Genetic analysis of the effects of heat stress before and after lambing on pre-weaning live weight in Spanish Merino lambs

Background: Heat stress (HS) is a major environmental effect on sheep production. Hereby, we estimated the genetic (co)variance component of HS on the pre-weaning performance of 19,022 Merino lambs by analysing the climatological index of temperature and relative humidity (recorded 30 days before lambing and after lambing) using transversal and longitudinal mixed linear models. Methods and Results: The global impact of HS during the last 30 days of pregnancy was −17% for birthweight and ranged between −4% and −8% for live weight at 15, 30 days of age (W30), and average daily gain from birth at 30 days. The results from both statistical approaches showed very similar heritabilities (h2), ranging from 0.192 to 0.237 for the direct genetic (D) effects and from 0.072 to 0.082 for the maternal genetic (M) effects, but the antagonism between (D) and (M) was higher when a longitudinal model was used. A significant genotype-environmental effect was also found regardless of whether the climatological covariables were considered in the model. In addition, we employed D and M breeding values for W30 as an example to create a new subjacent index by first using a principal component analysis and employing the leading eigenvalues as a weighted factor that provides the information needed to identify those genotypes that maximise the response for both genetic effects over a wide range of climate–environment levels. Conclusions: Our study revealed that the HS indexes of the mother during the gestation period have a significant effect on the growth of the lambs during the early stages of life.Fil: Molina, Antonio. Universidad de Córdoba; EspañaFil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Sánchez, Manuel. Universidad de Córdoba; EspañaFil: Serradilla, Juan M.. Universidad de Córdoba; EspañaFil: Menéndez Buxadera, Alberto. Universidad de Córdoba; Españ

Fine-Scale Analysis of Runs of Homozygosity Islands Affecting Fertility in Mares

The loss of genetic variability in livestock populations bred under strict selection processes is a growing concern, as it may lead to increased inbreeding values and lower fertility, as a consequence of the “inbreeding depression” effect. This is particularly important in horses, where inbreeding levels tend to rise as individuals become more and more closely related. In this study, we evaluated the effect of increased inbreeding levels on mare fertility by combining an SNP-based genomic approach using runs of homozygosity and the estimation of genetic breeding values for reproductive traits in a large population of Pura Raza Española mares. Our results showed a negative correlation between whole-genome homozygosity and fertility estimated breeding values (EBVs) at the genome level (ρ = −0.144). However, the analysis at chromosome level revealed a wide variability, with some chromosomes showing higher correlations than others. Interestingly, the correlation was stronger (−0.241) when we repeated the analysis in a reduced dataset including the 10% most and least fertile individuals, where the latter showed an increase in average inbreeding values (FROH) of around 30%. We also found 41 genomic regions (ROHi, runs of homozygosity islands) where homozygosity increased 100-fold, 13 of which were significantly associated with fertility after cross-validation. These regions encompassed 17 candidate genes previously related to oocyte and embryo development in several species. Overall, we demonstrated the relationship between increased homozygosis at the genomic level and fertility in mares. Our findings may help to deal with the occurrence of inbreeding depression, as well as further our understanding of the mechanisms underlying fertility in mares.Fil: Laseca, Nora. Universidad de Córdoba; EspañaFil: Molina, Antonio. Universidad de Córdoba; EspañaFil: Ramón, Manuel. Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal Castilla La Mancha; EspañaFil: Valera, Mercedes. Universidad de Sevilla; EspañaFil: Azcona, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Encina, Ana. Universidad de Sevilla; EspañaFil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Fine-tuning genomic and pedigree inbreeding rates in equine population with a deep and reliable stud book: the case of the Pura Raza Española horse

