Warmblood Sport Horses Research Articles

Monitoring for Equine Viral Arteritis has decreased its prevalence in European breeding sires

Equine viral arteritis (EVA) can induce a persistent carrier state in stallions and shedding of the virus with semen can spread EVA and cause abortions in seronegative pregnant mares. In the early 1990s, obligatory testing for EVA of stallions used for artificial insemination was implemented within the European Union (Council Directive 92/65/EEC). In addition, vaccination programs for young stallions and exclusion of carrier stallions from certain breed registry events were implemented in Warmblood sport horses. Information on the efficacy of these actions on the prevalence of EVA in reproductively active stallions are not yet available in Europe. This study retrospectively analyzed results of serological and virus antigen testing for EVA in sires (n=308, one sample set per sire, EVA-vaccination status unknown) of different age and breed referred to the Centre for Artificial Insemination of Vetmeduni Vienna for semen preservation between 2001 and 2021. For analysis, stallions were grouped by age (1-3, 4-10, 11-16, >16 years) and breed. The EVA antibody titer was determined by serum neutralization test and semen was analyzed for EVA virus by PCR and/or virus isolation test. Statistical analysis was performed by chi2-test, Kruskal-Wallis test or Mann-Whitney U-test using the IBM SPSS 28.0 statistics software. Of 308 stallions tested, 14.9% (n=46) were EVA seropositive and in 12 stallions EVAvirus was detected in semen (26% of seropositive and 3.8% of all tested stallions, respectively). The incidence of seropositive stallions (22% of sires tested during 2001-05 to 4.1% during 2016-21) and of stallions shedding EVA virus via semen (8.5% of all serologically tested stallions 2001-05 to 1.4% during 2016-21) decreased over time (p<0.05). No difference among breeds with regard to occurrence of seropositive stallions was detected. There was a tendency towards more Standardbred and Lipizzaner stallions (14% and 13%, respectively) shedding EVA virus in semen compared to all other breeds (<3%, p=0.074 among groups). Differences in the seroprevalence of EVA antibodies existed among stallions from different age groups (p<0.01) with the highest percentage of seropositive stallions in 11-16 year-stallions (45.7%). No differences among age groups with regard to virus shedding existed. The EVA antibody titer increased with age (p<0.01), reflecting a higher possibility of repeated virus challenge in older stallions. Antibody titer was not associated with carrier state. In conclusion, monitoring of stallions for EVA in combination with vaccination programs resulted in a decrease of the prevalence of seropositive and virus-shedding stallions during the past 20 years in a European stallion population and can therefore be considered successful.

The relationship between sperm quality parameters and stallion fertility

There are stallions with apparently good sperm quality that achieve low pregnancy rates when their semen is used for artificial insemination (AI). Thus, additional methods of evaluating sperm quality that result in better methods of predicting stallion fertility, are essential. Semen samples were obtained in April-June from 8 stallions, 4 trotters and 4 warmblood sport horses, which were sampled Monday, Wednesday and Friday each week. From each stallion, 1-4 samples were obtained, and evaluated after cold storage for 24 hours. The samples were evaluated for kinematic variables using CASA, and for membrane integrity, mitochondrial membrane potential (MMP), production of reactive oxygen species, acrosome integrity and chromatin integrity using flow cytometry. Relationships with fertility, calculated as number of pregnant mares/number of inseminated mares for samples used for artificial insemination after transport in cold storage, were evaluated by linear regression, following log-transformation of variables found not to be normally distributed. The following sperm variables were found to have a positive relationship with fertility: Straightness (r2=0.86, p= 0.0009), Viable with High mitosoxred/Low MMP (r2=0.70, p= 0.01), Viable non acrosome reacted (r2=0.68, p= 0.01), Viable by calceinviolet (r2=0.67, p= 0.01), Viable non H2O2-producing (r2=0.66, p= 0.01), Viable with High mitosoxred/High MMP (r2=0.65, p= 0.02), Viable non superoxide-producing (r2=0.60, p= 0.02), Linearity (r2=0.56, p= 0.03). The only variable found to have a negative relationship with fertility was Amplitude of lateral head displacement (r2=0.63, p= 0.02). The other 26 measured variables did not show a significant relationship with fertility. The results of the study shows that both kinematic variables as well as flow cytometric analysis can be valuable for relating fertility with sperm quality in vitro. The flow cytometry results indicate that analysis of the production of different reactive oxygen species can be valuable when predicting stallion fertility. Acknowledgments: Special thanks to Menhammar, Västerbo, Markebäck and Stockholm Seminstation for providing stallion semen. This work was supported by funding from FORMAS (2018-01083; awarded to AJ). The work was also supported by the Swedish University of Agricultural Sciences via the Cells for Life Platform.

