We examined commercial growth curves of three sheep genotypes in a Second-Grade cooperative context, with Spanish Merino used as a maternal base, Fleischschaf as a paternal base, and crossbred (Fleischschaf x Merino) lambs as the commercial product. We included weight-age data collected from 2013 to 2016 for 9846 lambs of both sexes belonging to 14 herds across the three genotypes. Five of the most-cited models (Brody, von Bertalanffy, Verhulst, Logistic, and Gompertz) were applied to the data, using the determinative coefficient, mean square error, number of iterations, Akaike information coefficient, and the biological coherence of the estimated parameters as best-fitting criteria. The dataset included lamb weights at different ages and sexes, grouped across nine age levels, for a total of 23,299 wt records. Models were fitted according to non-linear regression. The von Bertalanffy model was found to best fit lambs of both sexes for the Spanish Merino breed, whereas the Verhulst model best fit Fleischschaf and crossbred lambs. Parameters of the best-fit curve and derived parameters (inflection age and weight, asymptotic value, growth rate, maturity degree) were estimated for all sex-genetic groups to examine capacities for use as complementary selection criteria in the breeding program, resulting in promising traits for this purpose. Our findings demonstrate that current crossbreeding strategies implemented at the OVISO cooperative, which seek complementarities and/or heterosis, are not achieving the expected results; therefore, we recommend a new strategy for the breeding program. We also found that artificially conceived Spanish Merino lambs exhibited better performance than those conceived naturally, likely due to superior genetics of carefully selected sires.

Stemming from The Worldwide Donkey Breeds Project, an initiative aiming at connecting international researchers and entities working with the donkey species, molecularly tested pedigree analyses were carried out to study the genetic diversity, structure and historical evolution of the Andalusian donkey breed since the 1980s to infer a model to study the situation of international endangered donkey breeds under the remarkably frequent unknown genetical background status behind them. Demographic and genetic variability parameters were evaluated using ENDOG (v4.8). Pedigree completeness and generation length were quantified for the four gametic pathways. Despite mean inbreeding was low, highly inbred animals were present in the pedigree. Average coancestry, relatedness, and non-random mating degree trends were computed. The effective population size based on individual inbreeding rate was about half when based on individual coancestry rate. Nei's distances and equivalent subpopulations number indicated differentiated farms in a highly structured population. Although genetic diversity loss since the founder generations could be considered small, intraherd breeding policies and the excessive contribution of few ancestors to the gene pool could lead to narrower pedigree bottlenecks. Long average generation intervals could be considered when reducing inbreeding. Wright's fixation statistics indicated slight inbreeding between farms. Pedigree shallowness suggested applying new breeding strategies to reliably estimate descriptive parameters and control the negative effects of inbreeding, which could indeed, mean the key to preserve such valuable animal resources avoiding the extinction they potentially head towards, making the present model become an international referent when assessing endangered donkey populations.

This paper studies the genetic importance of growth curve parameters and their relevance as selection criteria in breeding programmes of Segureño sheep. Logistic and Verhulst growth functions were chosen for their best fit to BW/age in this breed; the first showed the best general fit and the second the best individual fit. Live weights of 41 330 individuals from the historical archives of the National Association of Segureña Sheep Breeders were used in the analysis. The progeny of 1464 rams and 27 048 ewes were used to study the genetic and phenotypic parameters of growth curve parameters and derived traits. Reproductive management in the population consists in controlled natural mating inside every herd, with a minimum of 15% of the females fertilized by artificial insemination with fresh semen; with the purpose being the herd genetic connections, all herd genealogies are screened with DNA markers. Estimates of growth curve parameters from birth to 80 days were obtained for each individual and each function by the non-linear regression procedure using IBM SPSS statistics (version 21) with the Levenberg–Marquart estimation method. (Co)variance components and genetic parameters were estimated by using the REML/Animal model methodology. The heritability of mature weight was estimated as 0.41±0.042 and 0.38±0.021 with the logistic and Verhulst models, respectively, and the heritability of other parameters ranged from 0.41 to 0.62 and 0.37 to 0.61, with the models, respectively. A negative genetic correlation between mature weight and rate of maturing was found.

The genetic diversity and population structure of the Spanish Murciano-Granadina goat breed were assessed by pedigree data analysis, which is essential for addressing conservation and improvement breed programs. We analysed 24,444 pedigree data records for the Murciano-Granadina goat breed (797 males and 23,647 females), distributed across 49 herds, for the period from 1992 to 2006. The average generation interval based on the age of the parents at the birth of offspring was 2.77 +/- 1.33 years. Although the study did not identify a genetic bottleneck (f(a)/f(e) = 1.00), 50% of the genetic variability was provided by only 366 ancestors, which may contribute to future genetic bottlenecks if the current mating policy is maintained. The number of equivalent generations increased from 1995 to 1997, followed by a decrease until 1999, when returned to growth. This oscillation could have been affected by difficulties in recording the genealogical data for young animals. The average values of F and AR for the entire analysed pedigree were 0.180% and 0.03%, respectively. Only 0.74% of the animals were inbred, but a high average (24.68%) was observed. The average GCI was very low (1.64), indicating a small, unbalanced contribution of the founders in the population. The average inbreeding was lower than the AR value during the studied period for the entire population, which indicates low genetic variation between populations but large intra-herd genetic diversity. (C) 2016 Elsevier B.V. All rights reserved.

