Artículos (Agronomía)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11297

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Pedigree estimation of the (sub) population contribution to the total gene diversity: the horse coat colour case
(Elsevier, 2010) Bartolomé Medina, Ester; Goyache, F.; Molina, Antonio; Cervantes, I.; Valera Córdoba, María Mercedes; Gutiérrez, J. P.; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
A method to quantify the contribution of subpopulations to genetic diversity in the whole population was assessed using pedigree information. The standardization of between- and within-subpopulation mean coancestries was developed to account for the different coat colour subpopulation sizes in the Spanish Purebred (SPB) horse population. The data included 166264 horses registered in the SPB Studbook. Animals born in the past 11 years (1996 to 2006) were selected as the ‘reference population’ and were grouped according to coat colour into eight subpopulations: grey (64836 animals), bay (33633), black (9414), chestnut (1243), buckskin (433), roan (107), isabella (57) and white (37). Contributions to the total genetic diversity were first assessed in the existing subpopulations and later compared with two scenarios with equal subpopulation size, one with the mean population size (13710) and another with a low population size (100). Ancestor analysis revealed a very similar origin for the different groups, except for six ancestors that were only present in one of the groups likely to be responsible for the corresponding colour. The coancestry matrix showed a close genetic relationship between the bay and chestnut subpopulations. Before adjustment, Nei’s minimum distance showed a lack of differentiation among subpopulations (particularly among the black, chestnut and bay subpopulations) except for isabella and white individuals, whereas after adjustment, white, roan and grey individuals appeared less differentiated. Standardization showed that balancing coat colours would contribute preserving the genetic diversity of the breed. The global genetic diversity increased by 12.5% when the subpopulations were size standardized, showing that a progressive increase in minority coats would be profitable for the genetic diversity of this breed. The methodology developed could be useful for the study of the genetic structure of subpopulations with unbalanced sizes and to predict their genetic importance in terms of their contribution to genetic variability.
Cross-validation analysis for genetic evaluation models for ranking in endurance horses
(Elsevier, 2018) García-Ballesteros, S.; Varona, L.; Valera Córdoba, María Mercedes; Gutiérrez, J. P.; Cervantes, I.; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Ranking trait was used as a selection criterion for competition horses to estimate racing performance. In the literature the most common approaches to estimate breeding values are the linear or threshold statistical models. However, recent studies have shown that a Thurstonian approach was able to fix the race effect (competitive level of the horses that participate in the same race), thus suggesting a better prediction accuracy of breeding values for ranking trait. The aim of this study was to compare the predictability of linear, threshold and Thurstonian approaches for genetic evaluation of ranking in endurance horses. For this purpose, eight genetic models were used for each approach with different combinations of random effects: rider, rider–horse interaction and environmental permanent effect. All genetic models included gender, age and race as systematic effects. The database that was used contained 4065 ranking records from 966 horses and that for the pedigree contained 8733 animals (47% Arabian horses), with an estimated heritability around 0.10 for the ranking trait. The prediction ability of the models for racing performance was evaluated using a cross-validation approach. The average correlation between real and predicted performances across genetic models was around 0.25 for threshold, 0.58 for linear and 0.60 for Thurstonian approaches. Although no significant differences were found between models within approaches, the best genetic model included: the rider and rider–horse random effects for threshold, only rider and environmental permanent effects for linear approach and all random effects for Thurstonian approach. The absolute correlations of predicted breeding values among models were higher between threshold and Thurstonian: 0.90, 0.91 and 0.88 for all animals, top 20% and top 5% best animals. For rank correlations these figures were 0.85, 0.84 and 0.86. The lower values were those between linear and threshold approaches (0.65, 0.62 and 0.51). In conclusion, the Thurstonian approach is recommended for the routine genetic evaluations for ranking in endurance horses.
