Avel och fruktsamhet hos nordsvenska hästen
en enkätundersökning
The fertility of the North Swedish horse was investigated using a questionnaire. Data concerning altogether 73 North Swedish stallions and 213 mares used for breeding during the season 2005 were collected and analysed. The survey also included the analyses of 305 breeding case books, especially distributed for this study, from 27 stallions. The aim was to collect information on how the breeding was carried out in the North Swedish horse, and to learn what categories of mares that were covered and what routines were used in these farms. Breeding statistics from 1999 to 2004 was also analysed to complete the questionnaire.
The majority (88 %) of the stallions were used for hand mating, whilst 15 % were used for free mating. Most (92 %) of the stallions, which were used for hand mating, covered the mare every other day, the others covered the mare daily, or every 36 hours. The median age of the stallions was 12 years (range 4-27 years).
The CEM status of the stallions was unknown except for two imported stallions, which both were negative.
The average age as well as the median age, of the mares in the investigation (n=213) was 9 years (range 3- 25 years).
There were 17 % maiden mares and their average age was 5 years (range 3-17 years). After mating only, about 50% of the mares where examined for pregnancy with a reliable method, such as rectal examination, with or without ultrasound. No information what so ever, was available about the result of mating for approximately 30% of the mares. This makes the available statistics of pregnancy as well as the data of resorption and abortion less reliable, since many mares were assumed to be pregnant, just because they had been covered.
Most of the stallions covered only a few mares every year, (on average 7 mares per stallion and year) which makes the fertility data less reliable.
It was found that 12% of the mares covered by North Swedish stallions were of another breed than North Swedish. This means that the number of North Swedish foals born was even lower than what has been estimated so far. Perhaps this could explain why fewer mares than expected are included in the North Swedish studbook.
The collected information from the breeding case books regarding the mares was difficult to interpret due to low percentage of answers (less than 50 %).
In conclusion, no single cause of the relative lower fertility in the North Swedish horse, compared to other breeds in Sweden was found in the study. However, several weaknesses in the handling at breeding were found. Attention should be paid to these weaknesses.