EFEITO DO ANÁLOGO DA SUBSTÂNCIA APAZIGUADORA BOVINA (ASAB) SOBRE O BEM-ESTAR E REPRODUÇÃO DE FÊMEAS NELORE SINCRONIZADAS PARA IA EM TEMPO FIXO

Abstract

The objective of this thesis was to evaluate the effect of bovine appeasing substance (BAS) on the temperament and reproductive parameters of Nellore females synchronized to AI at fixed time. In the literature review, it was initially addressed on the general physiology of stress and reproductive physiology, reporting the physiological and behavioral responses of the organism to adverse stimuli caused by various factors, such as climatic conditions, changes in the environment, nutritional changes, transport, and management. On the importance of stress in reproductive physiology, two specific topics were addressed, stress and reproduction and stress and pregnancy rate. These last two topics aimed to highlight the negative impacts of stress on the health and productivity of animals, as well as the relationship of stress and reproduction, emphasizing the hyperstimulation of the hypothalamic-pituitary-adrenal (HHA) axis and hormonal dysfunctions that impair fertility and reproductive performance. In chapter 1, a study evaluating the effects of bovine appeasing substance (BAS) at the beginning of the fixed-time artificial insemination protocol (FTAI) and subsequent change in body weight (BW), body condition score (BCS), temperament, quality of management, dirt in the perineal region, ovarian variables, pregnancy rate, conceptus size and serum variables of Nellore heifers was carried out. The data used came from a study using twenty-nine heifers selected according to temperament, BCS and diameter of the follicle or corpus luteum and that were later randomly allocated in two treatments: 1 - saline solution or 2 - BAS (n = 15), both solutions were applied topically between the horns in the neck region. Thus, the following results were observed: the heifers of the BAS treatment presented higher CP in d 30 (394 vs. 392 ± 0.77; P = 0.05) and higher BCS between d -9 to d 30 (0.05 vs. -0.21 ± 0.05; P < 0.01). Heifers with BAS vs. Salina treatment tended to have a lower entry score (P ≤ 0.09) and dirt in the perineal region (P ≤ 0.06), no treatment effect was observed for trunk score (P ≤ 0.39), exit score (P = 0.64), time to inseminate (P ≤ 0.49), percentage of aggression (P ≤ 0.96) and accident (P ≤ 0.61). Heifers from the BAS vs. Salina treatment had higher (P ≤ 0.02) estrus score and mount rate (100% vs. 50.0 ± 0.09%) and no effect was observed for the ovarian variables, progesterone, pregnancy rate and conceptus size. Moreover, treatments did not differ in serum variables. Therefore, the BAS increased WC, BCS, estrus score and mount rate and tended to decrease the temperament of the entrance score and dirt in the perineal region. In chapter 2, a study was conducted that evaluated the effects of bovine appeasing substance (BAS) at the beginning of the fixed-time artificial insemination protocol (FTAI) and subsequent change in body condition score (BCS), temperament, quality of management, dirt in the perineal region, estrus variables, ovarian variables, pregnancy rate, conceptus size and serum variables of Nellore cows. Sixty-eight cows (multiparous) were selected according to temperament and BCS and later randomly allocated into two treatments: 1) saline solution (Saline; 0.9 NaCl; n = 34) or BAS (n = 34) both solutions were applied topically between the horns in the neck region (5 mL/cow). During d -11 to d 7, the cows were kept in two paddocks, separated by treatment, and then (d 7 to d 60) regrouped into a single group. The BCS was evaluated at d -11, 0, 7, 14 and d 30. The temperament was evaluated using the input score and exit score and the trunk score, in the d -11, -2, 0, 7, 14 and 30, in the same period the blood samples were collected. The findings observed were; difference for day in the BCS rump and visual angle (P < 0.01), in the temperament variables, no differences were observed between the treatments (P = 0.68) and in the variables quality of management, aggression (P = 0.08) and time to inseminate (P < 0.01), the cows of the BAS treatment tended to be calmer during the management and gave less time to inseminate in relation to the Salina treatment. Thus, the BAS administered on the eleventh day before the IA did not interfere in the CCS, temperament, dirt in the perineal region, estrus variables, ovarian variables, progesterone, pregnancy rate, conceptus size and serum variables. Keywords: stress; beef cattle; production