Some aspects of artificial insemination in the bitch, using frozen semen : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University
The development of freezing techniques for dog semen allowing long term storage of
semen from valuable stud dogs and its use locally or thousands of miles away has
opened up exciting new prospects for dog breeding. However, it has not been possible
to consistently achieve acceptable pregnancy rates and litter sizes with frozen semen.
The reason for this arises from the many factors involved in processing and inseminating
frozen canine semen and their complex inter-relationships. In order to successfully
use semen prepared in this way it is essential to understand the effect processing has on
the fertilising capacity of sperm and the implications this may have regarding the techniques
required for semen insemination. The key problems revolve around establishing
the period for which such semen remains able to fertilise ova, being able to identify
when ovulation takes place so that timing of insemination occurs when ova are ready
for fertilisation, and having a technology that will allow placement of the semen in a
position from which fertilisation is likely to be achieved.
In this study 18 bitches were divided into three groups on a random basis. Group 1
bitches were inseminated twice with four straws of semen (a total insemination dose of
240 to 280 x 106 live sperm), the semen being deposited into the uterus using the 'Norwegian'
insemination technique. Group 2 bitches received the same insemination dose
deposited into the uterus using the 'Endoscopic' technique (a technique developed for
this trial), and Group 3 bitches received 25% of the semen dose in Group 1 and 2 (a
total insemination dose of 60 to 70 x 106 live sperm), inseminated using the 'Endoscopic'
technique. The semen all came from one stud dog. Insemination timing was
based on blood progesterone concentration determined using a commercial ELISA kit.
The results from the kit were compared with RIA determinations of plasma progesterone
to validate its accuracy. Visual observations of the bitch, vaginal cytology and vaginal
endoscopy observations were also considered in relation to the timing of insemination.
The pregnancy rate over all three groups was 83.3% with a mean litter size of 7.5
(range 4 - 11) pups. There was no difference in pregnancy rate or litter size between the
The insemination protocol adopted in respect of semen dose, insemination timing and
site of deposition of semen demonstrated that it was possible to achieve good pregnancy
rates and litter sizes following the insemination of frozen semen. The new 'Endoscopic'
method of depositing the semen into the uterus was shown to provide an effective
alternative method to the 'Norwegian' technique. The results of insemination with a
significantly lower sperm dose of frozen semen demonstrates that equivalent pregnancy
rates and litter sizes to those achieved with high doses of semen, can be achieved when
the semen used is of high quality. It was also shown that using blood progesterone concentration
as the basis for timing insemination provides an alternative and perhaps more
appropriate method of ensuring insemination occurs at the optimum time than traditional
methods used; the progesterone kits were found to be reliable in this trial and
were particularly useful because they were simple and provided results within hours.