Genetic Parameters of Performance and Conformation Traits of 3-Year-Old Warmblood Sport Horses in the Czech Republic.

The aim of this study was to estimate the genetic parameters of a one-day performance test together with the linear type traits of 3-year-old warmblood horses. The study of genetic parameters was based on 5958 tested horses in the period 1998-2021. A total of 22 traits of linear description, three quantitatively measured traits, and one summary mark from the performance test were tested. The model equation included the fixed effect of gender and combination effects of classifier-year of evaluation-place. A single-trait animal model was used for the estimation of heritability and genetic variance, while the two-trait animal model was applied for the estimation of variance and covariance between all traits. The heritability of the overall score of the performance test was 0.25. The range for heritability was between 0.04 and 0.33 for the linear type traits and between 0.46 and 0.57 for the quantitatively measured traits. Genetic correlations were between -0.47 and 0.92. The estimated genetic parameters suggest that the results from the performance test can be incorporated into genetic evaluation in the Czech Republic.

Evaluation of the stance phases of warmblood sport horses on soft and hard surfaces by infrared optical sensors

The aim of the study was to assertain the differences in walking time of sport horses by investigating their stance phases on soft versus hard surfaces using infrared sensors. A total of 15 warmblood sport horses were used in the study. Three different stages of the stance phase were examined, including initial contact, foot flat and propulsion, alongside assessment of walking pace and step-length. It was observed that the horses were inclined to walk more slowly on soft surfaces compared to hard ground. The amount of time spent in the foot flat position constituted the majority of the stance phase on both surfaces. Propulsion length during the stance phase was shorter on soft surfaces in comparison to hard ground. While the ratio of contact length in forelimbs was lower on hard ground compared to soft surfaces, in hind limbs this ratio was higher on hard ground. Objective data obtained through gait analysis systems are thought to serve as a potential auxiliary diagnostic tool in diseases associated with the locomotor system manifested by lameness, particularly in equine veterinary medicine. In the future, the relevant systems that could offer rapid results through current technology are anticipated to provide accurate preliminary assumptions to evaluate the potential of horses regarding their walking, trotting, and leaping capacity before competitions through such studies.

Influence of indirect factors and its effect analysis on performance level of Slovak warmblood horse breed