Genetic structure and connectivity analysis in a large domestic livestock meta-population: the case of the Pura Raza Espanol horses
(Wiley, 2018) Solé, Mariana; Valera Córdoba, María Mercedes; Fernández, Jesús; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
The Pura Raza Español (PRE) is an autochthonous Spanish horse population distributed in 65 countries and managed by a single association. Since 1960s, breeding animals have been steadily exported to other countries to establish local subpopulations. We analysed the genetic structure of a PRE horse meta-population (MP) of 215,500 animals from countries with at least 80 active animals (27 countries comprising 77% of the total animals in the complete pedigree). Genotypes from active animals (59% of the total animals in the complete pedigree) were also studied. Genetic analysis of the MP was performed using classical parameters such as inbreeding (F), coancestry, founder contribution, effective number of founders/ancestors (fe/fa) and gene flow between countries. Results showed that the MPF coefficient decreased in the last two decades (1990–2013), indicating an explicit management against F. Founder contribution to genetic variability across countries mainly came from females (73.6%). In general, unbalanced contributions of founders reflected the high loss of genetic diversity along generations (fe/fa as low as 32/19 for the whole MP). Despite this differential contribution, the proportional contribution to the global diversity of each country was similar. The highest within-country coancestry value corresponded to Cuba (0.1509), being the only country with highly inbred individuals (over 12%), and the lowest value corresponded to Spain (0.0574). These results should help to avoid further declines in genetic variability and increases in F levels, especially in small countries like Cuba. In parallel, only nine countries presented descendants in a single population, suggesting a common origin for all countries and/or a substantial exchange of genetic material between populations. Spain and the US showed the highest gene flow rates. These results support the need of a coordinated management strategy, especially promoting the exchange of genetic material to increase the effective population size and maintain the levels of genetic diversity in the PRE horse population.
A new molecular screening tool for the detection of chromosomal abnormalities in donkeys
(Wiley, 2018) Poyato Bonilla, Julia; Anaya-Calvo, Gabriel; Molina, Antonio; Valera Córdoba, María Mercedes; Moreno Millán, Miguel; Dorado, Jesús; Demyda-Peyras, Sebastián; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Chromosomal abnormalities are a major cause of infertility and reproductive problems in equids. Nowadays, their detection is rising due to the use of new diagnostic tools based on molecular markers instead of karyotyping. Reports of this kind of genetic aberrations in domestic donkeys (Equus asinus) are extremely scarce, despite their importance in human activities. In the present study, we analysed the implementation of a short-tandem-repeat (STR)-based molecular method initially developed for horses, as a diagnostic tool to detect chromosomal abnormalities in donkeys. The frequency of five X-linked (LEX003, LEX026, TKY38, TKY270 and UCEDQ502) and one Y-linked (ECAYM2) molecular markers and one Y-linked gene (sex-determining region Y, SRY) was characterized in 121 donkeys from two diverse breeds, the Spanish Andalusian and the African Moroccan breeds. The molecular panel showed 100% sensitivity and 99.67% specificity in detecting 10 different chromosomal abnormalities in the species. In conclusion, this methodology is a valid, rapid and low-cost tool for the detection and characterization of chromosomal abnormalities in domestic donkeys.
Drawbacks and consequences of selective strategies in the design of semen banks: case study of the Pura Raza Español horse breed
(Elsevier, 2019) Solé, M.; Valera Córdoba, María Mercedes; Sánchez Guerrero, María José; Azor, Pedro Javier; Fernández, Jesús; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Genome resource banks (GRB) are valuable tools for the maintenance of genetic diversity, especially in endangered species or local breeds but also for mainstream breeds. Minimum coancestry criterion is commonly implemented to decide the actual donors contributing to the GRB. This is (more or less) clear for local breeds with a pure conservation emphasis. However, in breeds with a productive or commercial nature other considerations are also taken into account beyond the original objective of the bank. For instance, the breeding criteria used in the living population for the maintenance of the genetic progress could be also implemented in the design of the bank. Using data of the Pura Raza Español (PRE) horse breed (males between 3 and 20 years old) as a case study, we aimed to investigate the effect on genetic diversity of different criteria for the selection of the donors (stallions) in the design of a GRB (semen bank). Studied scenarios included (i) minimisation of the global average coancestry; (ii) maximisation of the mean estimated breeding values (EBVs) of the donors with a restriction on the levels of coancestry incurred. We used genealogical (281,052 animals; 138,059 males and 145,869 females) and molecular information (70,572 genotypes from PRE with reproductive capacity), as well as the EBVs for two productive traits (Dressage sport discipline of 9000 males and morphological linear traits of 2597 males). When the genealogical coancestry was the only criterion, increasing the number of donors resulted in continuous increase in diversity stored (for the different parameters used for comparison). When pedigree coancestry was replaced by molecular coancestry results were not so consistent. The inclusion of EBVs as additional selective criteria (searching for the most ‘valuable’ donors) led to an increased relatedness between donors (and, correspondingly, to a decrease in the diversity kept). In this scenario, the inclusion of individuals with low performance may be arguable depending on the time horizon the bank has been designed for. In any case, in parallel as it is recommended for the management of living populations, restrictions in the levels of genetic diversity (inbreeding) should be included when deciding the sampling scheme.
