Combined effects of gonadotropin and flushing in pubertal gilts / Estudo dos efeitos combinados de gonadotrofinas e flushing em marrãs à puberdade

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The objective of this study, held at the Swine Research Laboratory of the School of Veterinary Medicine and Zootechnology of the Univ. of São Paulo in Pirassununga, São Paulo, was to verify the combined effects of exogenic gonadotropin (eCG and LH) and flushing on the duration and dispersion of the manifestation of initial and second estruses, cyclicity of females, number of ovulations, embryonic viability, and frequency of ovarian cysts. Used for the experiment were 72 pubertal gilts of Pen Ar Lan NAIMA® lineage, with an average age of 157.49±5.01 days, and weight of 96.65±7.70kg. They were distributed in four treatments in a factorial arrangement, with and without flushing, and with and without hormone treatment. The feed used contained 16% CP and 3,286.73 kcal/kg ME. Starting on the seven day of the first estrus, induced with homone, the females with flushing treament received a 50% increase in the amount of the same type feed that they had been receiving. On the sixteenth day of the first estrus the gilts that received hormone treatment were given 600 UI of eCG (Novormon®) and 2.5 mg of LH (Lutopin®), 72 hours later. All the gilts were exposed to boar twice at day, starting on the tenth day and inseminated during the second estrus with heterospermic semen containing 4 x 109 spermatozoon. At slaughter on the fifth day after insemination, the genitals were removed to examine the ovaries and collect the embryos. Interaction between the factors were not observed. The effects that were analyzed separately did not show significant differences in the number of ovulations (14.28±5.06 vs 13.47±5.57 with and without flushing, and 14.60±5.78 vs 13.23±4.83 with and without hormones, respectively, P>0.05), in the frequency of ovarian cysts (22.86% vs 11.11%, with and without flushing and 15.15% vs 18.42% with and without hormones, respectively, P>0.05), during the second estrus (85.71% vs 91.43% with and without flushing and 90.63% vs 86.84% with and without hormones respectively, P>0.05), at final weight (115.35 ± 8.23 vs 111.56 ± 8.30kg, with and without hormones, respectively, P>0.05), in the backfat (10.0±2.0 vs 10.2±1.8mm with and without hormones, respectively, P>0.05), and in the duration of the estruses (57.68±20.02 vs 59.68±14.76 hours, with and without hormones and 57.75±14.99 vs 59.62±19.43 hours, with and without flushing, respectively, P>0.05). A significant difference was found in embryonic viability (11.55±4.81 vs 8.50±5.32 viable embryos, with and without flushing and 8.39±5.66 vs 11.25±4.58 viable embryos with and without hormones, respectively P=0.02), which indicated higher numbers when treated with flushing and lower numbers when treated with hormones. At the final weight (117.48±9.82kg vs. 109.28±7.57kg with and without flushing respectively, P=0.0001) and in the backfat (10.7±12.2 vs 9.5±1.9kg, with and without flushing, respectively, P=0.03) flushing resulted in a higher number. It is concluded in this study that there is a lack of interactive effects between treaments with hormones and flushing. Utilization of gonadotropins (eCG e LH) reduced the dispersion of the second estrus within an effective synchronization. The utilization of flushing in the first estrous cycle in gilts gave positive results as regards to embryonic viability. The association of eCG and LH, plus flushing did not show an interactive effect, and a reduction was identified in embryonic viability based the action of hormones.

ASSUNTO(S)

flushing gonadotropins estrous synchronization puberty sincronização do cio puberdade marrãs flushing gonadotrofinas gilts

ACESSO AO ARTIGO

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