Article Details: Received: 2020-10-21 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.105-108 During their career, horses are affected by a large number of direct and indirect factors. The aim of our study was to determine the effect of indirect factors, such as year of start, sex, breed, number of starts, age and proportion of genes of Slovak Warmblood horse breed. For determination of indirect factors on performance level, results from test efficiency and final placement in showjumping category 4, 5 and 6 years old young horses were used. 540 horses of Slovak Warmblood breed were analysed between 2015 - 2019 and 1155 data samples were collected. Based on the results of the linear model, parameters – the effect of gender and the influence of the gene proportion of Slovak Warmblood horse had statistically significant influence (p&lt;0.05). High significant effect (p&lt;0.001) on performance of Slovak Warmblood horse was observed in parameters – year of start, age during start and breed. Keywords: horse, indirect factors, performance References CASTEJON-RIBER, C. et al. (2017). Objectives, Principles and Methods of Strength Training for Horses. Journal of Equine Veterinary Science , 56, 93-103. http://dx.doi.org/10.1016/j.jevs.2017.04.011 De MARÉ, L. et al. (2017). Standardized exercise tests in horses: current situation and future perspectives. Vlaams Diergeneeskundig Tijdschrift , 86(2): 63-72. http://dx.doi.org/10.21825/vdt.v86i2.16290 GOŠČÍK, Z. (1993). Fyziologický základ tréningu koňa atléta. Nitra: Mgr. Marta Ölvecká. ISBN 80-900413-6-1, 70p. GOŠČÍK, Z. (2000). Racionálny tréning športových koní a jeho vplyv na ich dlhodobé využitie. [online]: http://www.horses.sk/'konfer/kratr. htm HENNESSY, K. et al. (2008). Vendor and purchaser expectations: differential market segment requirements for sport horses. In proceeding from 4th International Conference of International Society for Equitation Science . Dublin (p. 53). KEARSLEY, C. G. S. et al. (2008). Use of competition data for genetic evaluations of eventing horses in Britain: analysis of the dressage, showjumping and cross country phases of eventing competition. Livestock Science , 118(1), 72-81. https://doi.org/10.1016/j.livsci.2008.01.009 KOENEN, E. (2002). Genetic evaluations for competition traits of warmblood sport horses. In WBFSH seminar , Budapest. KOENEN, E. P. C., ALDRIDGE, L. I. &amp; PHILIPSSON, J. (2004). An overview of breeding objectives for warmblood sport horses. Livestock Production Science , 88(1), 77-84. http://dx.doi.org/10.1016/j.livprodsci.2003.10.011 KRATTENMACHER, N. et al. (2014). The role of maternal lineages in horse breeding: Effects on conformation and performance traits. In proceeding from 10th World Congress on Genetics Applied to Livestock Production , Vancouver, Canada (p. 17-22). LUEHRS-BEHNKE, H. et al. (2002). Genetic associations among traits of the new integrated breeding evaluation method used for selection of German warmblood horses. Veterinarija ir zootechnika , 18(40), 90-93. RICARD, A.; BRUNS, E.; CUNNINGHAM, E. P. (2000). Genetics of performance traits. The genetics of the horse , (p. 411-538). http://dx.doi.org/ 10.1079/9780851994291.0000 RICARD, A. &amp; BLOUIN, C. (2011). Genetic analysis of the longevity of French sport horses in jumping competition. Journal of Animal Science , 89(10), 2988-2994. http://dx.doi.org/10.2527/jas.2011-3931 STEWART, I. D., WOOLLIAMS, J. A. &amp; BROTHERSTONE, S. (2010). Genetic evaluation of horses for performance in dressage competitions in Great Britain. Livestock Science , 128(1), 36-45. http://dx.doi.org/10.1016/j.livsci.2009.10.011 STEWART, M. et al. (2011). Assessment of positive emotions in horses: Implications for welfare and performance. Journal of Veterinary Behavior: Clinical Applications and Research , 6(5), 296. http://dx.doi.org/10.1016/j.jveb.2011.05.014 SCHUBERTOVÁ, Z., PAVLÍK, I. &amp; CANDRÁK, J. (2014). The influence of the genomic data on the showjumping horses performance evaluation. Journal of Central European Agriculture , 15(2), 33-40. http://dx.doi.org/10.5513/JCEA01/15.2.1447 SCHRÖDER, W. et al. (2012). A genome‐wide association study for quantitative trait loci of show‐jumping in Hanoverian warmblood horses. Animal genetics , 43(4), 392-400. http://dx.doi.org/10.1111/j.1365-2052.2011.02265.x Van VELDHUIZEN, A. E. (1997). Breeding value estimation for riding horses in the Netherlands. In 48th Ann. Meet. EAAP , Vienna, Austria

The effects of dried grape pomace supplementation on biochemical blood serum indicators and digestibility of nutrients in horses