Evidence for the effect of serotoninergic and dopaminergic gene variants on stress levels in horses participating in dressage and harness racing
(CSIRO Publishing, 2019) Negro, S.; Sánchez Guerrero, María José; Bartolomé Medina, Ester; Solé, M.; Gómez, M. D.; Membrillo, A.; Molina, Antonio; Valera Córdoba, María Mercedes; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Eye temperature assessed with infrared thermography is an adequate tool for stress level assessment in sport horses’ competitions having a moderate heritability. Serotonin and dopamine signal transduction-linked gene variants have been associated with anxiety-related traits in several species. In this study we examined the association between 10 gene variants in BDNF, COMT, HTR1A, TPH2 and SLC6A4 genes (and the haplotypes at SLC6A4 gene) with stress level (measured with eye temperature and heart rate) in 270 animals, 135 Spanish Trotter Horses (STH) participating in trotting races and 135 ‘Pura Raza Español’ (PRE) horses in dressage. Association analyses were performed using a unified mixed model (counting for population structure and individual relatedness) for the whole population and for each horse breed. The g.43865600G > A intronic gene variant located 11.0 kb downstream from the transcription start site of SLC6A4 gene was associated with an increase in eye temperature before competition with a relative contribution of this gene variant of 38.8% (P = 0.001), 31.8% just after (P = 0.001) and 29.8% 2 h after the competition (P = 0.003). In STH, the g.43865600G > A gene variant showed the same association with eye temperature before (P = 0.001, contribution 27.2%), just after (P = 0.0003, 29.0%) and after the competition (P = 0.002, 17.5%); and the c.*111G > A gene variant located at the 3'UTR region of COMT gene was associated with eye temperature 2 h after the competition (P = 0.001, 22.3%). These results showed that SLC6A4 and COMT gene variants are associated with stress level measured as eye temperature increase during competitions, and may be promising tools for genetic testing against resistance at high stress levels in trotter horses.
Acute stress assessment using infrared thermography in fattening rabbits reacting to handling under winter and summer conditions
(Consejo Superior de Investigaciones Científicas, 2020) Jaén Téllez, Juan Antonio; Sánchez Guerrero, María José; López Campos, José Luis; Valera Córdoba, María Mercedes; González Redondo, Pedro; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Aim of study: This study assesses acute stress by measuring, through infrared thermography in summer and winter, the temperature of the eye, outer ear, inner ear and nose in 40 fattening rabbits before and after handling. Area of study: Seville (Spain). Material and methods: Body thermographic temperatures were recorded during a 38-day fattening period twice weekly and twice a day, before and after the handler held the rabbits in their arms for one minute. Ambient temperature and relative humidity were also recorded, and their influence on body temperatures was assessed. For each anatomical part, the variation of the temperature between the handled and undisturbed rabbit, and the differential temperature between the anatomical part in the undisturbed rabbit and the ambient temperature were calculated. Main results: The variation in temperatures between handled and undisturbed rabbits ranged from 0.25±0.041 ºC for eye to 3.09±0.221 ºC for outer ear in summer and -0.41±0.182 ºC for nose to 2.09±0.178 ºC for outer ear in winter. The day of the fattening period influenced all the temperature traits during summer and winter, except for the inner ear in winter. In summer, unlike winter, the temperature variation at the end of fattening period between handled and undisturbed rabbits was lower than at weaning (-0.04 to 1.94 ºC vs. 0.54 to 5.52 ºC, respectively). The temperatures in undisturbed rabbits were correlated with ambient temperature. Research highlights: Measuring body temperature with infrared thermography is a useful tool to evaluate acute stress in handled rabbits, with the inner ear and eye the most reliable body parts for measuring it.
Screening and detection of chromosomal copy number alterations in the domestic horse using SNP-array genotyping data
(Wiley, 2021) Pirosanto, Y.; Laseca, Nora; Valera Córdoba, María Mercedes; Molina, Antonio; Moreno Millán, M.; Bugno-Poniewierska, Monika; Ross, P.; Azor, P.; Demyda-Peyrás, Sebastián; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Chromosomal abnormalities are a common cause of infertility in horses. However, they are difficult to detect using automated methods. Here, we propose a simple methodology based on single nucleotide polymorphism (SNP)-array data that allows us to detect the main chromosomal abnormalities in horses in a single procedure. As proof of concept, we were able to detect chromosomal abnormalities in 33 out of 268 individuals, including monosomies, chimerisms, and male and female sex-reversions, by analyzing the raw signal intensity produced by an SNP array-based genotyping platform. We also demonstrated that the procedure is not affected by the SNP density of the array employed or by the inbreeding level of the individuals. Finally, the methodology proposed in this study could be performed in an open bioinformatic environment, thus permitting its integration as a flexible screening tool in diagnostic laboratories and genomic breeding programs.
