Sincronização da ovulação com dispositivo intravaginal de progesterona (CIDR®) em novilhas Bos indicus, Bos indicus x Bos taurus e Bos taurus / Synchronization of ovulation with intravaginal progesterone device in Bos indicus, Bos indicus x Bos taurus and Bos taurus heifers

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

This study evaluated the effect of treatment with progesterone intravaginal device (CIDR®) associated to estradiol benzoate (BE) and prostaglandin F2α in the follicular dynamic of B. indicus (Nelore and Gir), B. taurus (Angus and BWH) and respectively cross-breed. Aiming to evaluate the effect of different plasmatic progesterone concentration (P4) in the follicular dynamic (3 by 2 factorial design), a half of heifers in each genetic group received PGF at moment of device insertion (D0). The ultrasonography was performed from D0 to D8 (device withdrawal) every 24 hours, and from D9 to ovulation every 12 hours to evaluate the follicular growth. All heifers were bled on D0, on D3, on D6, on D8 and on D10 for determination of serum progesterone concentration. The maximum diameter of DF was lower (P<0.05) in B. indicus heifers (9.5 ± 0.5mm) than in cross-breed (12.3 ± 0.4mm) and in B. taurus (11.6 ± 0.5mm) heifers. The PGF treatment on D0 increased (P<0.05) the diameter of DF (11.9 ± 0.4 x 10.5 ± 0.5mm). The growth rate of DF was lower (P<0.05) in B. indicus heifers (0.9 ± 0.1mm/day) than in cross-breed (1.2 ± 0.1mm/day) and in B. taurus (1.1 ± 0.1mm) heifers. The growth rate was higher (P<0.05) in heifers that received PGF on D0 (1.2 ± 0.1 x 0.9 ± 0.1mm/day). The ovulation rate was lower (P<0.05) in B. indicus heifers (39.1%) than in cross-breed (84.0%) and in B. taurus (72.7%). Heifers treated with PGF presented higher (P<0.05) ovulation rate (78.8 x 54.0%). The interval between device removal (D8) and ovulation was larger (P<0.05) in B. indicus (78.0 ± 2.3h) than in B. taurus heifers (73.5 ± 1.0h). The mean serum P4 concentration during the treatment (D0 to D8) differed (P<0.05) between B. indicus (5.4 ± 0.4ng/ml), B. taurus (3.3 ± 0.2ng/ml) and cross-breed (4.3 ± 0.3ng/ml) heifers. The P4 concentration was lower (P<0.05) in heifers that received PGF on D0 (3.3 ± 0.2 x 5.2 ± 0.3ng/ml). In brief B. indicus heifers presented lower growth rate (mm/day), lower maximum diameter of DF, lower ovulation rate and higher serum P4 concentration during the treatment than B. taurus heifers. The PGF treatment on D0 increased the follicular growth rate, the maximum diameter of DF and the ovulation rate, decreased the serum P4 concentration during the treatment in heifers.

ASSUNTO(S)

hormônios progestacionais bovines synchronization of ovulation sincronização da ovulação progestacional hormones dinâmica folicular follicular dynamic bovinos

ACESSO AO ARTIGO

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