Sperm Localization in the Oviducts of Artificially Inseminated Dairy Cattle

Abstract

Eight animals, 3 heifers and 5 primiparous cows, were artificially inseminated by intrauterine deposition of frozen-thawed semen. The insemination dose comprised 20×10⁶ or 200 × 10⁶ spermatozoa, frozen in French mini straws. Four animals were inseminated at fixed time interval (72 or 84 h) after cloprostenol injection. The remaining 4 animals were inseminated in spontaneous oestrus. Slaughter took place 2 or 12 h after insemination. After fixation the oviducts were cut into segments, which were serial-sectioned and stained. Six sections per segment were examined under the microscope for sperm recovery.

The number of spermatozoa recovered from the oviducts varied considerably among animals. Recovery was poor (less than 50 spermatozoa) in 4 animals. Recovery was low when insemination took place in induced oestrus and with the lower sperm number (20×10⁶). In animals in which more than 50 spermatozoa were found the distribution varied both between animals and between oviducts within the same animal. Overall, more spermatozoa were found in the lower (UTJ, isthmus and AIJ) than in the upper (ampulla) parts of the oviducts. In 3 out of 4 animals more spermatozoa were recovered from the left than from the right oviduct. Only in 1 animal were the majority of spermatozoa found in the oviduct ipsilateral to the follicle-bearing ovary.

Sammanfattning

Åtta djur, 3 kvigor och 5 förstakalvare, inseminerade med tjursperma fryst i mini-payetter. Varje dos innehöll 20×10⁶ eller 200 ×10⁶ spermier, som deponerades i corpus uteri. Fyra djur inseminerades i spontan brunst medan de övriga 4 inseminerades på bestämda tidsintervall (72 eller 84 timmar) efter cloprostenol injektion (Estrumat, Leo). Två eller 12 timmar efter insemination en slaktades djuren. Äggledarna fixerades och indelades i segment. Segmenten seriesnittades och färgades. Sex snitt per segment undersöktes i mikroskop avseende förekomst och lokalisation av spermier.

Antalet spermier, som återfanns i äggledarna, varierade mellan de olika djuren. Hos 4 djur var antalet återfunna spermier lågt (färre än 50). Få spermier återfanns när insemination en skedde i inducerad brunst och med det lägre spermieantalet (20×10⁶). Hos de djur, där fler än 50 spermier återfanns, varierade fördelningen av spermier både mellan djur och mellan äggledare från samma djur. Sammanfattnings vis återfanns flera spermier i de nedre delarna (UTJ, isthmus och AIJ) av äggledarna jämfört med de övre (ampulla). Hos 3 av 4 djur fanns fler spermier på vänster än på höger sida. Bara ett djur hade merparten av spermierna på den sidan där äggstocken med den preovulatoriska follikeln fanns.