EFEITO DO ESTRESSE TÉRMICO SOBRE A REPRODUÇÃO DE ANIMAIS NO SEMIÁRIDO

• DOI: 10.22533/at.ed.91619150314

• Palavras-chave: Ambiência, bem-estar animal, produção animal.

• Keywords: Ambience. Animal welfare. Animal production.

• Abstract:

  Climate is considered as a regulating or even limiting factor of animal

  exploration for economic purposes, stress is accompanied by an increase in the activity

  of the hypothalamic-pituitary-adrenal (HHA) axis and by a decrease in the reproductive

  function, with a possible relationship with hypothalamic-pituitary-gonadal (HHG) axis

  hormones. Stress-related hormones may influence sexual function in three levels of

  the HHG axis: in the hypothalamus, through CRH (corticotrophin releasing hormone),

  where it inhibits the secretion of GnRH (gonadotrophin releasing hormone) and,

  consequently, in the pituitary gland decreases the release of LH (luteinizing hormone)

  and FSH (follicle stimulating hormone), thus impairing animal reproduction. In this way

  authors mention that they found a variation of 20 and 30% in conception rate when

  comparing the hot and cold seasons. Researchers also found a higher percentage

  of pregnancy (55.5%) in the cold period when compared to the hot period (44.5%),

  consequently gestational losses in the cold period were lower (2.1%) when compared to

  the hottest period (12.3%). The high temperature at which an embryo is exposed causes

  it to become hyperthermic, which can lead to death. In males it was also observed that

  the ambient temperature is the most important factor in the spermatogenesis of males

  of any species and, when very high (on the order of 34.5ºC), it is detrimental both to the

  stages of sperm formation and to those already formed elements and in transit through

  the epididymis.

• Número de páginas: 15