| dc.description.abstract | The increase of the ambient temperature has a negative effect; it is altering the
physiology of the reproductive system of the cow including the oocyte, granulose and the
theca cell, the developing embryo during the early stages of development, and the quality of
the sperm . The low LH and estradiol is one of the main factors for low fertility during the hot
weather. The decrease of FSH and the low concentration of inhibin decrease the quality of the
preovolatory follicle and therefore the fertility. The primary site affected by heat stress seems
to by the hypothalamic axis. There are two ways how heat stress affects the bovine animal and
decreases fertility: The first is before conception, the animal fails to enter into estrus due to
immature follicle or hormonal alteration affecting the Oestrus cycle, or during heat stress the
Estrus behavior is weak. The second way is after conception, showing that heat stress has a
high effect on the first days of the embryonic development. The high rectal temperatures of the
animal have direct negative effect and indirect effect on the hormones responsible to sustain
the pregnancy. | en |
