Protocolos de inseminación artificial a tiempo fijo en vacas Bos indicus: efecto de la presincronización del celo presynch utilizando altas dosis de progesterona
In tropical and subtropical regions, zebu cattle (Bos indicus) predominate, due to their adaptation and productivity characteristics. Bovine reproduction in these regions is low due to intrinsic and extrinsic factors. The objective was to evaluate the effects of pre- synchronization of heat through...
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| Format: | masterThesis |
| Jezik: | spa |
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2024
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| Online dostop: | https://dspace.unl.edu.ec/jspui/handle/123456789/29529 |
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Označite | Izvleček: | In tropical and subtropical regions, zebu cattle (Bos indicus) predominate, due to their adaptation and productivity characteristics. Bovine reproduction in these regions is low due to intrinsic and extrinsic factors. The objective was to evaluate the effects of pre- synchronization of heat through the application of long-term progesterone (pre-synch): in conventional AITF protocols and its influence on the pregnancy rate in Bos indicus cattle. The present research was carried out in the province of El Oro, Piñas canton, a total of 94 animals with a live weight of 500 kg ± 50 kg were used; age: 2 to 8 years, body condition: 3 ± 0.5 on a scale of 1 to 5, with 1 animal being extremely skinny and 5 being in normal conditions. The animals were kept under the same environmental, nutritional and management conditions in an extensive regime, grazed and previously dewormed and vitaminized. The individuals were randomly distributed into two experimental groups: control group (conventional IATF protocol = T0), and experimental group = T1 (conventional protocol with the inclusion of progesterone P4 (long acting). An evaluation of the ovarian structures was carried out (day -8,0,8,10) using transrectal ultrasonography to evaluate ovarian cyclicity and the diameter of the right and left ovaries, pregnancy was determined by ultrasonography on day 40 post insemination after verification of the presence of the embryo(s). Regarding the diameter of the pre-ovulatory follicle on day 9 of heat, its diameter was from 2 mm to 18 mm for the treatment group and from 2 mm to 16 mm for the control group. On day 37 A greater number of pregnant animals could be seen in the treatment group (n=30) compared to the control group (n=22). The diameter of the pre-ovulatory follicle on day 9 of heat, its diameter in the animals subjected to IATF were from 2 mm. to 18 mm, while for the treatment group and 2 mm. at 16mm. for the control group. However, there are significant differences in the size of the LE preovulatory follicle, being greater in the control group compared to the treatment group. Regarding pregnancy, no significant statistical difference was observed between the treatment group and the control group. Despite this, it can be seen that the pregnancy rate is 64% for the treatment group and 47% for the control group. Therefore, the incorporation of long-acting progesterone (pre-synch) in conventional AITF protocols could be an important tool to improve pregnancy rate in Bos indicus cattle in tropical and subtropical environments. |
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