Challenging the selection for consistency in the rank of endurance competitions
(BioMed Central, 2020) Cervantes, Isabel; Bodin, Loys; Valera Córdoba, María Mercedes; Molina, Antonio; Gutiérrez, Juan Pablo; Agronomía; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Control of the environmental variability by genetic selection offers possibilities for new selection objectives for productive traits. This methodology aims at reducing heterogeneity in productive traits and has been applied to several traits and species for which animal homogeneity is profitable. In horse breeding programmes, rank in competitions is a common selection objective but has been challenging to model. In this study, the parameters of environmental variability for the rank of a horse were computed to analyse the capability of a horse to maintain the best ranking across competitions that consist of long-distance races in which the adapted physical condition of the horse is essential. The genetic component of the environmental variance for the rank in endurance competitions was evaluated, which resulted in proposing a new transformation of horse scores in competitions.
Relationship between rectal temperature measured with a conventional thermometer and the temperature of several body regions measured by infrared thermography in fattening rabbits. Influence of different environmental factors
(Universidad Politécnica de Valencia, 2021) Jaén Téllez, Juan Antonio; Bartolomé Medina, Ester; Sánchez Guerrero, María José; Valera Córdoba, María Mercedes; González Redondo, Pedro; Agronomía; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
In clinical examination of rabbits, the temperature is usually recorded with a digital thermometer introduced rectally, an invasive procedure that could cause handling stress. The aim of this study was to assess body temperature using infrared thermography (IRT) in four areas of the rabbit’s anatomy: eye (ETT), outer ear (OETT), inner ear (IETT) and nose (NTT), and then validate it as an alternative measure to rectal temperature (RT) assessed with a conventional thermometer.Temperature samples were taken twice a week from 48 weaned rabbits of Spanish Common Rabbit breed during a 38-d fattening period. The factors considered were: doe from which the rabbits came (8 does), weeks of fattening period (4 to 5 wk), batch (3 periods of the year: April-May, June-July and January-February) and group size (cages with 1 to 7 rabbits). On average, the results were an RT of 38.48±0.02 °C; ETT of 37.31±0.05 °C; OETT of 29.09±0.26°C; IETT of 30.53±0.25 °C, and NTT of 33.29±0.11 °C (mean±se). Moderate, statistically significant positive correlations (P<0.001) were observed between RT and temperatures measured with infrared thermography (IETT, OETT, ETT and NTT), both in general (0.39 to 0.49) and intraclass (0.36 to 0.39), based on the batch, group size, week of fattening period and doe. The thermographic measurements which showed the highest correlation with RT were OETT and IETT. We also studied the effects that could influence the temperature variables evaluated by IRT and RT within each batch: for each week of the fattening period, for the group size and for the doe effect. We found significant differences (P<0.001) between weeks within the batch, with a tendency for the temperature of the rabbits to increase as the fattening period progressed. The doe effect (within the batch) did not show, on the whole, any statistically significant differences within batches. On the other hand, we did observe a trend towards higher temperatures as the group size increased. In conclusion, infrared thermography is an effective tool for body temperature assessment and correlates closely with RT, with IETT appearing as the best reference point for taking body temperature in fattening rabbits. Infrared thermography appeared as a suitable alternative to RT for body temperature assessment in rabbits, thus avoiding handling stress.
Copy Number Variation (CNV): A New Genomic Insight in Horses
(MDPI, 2022) Laseca, Nora; Molina, Antonio; Valera Córdoba, María Mercedes; Antonini, Alicia; Demyda-Peyrás, Sebastián; Agronomía; Ministerio de Economia, Industria y Competitividad (MINECO). España; Agencia Nacional de Promoción Científica y Tecnológica. Argentina; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Copy number variations (CNVs) are a new-fangled source of genetic variation that can explain changes in the phenotypes in complex traits and diseases. In recent years, their study has increased in many livestock populations. However, the study and characterization of CNVs in equines is still very limited. Our study aimed to investigate the distribution pattern of CNVs, characterize CNV regions (CNVRs), and identify the biological pathways affected by CNVRs in the Pura Raza Española (PRE) breed. To achieve this, we analyzed high-density SNP genotyping data (670,804 markers) from a large cohort of 654 PRE horses. In total, we identified 19,902 CNV segments and 1007 CNV regions in the whole population. The length of the CNVs ranged from 1.024 kb to 4.55 Mb, while the percentage of the genome covered by CNVs was 4.4%. Interestingly, duplications were more abundant than deletions and mixed CNVRs. In addition, the distribution of CNVs across the chromosomes was not uniform, with ECA12 being the chromosome with the largest percentage of its genome covered (19.2%), while the highest numbers of CNVs were found in ECA20, ECA12, and ECA1. Our results showed that 71.4% of CNVRs contained genes involved in olfactory transduction, olfactory receptor activity, and immune response. Finally, 39.1% of the CNVs detected in our study were unique when compared with CNVRs identified in previous studies. To the best of our knowledge, this is the first attempt to reveal and characterize the CNV landscape in PRE horses, and it contributes to our knowledge of CNVs in equines, thus facilitating the understanding of genetic and phenotypic variations in the species. However, further research is still needed to confirm if the CNVs observed in the PRE are also linked to variations in the specific phenotypical differences in the breed.
