Artificial insemination with frozen semen in dogs: A retrospective study of 10 years using a non-surgical approach
Abstract
From 1994 to 2003, a total of 526 bitches of 99 different breeds were artificially inseminated in 685 estrus cycles with domestic (n
=
353) or imported (n
=
332) frozen-thawed semen from 368 males. The overall whelping rate was 73.1% and mean (±S.E.M.) litter size 5.7
±
0.1 pups. The whelping rate was higher after intrauterine insemination (75.0%; n
=
665) than after intravaginal insemination (10.0%, n
=
20; P
<
0.05). Insemination at the optimal time resulted in a higher whelping rate (78%, n
=
559; P
<
0.01) and larger litter size (5.8
±
0.2; P
<
0.05) than inseminations performed late or too late (55.7% and 4.5
±
0.5, n
=
61). Two inseminations (n
=
384) yielded a higher whelping rate (P
<
0.05) and mean litter size (P
<
0.01) than one insemination (n
=
241), 78.1% and 6.0
±
0.2 and 70.5% and 5.1
±
0.2, respectively. For inseminations performed at the optimal time, however, the whelping rate was not significantly different for bitches inseminated twice (79.3%, n
=
358) versus once (76.8%, n
=
168), but the litter size was larger (6.0
±
0.2 and 5.3
±
0.3). Semen classified as of poor quality (progressive motility <50% or percentage abnormal sperm >20%) resulted in a lower whelping rate (P
<
0.01) than semen classified as of good quality (progressive motility ≥50% and percentage abnormal sperm ≤20%), 61 and 77%, respectively. Small breeds (n
=
50) had a smaller litter size (3.9
±
0.3; P
<
0.01) than larger breeds (medium [5.7
±
0.3, n
=
94], large [5.9
±
0.2, n
=
295] or giant breeds [6.1
±
0.5, n
=
62] [P
<
0.01]). Bitches older than 6 years had a lower whelping rate (68.2%) than younger ones (77.0%; P
<
0.05). The duration of pregnancy was longer (P
<
0.01) for bitches with a litter size of <3 pups (61.7
±
0. 4 days, n
=
30) than for bitches with larger litters (60.5
±
0.1 days, n
=
177). These results show the potential of transcervical intrauterine insemination for routine artificial insemination in dogs. The results with frozen semen inseminations were optimised by inseminating bitches ≤6 years old 2 and 3 days after ovulation with semen of good quality from males ≤8 years old.
Keywords: Dog, Artificial insemination, Frozen semen, Transcervical insemination
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PII: S0093-691X(06)00035-5
doi:10.1016/j.theriogenology.2006.01.022
© 2006 Elsevier Inc. All rights reserved.