Background: Estimating inbreeding, which is omnipresent and inevitable in livestock populations, is a primary goal for management and animal breeding especially for those interested in mitigating the negative consequences of inbreeding. Inbreeding coefficients have been historically estimated by using pedigree information; however, over the last decade, genome-base inbreeding coefficients have come to the forefront in this field. The Pura Raza Española (PRE) horse is an autochthonous Spanish horse breed which has been recognised since 1912. The total PRE population (344,718 horses) was used to estimate Classical (F), Ballou’s ancestral, Kalinowski’s ancestral, Kalinowski’s new and the ancestral history coefficient values. In addition, genotypic data from a selected population of 805 PRE individuals was used to determine the individual inbreeding coefficient using SNP-by-SNP-based techniques (methods of moments -FHOM-, the diagonal elements of the genomic -FG-, and hybrid matrixes -FH-) and ROH measures (FRZ). The analyse of both pedigree and genomic based inbreeding coefficients in a large and robust population such as the PRE horse, with proven parenteral information for the last 40 years and a high degree of completeness (over 90% for the last 70 years) will allow us to understand PRE genetic variability better and the correlations between the estimations will give the data greater reliability. Results: The mean values of the pedigree-based inbreeding coefficients ranged from 0.01 (F for the last 3 generations -F3-) to 0.44 (ancestral history coefficient) and the mean values of genomic-based inbreeding coefficients varied from 0.05 (FRZ for three generations, FH and FHOM) to 0.11 (FRZ for nine generations). Significant correlations were also found between pedigree and genomic inbreeding values, which ranged between 0.58 (F3 with FHOM) and 0.79 (F with FRZ). In addition, the correlations between FRZ estimated for the last 20 generations and the pedigree-based inbreeding highlight the fact that fewer generations of genomic data are required when comparing total inbreeding values, and the opposite when ancient values are calculated. Conclusions: Ultimately, our results show that it is still useful to work with a deep and reliable pedigree in pedigree-based genetic studies with very large effective population sizes. Obtaining a satisfactory parameter will always be desirable, but the approximation obtained with a robust pedigree will allow us to work more efficiently and economically than with massive genotyping.Fil: Perdomo González, Davinia Isabel. Universidad de Sevilla; EspañaFil: Laseca, Nora. Universidad de Córdoba; EspañaFil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Valera, Mercedes. Universidad de Sevilla; EspañaFil: Cervantes, Isabel. Universidad Complutense de Madrid; EspañaFil: Molina, Antonio. Universidad de Córdoba; Españ

Effect of inbreeding depression on bull sperm quality and field fertility

The present study investigated the effect of inbreeding depression on sperm quality using automated and objective methods and subsequent effects on beef bull field fertility. Individual inbreeding coefficient (F) values and field fertility data were determined using a dataset of AI bulls belonging to the Spanish Retinta Breeders Association (Asociación Nacional de Criadores de Ganado Vacuno Selecto de Raza Retinta (ANCRE)). Animals were clustered in two groups according to the F values as follows: (1) a high inbreeding group (HI; F≥13.5%, mean 16.3); and (2) a non-inbreeding group (NI; F≤0%). In total, 17 different assessments were performed in both experimental groups, including evaluation of sperm morphology, acrosomal and DNA status, sperm plasma membrane integrity and function (hypo-osmotic swelling test), 10 kinetic parameters and the structure of sperm subpopulations. Sperm morphology, acrosomal and DNA status and osmotic tolerance were similar in both groups. Three velocity parameters (curvilinear velocity, straight line velocity and average path velocity) and the amplitude of lateral head displacement were higher in HI (P<0.05). Cluster analysis of kinematic parameters revealed three different sperm subpopulations (sP1, sP2 and sP3), with the proportion of the sP1 population (highly active but non-progressive spermatozoa) being significantly (P<0.05) higher in the HI group. Field fertility was assessed using two calving record datasets. In a smaller database including only bulls evaluated in the present study, there was a significant increase in the calving interval of cows sired with HI bulls. Conversely, in an extended genetic analysis of the ANCRE database, inbreeding only explained a small part of the variation in calving interval, and the results of regression analysis were not significant among bulls. The findings of the present study suggest that high inbreeding levels have a moderate effect on bull semen quality, with an increased percentage of highly active but non-progressive spermatozoa, but only when F values reached a certain threshold. This motility pattern could explain, in part, the higher calving interval produced by inbred bulls under field conditions.Fil: Dorado, Jesús. Universidad de Córdoba; EspañaFil: Morales Cid, Rosa. Universidad de Córdoba; EspañaFil: Molina, Antonio. Universidad de Córdoba; EspañaFil: Hidalgo, Manuel. Universidad de Córdoba; EspañaFil: Ariza, Julia. Universidad de Córdoba; EspañaFil: Moreno Millán, Miguel. Universidad de Córdoba; EspañaFil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin

Aplicaciones de la edición genética en reproducción humana: Dónde estamos y hacia dónde vamos

La edición génica es el proceso por el cual se producen modificaciones dirigidas y controladas en el genoma de un individuo con el fin de alterar el fenotipo resultante. Esta técnica comenzó a ser utilizada masivamente en modelos animales experimentales (principalmente en el ratón de laboratorio) a fines de los años 80, luego del desarrollo de una metodología conocida como mutagénesis dirigida (gene targeting en inglés; Thomas and Capecchi (1987), que fuera galardonada en el año 2007 con el Premio Nobel de Fisiología y Medicina. En esta metodología, el primer paso es la construcción de un fragmento artificial de ADN que incluya una variante genética alternativa (secuencia de bases nucleotídicas) a la variante genética normal (conocida como “wild type”) existente en los individuos, la cual era combinada con secuencias nucleotídicas laterales específicas (“flankers”) que permitían direccionar el proceso de mutagénesis hacia un gen determinado. Esta secuencia, conocida vulgarmente como constructora introducida dentro de líneas celulares cultivadas in vitro mediante diversas técnicas biotecnológicas con el objetivo de su incorporación al genoma celular mediante un proceso de recombinación homóloga durante el proceso de replicación celular (Folger et al., 1984). Si bien el proceso fue exitoso, su eficacia era tan baja (la tasa de células que resultaban editadas era menor que 1 por mil), así como la aparición de mutaciones incompatibles con las esperadas en un gran porcentaje de los casos hizo que esta metodología no fuese válida para la edición de líneas germinales o de embriones, quedando su uso limitado a líneas celulares de laboratorio (Capecchi, 2005). Sin embargo, este inconveniente fue elegantemente solucionado mediante un proceso de quimerización artificial, en el cual la edición génica se realizaba sobre líneas de células madre que posteriormente eran inyectadas dentro de un blastocisto de ratón. Estos embriones, compuestos por células normales y células editadas, eran transferidos a madres subrogantes en las cuales completaban su desarrollo, generando animales quiméricos que poseían parte de sus células de tipo “wild type” y parte de sus células editadas genéticamente. Posteriormente, los individuos machos eran retrocruzados con el objetivo de producir progenie que haya sido generada por un espermatozoide proveniente de una célula germinal con su genoma editado (Bradley et al., 1984), permitiendo establecer líneas de ratones modificados al cabo de pocas generaciones de cría. Si bien estas tecnologías seguían siendo poco eficientes, su perfeccionamiento permitió el desarrollo exponencial de los estudios de funcionalidad génica mediante la creación de modelos experimentales para más de 7000 genes diferentes (Capecchi, 2005). Cabe destacar que el desarrollo completo de un modelo experimental validado para un gen específico en el ratón de laboratorio utilizando esta técnica podía demorar más de doce meses. Por la misma razón, era imposible el pensar en desarrollar modelos animales en especies con gestaciones prolongadas como el cerdo o el bovino, que requerirían de años de espera.Fil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentin

The influence of foreign lineages in the genetic component of reproductive traits in Criollo Argentino mares: A 30-year study

