Browsing by Subject "suomenhevonen"

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  • Back, Susanna (Helsingfors universitet, 2016)
    The purpose of this study was to estimate prevalence and genetic parameters of osteochondrosis in the Finnhorse population. Osteochondrosis is characterized by a failure of normal endochondral ossification. This developmental orthopedic disease is widely recognized in young warmblood horses across many breeds. The data consisted of 654 young Finnhorses (Group 1), presented for radiographic examination in the years 2014 – 2015. The total data (n=1829) included also most of the recently used breeding stallions with a high number of progeny. Because of the low frequency of the disease, a low number of analysed horses and challenging pedigree structure with highly variable family size, there were problems in genetic analyses. Heritabilities (h2) were estimated using linear sire model for categorical data and the results were augmented by using non-linear animal model on the liability scale. Statistical analysis was made by R program MCMCglmm which gives posterior distribution (incl. 95 % credibility area). The heritabilities were analysed by joint –specific analyses. The presence of at least one osteochondral lesion was documented for 16,9 % of the studied horses. The lesions were most common in hock (5,2 %) where h2 with linear sire model was 0,18 (95 % credibility area 0,03-0,35). By using linear sire model in Group 1 h2 estimates were in hoof joint of front legs 0,31 (0,12 - 0,55), stifle joint 0,31 (0,09 - 0,54) and dorsodistal osteochondral fragments in fetlock which are originating from metacarbal bone 0,22 (0,07 - 0,40). The prevalence of osteochondrosis is more common in Finnhorse population than has been expected. In future we should focus on the affected joints with the highest frequency and heritability rather than the entire disease complex. The observed genetic variation allows the use of breeding selection for the systematic reduction of osteochondrosis in the Finnhorse population.
  • Karlsson, Elina (Helsingfors universitet, 2017)
    The aim of this study was to investigate the effect of cultivated pasture and semi-natural grassland on body condition and insulin sensitivity in horses. The main hypothesis was that the horses would fatten more when grazing on cultivated pasture compared to semi-natural grassland, and that insulin, glucose and non-esterified fatty acid (NEFA) responses to i.v. glucose challenge would indicate higher degree of insulin resistance of these horses. The experiment was carried out between May–September 2014 at a research farm of the former MTT Agrifood Research Finland (now Natural Resources Institute Finland) in Ypäjä. Body weight, body condition score, waist circumference, and fat thickness were measured before and after grazing season. Intravenous glucose tolerance tests (IVGTT) were performed on 16 horses (8 of each group) in May and September. A dose of glucose was administered through a jugular vein catheter. Multiple blood samples were then collected to assess glucose, insulin and NEFA responses. There were no differences between treatments in body measurements, or glucose, insulin, and NEFA responses to IVGTT before grazing. Horses grazing on cultivated pasture had higher body weight, median body condition score and waist circumference compared to horses on semi-natural grassland in September. Slower glucose clearance rate and a smaller decrease in NEFAs during IVGTT was noticed in horses grazing on semi-natural grassland compared to those on cultivated pasture after grazing season. Minimal Model estimates on insulin sensitivity were compromised by the large variation in insulin responses to glucose challenge. Two thirds of the Si estimates were classified as insulin resistant or implausible (extreme insulin resistance or sensitivity). The differences in pasture composition between high-yielding cultivated pasture and semi-natural grassland induced only minor changes in the insulin resistance status of grazing Finnhorse mares. Grazing on the cultivated pasture did not increase the level of peripheral insulin resistance compared to semi-natural grassland or compromise horses’ ability to maintain normal blood glucose concentration in spite of their fattening. Contrary to the hypothesis, horses grazing on semi-natural grassland expressed higher degree of insulin resistance in adipose tissue. Horses were rather insulin resistant already before grazing which may be derived from a possible innate tendency to low insulin sensitivity of Finnhorse.