The extent of inbreeding as well as environmental factors such as parity order, age at kidding and contemporary group (herd-year-season) was evaluated for their effects on the total production of milk, fat, protein and dry extract in Murciano-Granadina goats in Spain. The pedigrees of 11,926 females were traced to calculate the inbreeding coefficient for each animal. The lactations of these 22,832 females were analysed, standardised to 210 days of lactation, and information on the whole milk, fat, protein and dry extract production was recorded. The least squares method was used, and fixed effects in the model included parity order, the age of goat at kidding and contemporary group, and the inbreeding rate as a continuous variable, considering linear and quadratic effects. Based on this model, only 1.18% of the animals presented inbreeding, and the average population was of low magnitude (0.24%). However, among inbred animals, the average was considered high (20.31%). The total average of milk, fat, protein and dry extract production is within the range considered normal for the breed. The variables of parity order, the age of goat at kidding and contemporary group, exerted a statistically significant influence on the milk production and composition traits. Inbreeding had a quadratic effect on total milk production with a minimum point at 10.59% of inbreeding. Inbreeding had a positive linear correlation with total fat and dry extract yield. There was no statistically significant effect of inbreeding on total protein production. In general, the inbreeding levels in the Murciano-Granadina goat population did not negatively affect milk traits in the evaluated period. (C) 2015 Published by Elsevier B.V.

Genetic parameters for harmony and gaits (walk, trot and canter) were estimated in the Hispano-Arabe horse breed. The data set included 12,957 records of 901 animals, collected from 2000 to 2014, and was analysed by Bayesian procedures (Gibbs Sampling) and Restricted Maximum Likelihood. The multivariate animal model with repeated records included management group, sex, combination of year and event of evaluation, season of evaluation as fixed effect, plus age at classification and proportion of Arabian genes as linear covariates and additive genetic, permanent environmental and judge as random effects. Bayesian heritability/repeatability estimates for harmony, walk, trot and canter were 0.18/0.35, 0.10/0.18, 0.13/0.27 and 0.13/0.20, respectively, with standard errors from 0.02 to 0.05. Estimates of additive genetic correlations among harmony and gaits traits ranged from 0.45 to 0.83, and were stronger between harmony and trot or canter than between walk and trot. Analyses by Restricted Maximum Likelihood yielded similar results, and correlations between breeding values estimated by both procedures ranged from 0.80 to 0.94.

Non-linear models were analysed to describe both the biological and commercial growth curves of the Segureña sheep, one of the most important Spanish breeds. We evaluated Brody, von Bertalanffy, Verhulst, logistic and Gompertz models, using historical data from the National Association of Segureña Sheep Breeders (ANCOS). These records were collected between 2000 and 2013, from a total of 129 610 weight observations ranging from birth to adulthood. The aim of this research was to establish the mathematical behaviour of body development throughout this breed’s commercial life (birth to slaughter) and biological life (birth to adulthood); comparison between both slopes gives important information regarding the best time for slaughter, informs dietary advice according to animals’ needs, permits economical predictions of productions and, by using the curve parameters as selection criteria, enables improvements in growth characteristics of the breed. Models were fitted according to the non-linear regression procedure of statistical package SPSS version19. Model parameters were estimated using the Levenberg–Marquardt algorithm. Candidate models were compared using the determinative coefficient, mean square error, number of iterations, Akaike information coefficient and biological coherence of the estimated parameters. The von Bertalanffy and logistic models were found to be best suited to the biological and commercial growth curves, respectively, for both sexes. The Brody equation was found to be unsuitable for studying the commercial growth curve. Differences between the parameters in both sexes indicate a strong impact of sexual dimorphism on growth. This can emphasize the value of the highest growth rate for females, indicating that they reach maturity earlier.

Para estudiar el efecto del área de distribución de las ganaderías sobre los caracteres de crecimiento del ovino segureño fue utilizada la información de los registros de control de rendimientos obtenidos por la Asociación Nacional de Criadores de Ovino Segureño – ANCOS – durante los años comprendidos entre 2000 y 2011, y que constaron de un total de 129.377 pesadas realizadas sobre 60.461 individuos pertenecientes a 213 ganaderías. Fueron localizadas las ganaderías en 3 zonas geográficas con la finalidad de estudiar el efecto del área de ubicación geográfica sobre los caracteres de peso del ovino segureño, tomado en las distintas edades de referencia: peso al nacimiento, destete temprano (30 días), destete tardío (45 días) y sacrificio (75 días). Este análisis también fue realizado en los corderos clasificados por sexo. Se ha observado que el área de distribución tiene influencia sobre el peso de los corderos de raza ovina Segureña a las distintas edades de referencia y también cuando clasificados por sexo. Fue utilizado el programa ArcGis version 9.3.1. y el paquete estadístico IBM SPSS Statistics v.19 para el cálculo de las informaciones presentadas.

The lactation curve of Murciano-Granadina goats was studied by using records collected between 2004 and 2010 under its Official Dairy Recording program, which includes three milking control programs (Granada, Almeria and Cordoba). A total of 518,557 test-day records corresponding to 69,330 lactations by 38,039 does in 130 herds were included in the analyses. Different mathematical models were fitted, and average curves for region of production, parity, kidding season and type of kidding were estimated. A quadratic spline function gave the best fitting performance and provided a good description of the Murciano-Granadina lactation curve. All the factors studied affected both the scale of the lactation curve and its shape, with more distinct curves in first lactations, goats kidding in the summer and those producing singletons. When compared with later parities, first-parity does had a lower initial level of production, later and lower peak yield, and a smaller decline in milk production after the peak. Goats kidding in the Summer had a steep increase in milk yield up to the peak, which occurred earlier and with a higher yield than in other seasons, but seasonal effects differed slightly among regions. The lactation curve was flatter and with a later peak in goats producing single kids, and a steeper increase in yield up to the peak was observed as the number of kids increased.