The Criollo horse is the most important equine breed in Argentina. These horses are characterized by their strength, resistance, and increased fertility even at old ages, and they are also associated with Argentine tradition and livestock heritage. However, over the last 70 years, the Criollo Argentino breed has been influenced by other South American Criollo horses from Brazil, Uruguay, or Chile. In this study, we aimed to determine the genetic influence of foreign individuals on the reproductive performance of Criollo Argentino mares. To achieve this, we analyzed a large dataset including pedigree records of nearly 212,000 individuals. For the analysis, the individuals were organised into clusters based on their genetic origin (foreign or native Criollos). We then performed a comprehensive genetic characterization of each group, as well as an estimation of the estimated breeding values (EBVs), heritabilities, and genetic correlations for the three traits, using a multi-trait mixed model. Our results demonstrate a positive trend toward the introgression of foreign breeding lineages in the Criollo Argentino population. However, we also quantified a low-to-moderate genetic influence on all the fertility traits analysed, and the absence of any negative effect associated with inbreeding. Despite the fact that the genetic origin produced certain differences between foreign and native individuals in terms of fertility at the beginning of the study, the use of foreign lineages did not significantly change the fertility of the Criollo Argentino mares. To our knowledge, this is the first study analysing the fertility of Criollo horses from a genetic point of view.Fil: Karlau, Ayelen. Catedra de Genetica de Poblaciones y Mejoramiento Animal ; Departamento de Produccion Animal ; Facultad de Cs.veterinarias ; Universidad Nacional de la Plata; . Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Molina, Antonio. Universidad de Córdoba; EspañaFil: Antonini, Alicia Graciela. Catedra de Genetica de Poblaciones y Mejoramiento Animal ; Departamento de Produccion Animal ; Facultad de Cs.veterinarias ; Universidad Nacional de la Plata;Fil: Demyda-peyrás, Sebastian. Catedra de Genetica de Poblaciones y Mejoramiento Animal ; Departamento de Produccion Animal ; Facultad de Cs.veterinarias ; Universidad Nacional de la Plata; . Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Abordaje preliminar de la utilidad de las etapas en una prueba de doma

En los últimos años, el bienestar de los caballos que participan en los deportes ecuestres se ha convertido en un tema polémico. La atención de los medios de comunicación y la concienciación del público han dado lugar a la observación de los mismos para garantizar que el rendimiento deportivo no se logre a expensas del bienestar de los caballos y los concursos de doma. Los concursos de doma tienen como objetivo la cualificación profesional de los domadores participantes. La finalidad de la evaluación en las pruebas de doma mediante jurados es evaluar el aspecto técnico, la ejecución de los movimientos y su recorrido, las habilidades y posición del domador, la precisión en el trazado, así como la impresión general o presentación. El objetivo de este trabajo es analizar la utilidad de las etapas de “La IV Prueba de Doma Bien Montados 2022”, que fue desarrollada en Lincoln, Provincia de Buenos Aires, Argentina. Este concurso procura mejorar la industria hípica, donde la Doma es el pilar fundamental para todas las actividades ecuestres. Para este estudio se tomaron en cuenta los puntajes de los 21 finalistas. Los participantes concursaron con un equino de 30 meses de edad de raza Polo Argentino, que no debe haber sido montado 6 meses previo a la revisión. El jurado se conformó por 3 expertos. La competencia estaba integrada por 10 etapas: 1) Abrir/cerrar (AC); 2) Figura (Fig); 3) Paradas (Pa); 4) Andares (And); 5) Presentación (Pres); 6) Mansedumbre (Mans); 7) Movimiento/libre/doma (MLD); 8) Corrida/parada (CP); 9) Movimiento/libre/polo (MLP); 10) Corrida/parada/reculada (CPR). Las pruebas se analizaron mediante el coeficiente de correlación de Pearson. Se consideró un intervalo de confianza 95%. Se destacan las siguientes correlaciones: CP/Pres 0,52 p=0,015; CPR/MLD 0,52 p=0,016; And/Fig 0,58 p< 0,01; Pres/Fig 0,58 p< 0,01; MLP/MLD 0,57 p< 0,01; CPR/CP 0,57 p< 0,01; CP/MLD 0,64 p< 0,01. Las 3 etapas que no figuran dentro de las correlaciones son la 1, 3 y 6, que se corresponden con pruebas que en su ejecución estaban asociadas a evaluar la mansedumbre general y la boca. Esto podría reflejar la posibilidad de que las pruebas sean redundantes en su ejecución o bien que los jurados terminen evaluando lo mismo. A futuro, podría plantearse la posibilidad de reducir el número de etapas del concurso o bien reformularse para poder evaluar otros aspectos importantes.Fil: Alvarez, R. P.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Demyda-peyrás, Sebastian. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arroyo, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Trigo, Pablo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaXXII Jornadas de Divulgación Técnico-Científicas FCV-UNR 2022CasildaArgentinaUniversidad Nacional de Rosario. Facultad de Ciencias Veterinaria

