Influência de aspectos técnicos e anatômicos nos índices de fertilidade baseado no desempenho da inseminação artificial transcervical em ovinos

The aim of this work was to examine both the influence of anatomical and technical aspects on fertility rate of sheep based on the performance of transcervical artificial insemination (TCAI). Transcervical artificial insemination was performed with traction of the cervix in 122 ewes using frozen semen from 11 rams, both Santa Ines breed. The data collected were the type of external cervical opening (CO): P (papilla); FL (flap); DB (duckbill), S (spiral); RO (rosette), duration of cervical manipulation (2-3, 4-5 and 6-7 minutes), degree of difficulty in cervical transposition (low, moderate, high) and presumed site of semen deposition (SC - superficial cervical; DC - deep cervical; IU - intrauterine). The influence of these variables on pregnancy rate was evaluated. OS types and duration of cervical manipulation had no influence (p>0.05) on fertility. The degree of difficulty in cervical manipulation influenced (p<0.05) pregnancy rate, since insemination classified as low grade had 52% of pregnancy, while those classified as high recorded only 20%. The presumed site of semen deposition influenced significantly (p<0.05) the fertility. Pregnancy rates of deposition at each site were: UI – 45.8%, DC – 25.7%; SC – 15.4%. As expected, the deeper depositions resulted in higher fertility. In conclusion, the performance of TCAI did not depend on the anatomical classification of external cervical OS of ewe and the duration of cervical manipulation within the range tested (2-7 minutes). The TCAI may have higher fertility rates if difficulties in their application were reduced and the semen deposition were deeper.