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

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

Differences in preservation of canine chilled semen using simple sperm washing, single-layer centrifugation and modified swim-up preparation techniques

This study compared the efficacy of simple sperm washing (SW), single-layer centrifugation (SLC) and modified swim-up (SU) techniques in the preparation of dog spermatozoa for cooling. Eighteen ejaculates, collected from three dogs (six per dog), were pooled (three ejaculates per pool) and divided into three aliquots: (1) one aliquot was washed and cooled at 5°C for 72h, considered as control (SW-control), (2) the second aliquot was selected by SLC through Androcoll-C and subsequently cooled in the same way as the SW-control samples (SLC-AC) and (3) the last aliquot was selected by a modified SU method with Androcoll-C and cooled as mentioned above (SU-AC). Assessment of sperm motility, sperm morphology, sperm membrane integrity and acrosome integrity were performed on aliquots of fresh semen and chilled-rewarmed samples. Sperm membrane integrity and progressive motility were significantly (P0.05). The recovery rates were not significantly (P>0.05) different between SW-control, SLC-AC and SU-AC samples. Our results confirm that SU-AC may be a successful method for the preparation of dog spermatozoa for cooling.Fil: Dorado, J.. Universidad de Córdoba; EspañaFil: Gálvez, M.J.. 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; Argentina. Universidad de Córdoba; EspañaFil: Ortiz, I.. Universidad de Córdoba; EspañaFil: Morrell, J.M.. Swedish: Sveriges Lantbruksuniversitet; SueciaFil: Crespo, F.. Ministerio de Defensa. Fondo de Explotación de los Servicios de Cría Caballar y Remonta. Centro Militar de Veterinaria de la Defensa; EspañaFil: Gósalvez, J.. Universidad Autónoma de Madrid; EspañaFil: Hidalgo, M.. Universidad de Córdoba; Españ

Impact of reproductive biotechnologies on genetic variability of Argentine Polo horses

The Argentine Polo Horse (AP), an autochthonous breed officially created in Argentina in the early 1980s, is globally recognized as the best equid for playing polo. Their breeding is characterized by the use of cutting-edge assisted reproductive techniques such as large-scale embryo transfer (ET) programs and cloning. The aim of this study was to determine the impact of the use of those reproductive biotechnologies on the genetic structure, variability and reproductive parameters of the AP breed using genealogical data (81,633 pedigree records). In total, 18,077 animals drawn from the last generation (2006–2015) were employed as the reference population (WP), which was further divided into two subsets: animals produced (ET; n = 13,478) and not produced by ET (NOT-ET; n = 4,599). Horses produced by ET showed a significant decrease in generation interval compared with NOT-ET. On the other hand, the number of foals per stallion and broodmare as well as inbreeding (F = 0.89%) and average relatedness (AR=1%) were higher in ET compared with NOT-ET (F = 0.6%; AR = 0.54%), depicting an increased selective intensity. Our analysis also revealed that the effective number of founders and ancestors in ET showed a disproportionate gene contribution and a strong genetic bottleneck as well as the inter-herd fixation index (FST) revealed an increased genetic flow among herds and higher internal relatedness values within ET horses. In conclusion, the use of large-scale ET programs decreased genetic variability (lower effective population size and number of founders and ancestors and higher F, AR and coancestry), increased the genetic flow among herds and decreased the generation interval, contributing to the possibility of higher rates of genetic progress in the AP.Fil: 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: Valera Córdoba, Mercedes. Universidad de Sevilla; EspañaFil: Molina, Antonio. Universidad de Córdoba; EspañaFil: 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; ArgentinaFil: Peral Garcia, Pilar. 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: Solé, Marina. Swedish University of Agricultural Sciences; SueciaFil: 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

Sex chromosomal abnormalities associated with equine infertility: validation of a simple molecular screening tool in the Purebred Spanish Horse

Chromosomal abnormalities in the sex chromosome pair (ECAX and ECAY) are widely associated with reproductive problems in horses. However, a large proportion of these abnormalities remains undiagnosed due to the lack of an affordable diagnostic tool that allows for avoiding karyotyping tests. Hereby, we developed an STR (single-tandem-repeat)-based molecular method to determine the presence of the main sex chromosomal abnormalities in horses in a fast, cheap and reliable way. The frequency of five ECAX-linked (LEX026, LEX003, TKY38, TKY270 and UCDEQ502) and two ECAY-linked (EcaYH12 and SRY) markers was characterized in 261 Purebred Spanish Horses to determine the efficiency of the methodology developed to be used as a chromosomal diagnostic tool. All the microsatellites analyzed were highly polymorphic, with a sizeable number of alleles (polymorphic information content > 0.5). Based on this variability, the methodology showed 100% sensitivity and 99.82% specificity to detect the most important sex chromosomal abnormalities reported in horses (chimerism, Turner's syndrome and sex reversal syndromes). The method was also validated with 100% efficiency in 10 individuals previously diagnosed as chromosomally aberrant. This STR screening panel is an efficient and reliable molecular–cytogenetic tool for the early detection of sex chromosomal abnormalities in equines that could be included in breeding programs to save money, effort and time of veterinary practitioners and breeders.Fil: Anaya, G.. Universidad de Córdoba; EspañaFil: Molina, A.. Universidad de Córdoba; EspañaFil: Valera, Maria Analia. Universidad de Sevilla; EspañaFil: Moreno Millán, Miguel. Universidad de Sevilla; EspañaFil: Azor, P.. Universidad de Sevilla; EspañaFil: Peral Garcia, Pilar. 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: 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