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| Author(s): |
André Fernando Freire
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2006-04-19 |
| Examining board members: |
Mario Binelli;
Eduardo Harry Birgel Júnior;
José Luiz Moraes Vasconcelos
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| Advisor: | Mario Binelli |
| Abstract | |
In cattle, embryonic mortality associated with failure in the process of maternal recognition of pregnancy reaches 30 to 40%. Successful pregnancies depend on appropriate biochemical interactions between the maternal endometrium and conceptus. Overall objective was to develop a surgical technique to probe the uterine microenvironment of cyclic and pregnant cows days 14 to 20 post- estrus. Specific objectives were to verify whether presence and operation of uterine catheters would affect (1) maintenance of pregnancy, (2) luteal function and (3) follicular growth. Non-lactating, cyclic, Holstein cows were fitted with a silicone catheter in each uterine horn on day 2 after estrus. On day 15 they received an injection of D-cloprostenol and ovulations were confirmed by transrectal ultrasonography (US; experimental day 1). On experimental day 7, cows received (n=6) or not (n=3) embryos by trans-cervical transfer to the uterine horn ipsilateral to ovary containing the corpus luteum (CL). On experimental days 14, 16, 18 and 20, ovarian strutures were observed by US and each uterine horn was washed through the catheter (three sessions of 6 ml each). Blood samples were collected from experimental days 1 to 20 and progesterone (P4) concentrations were measured by radioimmnoassay. Cows were slaughtered on experimental day 20 and pregnancies were diagnosed by macroscopic visualization of a conceptus after dissection of uterus. Conception rate at day 20 was 0%. On experimental day 7, both a CL and a large follicle (9 to 17mm) were present in ovaries of all cows. Rate of increase of P4 concentrations from days 1 to 5 was 0ng/ml/day in 7/9 cows. Luteolysis occurred before day 15 in 3/9 cows, between days 16 and 20 in 3/9 cows and after day 20 on 2/9 cows. No luteal phase rise in P4 was noticed for one cow. Ovulation before day 20 was verified in 3/9 cows. Rate of growth of the last dominant follicle was 1.3mm/day in 2/9 cows and less in the remaining. Follicular cysts, poorly luteinized CL and endometries were diagnosed in 2/9, 2/9 and 1/9 cows respectively. In summary, alterations in ovarian and uterine functions were caused by presence and operation of uterine catheters and such alterations were incompatible with maintenance of pregnancy. In conclusion, the surgical approach tested was not adequate for studyng the uterine microenvironment of pregnant cows (AU) | |