Respostas fisiológicas de potros submetidos à marcação e ao desmame na prática agropecuária

Abstract

Many animal production management techniques invariably produce stress and compromise animal welfare. A better understanding of stress effects can help develop strategies to reduce the deleterious effects of stress. In this sense, acupuncture has been a complementary medicine tool widely used in stress reduction. The present study had the objective of evaluating, through the physiological responses (heart rate variability (HRV)) and behavioral analysis; two widely used agricultural practices with great impact on foals: branding and weaning. For HRV analysis, the RR intervals were recorded by the Polar Equine® heart rate monitor, and the behavior was recorded for further analysis using the etogram. In the first chapter, the practice of identification through the use of permanent branding in foals was analyzed. The objective was to compare hot branding (hot iron) and cold branding (liquid nitrogen) for stress and brand quality. In branding it was used the symbol 47 (6.5X8.5 cm) in the left arm in 23 foals. The animals were split into fire group (n = 11) and nitrogen group (n = 12). In the HRV analysis, a significant increase in heart rate (HR), low frequency band (LF), LF / HF ratio, standard deviation of all normal RR intervals (SDNN) and decrease in the power of high frequency band (HF) suggesting autonomic activation of sympathetic predominance over the parasympathetic, representing a higher level of stress in the fire group compared to nitrogen. In the behavioral evaluation, in the fire group, intense movements of limbs were observed compared to nitrogen. At the second chapter, we evaluated the weaning of horses as a stressful process. The objective was to compare the physiological and behavioral responses of weanling foals when submitted to three treatment groups prior to weaning. Control Group (n = 9), without manipulation; Sham group (n = 8), false acupuncture located at a distance of 2 cm from points VG16, B49, B23, B52, Bai Hui, VG1; Acupuncture group (n = 9), acupuncture points VG16, B49, B23, B52, Bai Hui, VG1. On the seventh day before weaning, treatments were started, which occurred on alternate days. For weaning, the method was used in groups with the presence of an adult mare that was not related to the foals. Weaning induced autonomic responses in HRV and behavioral response indicative of stress in all treatments (Control, Sham and Acupuncture). The agricultural and livestock practices, involving marking and weaning, generated important physiological and behavioral changes, indicative of stress, but alternative methods such as cold marking have provided lower levels of stress in HRV analysis. The study of stress that involves routine management in general is important for the evaluation and maintenance of animal welfare.