  • Ettala, Anna (Helsingfors universitet, 2015)
    The aim of this study was to analyze the development and population structure of the Finnhorse's parentage. The coefficient of inbreeding, the time between generations and the effective population size was studied in the whole population. The effective number of founders and ancestors in the population was determined. The number of horses in the whole population was 77 925 animals. The time between generations was 12.6 years on average. On average, the time between generations was two years longer for stallions than for mares. The effective population size of the Finnhorse was 181, which is sufficient to preserve the genetic diversity of the gene pool. It also examined the degree of kinship and inbreeding with the development of advanced, runner, riding, working - and small horse the direction of the corresponding parameters between the years 1960-2012 and compared with the results obtained in this term. There were 9 585 horses registered in different breeding sections: 6 385 horses in the trotter section, 1 734 horses in the working section, 1 027 horses in the riding second and 439 small Finnhorses. The average coefficient of relatedness in the whole population in 1960–2012 was 2,7-10,7%. The average inbreeding coefficient of inbreeding in the whole population was 1-4,4%. Inbreeding has evolved over the last few decades in the same way as in the past. Stock recorded a runner horses degree of relatedness is, however, significantly increased in recent years. The relatedness between the trotter section and the rest of the population was in the same range than in the whole population. The results of this research concerning different variables were similar to those gathered from studies on other horse breeds. The coefficient of inbreeding and relatedness of the Finnhorse is low enough to ensure that the genetic diversity of the breed will not diminish in the future.
  • Aminoff, Aino (Helsingfors universitet, 2017)
    Tämän tutkimuksen tavoitteena oli arvioida suomenhevosten askel- ja hyppyominaisuuksien periytymisasteita sekä ominaisuuksien välisiä geneettisiä- ja fenotyyppisiä korrelaatioita. Vastaavaa tutkimusta ei ole suomenhevosten osalta tehty aiemmin, vaan tutkimukset olivat käsitelleet puoliveristen ratsuhevosten suorituskykyominaisuuksien periytymistä. Tutkimuksessa käytetty suomenhevosten sukupuu sekä tulokset suomenhevosten laatuarvostelutapahtumista saatiin Suomen Hippos ry:ltä. Sukupuuaineisto sisälsi kaikki rekisteröidyt suomenhevoset, yhteensä 81 403 hevosta vuosilta 1864–2014. Laatuarvosteluaineisto rajattiin koskemaan 3-vuotiaiden karsintatuloksia; se sisälsi 656 hevosen tulokset vuosilta 2007–2014. Tutkittavat askelominaisuudet olivat käynti, ravi ja laukka ja hyppyominaisuudet olivat hyppykyky, hyppytekniikka sekä luonne ja yhteistyöhalukkuus. Varianssikomponenttien arvioitiin käytettiin DMU-ohjelmaa ja restricted maximum likelihood (REML) -menetelmää. Periytymisasteiden arvioiksi saatiin askelominaisuuksille 0,09–0,24 ja esteominaisuuksille 0,11–0,13. Periytymisasteiden arvioiden keskivirheet olivat melko korkeita aineiston pienen koon vuoksi. Suurimmat geneettiset korrelaatiot saatiin ravin ja käynnin välille (0,99) sekä tekniikan ja hyppykyvyn välille (0,99). Pienin geneettinen korrelaatio oli käynnin ja hyppykyvyn välillä (0,02.) Suomenhevosten askel- ja hyppyominaisuuksien periytymisasteet ovat tämän tutkimuksen perusteella melko matalia, ja sen vuoksi näiden ominaisuuksien jalostaminen on hankalaa. Eräiden ominaisuuksien välisistä korkeista geneettisistä korrelaatioista voidaan päätellä, että näiden ominaisuuksien kohdalla on saatettu todellisuudessa arvioida samaa ominaisuutta tai niihin vaikuttavat samat geenit. Askel- ja hyppyominaisuuksien väliset geneettiset yhteydet ovat laukkaa lukuun ottamatta matalia. Tämän tutkimuksen tuloksia voidaan hyödyntää suomenhevosten askel- ja hyppy-ominaisuuksien laatuarvostelukäytäntöjen parantamisessa sekä mahdollisen kansallinen BLUP-pohjaisen jalostusarvostelun kehittämisessä.