Prevalence of Sex-Related Chromosomal Abnormalities in a Large Cohort of Spanish Purebred Horses
(MDPI, 2023) Demyda-Peyrás, Sebastián; Laseca, Nora; Anaya, Gabriel; Kij-Mitka, Barbara; Molina, Antonio; Karlau, Ayelén; Valera Córdoba, María Mercedes; Agronomía; Universidad de Córdoba; Junta de Andalucía; Ministerio de Economia, Industria y Competitividad (MINECO). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Chromosomal abnormalities are largely associated with fertility impairments in the domestic horse. To date, over 600 cases of individuals carrying abnormal chromosome complements have been reported, making the domestic horse the species with the highest prevalence. However, studies analyzing the prevalence of chromosomal diseases in whole populations are scarce. We, therefore, employed a two-step molecular tool to screen and diagnose chromosomal abnormalities in a large population of 25,237 Pura Raza Español horses. Individuals were first screened using short tandem repeats parentage testing results and phenotypic evaluations. Those animals showing results suggesting chromosomal abnormalities were re-tested using a single nucleotide polymorphism (SNP)-based diagnostic methodology to accurately determine the chromosomal complements. Thirteen individuals showed a positive screening, all of which were diagnosed as chromosomally abnormal, including five 64,XY mares with sex development disorders (DSD) and four cases of blood chimerism (two male/female and two female/female cases). In addition, we detected one Turner and one Klinefelter syndrome and two individuals carrying complex karyotypes. The overall prevalence in the entire population was ~0.05%, with the prevalence of 64,XY DSD and blood chimerism ~0.02% and ~0.016%, respectively. However, the overall results should be taken with caution since the individuals carrying Turner syndrome (in full (63,X) or mosaic (mos 63,X/64,XX) forms) cannot be detected due to limitations in the methodology employed. Finally, the lack of agreement between populational studies performed using karyotyping or molecular methods is discussed. To our knowledge, this is the largest populational study performed evaluating the prevalence of the most common chromosomal abnormalities in the domestic horse.
Genomic screening of allelic and genotypic transmission ratio distortion in horse
(Public Library of Science, 2023) Laseca, Nora; Cánovas, Ángela; Valera Córdoba, María Mercedes; Id-Lahoucine, Samir; Perdomo González, Davinia Isabel; Fonseca, Pablo A. S.; Demyda-Peyrás, Sebastián; Molina, Antonio; Agronomía; Ministerio de Economía y Competitividad (MINECO). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
The phenomenon in which the expected Mendelian inheritance is altered is known as transmission ratio distortion (TRD). The TRD analysis relies on the study of the transmission of one of the two alleles from a heterozygous parent to the offspring. These distortions are due to biological mechanisms affecting gametogenesis, embryo development and/or postnatal viability, among others. In this study, TRD phenomenon was characterized in horses using SNP-by-SNP model by TRDscan v.2.0 software. A total of 1,041 Pura Raza Español breed horses were genotyped with 554,634 SNPs. Among them, 277 horses genotyped in trios (stallion-mare-offspring) were used to perform the TRD analysis. Our results revealed 140 and 42 SNPs with allelic and genotypic patterns, respectively. Among them, 63 displayed stallion-TRD and 41 exhibited mare-TRD, while 36 SNPs showed overall TRD. In addition, 42 SNPs exhibited heterosis pattern. Functional analyses revealed that the annotated genes located within the TRD regions identified were associated with biological processes and molecular functions related to spermatogenesis, oocyte division, embryonic development, and hormonal activity. A total of 10 functional candidate genes related to fertility were found. To our knowledge, this is the most extensive study performed to evaluate the presence of alleles and functional candidate genes with transmission ratio distortion affecting reproductive performance in the domestic horse.
