Doses e vias de aplicação de cloprostenol sódico para sincronização de estro em receptoras de embrião bovino

• Autor(a) principal: Gioso, Marilu Martins
• Data de Publicação: 2003
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5209
• topic: Novilhas; Receptoras de embriões; Estro; Sincronização; Bovine; Embryo recipients; Estrous synchronization; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

This work had as objective the administration of an luteolytic agent (Cloprostenol Sodic-Ciosin) in different doses and routes, to evaluate the synchronization rates, interval of the application to the estrus, hormonal plasma concentrations of progesterone (P4) and pregnant rates of fresh embryos transferred. Still, genital organs of bovine females were collected at slaughterhouses for the study of the angioarchitecture, through veined infusions of radiographic contrasts. There were used 199 Holstein-Zebu embryo recipients with corporal score &#8805; 3,0 in a scale from 1 to 5 and live weight among 320-450 kg. A total of 103 animals presented historic of estrus previous to the treatments (between days 7-16 of the estrous cycle; estrous = day 0) and 96 animals didn't present historic of estrous, these were examined by rectal palpation for the presence of ripe CL in one of the ovaries. The animals were randomly assigned to three experimental groups. Treatment 1: 68 animals (38 with report of previous estrus) received 1 mL of Cloprostenol via intra-vulvo-submucosal (IVSM). Treatment 2: 66 animals (33 with report of previous estrus) received 1 mL of Cloprostenol via intramuscular (IM) and in Treatment 3, 65 animals (32 with report of previous estrus) received 2 mL of Cloprostenol via IM. It was considered immobility reflex as an indicative of estrous and only the animals that showed estrus up to 96 hours after the application of the Cloprostenol were used. The averages of plasma progesterone concentrations (P4) were analyzed by RIA in the moment previous to the application of the drug and 48 hours after. There was no difference in synchronization rates (P>0,05) between the three treatments (72,1%, 53,0% , 64,6%, respectively), when just the animals with report of previous estrus were appraised (76,3%, 60,6% , 68,8%, respectively) and when the animals without report of previous estrus were appraised (66,7%, 45,5% , 60,6%, respectively). The answer interval to the estrus was similar (p >0,05) among the three treatments (69,3± 15,2; 67,9± 16,7; 68,3± 16,9 hours, respectively), but they showed differences (p<0,05) when the animals with report of estrus were divided in luteal classes, in witch animals belonging to days 11-13 of estrous cycle showed larger intervals (75,3 ± 13,3 hours), in relation to days 7-10 of the estrous cycle (63,6 ± 18,3 hours) and to days 14-16 (61,1 ± 11,3 hours). Synchronization rates were similar among the three luteal classes (P>0,05). Regarding pregnant rates there were not differences (P>0,05) in the animals fertility among the three treatments, (45,5%, 50,0%, 55,0% respectively). As for the plasma P4 concentrations, the percentile fall of the progesterone values after 48 hours of the application was similar (p>0,05) in the three treatments (79%; 68% and 83%, respectively). Regarding the angioarchitecture of the genital organs it was observed through radiographic sheets that the caudal vaginal vein drains the vagina mucosal and it presents anastomoses with the vases from the cervix, body and uterine horns. The present study demonstrated that embryo recipients with and/or without report of previous estrus, when synchronized with Sodic Cloprostenol in reduced doses (50% of the conventional), as by IM or IVSM roads showed similar synchronization rates, answer intervals to the estrus, fall of the progesterone concentrations and pregnat rates. The variations in the answer intervals to the estrous are influenced by the diestrous phase in the moment of treatment and not for the route or dose of administration of an luteolytic agent. A portion of luteolytic agents administered through IVSM can be transported directly to the uterus and consequently to the ovary for a local route without passing for the systemic circulation is suggested.