Twelve adult Slovak warmblood sport horses were used to study the effect of dried grape pomace (DGP) on health through blood serum biochemical indicators, and on apparent total tract digestibility of dry matter (DM), organic matter (OM), crude protein (CP), acid detergent fibre (ADF) and neutral detergent fibre (NDF). The digestibility analysis was carried out by two in vivo methods, total faeces collection (TFC) and using lignin as a marker (ADL). Animals were divided into 3 groups: control group (C, without supplementation), experimental group 1 (E1, feed rations + 200 g of DGP) and experimental group 2 (E2, feed rations + 400 g of DGP). In animals, no health problems were detected during the trial. Of the blood serum indicators, only the concentrations of potassium (increase in E2 group compared to C group) and alanine aminotransferase (decrease in E2 group in comparison with E1 and C group) were affected (P &amp;lt; 0.05). The ADL method resulted in underestimated digestibility coefficients due to low recovery rates of lignin (less than 90%) in C group and E1 group. According to TFC, in E1 group higher digestibility coefficients were detected for DM, OM and CP (P &amp;gt; 0.05) compared to C group. However, in E2 group lower digestibility of all the studied nutrients was found (P &amp;gt; 0.05) in comparison with C group and E1 group. These results suggest that DGP could be used in horse diets up to 200 g without negative effect on their health and for a possible digestibility improvement of some nutrients.

The use of new technologies in horse selection

Received: 2018-09-12 | Accepted: 2018-11-27 | Available online: 2018-12-31 https://doi.org/10.15414/afz.2018.21.04.186-189 Most successful selection strategies are not in use in horse selection. This study describes the use of current strategies of selection in horse and tries to answers why well known, scientifically proven selection strategies are still not implemented. In the era of genomic selection (GS) in animal breeding, decision making in horse selection, even classical values (BV), are not fully taken advantage of. Breeding organizations (BO) which implement BVs as selection criteria in their programs show great success in genetic gain. However, a horse's achievements and the popularity of its relatives still plays an important role in selection level. Genomic based selection tools in horse have limitations in quantitative traits since it is difficult to establish reference population. Mendelian traits have been studied for several years, especially those related to horse health and functional longevity (long sport or race careers), yet there are still only a small number of validated mendelian traits offered for horses. The important benefit of GS is the prevention of related mating based on genomic data, in addition to pedigree data. The specialty in horse is the use of cloning. From the point of view of genetic variability, cloning is useful in enabling geldings or non-genetically infertile animals to carry genes to next generations. In sport and race BOs, stallions from foreign BOs are frequently used. In such cases a need for comparable BVs exists. These factors were the motivation behind the establishment of Interstallion 20 years ago. Due to difficulties in BO collaboration, Interstallion has not been as successful as planned. On the whole, it is expected that the sector of horse selection will need to change considerably in the future. Keywords: value, cloning selection, genomic selection, inbreeding, strategies References Arnason, T. (1984) Genetic studies on conformation and performance of Icelandic toelter horses: IV Best linear unbiased prediction of ten correlated traits by use of an animal model. Acta Agric. Scand. 