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The aim of this study was to describe the population structure of Morada Nova sheep breed using pedigree analysis to support development strategies for conservation and breeding programs. Data was available on 10,015 Morada Nova animals born between 1973 and 2014, registered by ARCO (Brazilian Association of Sheep Breeders). The animals were divided into three categories: (1) Base: animals of unknown origin showing strong breed morphology; (2) Prov: animals with genealogy control for one (Prov I), two (Prov II) or three (Prov III) complete generations; (3) PO: animals with four or more complete generations of controlled genealogy. Data was analyzed using the ENDOG software v4.8 to determine individual inbreeding (F), effective population size (Ne), effective number of founders (fe), effective number of ancestors (fa) and number of founder genome equivalents (fg), generation intervals (Int) and genetic conservation index (GCI), of the Morada Nova sheep breed. The Base population (one or more unknown parents) contained 4,709 animals. Only 53.03% and 52.98% had known sire and dam, respectively. Most animals were found in the Brazilian Northeast, but in recent years numbers have increased in Sao Paulo State. Generation interval in this breed was approximately 3.6 years. Most farms buy rams or semen which helps maintain low inbreeding levels, as well as using their own rams. There is a need to increase registration beyond Base animals and use pedigree to avoid crosses between related animals. Nevertheless, no immediate problems were seen for maintenance of genetic diversity within the Morada Nova sheep breed.

The objectives of this study were to achieve phenotypic characterization of three domestic Egyptian goose populations collected from three different geographical zones (Kafr El-Sheikh, Fayoum and Luxor) and to perform genetic characterization of these three populations based on mtDNA D-loop and 12 microsatellite markers. The body measurements of 402 domestic mature geese belonging to these three governorates showed that the lengths of the head, culmen and tarsus and the live body weight varied significantly among the three studied Egyptian goose populations. After alignment of a 710-base-pair segment of the goose mtDNA control region, there was a single haplotype in the three Egyptian goose populations, indicating the same maternal origins. The genotyping of the 12 microsatellite markers showed low diversity indices, including average observed (NA) and effective (NE) number of alleles and observed (HO) and expected heterozygosity (HE) (3.333, 1.760, 0.277 and 0.352, respectively), and a high inbreeding coefficient (FIS = 0.203) across the three Egyptian goose populations. The high inbreeding and low genetic and morphological differentiation of Egyptian geese could be corrected by establishing a large base population through capturing small populations with the highest genetic variation. The findings of the current study can therefore serve as an initial guide to design further investigations for developing conservation programs of Egyptian geese genetic resources.

Data for birth weight (BW), lamb survival (LS) and neonatal behaviour, including records of between 1494 (latency of birth to first suckling or LBS) and 2705 (BW and LS) lambs were used. Additionally to the lamb data, ewe data comprising of between 1003 ewe-year records for the latency of stay on the birth site (SBS) and 2024 ewe-year records for number of lambs weaned per ewe mated (NLW) were analysed. These records were from selection lines that had been divergently selected from the same base population since 1986, either for NLW (termed the High or H line) or against NLW (termed the Low or L line). Overall, H line lambs had an improved LS compared to their L line contemporaries, while H line ewes were superior to L line ewes for NLW. Latency of parturition of H line progeny was shorter than in L line progeny while ewe lambs had shorter births than ram lambs. Lamb sex and selection line had no effect on the latency from birth to suckling, which decreased as dam age increased. The second of multiples took longest to progress to suckling from birth, with singles being the quickest. H line ewes had shorter parturitions and cooperated better with the first suckling attempts of their offspring. Single-trait direct heritability estimates (h²) in lambs were 0.15 for BW, 0.07 for LS, 0.06 for latency of parturition (LP) and 0.14 for LBS. The inclusion of the maternal genetic variance ratio (m²) resulted in an improvement in the log likelihood ratio for BW, LP and LBS, yielding estimates of respectively 0.37, 0.18 and 0.12. The maternal permanent environment variance ratio for LS amounted to 0.07. The genetic correlation of LS with LP was favourable at -0.69. Estimates of h², as ewe traits, were 0.04 for NLW, 0.17 for LP, 0.07 for ewe cooperation score (ECS) and 0.20 for SBS. Genetic correlations indicated that ewes with a high NLW had shorter parturitions while ECS was genetically correlated to SBS. Genetic trends suggested divergence between the lines for breeding values for LP, suggesting that parturitions became shorter in the H line and longer in the L line. Selection for NLW would yield desirable outcomes for ewe and lamb behavioural traits based on genetic trends and correlations. Such selection would putatively benefit animal welfare by reducing birth stress in ewes and lambs and by promoting maternal cooperation with their offspring’s first suckling attempts in ewes.

