The effects of age, parity, breed, weight and fertilization method on pregnancy rates and litter size were studied in 681 bitches of 124 different breeds. Furthermore, the effect of season on the distribution of presenting dogs for ovulation timing was examined. Data collected from Utrecht University during 2003-2010 were analyzed. The number of dogs presented for ovulation timing was reduced between 2003 and 2008. Pregnancy rates of dogs presented without fertility problems (85.4%) were higher than pregnancy rates of dogs presented with fertility problems (66.5%). In bitches of one (P = 0.037) and two years old (P = 0.048), which gave birth to their first litter, pregnancy rates were higher than those of bitches of seven years old. Labrador retrievers had a significant (P = 0.01) higher pregnancy rate than Golden retrievers (respectively 90.2% and 74.6%). The mean number of total Doberman pups per litter (8.43± 3.52) was higher than the mean number of German shepherd pups (6.17 ± 3.07, P = 0.04). The median weight of the bitches presented for ovulation timing was 29.4 kg, ranging from 2.0 to 71.1. Pregnancy rates were higher in bitches of 10.0-24.9 kg (87.7%) compared to bitches over 45.0 kg (72.7%, P = 0.02). Weight was also found to effect total litter size. Dogs up to 9.9 kg had smaller litters (4.15 ± 1.39, P = 0.005) than dogs between 10.0-24.9 kg (6.49 ± 2.73). Both those groups had smaller litters (respectively P ≤ 0.001 and P ≤ 0.02) than dogs of 25.0-44.9 kg (7.47 ± 2.86) and dogs of more than 45.0 kg (8.40 ± 3.73). A difference (P ≤ 0.001) in pregnancy rate was found between natural matings (85.1%), artificial inseminations with fresh semen (66.7%) and artificial inseminations with frozen-thawed semen (27.8%). Parity did not have an effect on both pregnancy rates and litter size and season did not affect the number of dogs presented for ovulation timing.
The opinion of dog owners concerning the ovulation timing service at Utrecht University (UKG) was examined by an online survey. All clients from the Netherlands (n = 386) between 2003 and 2010, were invited to fill in the questionnaire. The overall response rate was 22.7%. Propositions were rated on a scale of one to five. Veterinarians were evaluated to be capable for examination (mean = 4.6) and the oral information given by them was understandable (mean = 4.4). Co-assistants handled the dogs in a responsible way (mean = 4.2). Least satisfied, were people about the waiting time (mean = 3.8) and reasonableness of the costs (mean = 3.6). Dog owners, who had been to UKG for ovulation timing more than 5 times, were less satisfied about the costs than people who used this service infrequently. 60% of the respondents indicated that they would like to receive additional written information. In general, the ovulation timing service was rated with a median of 8.0 (range 1-10, n = 95) on a scale of 1 to 10.||