34, 450–462. Broere Jazz (2018) Jazz – one in a million. [Online] Alblasserdam. Available at: http://www.broerejazz.com/en/sperma-bestellen/ [Accessed 12 August 2018]. FMITCHELL07 (2009) Inbreeding to broodmares: an in-depth statistical analysis of the Rasmussen Factor, Part 1 [Online] https://fmitchell07.wordpress.com/2009/07/29/inbreeding-to-broodmares-an-in-depth-statistical-analysis-of-the-rasmussen-factor-part-1/ [Accessed 12 August 2018]. Henderson, C. R. (1953) Estimation of variance and covariance components. Biometrics, 9, 226–252. Jorjani, H., Jakobsen, J., Hjerpe, E., Palucci, V., Durr, J. (2012) Status of genomic evaluation in the Brown Swiss populations. Interbull Bull., 46, pp. 46–54. Koenen, E. (2005) Publication of values: Interstallion guidelines. Workshop Use of genetic evaluations in sport horse breeding Warendorf, Germany. [Online] In: Leuven: KU Leuven. Available at: https://www.biw.kuleuven.be/Genlog/livgen/research/interstallion/workshop_docs/koenen1.pdf [Accessed 12 August 2018]. Koenen, E., Aldridge, L.I., Philipsson, J. (2004) An overview of objectives for warmblood sport horses. Livestock Production Science, 88(1-2), pp. 77-84. Liljenstolpe, C. (2009) Horses in Europe. [Online] Maarslet: WBFSH. Available at: http://www.wbfsh.org/files/EU%20Equus%202009.pdf [Accessed 16 August 2018]. Mark, T. (2013) Genomic selection for performance and health http://www.wbfsh.org/files/Thomas_Mark_Genomic_Selection_in_Horse_Breeding_Oct._7th_2013_Warsaw.pdf [Accessed 12 August 2018]. OMIA (2018) Online Mendelian Inheritance in Animals (OMIA). [Online] Maarslet: WBFSH. Available at: http://omia.org/home/ [Accessed 6 September 2018]. Philipsson, J. (2009) Mace for horse evaluations. Interstallion: Workshop Le Pin au Haras, 26th March 2009. [Online. Available at: ] https://www.biw.kuleuven.be/Genlog/livgen/research/interstallion/workshop_LePin/I_MACE%20for%20horse%20evaluations.pdf [Accessed 12 August 2018]. Reed, T. (2018) Johan Knaap on genomic selection – an interview. [Online]. Available at: http://www.irish-warmblood.com/pdf/Johan_Knaap_on_Genomic_Selection.pdf [Accessed 6 September 2018]. Reis, A.P., Palmer, E., Nakhla, M. (2012) Biotechnologies of reproduction in the horse: what has changed? In: Book of Abstracts of the 63 rd Annual Meeting of the European Federation of Animal Science Wageningen. Wageningen: Wageningen Academic Publishers. Shelbourne Farm. (2018) Cruising Clones. [Online]. Available at: http://www.shelbournefarm.com/stallions/cruising-clones/ [Accessed 6 September 2018]. Stock, K., Quinn Brady, K., Christiansen, K., Viklund, A., Cervantes, I., Ricard, A., Ducro, B., Janssens, S. (2015). Breeding objectives and practices of sport horse studbooks : Results of a worldwide inventory. In: Book of Abstracts of the 66 th Annual Meeting of the European Federation of Animal Science Wageningen.Wageningen: Wageningen Academic Publishers. Stock, K., Viklund, A., Cervantes, I., Ricard, A., Christiansen, K., Vangen, O., Janssens, S. (2018). The role of Interstallion in supporting international sport horse by improved transparency. In: Book of Abstracts of the 69 th Annual Meeting of the European Federation of Animal Science Wageningen. Wageningen: Wageningen Academic Publishers. Thoren Hellsten, E. (2008) International Sport Horse Data for Genetic Evaluation. Doctoral Thesis. Uppsala: Swedish University of Agricultural Sciences. Waikato (2018) Waikato Stud offers a truly world-class stallion line up. [Online]. Available at: https://waikatostud.com/stallions/ [Accessed 6 September 2018]. WBFSH (2018) World federation for sport horses: Breeder and Studbook rankings. [Online]. Available at: http://www.wbfsh.org/GB/Rankings/Breeder%20and%20Studbook%20rankings.aspx [Accessed 12 September 2018].

