Heritability of reproduetive traits in Asturiana de los Valles beef cattle breed

Heritability was estimated for four reproduetive traits in the Asturiana de los Valles breed in order to evaluate the possibility of include this information in the breed's current improvement program. The estimations were done using an animal model except for calving ease score. For this last trait, a threshold model under a sire model was fitted, with the sire effect as the only random effect in the model besides the residual. Estimated heritabilities for calving interval age at first calving, gestation length, as dam traits, and calving ease were 0.12, 0.27, 0.15 and 0.42, respectively. The estimated heritability for calving interval and age at first calving could justify a sire selection program in the Asturiana de los Valles breed taking account their female offsprings' reproduetive characteristics. Heritability estimates for gestation length and calving ease suggested a close genetic relationship of these two traits and birth weight. Further research is needed to estimate the genetic (co)variances between these three traits to allow the use of this information in a breed improvement program to reduce dystocia without affecting preweaning growth traits.Es erfolgten Heritabilitätsschätzungen bei vier Reproduktionsmerkmalen von Rindern der Rasse „Asturiana de los Valles". Es sollten die Möglichkeiten einer Verbesserung der Merkmale bei Einbeziehung dieser in ein Zuchtprogramm geprüft werden. Die Schätzungen erfolgten mittels Tiermodell. Die h2 Schätzwerte für die Merkmale Zwischenkalbezeit, Erstkalbealter, Trächtigkeitsdauer und Kalbeverlauf werden vorgestellt und diskutiert. Sie rechtfertigen die Einbeziehung ausgewählter Merkmale in das Zuchtprogramm zur züchterischen Verbesserung dieser Population. Das gilt besonders ftlr die Reduzierung von Schwergeburten ohne Einbuße von Wachstumsleistungen

Estimation of genetic parameters of type traits in Asturiana de los Valles beef cattle breed

Ten type traits and a final score were analysed in 5868 records of the Asturiana de los Valles beef cattle breed. Traits were grouped into two classes: (i) traits scoring skeletal and muscular development and (ii) traits scoring adjustment to the breed standard. Heritabilities were moderate to low, ranging from 0.04 to 0.26. Genetic correlations among traits were, in general, in the same direction as, but higher than, phenotypic correlations. The genetic variability shown, in general, for the analysed traits would justify the inclusion of morphological assessment in the Asturiana de los Valles beef cattle breed sire selection programme. Main characteristics of the current type classification system are criticized. The knowledge of (co)variances among type and economically important productive and reproductive traits is recommended before revision of the classification methodology.5868 registrierte Asturiana de los Valles Tiere wurden bezu¨ glich 10 Exterieurmerkmalen und eines Gesamtwertes auf der Basis einer gewichteten Beru¨ cksichtigung dieser Einzelmerkmale untersucht. Die Merkmale wurden in zwei Klassen unterteilt: (i) Merkmale, die Skelett- und Muskelentwicklung betreffen und (ii) rassespezifische Merkmale. Die Heritabilita¨ten lagen zwischen 0,04 und 0,26. Genetische Korrelationen zwischen den Merkmalen waren allgemein mit den pha¨notypischen Korrelationen gleichgerichtet, aber mit ho¨ heren Werten. Die aufgezeigte genetische Variabilita¨t der untersuchten Merkmale wu¨ rde deren Eingliederung in die morphologische Bewertung im Rahmen des Asturiana de los Valles Fleischrinder Selektionsprogrammes fu¨ r Bullen rechtfertigen. Wichtige Charakteristika der gegenwa¨rtigen Exterieurbeurteilung werden kritisiert. Es wird empfohlen erst (Ko-)varianzen zwischen Exterieur und o¨ konomisch wichtigen Produktions- und Reproduktionsmerkmalen zu ermitteln, bevor die Bewertungsmethodik u¨ berarbeitet wird

Estimation of direct and maternal genetic parameters for pre-weaning traits in the Asturiana de los Valles beef cattle breed through animal and sire models

Estimates of variance components for birth weight, weaning weight and average daily gain were obtained comparing different animal and sire univariate models for an important local beef cattle breed. Problems encountered with models involving maternal effects were discussed. Direct and maternal heritabilities were respectively 0.32 and 0.13 for birth weight, 0.60 and 0.30 for weaning weight and 0.49 and 0.37 for average daily gain. The correlation between direct and maternal genetic effects was not important for birth weight, but high and negative for weaning weight (-0.73), and average daily gain (-0.87), in close agreement with the most recent estimates in other breeds

Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

A total of 42,197 records of test-day milk yield (TDY) and 7654 lactations from 3854 individuals belonging to the Spanish Assaf (Assaf.E) breed were analysed using univariate and multivariate models to estimate genetic parameters affecting TDY, total milk yield standardised to 180 days (MY180) and lactation length (LL) in order to asses their possibilities of use in the selection scheme of the Assaf.E population. Estimates of h2 were, in general, on the lower limit of those usually reported for the three analysed traits. Estimates of heritability for MY180 varied from 0.131 to 0.177. Estimates of h2 for LL and TDY were consistent regardless the estimation model being of, roughly, 5% and 10%, respectively. The estimates for the permanent environmental effect (c2) of TDY were consistently the same (0.27–0.28) regardless the fitted model whilst they showed large differences for LL and MY180. Genetic correlations were always positive and high ranging from 0.792 for the pair LL-TDY to 0.999 for the pair MY180-TDY. Correlations between permanent environmental effects were even higher ranging from 0.932 for the pair LL-MY180 and 0.999 for the pair MY180-TDY. The advantages of using TDY as selection criterion in the Assaf.E improvement scheme are discussed

Revealing the History of Sheep Domestication Using Retrovirus Integrations

The domestication of livestock represented a crucial step in human history. By using endogenous retroviruses as genetic markers, we found that sheep differentiated on the basis of their “retrotype” and morphological traits dispersed across Eurasia and Africa via separate migratory episodes. Relicts of the first migrations include the Mouflon, as well as breeds previously recognized as “primitive” on the basis of their morphology, such as the Orkney, Soay, and the Nordic short-tailed sheep now confined to the periphery of northwest Europe. A later migratory episode, involving sheep with improved production traits, shaped the great majority of present-day breeds. The ability to differentiate genetically primitive sheep from more modern breeds provides valuable insights into the history of sheep domestication

Genetic relationships among calving ease, gestation length, and calf survival to weaning in the Asturiana de los Valles beef cattle breed

The aim of this paper was to estimate the genetic relationships among calving ease (CE), calf survival (CS), and gestation length (GL) to assess the possibility of including this information in beef cattle breeding programs. A total of 35,395 field records were available for CE, 30,684 for GL, and 36,132 for CS from the Asturiana de los Valles beef cattle breed. The 3 traits were analyzed as traits of the calf fitting a multivariate linear mixed model. Estimates of heritability (+/-SE) for the direct genetic effects (CEd, GLd, and CSd) were 0.325 +/- 0.022, 0.331 +/- 0.026, and 0.226 +/- 0.018, respectively, whereas the estimates for maternal genetic effects (CEm, GLm, and CSm) were 0.066 +/- 0.018, 0.066 +/- 0.017, and 0.034 +/- 0.011. The estimates for the ratio of permanent environmental variance to phenotypic variance were CEc 0.090 +/- 0.011, GLc 0.066 +/- 0.011, and CSc 0.024 +/- 0.007. Genetic correlations between direct, maternal genetic, or permanent environmental effects involving CE and GL were, in general, positive and moderate, whereas those involving CE and CS were high. All were significant except for the pair CEm-GLm (0.277 +/- 0.172). Correlations between GL and CS were nonsignificant. Genetic correlations for CEd-CEm, GLd-GLm, and CSd-CSm were negative and high, ranging from -0.461 +/- 0.120 for GLd-GLm to -0.821 +/- 0.145 for CSd-CSm. The genetic correlations for CEd-CSm and for CSd-CEm were negative, significant, and high, whereas that for GLd-CEm was moderate (-0.323 +/- 0.124) and that for GLd-CSm was nonsignificant. The genetic correlations for GLm with the direct effects of the other traits were non-significant. Strong selection for CE will result in a significant correlated response in CS. Therefore, CE can be considered an early indicator of CS performance. The benefit of using GL as a correlated trait in a genetic evaluation with CE and CS seems limited

Pedigree information reveals moderate to high levels of inbreeding and a weak population structure in the endangered Catalonian donkey breed