Summary Quantifying and predicting microevolutionary responses to environmental change requires unbiased estimation of quantitative genetic parameters in wild populations. ‘Animal models’, which utilize pedigree data to separate genetic and environmental effects on phenotypes, provide powerful means to estimate key parameters and have revolutionized quantitative genetic analyses of wild populations.However, pedigrees collected in wild populations commonly contain many individuals with unknown parents. When unknown parents are non‐randomly associated with genetic values for focal traits, animal model parameter estimates can be severely biased. Yet, such bias has not previously been highlighted and statistical methods designed to minimize such biases have not been implemented in evolutionary ecology.We first illustrate how the occurrence of non‐random unknown parents in population pedigrees can substantially bias animal model predictions of breeding values and estimates of additive genetic variance, and create spurious temporal trends in predicted breeding values in the absence of local selection. We then introduce ‘genetic group’ methods, which were developed in agricultural science, and explain how these methods can minimize bias in quantitative genetic parameter estimates stemming from genetic heterogeneity among individuals with unknown parents.We summarize the conceptual foundations of genetic group animal models and provide extensive, step‐by‐step tutorials that demonstrate how to fit such models in a variety of software programs. Furthermore, we provide new functions in r that extend current software capabilities and provide a standardized approach across software programs to implement genetic group methods.Beyond simply alleviating bias, genetic group animal models can directly estimate new parameters pertaining to key biological processes. We discuss one such example, where genetic group methods potentially allow the microevolutionary consequences of local selection to be distinguished from effects of immigration and resulting gene flow.We highlight some remaining limitations of genetic group models and discuss opportunities for further development and application in evolutionary ecology. We suggest that genetic group methods should no longer be overlooked by evolutionary ecologists, but should become standard components of the toolkit for animal model analyses of wild population data sets.

International audience; AbstractBackgroundA common measure employed to evaluate the efficacy of livestock improvement schemes is the genetic trend, which is calculated as the means of predicted breeding values for animals born in successive time periods. This implies that different cohorts refer to the same base population. For genetic evaluation schemes integrating genomic information with records for all animals, genotyped or not, this is often not the case: expected means for pedigree founders are zero whereas values for genotyped animals are expected to sum to zero at the (mean) time corresponding to the frequencies that are used to center marker allele counts when calculating genomic relationships.MethodsThe paper examines estimates of genetic trends from single-step genomic evaluations. After a review of methods which propose to align pedigree-based and genomic relationship matrices, simulation is used to illustrate the effects of alignments and choice of assumed gene frequencies on trajectories of genetic trends.ResultsThe results show that methods available to alleviate differences between the founder populations implied by the two types of relationship matrices perform well; in particular, the meta-founder approach is advantageous. An application to data from routine genetic evaluation of Australian sheep is shown, confirming their effectiveness for practical data.ConclusionsAligning pedigree and genomic relationship matrices for single step genetic evaluation for populations under selection is essential. Fitting meta-founders is an effective and simple method to avoid distortion of estimates of genetic trends.