Genetic conditions of joint Nordic genetic evaluations of lifetime competition performance in warmblood sport horses.

Breeding programmes for warmblood sport horses are similar in the Nordic countries Sweden, Denmark, Finland and Norway, and stallions of same origin are used. The aim was to investigate whether a joint Nordic genetic evaluation based on lifetime competition performance is feasible and beneficial for breeding competitive sport horses in the Nordic countries. Results for almost 45,000 horses in show jumping and 30,000 horses in dressage were available. The larger populations in Sweden and Denmark contributed with 85% of the results. Heritabilities and genetic correlations between performances in the different countries were estimated, and comparisons of accuracies of estimated breeding values (EBVs) and number of stallions with EBVs based on national or joint data were studied. The heritabilities ranged between 0.25 and 0.42 for show jumping and between 0.14 and 0.55 for dressage. The genetic correlations between competition performances in the Nordic countries were estimated to 0.63-1.00. EBVs based on joint data increased accuracies for EBVs for stallions by 38-81% and increased the number of available stallions with EBVs by 40-288%, compared to EBVs based on national data only. A joint Nordic genetic evaluation for sport horses is recommended.

The radiographic frequency of impingement of the dorsal spinous processes at purchase examination and its clinical significance in 220 warmblood sporthorses

The radiographic frequency of impingement of the dorsal spinous processes at purchase examination and its clinical significance in 220 warmblood sporthorses

Development of laryngeal and pharyngeal function during long-term treadmill exercise in warmblood sport horses

Development of laryngeal and pharyngeal function during long-term treadmill exercise in warmblood sport horses

The Effect of Phytogenic Additive on In Vivo Saccharides Digestibility of Sport Horses

Background: Phytoadditives have a positive effect on animal performance. The aim of the study was to determine the effect of plant extract additives on digestibility of nitrogen free extract, crude fi bre, NDF and ADF in sport horse's nutrition. Methods: In the trial we used 14 adult healthy warm blood sport horses (BW: 525±75 kg, age: 6.8±3 years). Animals were divided in two groups: control group C and experimental group E. The feed rations for sport horses were formulated from crimped barley, meadow hay and mineral feed mixture. Results: Feed rations of horses in the experimental group were added with phytogenic additive at a dosage of 1g/kg of concentred feed. Signifi cantly (P<0.05) higher digestibility of nitrogen free extract was found in experimental group of horses, which were fed by rations added with plant extract. The average digestibility coeffi cient of nitrogen free extract was 76.07% (control group) and 80.08% (experimental group). In crude fi bre we found a signifi cant (P<0.05) effect of plant extract addition to the feed rations. In the control group of sport horses we found statistically lower in vivo digestibility coeffi cient (47.29%) in comparison with experimental group (51.61%). Signifi cant (P<0.05) higher NDF digestibility we detected in experimental group of horses in comparison with control group (47.35 vs. 42.41%). Digestibility coeffi cients of ADF were signifi cant (P<0.05) higher in experimental group. Conclusion: In the experiment we found signifi cant effect of aromatic plants extract on faecal digestibility of saccharide. After the additive feeding we found higher saccharides digestibility.

Vplyv fytoaditív na biochemické ukazovatele a stráviteľnosť živín vo výžive športových koní

The aim of the study was to determine the effect of a phytogenic additive on blood serum indicator levels and faecal nutrients digestibility. The experiment was realized in Riding Centre of the Department of Animal Husbandry, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra. Total 14 warmblood sport horses (geldings) were used (7 horses in control group, 7 horses in experimental group respectively); Slovak warmblood bred, average body weight 525±75 kg and 6.8±3 Years. The control group of horses were fed by crimped barley, meadow hay and mineral feed mixture. Feed rations in experimental group were supplemented with a phytogenic additive containing a blend of essential oils from origanum, anise and citrus, as well as a prebiotic rich in fructooligosaccharides. Blood serum was collected 3 times during the experiment, in the beginning of the experiment, and every 45 days. The experiment lasted 90 days. After the 45 days of phytoadditive supplementation we found a tendency of lower concentrations of serum triglycerides (0.07 vs. 0.23 mmol.l-1) and total cholesterol (2.18 vs. 2.27 mmol.l-1) in experimental group of horses (P>0.05). In serum concentrations of glucose, total proteins and urea we find similar values in all of groups. The same tendency we analyzed in activity of AST, ALT, and ALP enzymes (P>0.05). After the 90 days of the phytoadditive supplementation in feed rations of sport horses, we detected a tendency of lower serum triglycerides concentration in experimental group of horses and higher cholesterol, glucose, total protein and urea concentrations (P>0.05). We didn´t find a significant effect of a phytoadditive supplementation on blood serum indicator levels. Higher faecal digestibility coefficient of dry matter was found in experimental group of horses (62.98%) in comparison with control group (56.87%). In control group of horses we detected tendency of lower crude protein digestibility (71.36%) in comparison with phytogenic additive group feeding (72.86%). We analyzed a positive effect of phytogenic additive on organic matter digestibility of feed ration. In experimental group of horses we found significantly (P<0.05) higher organic matter faecal digestibility coefficient (73.31%) in comparison with control group (68.32%). We analyzed insignificant (P>0.05) effect of a phytoadditive on blood serum concentrations during 90 days of experiment. We found positive effect of phytoadditve supplementation on total faecal digestibility of organic nutrients.

