each weight group at the middle and end of the FP. The FCM were measured through enzyme immunoassay. The 271-320 kg group had higher FCM at the end of the FP (P < 0.05), the 321-370 kg group had similar FCM throughout the FP (P > 0.05), and the >370 kg group showed higher FCM at the start and end of the FP (P < 0.05). Higher FCM were observed at the middle of the FP in the 321-370 kg group, and at the end of the FP in the 271-320 kg and >370 kg groups (P < 0.05). Mean FCM obtained throughout the FP were within normal ranges for cattle, suggesting that appropriate management in feedlots in humid-tropical regions can provide bulls with a low-stress environment.

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