engleski

First induced heterospermic litter in Croatia - a case report

The idea of a dual-sired breeding is to give equal chances to both possible males to fertilise the eggs due to specific oestrus cycle of the bitch. Successful multiple-sired litters allow breeders to maximise offspring possibilities as well as the female’s potential by creating more genetic combinations. Three stud dogs (A, B and C) were presented to the clinic a month before breeding to undergo sperm quality testing in order to choose 2 potential sperm donors. All dogs had a history of prior normal fertility and had a DNA profile. The semen was collected by manual manipulation and only sperm-rich fractions were collected. Immediately after the collection, the semen was evaluated based on the following parameters: colour, volume, pH, progressive motility, concentration, viability and functional integrity of the sperm membrane (HOS test and Bloom staining). After the evaluation, the semen samples were mixed according to the factorial design Stud A and B, Stud A and C and Stud B and C. The mixed samples were evaluated for semen characteristics after 1, 2, 3 and 5 hours. In addition, the mixed samples were subjected to a longevity exam at 4 °C, and the semen quality was assessed on days 3 and 5. The breeding time of the bitch was determined by measuring progesterone (P4) levels. P4 concentration at the onset of ovulation was 4.2 ng/mL. The bitch was inseminated 3 times starting on day 2 after ovulation. Based on semen quality parameters, studs A and B were chosen for insemination. On all 3 days of insemination, the semen of 2 males was collected, evaluated and mixed prior to insemination. Semen volume was adjusted based on quality parameters, to give an equal final concentration for both males. The bitch was inseminated vaginally. The puppies were born 60 days after the first insemination. Blood samples were collected on week 5 via jugular venepuncture into EDTA vacutainer tubes for a genetic analysis. The final results showed 6 puppies from stud A (4 ♂, 2 ♀) and 1 puppy from stud B (♂). No monozygotic twins were born.

dog, dual sire breeding, sperm quality

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