Sperm transport and distribution during the puberal transition in ewe lambs

Sperm transport through and distribution within the anterior reproductive tract were evaluated at either 2 or 22 h after artificial insemination in ewe lambs at first (1E; n = 15) or third (3E; n = 14) estrus and in mature (MAT; n = 12) ewes. Each ewe was inseminated immediately upon detection of estrus with 7.5 x 10(8) progressively motile sperm placed into the external os cervix. Ewes were hysterectomized at either 2 or 22 h after insemination. Sperm were recovered from the uterus, isthmi, and ampullae by flushing with sterile .9% saline. The distribution of sperm recovered from the uterus, isthmus, and ampulla did not differ (P > .10) among 1E, 3E, and MAT ewes at either 2 or 22 h. However, there was a tendency (P = .08) for more sperm to be recovered from the anterior reproductive tract in 3E and MAT ewes than from that in 1E ewes. There was a time of hysterectomy x anatomical segment interaction (P < .05) for percentage of sperm recovered of the total number of sperm in the inseminate because more sperm were recovered from the isthmus and ampulla at 22 h than at 2 h after insemination. Percentages of 1E, 3E, or MAT ewes from which sperm were recovered from the anterior reproductive tract did not differ (P > .10). However, sperm were recovered from the oviducts in a greater (P < .05) percentage of ewes at 22 h after insemination than at 2 h.(ABSTRACT TRUNCATED AT 250 WORDS)