Parâmetros reprodutivos e metabólicos de cabras leiteiras submetidas a condições bioclimáticas artificiais, semelhantes à Zona Equatorial Brasileira

• Autor(a) principal: Pinho, Rogério Oliveira
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5219
• topic: Reprodução; Cabras; Fotoperíodo; Reproduction; Dairy goats; Photoperiod; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

This work deals with the reproductive behavior of Alpine and Saanen female goats submitted to artificial bioclimatic conditions similar to those of the the Brasilian Equatorial Region, when compared to female goats raised under normal typical bioclimatic conditions of regions where they demonstrate seasonality. The study was conducted during the reproductive season for goats (April to July of 2007), consisting of an adaptation period of 30 days (Phase 1) and an experimental period (Phase 2) of 60 days, in the bioclimatic chamber. Two groups of animals were used in this study. Group 1 (n = 4) remained in the bioclimatic chamber with temperature and air humidity control (8:00 - 12:00 hours - 30 ºC; 12:00 - 18:00 - 36 ºC; 18:00 - 8:00 - 26 ºC; with 60 % of average humidity; and a 12 hour fotoperiod), thus simulating bioclimatic conditions of the northern region of Brazil (next to the Equator line), whereas group 2 (n = 4) was kept under influence of the natural climatic variations of the season. The physiological parameters of respiratory (FR) and cardiac frequencies (FC), rectal temperature (TR) and rumination behavior (MR) were measured twice a day, with daily follicular dynamics accompaniment, besides blood collection twice a week for triiodotironine (T3), tiroxine (T4), cortisol, total cholesterol, total proteins (PT), albumine (ALB), progesterone (P4) and estrogen (E2) dosages. The average values for water consumption were different (p < 0.05) as a function of group and time, showing that the animals of group 1 consumed more than the double (4,386.3 mL/day) than those of group 2 (1,663.2 mL/day). In relation to the ration consumption, there was a difference both between groups and periods (499.0 and 490.8 g/day, for groups 1 and 2, respectively). There was no variation in the average values for corporal weight and corporal score condition (ECC) as a function of time, however, during the experimental period, there was a difference in the weight of the animals between groups (50.5 and 41.5 kg, for groups 1 and 2, respectively). During the experimental period, a difference was observed (p < 0.05) for the studied physiological parameters between the morning and the afternoon, being the afternoon values always higher than the ones in the morning. With regard to cholesterol, ALB and PT concentrations behavior as a function of the days, in the different groups and experimental and adaptation periods, no difference was registered between the obtained average values during the observation period (p > 0.05). With regard to T3, T4 and cortisol concentrations behavior as a function of the days, in the different groups and experimental and adaptation periods, no difference was registered between the obtained values during the experimental period (p > 0.05). There was no difference (p > 0.05) in the duration of estral cycle and estrus for the animals of groups 1 and 2. There was no difference (p > 0.05) in relation to the number of follicles observed in the day of the estrus and to the ovulatory follicle diameter, as a function of the groups and number of estrus evaluated, with average values of 4 and 3.5 in the 1st estrus, 5 and 3 in the 2nd estrus, and 4 and 4.5 in the 3rd estrus, for groups 1 and 2, respectively. The number of follicular waves observed varied from 4 to 5 in group 1 and 2, to 4 waves in group 2. The day after the ovulation where the corpus luteum (CL) presented greater diameter was 5.2 ± 2.0; 9.7 ± 2.7 and 7.7 ± 2.6 for the 1st, 2nd and 3rd estral cycles, respectively, and the CL area in the day of its higher diameter was 9.7 ± 3.0; 12.1 ± 4.4 and 7.0 ± 1.3 mm3 for the 1st, 2nd and 3rd estral cycles, respectively. There was no difference (p > 0.05) in any of the studied reproductive parameters, neither as a function of the group nor as of the estrus. Although the animals of group 1 demonstrated higher values of P4 and E2 in relation to the animals of group 2, the endocrine secretion standard of these hormones revealed to be similar for both groups in all the studied estral cycles, as a function of time. Although the number of animals observed in bioclimatic conditions similar to the Eastern Amazon was small, the average values obtained for the physiological parameters, food and water ingestion, metabolic and hormonal, indicated that female goats can be raised under bioclimatic conditions, without modifying the related physiological standards.