Fertility of weaned sows after deep intrauterine insemination with a reduced number of frozen-thawed spermatozoa

The present study evaluates the effectiveness of the transcervical deep intrauterine insemination (DUI) with a reduced number of frozen-thawed boar spermatozoa in weaned sows. DUI was performed using a specially designed flexible device (length 180 cm, outer diameter 4 mm, working channel 1.8 turn, working channel's volume 1.5 ml) that was inserted through an artificial insemination spirette to cross the cervix lumen and moved into one uterine horn as far as possible. Spermatozoa diluted in 7.5 ml of BTS were flushed into the uterine horn by a syringe attached to the working channel. In Experiment 1, 111 hormonally treated (eCG/hCG) weaned sows were inseminated once using one of the following, three regimens: (4) DUI with frozen-thawed spermatozoa (1000 x 10(6) cells per dose; n = 49); (2) DUI with fresh semen (150 x 10(6) cells per dose; n = 29, as control of DUI procedure); and (3) cervical insemination with frozen-thawed spermatozoa (6000 x 10(6) cells diluted in 100 ml; n = 33). No differences (P > 0.05) were found for farrowing rates (77.55, 82.76, and 75.76, respectively) or litter sizes (9.31 +/- 0.41, 9.96 +/- 0.32, and 9.60 +/- 0.53 piglets born per litter, respectively) among the groups. In Experiment 2, DUI was performed on the spontaneous estrus in weaned sows (2-6 parity) with 1000 x 10(6) frozen-thawed (40 sows) or 150 x 10(6) fresh spermatozoa (38 sows). The farrowing rate of sows inseminated twice with frozen-thawed spermatozoa (70%) was significantly (P < 0.05) lower than with fresh semen (84.21%). No significant difference (P > 0.05) was found in litter size between frozen-thawed spermatozoa (9.25 +/- 0.23 piglets born per litter) and fresh semen (9.88 +/- 0.21 piglets born per litter). These preliminary results indicate that application of DUI provides acceptable fertility in weaned sows using a relatively low numb er of frozen-thawed spermatozoa. (C) 2002 Elsevier Science Inc. All rights reserved.