VPLYV FYTOADITÍV NA STRÁVITEĽNOSŤ MAKROELEMENTOV U ŠPORTOVÝCH KONÍ

The aim of this study was to determine the effect of a phytogenic additive in sport horses feed rations on faecal macroelements digestibility. The experiment was realized in Riding Centre of the Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra, using 6 warm blood sport horses (geldings). The control group was fed with crimped barley, meadow hay, feed mixture and mineral premix. The experimental feed rations were supplemented with a phytogenic additive containing a blend of essential oils from origanum, anise and citrus, as well as a prebiotic rich in fructooligosaccharides. Higher digestibility of calcium (Ca) (71.11% vs. 69.09%) and phosphorus (P) (52.74% vs. 47.55%) was determined in horses fed the phytogenic additives (P>0.05). In this group of horses we found significantly (P<0.05) higher digestibility of magnesium (Mg), 64.32% in comparison with the control group (43.55%). Insignificantly differences in sodium (Na) digestibility we found (75.98% in control group vs. 76.58% in experimental group). Significantly (P<0.05) higher potassium (K) digestibility we found in horses fed with phytoadditives (57.11%). In horses fed without phytoadditives we detected significantly (P<0.05) lower digestibility of K (30.55%). In conclusion, we found positive effects of a phytogenic additive on macroelements faecal digestibility in sport horses.

Effects of long-time series of data on genetic evaluations for performance of Swedish Warmblood riding horses

For Swedish Warmblood sport horses, breeding values (BVs) are predicted using a multiple-trait animal model with results from competitions and young horse performance tests. Data go back to the beginning of the 1970s, and earlier studies have indicated that some of the recorded traits have changed through the years. The objective of this study was to investigate the effects of including all performance data or excluding the older ones compared to a bivariate model (BM) considering performance traits in early and late periods as separate traits. The bivariate approach was assumed to give the most correct BVs for the actual breeding population. Competition results in dressage and show jumping for almost 40 000 horses until 2006 were available. For riding horse quality test (RHQT), data of 14 000 horses judged between 1973 and 2007 were used. Genetic correlations of 0.69 to 1.00 were estimated between traits recorded at different time periods (RHQT data) or different birth year groups (competition data). A cross-validation study and comparison of BVs using different sets of data showed that most accurate and similar results were obtained when BVs were predicted from either the BM or the univariate model including all data from the beginning of the recording. We recommend using all data and applying the univariate model to minimise the computational efforts for genetic evaluations and for provision of reliable BVs for as many horses as possible.

A whole-genome scan for recurrent airway obstruction in Warmblood sport horses indicates two positional candidate regions

Recurrent airway obstruction (RAO), or heaves, is a naturally occurring asthma-like disease that is related to sensitisation and exposure to mouldy hay and has a familial basis with a complex mode of inheritance. A genome-wide scanning approach using two half-sibling families was taken in order to locate the chromosome regions that contribute to the inherited component of this condition in these families. Initially, a panel of 250 microsatellite markers, which were chosen as a well-spaced, polymorphic selection covering the 31 equine autosomes, was used to genotype the two half-sibling families, which comprised in total 239 Warmblood horses. Subsequently, supplementary markers were added for a total of 315 genotyped markers. Each half-sibling family is focused around a severely RAO-affected stallion, and the phenotype of each individual was assessed for RAO and related signs, namely, breathing effort at rest, breathing effort at work, coughing, and nasal discharge, using an owner-based questionnaire. Analysis using a regression method for half-sibling family structures was performed using RAO and each of the composite clinical signs separately; two chromosome regions (on ECA13 and ECA15) showed a genome-wide significant association with RAO at P < 0.05. An additional 11 chromosome regions showed a more modest association. This is the first publication that describes the mapping of genetic loci involved in RAO. Several candidate genes are located in these regions, a number of which are interleukins. These are important signalling molecules that are intricately involved in the control of the immune response and are therefore good positional candidates.