The Catalonian donkey is one of the most endangered donkey breeds in the world. At present, five main subpopulations exist: AFRAC, which consists of many genetically connected Catalonian localities; Berga, which consists of a single herd located also in Catalunya but under private management; and three minor non-Catalonian subpopulations (Huesca, Sevilla and Toledo). In this study, we analysed the pedigree information of the Catalonian donkey herdbook to assess the genetic diversity and population structure of the breed. We found that the Catalonian donkey has suffered an important loss of genetic diversity and moderate to high increases of inbreeding because of the abuse of a few individuals in matings. This scenario is mainly characterized by the fact that both the effective number of founders and ancestors for the whole population was 70.6 and 27, respectively, while the equivalent number of founders was 146.5 and the number of ancestors explaining overall genetic variability was 93. In addition, only 14% of animals born between the 1960s and 1970s were significantly represented in the pedigree. Our results also show that subpopulations where breeders exchanged reproductive individuals had low levels of inbreeding and average relatedness. One subpopulation, Berga, was reproductively isolated and showed high levels of inbreeding (F = 7.22%), with average relatedness (AR = 6.61%) playing an important role in increasing the values of these coefficients in the whole pedigree. Using genealogical F-statistics we have found little evidence of population structuring (F(ST) = 0.0083) with major genetic differences among non-Catalonian subpopulations

Using artificial intelligence to design and implement a morphological assessment system in beef cattle

In this paper a methodology is developed to improve the design and implementation of a linear morphological system in beef cattle using artificial intelligence. The proposed process involves an iterative mechanism where type traits are successively defined and computationally represented using knowledge engineering methodologies, scored by a set of trained human experts and finally, analysed by means of four reputed machine learning algorithms. The results thus achieved serve as feed back to the next iteration in order to improve the accuracy and efficacy of the proposed assessment system. A sample of 260 conformation records of the Asturiana de los Valles beef cattle breed is shown to illustrate the methodology. Three sources of inconsistency were detected: (a) the existence of different interpretations of the trait’s definition, increasing the subjectivity of the assessment; (b) the narrow range of variation of some of the anatomical traits assessed; (c) the inclusion of some complex traits in the assessment system. In this sense, the reopening of the evaluated Asturiana de los Valles assessment system is recommended. In spite of the difficulty of collecting data from live animals, further implications of the artificial intelligence systems on morphological assessment are pointed out

Population history and genetic variability in the Spanish Arab Horse assessed via pedigree analysis

The studbook of the Spanish Arab Horse was analysed in order to assess the available genetic variability in the population via genealogical analyses and to ascertain the influence of different countries in the formation of the population. The Spanish Arab horse studbook could be traced back to the late 19th century with a total of 18,880 animals. A 15.7% (2965) of the registered individuals were Arab horses imported from foreign populations. The total number of founders was 1626: from these, 1495 individuals were identified as imported from foreign countries. The sum of the genetic contributions of the founders to the population revealed that those imported from the ‘Middle East’, Poland, the United Kingdom and Egypt had a higher importance in the formation of the Spanish Arab Horse, contributing, respectively, 36.4%, 18.7%, 11.9% and 9.1% of the genetic variability. The effective number of founders was 38.6 and the effective number of ancestors was 19 thus characterising the abusive use of a little number of individuals for reproduction. This was due to a breeding policy that included mating between relatives, but also due to the limited availability of reproductive individuals after the Spanish Civil War. The average inbreeding of the population was 7.0% (9.8% for the individuals born during 1995–2004). Individuals with very high levels of inbreeding (≥12.5%) were 17.7% in the whole population and 26.7% of the individuals born in the last decade. Positive genealogical FIS near 2% characterised a breeding policy including matings between relatives. No clear within-population differentiation (inferred via genealogical FST) could be assessed between sire lines (FST=0.01) and no differentiation between geographical areas existed. Overall, the Spanish Arab Horse can be described as a population without genetic subdivision and with a mating policy and historical constraints that reduced the available genetic variability regardless of the relatively large size of its founder population. The obtained information will be useful to implement a selection program in the Spanish Arab Horse

Individual increase in inbreeding allows estimating effective sizes from pedigrees.

We present here a simple approach to obtain reliable estimates of the effective population size in real world populations via the computation of the increase in inbreeding for each individual (delta Fi) in a given population. The values of delta Fi are computed as t-root of 1 (1 Fi) where Fi is the inbreeding coefficient and t is the equivalent complete generations for each individual. The values of delta F computed for a pre-defined reference subset can be averaged and used to estimate effective size. A standard error of this estimate of Ne can be further computed from the standard deviation of the individual increase in inbreeding. The methodology is demonstrated by applying it to several simulated examples and to a real pedigree in which other methodologies fail when considering reference subpopulations. The main characteristics of the approach and its possible use are discussed both for predictive purposes and for analyzing genealogies