Resynchronization of ovulation with new and reused intravaginal progesterone‐releasing devices without previous pregnancy diagnosis in Bos taurus indicus cows subjected to timed‐artificial insemination |
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| Authors: | Danilo Amadori Martins de Oliveira Luiz Ernandes Kozicki Francisco Romano Gaievski Victor Breno Pedrosa Romildo Romualdo Weiss Mrcio Saporski Segui Tcia Gomes Bergstein‐Galan |
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| Institution: | Danilo Amadori Martins de Oliveira,Luiz Ernandes Kozicki,Francisco Romano Gaievski,Victor Breno Pedrosa,Romildo Romualdo Weiss,Márcio Saporski Segui,Tácia Gomes Bergstein‐Galan |
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| Abstract: | The study aimed to evaluate pregnancy per artificial insemination (P/AI) of cows subjected to synchronization and resynchronization in ovulation protocols using intravaginal progesterone‐releasing insert (P4) before pregnancy diagnosis (PD) and the relationship of PR with the diameter of preovulatory follicles (ØPOF) before TAI. Cows (n = 378) were distributed into two groups: a resynchronization group with new devices (GRN; n = 185) and resynchronization group with used devices (GRU; n = 193). On Day 0, both groups received a new P4 and estradiol benzoate (EB). On D8, P4 removal + D‐cloprostenol + eCG + estradiol cypionate (EC) was done. On d10, TAI was conducted. On d32, cows were resynchronized and divided into two groups, GRN (n = 185) and GRU (n = 193). The GRN group received a new P4 + EB, and the GRU group received a used P4 + EB. On d40, the P4 was removed + PD. The non‐pregnant cows received D‐cloprostenol + eCG + EC. US was done again on d42 to determine ØPOF before the second TAI. The P/AI of the GRN and GRU groups after synchronization were 56.2% and 57.0% (p = 0.87), respectively, and those after resynchronization were 58.0% and 37.3% (p < 0.008), respectively. The P/AI of the GRN and GRU groups observed after TAI (synchronization + resynchronization) were 81.6% and 73.1%, respectively (p = 0.047). No difference (p = 0.067) in ØPOF between the pregnant and non‐pregnant cows in the GRN was found, whereas the GRU group showed a significant difference (p = 0.003). Resynchronization protocols optimized the P/AI in both groups. New intravaginal devices resulted in greater P/AI and P/AI accumulation in resynchronization as compared with the GRU; the ØPOF was related with P/AI. |
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| Keywords: | cattle preovulatory follicle resynchronization synchronization ovulation |
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