Revista Interdisciplinar de Direito (Dec 2011)

Estrógeno exógeno no início do ciclo estral de vacas leiteiras na indução do estro e na dinâmica ovariana

  • José Rogério Moura Almeida Neto,
  • Eduardo Paulino da Costa,
  • Ademir de Moraes Ferreira,
  • Wanderlei Ferreira de Sá,
  • Giancarlo Magalhães Santos,
  • Rafael José Otero Arroyo

Journal volume & issue
Vol. 8, no. 1

Abstract

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The objective of this work was to check the exogenous estrogen, in early phase of estrous cycle, on the range of estrus reduction and ovarian dynamics. Animals cycling regularly were selected, without any clinical or reproductive alterations were used in the experiment. Sixteen Holstein-zebu crossbred cows were casually included in their treatments. Treatment 1: eight cows received 2,5 mL of estradiol cipionate at the fi rst day of the estrous cycle. Treatment 2 (control): eight cows without treatment. Th e expression of estrus was monitored visually. Th e ultrasound scans were conducted via transrectal. Th e measurements began at the estrus day and were done daily in the morning. Th e blood collections for the measurements of the levels of progesterone began at the estrus day (0 day) and were conducted once every three days until the next estrus day. All the animals that received estrogen at the fi rst day after the estrus showed the estrus signals (psychics, turgid uterus and abundant mucus) the next day. Th is reduction of the range of estrus for two days can promote the elimination of uterus bacteria (if present), enhancing, consequently, the reproductive capacity. It’s known that some estrus alterations can promote the elimination of in-uterus infections (clinical or sub clinical), and the reduction of the range of estrus is indicated for the treatment of such diseases. Except for the day of the fi rst follicular wave emergence, all the other studied variables (number and wave length, characteristics of dominant and subordinate follicles and the parameters related to the corpus luteum and progesterone production) weren’t aff ected by the application of estrogen the day after the estrus. Th e application of estradiol cipionate in crossbred cows the day after the natural estrus promote the emergence of estrus sign two days after the natural estrus, without aff ecting the next estrous cycle.

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