Effect of time for mating and gestation length on reproductive efficiency in dogs

The purpose of this study was to examine the effect of time for mating and gestation length on reproductive efficiency in dogs. Groups of eight, six and six beagle bitches were mated with a total of three sires on days 3, 5 and 7, respectively, after the luteinizing hormone (LH) surge. All the bitches whelped successfully. The gestation lengths (the intervals from the LH surge to the whelping) were 65.1 +/- 1.9, 65.5 +/- 1.9 and 68.0 +/- 1.8 days, respectively. This length of mating 7 days after the LH surge was significantly longer than that of mating 3 and 5 days after the LH surge (p < 0.05). The litter sizes were 5.5 +/- 2.2, 6.2 +/- 1.9 and 4.8 +/- 2.1, respectively and there was no significant difference between any of the groups. In conclusion, mating 3-7 days after a bitch's LH surge results in a good reproductive efficiency and the intervals from the LH surge to the whelping of mating 7 days after the LH surge shows a longer day significantly in comparison with mating 3 and 5 days after the LH surge.