Influence of foreign stallions on the Swedish Warmblood breed and its genetic evaluation

The objective of this study was threefold: 1) To survey the use and impact of foreign stallions in the Swedish Warmblood (SWB) breed 2) To investigate the impact of including genetic groups in the genetic evaluation of the SWB and 3) To estimate the impact of incomplete pedigree information on the estimated breeding values (EBVs) for stallions. Data consisted of 189,330 horses of which 50,907 had performance information. Studbook of origin was determined for stallions with at least 5 progeny tested in Sweden. Those 757 stallions had together 116,505 progeny registered in the SWB. Genetic groups were formed according to preliminary analyses of the genetic levels in dressage and show jumping of the different populations. During the first studied period, comprising horses born before 1980, about 80% of the foals were sired by Swedish born stallions, whereas these only sired 40% of the horses born 1990–2003. In this period Holstein stallions had sired 21% of the foals and Dutch stallions (KWPN) 10%. The proportion of mares covered by foreign stallions increased after the early 1980s to about 80% in 2006. Some of the foreign populations, e.g., Holstein, Selle Francais and KWPN, have significantly affected the show jumping performance level of the SWB breed in the past although the deviation from SWB stallions has become smaller over time. Regarding dressage, no particular foreign population has consistently shown such an impact on the performance although Oldenburg stallions seem to be influential lately. The pedigree completeness (PEC values) of the horses included amounted on average to 0.845 for horses with performance data and to 0.907 for stallions with at least 15 progeny. Foreign stallions had an average PEC value of 0.858. When simulating no pedigree information available for foreign stallions, the EBVs of these stallions changed on average by 19–22 index units, which equals about one genetic standard deviation. Thus, keeping complete and correct pedigree registers is crucial for the assessment of reliable EBVs of SWB horses. Including genetic groups in the genetic evaluation of the SWB resulted in hardly any re-ranking of horses. Correlations between EBVs were about 0.99. Inclusion of genetic groups caused larger standard errors of the EBVs. Furthermore, as the pedigrees on average have great depth, and partially also because Warmblood sport horses have become a mix of many different populations, it was not recommended to include genetic groups in the model for future routine genetic evaluations of SWB.

Genetic parameters for traits evaluated at field tests of 3- and 4-year-old Swedish Warmblood horses

There are two types of 1-day field tests available for young Swedish Warmblood sport horses; one test for 3-year olds and one more advanced test for 4-year olds. Conformation, gaits and jumping ability are evaluated at both tests. Studies on various genetic parameters were based on about 20 000 tested horses. The data for 4-year olds consisted of 30 years of testing. The aims of the study were to estimate genetic parameters for results from different time periods, and to estimate heritabilities for, and genetic correlations between, traits scored in the two tests. The judgement of traits was shown to have been changed during the 30 years of testing, resulting in changes in higher heritabilities in, and stronger genetic correlations between, later time periods. In the first time period, records showed higher residual and lower genetic variances than in the subsequent time periods. Genetic correlations between traits recorded in the first and last time period deviated considerably from unity. Further studies are needed to investigate how to treat data from the early period in genetic evaluations. Heritabilities were moderate to high for conformation traits (0.24 to 0.58) at both types of tests, except for correctness of legs (0.08). The heritabilities for gait traits were also moderate to high (0.37 to 0.53). For jumping traits, the heritabilities ranged between 0.17 and 0.33. The highly positive genetic correlations (0.82 to 0.99) between corresponding traits tested at the simpler test for 3-year olds and at the ridden test of 4-year olds implied that it would be desirable to include the test results of 3-year olds into the genetic evaluation as breeding values for Swedish Warmbloods for many years has only been based on results from 4-year olds.

An overview of breeding objectives for warmblood sport horses

The aim of this paper is to review the current breeding objectives of organisations that run a selection programme for warmblood riding horses in the light of an increasing trend in trade of semen across countries. In a questionnaire, 19 horse breeding organisations provided information on breeding objective traits. Variation both in length and amount of details used to define individual breeding objectives was large, reflecting that many traits in sport horse breeding are not easy to measure, and therefore, have to be defined in a subjective way. The majority of the breeding objectives included conformation, gaits and performance in show jumping and dressage. Some breeding objectives also included behaviour, soundness, health and fertility. However, several organisations did not specify the sport discipline and the level of competition (amateur, national or international level) in the breeding objective. In general, relative weightings of the traits within the verbally presented breeding objectives were not given, but were assessed by the organisations in response to this study. The relevance of more information on expected future production circumstances and on the genetic parameters of the traits of interest are discussed. A further review of the consistency, completeness and the number of traits of the present breeding objectives for sport horses is recommended to optimise the efficiency of selection decisions.