Stress and behavior assessment in police dogs due to challenging situations: Differences due to training objectives
(Edizioni ETS, 2023) Bartolomé Medina, Ester; Sánchez Guerrero, María José; Perdomo González, Davinia Isabel; Valera Córdoba, María Mercedes; Agronomía; Universidad de Sevilla; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Police dogs have been trained to maximize their search capabilities and are required to maintain levels of intense concentration during their working time. The main aim of this study was to evaluate stress and behavior differences in police dogs due to different scenarios and distractors according to type of training: detecting narcotics or explosives. A total of 18 dogs (14 males and 4 females) were measured. 8 were trained for narcotics detection and 10 for explosives detection. In order to test the stress reaction of dogs, 3 scenarios were developed for each type of training, being differentiated by the difficulty, Scenario 1 the easiest one, Scenario 2 an intermediate-difficulty test and Scenario 3 the most challenging one. Then, these scenarios were performed a second time, including an environmental distractor: an olfactory distractor for S1 (S1D1), an auditory distractor for S2 and a visual distractor for scenario 3. The animals’ stress levels were measured with eye temperature (ET), assessed with infrared thermography, and heart rate (HR). Behavior was recorded for each animal on each scenario. These parameters were then grouped in 3 behavior aggrupation’s counted in 4 scores each: Attention, Effectiveness and Fear. A descriptive analysis showed higher ET means in dogs trained for explosives’ detection for most of the scenarios. A General Linear Model and Tuckey post-hoc analysis for different environmental and behavioral effects, found that ET showed statistically significant differences for scenario effect with both narcotics’ and explosives’ trained dogs, with S2 showing the highest ET values and S1D1 the lowest, whereas, according to behavioral effects, statistically significant differences were found for attention in narcotics’ trained dogs and for effectiveness in explosives’ trained dogs, with score 4 showing the highest ET means for both behavioral aggrupation’s. On the other hand, Mann-Whitney U Test between behavioral means, showed that, explosives’ trained dogs showed higher Attention scores but lower Effectiveness scores than Narcotics’ trained dogs. Finally, ET showed medium and positive statistically significant correlations with Attention in narcotics’ trained dogs (0.34) and with Fear in explosives’ trained dogs (0.26), HR parameter showed a medium and negative statistically sig-nificant correlation with Attention in narcotics’ trained dogs (-0.31). Our results indicated that explosives’ detection dogs showed more excitability, and less effectiveness behavioral signs than narcotics’ detection dogs, with no differenc-es found related to fear signs.
The Use of Genomic Screening for the Detection of Chromosomal Abnormalities in the Domestic Horse: Five New Cases of 65,XXY Syndrome in the Pura Raza Español Breed
(MDPI, 2024) Valera Córdoba, María Mercedes; Karlau, Ayelén; Anaya, Gabriel; Bugno-Poniewierska, Monika; Molina, Antonio; Encina, Ana; Azor, Pedro; Demyda-Peyrás, Sebastián; Agronomía; Asociación Nacional de Criadores de Caballos de Pura Raza Española; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Sex chromosomal abnormalities are a major cause of reproductive failure in horses. While some horses with abnormal karyotypes exhibit reproductive abnormalities, others appear normal, remaining misdiagnosed until late age. The Pura Raza Español breeding program screens all horses for these abnormalities using genomics before adding them to the studbook. This process includes an initial assessment using the results of Short Tandem Repeat (STR) parentage testing, followed by confirmation using Single-Nucleotide Polymorphism (SNP) analysis for copy number aberrations. Hereby, we identified five new cases of 65,XXY syndrome among 27,330 foals over two breeding seasons. These horses were flagged as possibly affected by a chromosomal number aberration (CNA) due to abnormal STR and confirmed as 65,XXY by genomic analysis. All of them showed a male phenotype. One horse showed abnormal gonad development, whereas the others did not have visible abnormalities. This study represents the largest group of horses diagnosed with 65,XXY and emphasizes the importance of genomic screening for chromosomal testing.