Breeding beef cattle for an extended productive life: Evaluation of selection criteria in the Retinta breed

We characterized genetically the longevity and the productive life of beef cows considering three different traits: length of true life (LTL), the length of productive life (LPL) and a number of calvings (NC), in the Retinta breed. Data considered in the analysis were collected in 30 Spanish herds and consisted of 3,187 cows born between 1993 and 2013: 1,802 cows had complete information while 1,385 cows had censored information. Pedigree information accounted for 7,359 individuals and the genetic evaluation was performed under an animal model using the Weibull proportional hazard model for survival analysis. Results indicated that cow effects (age at first calving, herd, season-year of cow birth), as well as some calf effects (breed group, season-year of birth), were significant (P<0.05) for all traits; however, sex of calves did not affect the traits. The low heritabilities obtained for LTL and LPL (0.14 ± 0.01 and 0.14 ± 0.01 respectively) and modest heritability for NC (0.30 ± 0.01), suggest that a higher response to selection can be expected for NC than for LTL and LPL.Fil: Morales, R.. Universidad de Córdoba; EspañaFil: Phocas, F.. Institut National de la Recherche Agronomique; Francia. Université Paris-Saclay; FranciaFil: Solé, Marina. Université de Liège; BélgicaFil: Demyda-peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria ; ArgentinaFil: Menéndez Buxadera, Alberto. Universidad de Córdoba; EspañaFil: Molina, A. Universidad de Córdoba; Españ

Effect of cooling rate on sperm quality of cryopreserved Andalusian donkey spermatozoa

The aim of this study was to evaluate the effect of different cooling rates on post-thaw quality of cryopreserved donkey spermatozoa. Eighteen ejaculates from six adult Andalusian donkeys (three ejaculates per donkey) were collected using an artificial vagina. Pooled semen samples (two ejaculates per pool) were divided into three aliquots, and frozen in Gent freezing extender using three different cryopreservation protocols (P): P1 (conventional slow freezing, as control): semen pre-cooled in an Equitainer for 2 h and frozen in liquid nitrogen (LN2) vapour; P2 (controlled pre-freeze cooling rate): semen pre-cooled at a controlled rate for 73 min and frozen in LN2 vapour; and P3 (rapid freezing) semen frozen immediately in LN2 vapour. After thawing at 37 °C for 30 s, semen samples were assessed for motility, morphology, acrosome and plasma membrane integrity; spermatozoa were also tested for DNA integrity. Significant (P < 0.01) differences were found between the cryopreservation protocols for all sperm parameters evaluated, except for DNA integrity. Semen samples frozen using P2 showed significantly (P < 0.01) higher values for sperm motility, morphology, sperm membrane integrity, and acrosome integrity. On the contrary, P3 reduced sperm motility (P < 0.01) and increased the percentage of spermatozoa with damaged plasma membrane (P < 0.001). In our study, we demonstrated that the sperm of Andalusian donkey is particularly sensitive to the cooling rate used before freezing. Furthermore, Andalusian donkey semen can be successfully cryopreserved using controlled cooling rates combined with freezing in LN2 vapour.Fil: Demyda-Peyrás, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Universidad de Córdoba; EspañaFil: Bottrel, M.. Universidad de Córdoba; EspañaFil: Acha, D.. Universidad de Córdoba; EspañaFil: Ortiz, I.. Universidad de Córdoba; EspañaFil: Hidalgo, M.. Universidad de Córdoba; EspañaFil: Carrasco, J.J.. Centro de Selección y Reproducción Animal; EspañaFil: Gómez Arrones, V.. Centro de Selección y Reproducción Animal; EspañaFil: Gósalvez, J.. Universidad Autónoma de Madrid; EspañaFil: Dorado, J.. Universidad de Córdoba; Españ