D M Burgess1, K E Mitchell, P G A Thomas. 1. Queensland Veterinary Specialists, 263 Appleby Road, Stafford Heights, Queensland 4053, Australia. dave.burgess@qldvetspecialists.com.au
Abstract
OBJECTIVE: (1) To report whelping rates and litter sizes following coeliotomy-assisted intrauterine inseminations (CAII) performed commercially and (2) to identify factors that may influence these outcomes. DESIGN: Retrospective single cohort observational study. PROCEDURE: All oestrous cycles in bitches that presented to the study hospital for CAII between 1 January 2005 and 31 December 2010 were included. One insemination was performed per oestrus. Whelping and litter size following CAII were recorded. Potential determinants of these outcomes were assessed. RESULTS: Of 238 inseminations performed, 174 (73.1%) resulted in whelping. The known litter size ranged from 1 to 16 pups (mean ± SD 6.12 ± 3.12 pups). From univariable analyses, progressive motility percentage was the only variable significantly associated with odds of whelping (P = 0.020); bitch parity and weight were associated with litter size when adjusted for each other (P = 0.035 and 0.003, respectively). Inseminations performed with >200 × 10(6) progressively motile sperm were more likely to result in whelping relative to inseminations with >100-200 × 10(6) progressively motile sperm (odds ratio 3.61, 95% confidence interval 0.84-15.5, P = 0.084), and, in a separate model, relative to >75-125 × 10(6) progressively motile sperm (odds ratio 6.09, 95% confidence interval 1.41-26.36, P = 0.016). CONCLUSION: Whelping rates and litter sizes were similar to other case studies and the experimental reports of CAII. Progressive motility percentage affects the odds of whelping, and litter size is affected by both the weight and parity of the bitch. Importantly, these findings provide some evidence that whelping rates with CAII are not maximised unless more than 200 × 10(6) progressively motile sperm are inseminated.
OBJECTIVE: (1) To report whelping rates and litter sizes following coeliotomy-assisted intrauterine inseminations (CAII) performed commercially and (2) to identify factors that may influence these outcomes. DESIGN: Retrospective single cohort observational study. PROCEDURE: All oestrous cycles in bitches that presented to the study hospital for CAII between 1 January 2005 and 31 December 2010 were included. One insemination was performed per oestrus. Whelping and litter size following CAII were recorded. Potential determinants of these outcomes were assessed. RESULTS: Of 238 inseminations performed, 174 (73.1%) resulted in whelping. The known litter size ranged from 1 to 16 pups (mean ± SD 6.12 ± 3.12 pups). From univariable analyses, progressive motility percentage was the only variable significantly associated with odds of whelping (P = 0.020); bitch parity and weight were associated with litter size when adjusted for each other (P = 0.035 and 0.003, respectively). Inseminations performed with >200 × 10(6) progressively motile sperm were more likely to result in whelping relative to inseminations with >100-200 × 10(6) progressively motile sperm (odds ratio 3.61, 95% confidence interval 0.84-15.5, P = 0.084), and, in a separate model, relative to >75-125 × 10(6) progressively motile sperm (odds ratio 6.09, 95% confidence interval 1.41-26.36, P = 0.016). CONCLUSION: Whelping rates and litter sizes were similar to other case studies and the experimental reports of CAII. Progressive motility percentage affects the odds of whelping, and litter size is affected by both the weight and parity of the bitch. Importantly, these findings provide some evidence that whelping rates with CAII are not maximised unless more than 200 × 10(6) progressively motile sperm are inseminated.