Comparative Analysis of Genomic and Pedigree-Based Approaches for Genetic Evaluation of Morphological Traits in Pura Raza Española Horses
(MDPI, 2025) Ziadi, Chiraz; Demyda-Peyrás, Sebastián; Valera Córdoba, María Mercedes; Perdomo González, Davinia Isabel; Laseca, Nora; Rodríguez-Sainz de los Terreros, Arancha; Encina, Ana; Azor, Pedro; Molina, Antonio; Agronomía; Ministerio de Agricultura, Pesca y Alimentación (MAPA). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
The single-step best linear unbiased predictor (ssGBLUP) has emerged as a reference method for genomic selection in recent years due to its advantages over traditional approaches. Although its application in horses remains limited, ssGBLUP has demonstrated the potential to improve the reliability of estimated breeding values in livestock species. This study aimed to assess the impact of incorporating genomic data using single-step restricted maximum likelihood (ssGREML) on reliability (R2) in the Pura Raza Española (PRE) horse breed, compared to traditional pedigree-based REML. Methods: The analysis involved 14 morphological traits from 7152 animals, including 2916 genotyped individuals. Genetic parameters were estimated using a multivariate model. Results: Results showed that heritability estimates were similar between the two approaches, ranging from 0.08 to 0.76. However, a significant increase in reliability (R2) was observed for ssGREML compared to REML across all morphological traits, with overall gains ranging from 1.56% to 13.30% depending on the trait evaluated. R2 ranged from 6.93% to 22.70% in genotyped animals, significantly lower in non-genotyped animals (0.82% to 12.37%). Interestingly, individuals with low R2 values in REML demonstrated the largest R2 gains in ssGREML. Additionally, this improvement was much greater (5.96% to 19.25%) when only considering stallions with less than 40 controlled foals. Conclusions: Hereby, we demonstrated that the application of genomic selection can contribute to improving the reliability of mating decisions in a large horse breeding program such as the PRE breed.
Enhanced Reliability of the Evaluation of Fertility Traits in Pura Raza Española Horses Using Single-Step Genomic Best Linear Unbiased Prediction
(MDPI, 2025-05) Ziadi, Chiraz; Valera Córdoba, María Mercedes; Laseca, Nora; Perdomo González, Davinia Isabel; Demyda-Peyrás, Sebastián; Rodríguez-Sainz de los Terreros, Arancha; Molina, Antonio; Agronomía; Ministerio de Agricultura, Pesca y Alimentación (MAPA). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
By simultaneously integrating both genotyped and non-genotyped animals into genetic evaluation, the single-step genomic BLUP method enhanced the accuracy of genetic assessments. This study aimed to compare the increase in prediction reliability (R2) between restricted maximum likelihood (REML) and single-step genomic REML (ssGREML) in the Pura Raza Española (PRE) horse breed. Methods: The dataset comprised reproductive records for seven fertility traits from 47,502 females, with a total of 57,316 animals represented in the pedigree. A total of 4009 animals were genotyped using the EQUIGENE 90K SNP array, and 71,322 SNPs were retained for analysis after quality control. Genetic parameters were estimated using a multivariate model with the BLUPF90+ v2.60 software. Results: Heritability estimates were similar between REML and ssGREML, ranging from 0.07 for IF12 to 0.349 for ALF. An increase in R2 was observed with ssGREML compared to REML across all traits, with overall gains ranging from 2.20% to 3.71%. Among genotyped animals, R2 values ranged from 17.81% to 24.04%, while significantly lower values (0.80% to 2.34%) were observed in non-genotyped animals. Notably, individuals with low initial R2 values under the REML approach exhibited the most significant gains using ssGREML. This improvement was particularly pronounced among stallions with fewer than 40 controlled foals. Conclusions: Our results demonstrated that incorporating genomic data improves the reliability of genetic evaluations for mare fertility in PRE horses.
Genetic relationship between Neck and Limb defects in Pura Raza Española Horses
(Elsevier, 2025) Ripollés Lobo, María; Perdomo González, Davinia Isabel; Dos Santos, R.; Sánchez Guerrero, María José; Azor, P.; Valera Córdoba, María Mercedes; Agronomía; Asociación Nacional de Criadores de Caballos de Pura Raza Española; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
Background: Neck and limb conformational defects can impair functionality and performance in Pura Raza Espa˜ nola (PRE) horses. However, their potential genetic relationship has not been previously explored. Aims/Objectives: To estimate the genetic correlations between two types of neck defects (Cresty neck -CN-, Ewe neck -EN-) and twelve conformational limb defects: Forelimb (Buck knee -BUK-, Calf knee -CK-, Bench knee -BEK- , Knock knee -KK-, Splay-footed forelimb -SFF-, Pigeon-toed forelimb -PTF-), rear limb (Closed hock -CH-, Open hock -OH-, Convergent hock -CVH-, Divergent hock -DVH-, Splay-footed rear limb -SFR-, Pigeon-toed rear limb -PTR-). We hypothesized that a genetic relationship exists between neck and limb morphology. Methods: This study analyzed 56,644 PRE horses evaluated between 2012 and 2023. Neck and limb conformation traits were scored using two approaches: A) two-class scale (0-no defect, 1-presence of defect); B) three-class scale for limb defects (0-no defect, 1-slight defect, 2-serious defect) and four-class scale for neck defects (0-no defect, 1-slight defect, 2-serious defect, 3-disqualifying defect). Genetic parameters were estimated, including age as a covariate, and sex, genetic origin, management of breeder’s stud farm and inbreeding as fixed effects. Results: The most frequent limb defect among horses with neck defects was SFR (80.15 % in CN and 72.45 % in EN). Genetic correlations showed moderate relationships, ranging from -0.22(s.d.: 0.090) for EN-SFR to 0.44(s.d.: 0.123) for CN-DVH in approach A, and oscillating from -0.25(s.d.: 0.028) for CNCVH to 0.51(s.d.: 0.228) for CN-SFF in approach B. Conclusion: Results support the need for integrated selection strategies targeting both anatomical regions.
