DIFFERENT WAYS OF SHEEP ARTIFICAL INSEMINATION USING COOLED SEMEN

Authors

  • Viviane MILCZWSKI

DOI:

https://doi.org/10.5380/rsa.v1i1.999

Abstract

The aim of this work was to compare in vitro efficiency of 6 extenders in the conservation of ram semen at 5º C for 8 hours. Subsequently, with best in vitro results were used to inseminate 140 ewes. Twenty-three pooled ejaculates were diluted in 6 extenders: Cornell University Extender (CUE), Cornell University - 16 (CU-16), glycine-yolk, citrate-yolk, TRIS-yolk and UHT skim milk-yolk. After 1+3 dilution, the semen samples were cooled during 8 hours at 5º C following analysis of progressive motility, vigor, wave motion, morphology of spermatozoa and thermoresistance test (TT). Citrate-yolk extended semen results were significantly (P<0.05) superior. Glycine-yolk extended semen results were significantly inferior. During TT, citrate-yolk extended semen demonstrated the best results (P<0.05), finishing the test with tghe average of 50% of progressive motility. When glycine-yolk an UHT skim milk-yolk extenders were used progressive motiligy was near zero. There were no significant differences in percentage of major defects and detached acrosomal caps with all 6 diluters after 8 hours of conservation. CUE, CU-16, citrate-yolk, TRIS-yolk and UHT skim milk-yolk extended semen showed significantly increased rates of bent tail. When all characteristic studied in vitro were analyzed, the citrate-yolk extender showed the best semen preservability followed by CUE. So both were evaluated in vivo with cooled semen for 8 hours at 5º C. One hundred and forty crossbred Suffolk ewes had the estrus synchronized with intravaginal pessaries containing 50 mg of medroxyprogesterone acetate. In the fourteenth day, at the same time of the removal of the pessaries, 500 UI of Equine Chorionic Gonadotrophin (eCG), were injected intramuscularly. Cervical and intrauterine insemination were performed with the aid of a laparoscope. CUE extended semen showed insemination pregnancy rates of 69.56% and 8.33% with the uterine and cervical methods respectively. Citrate-yolk extended semen showed 85.71% and 21,74% with the uterine and cervical methods respectively. Citrate-yolk extended semen resulted in higher pregnancy rates, using both insemination methods, however, without statistic significance (P>0.05). These insemination rates confirmed in vitro performances in which citrate-yolk extended semen demonstrated superiority results. The pregnancy rates of the groups inseminated with cooled semen extended in citrate-yolk, 55-58 hours after pessaries removal were 85.75% and 43.75% for intrauterine and cervical insemination, respectively. There was significant difference (P<0.05) between the groups. The cervical inseminations with cooled semen extended in citrate yolk at 57±1 hours and 49±1 hours after pessaries removal, resulted in 43.75% and 21.74% pregnancy rates, respectively. The group inseminated at 57±1 hours presented significantly superior results (P<0.05). It was possible cool ram semen for 8 hours in citrate-yolk extender with good pregnant rates when intrauterine insemination was used, but the results were modest when cervical inseminations were used. The fertilization capability of cooled ram semen is satisfactory in the semen is deposited near the fertilization site.

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How to Cite

MILCZWSKI, V. (2000). DIFFERENT WAYS OF SHEEP ARTIFICAL INSEMINATION USING COOLED SEMEN. Scientia Agraria, 1(1), 88–88. https://doi.org/10.5380/rsa.v1i1.999

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Thesis and dissertation abstracts