The Role of Genetic and Environmental Factors in White Leg Markings: Prevalence and Heritability Analysis in Pura Raza Española Horses
(MDPI, 2025-10) Encina, Ana; Sánchez Guerrero, María José; Ligero, Manuel; Rodríguez-Sainz de los Terreros, Arancha; Valera Córdoba, María Mercedes; Agronomía; Universidad de Sevilla; Fundación de Investigación de la Universidad de Sevilla; Asociación Nacional de Criadores de Caballos de Pura Raza Española; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos
White leg markings in horses are phenotypic traits influenced by genetic and environmental factors. This study analyzed their prevalence, symmetry, and genetic parameters in 38,825 Pura Raza Española (PRE) horses registered in the official studbook. White markings were scored using a binary (affected/unaffected) and a four-level ordinal scale. Most horses (38,341 out of 38,825; 98.8%) had at least one limb without white markings. The prevalence of white markings was higher in the hindlegs (17.9% LH; 14.5% RH) than in the forelegs (5.3% LF; 4.6% RF). Markings were most frequent above the fetlock (≈64%), chestnut horses showed the highest prevalence, whereas black coats showed the lowest. Genetic analyses using Bayesian animal models revealed moderate-to-high heritabilities, ranging from 0.488 for Right hindlegs to 0.574 for Left hindlegs in the multinomial model, which outperformed the dichotomous model (h2 = 0.030–0.515 for all legs and left foreleg, respectively). Additive genetic variance was highest in the left hindleg (σ2u = 7.904). Genetic correlations were high between contralateral homologous limbs (0.991 forelegs; 0.995 hindlegs), confirming strong bilateral genetic control, while diagonal correlations were lower (≈0.886). These findings confirm a substantial genetic component underlying white leg markings in PRE horses and highlight the importance of refined phenotyping and genetic evaluations for breeding strategies, particularly when markings are penalized as in the PRE breeding program.
Time-Weighted Result-Based Strength Indicators from Head-to-Head Outcomes: An Application to Trotter (Harness) Racing
(MDPI, 2026) Ligero Acosta, Manuel; Muñoz Pichardo, Juan Manuel; Gómez, María Dolores; Ripollés Lobo, María; Valera Córdoba, María Mercedes; Agronomía; Estadística e Investigación Operativa; AGR273: Nuevas Tecnologías de Mejora Animal y de Sus Sistemas Productivos; FQM153: Estadística e Investigación Operativa
We propose a general methodology for constructing dynamic performance indicators (or strength metrics) in any sport that relies on comparative outcomes among competitors, using chronological positional data. Specifically, we develop a family of strength indicators for harness trotting races based on time-weighted, head-to-head results. Using the official Balearic trotting records (1990–2023), we construct win, draw, and confrontation matrices up to each event and apply a triweight kernel to reduce the influence of older results. From these matrices, we derive a family of five bounded, interpretable indicators on the interval: an overall average win rate, a category-adjusted version, and three distance-specific versions (short, medium, and long). Indicator validation is performed via predictive validation, employing regularized logistic regression models (Elastic Net) based on indicator differences between horse pairs. Standard metrics (accuracy, calibration, discrimination, and Brier score) are used for the validation analysis. The results confirm that the indicators are coherent, stable, and interpretable, demonstrating that the generic construction procedure yields robust outcomes. We conclude that these indicators establish a solid and easily updatable foundation for developing dynamic ranking systems and practical selection/handicap procedures in trotting.

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