Background: Metafounders are pseudo-individuals that encapsulate genetic heterozygosity and relationships within and across base pedigree populations, i.e. ancestral populations. This work addresses the estimation and usefulness of metafounder relationships in single-step genomic best linear unbiased prediction (ssGBLUP). Results: We show that ancestral relationship parameters are proportional to standardized covariances of base allelic frequencies across populations, such as Fst fixation indexes. These covariances of base allelic frequencies can be estimated from marker genotypes of related recent individuals and pedigree. Simple methods for their estimation include naïve computation of allele frequencies from marker genotypes or a method of moments that equates average pedigree-based and marker-based relationships. Complex methods include generalized least squares (best linear unbiased estimator (BLUE)) or maximum likelihood based on pedigree relationships. To our knowledge, methods to infer Fst coefficients from marker data have not been developed for related individuals. We derived a genomic relationship matrix, compatible with pedigree relationships, that is constructed as a cross-product of {-1,0,1} codes and that is equivalent (apart from scale factors) to an identity-by-state relationship matrix at genome-wide markers. Using a simulation with a single population under selection in which only males and youngest animals are genotyped, we observed that generalized least squares or maximum likelihood gave accurate and unbiased estimates of the ancestral relationship parameter (true value: 0.40) whereas the naïve method and the method of moments were biased (average estimates of 0.43 and 0.35). We also observed that genomic evaluation by ssGBLUP using metafounders was less biased in terms of estimates of genetic trend (bias of 0.01 instead of 0.12), resulted in less overdispersed (0.94 instead of 0.99) and as accurate (0.74) estimates of breeding values than ssGBLUP without metafounders and provided consistent estimates of heritability. Conclusions: Estimation of metafounder relationships can be achieved using BLUP-like methods with pedigree and markers. Inclusion of metafounder relationships reduces bias of genomic predictions with no loss in accuracy. Fil: García Baccino, Carolina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina Fil: Legarra, Andres. Institut National de la Recherche Agronomique; Francia. Instituto Polytechnique de Toulouse; Francia. École Nationale Vétérinaire de Toulouse; Francia Fil: Christensen, Ole F.. University Aarhus; Dinamarca Fil: Misztal, Ignacy. University of Georgia; Estados Unidos Fil: Pocrnic, Ivan. University of Georgia; Estados Unidos Fil: Vitezica, Zulma G.. Institut National de la Recherche Agronomique; Francia. Instituto Polytechnique de Toulouse; Francia. École Nationale Vétérinaire de Toulouse; Francia Fil: Cantet, Rodolfo Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina

Inbreeding is the mating of relatives that produce progeny having more homozygous alleles than non-inbred animals. Inbreeding increases numbers of recessive alleles, which is often associated with decreased performance known as inbreeding depression. The magnitude of inbreeding depression depends on the level of inbreeding in the animal. Level of inbreeding is expressed by the inbreeding coefficient. One breeding goal in livestock is uniform productivity while maintaining acceptable inbreeding levels, especially keeping inbreeding less than 20%. However, in closed herds without the introduction of new genetic sources high levels of inbreeding over time are unavoidable. One method that increases selection response and minimizes inbreeding is selection of individuals by weighting estimated breeding values with average relationships among individuals. Optimum genetic contribution theory (OGC) uses relationships among individuals as weighting factors. The algorithm is as follows: i) Identify the individual having the best EBV; ii) Calculate average relationships ( [Formula: see text]) between selected and candidates; iii) Select the individual having the best EBV adjusted for average relationships using the weighting factor k, [Formula: see text]. iv) Repeat process until the number of individuals selected equals number required. The objective of this study was to compare simulated results based on OGC selection under different conditions over 30 generations. Individuals (n = 110) were generated for the base population with pseudo random numbers of N~ (0, 3), ten were assumed male, and the remainder female. Each male was mated to ten females, and every female was assumed to have 5 progeny resulting in 500 individuals in the following generation. Results showed the OGC algorithm effectively controlled inbreeding and maintained consistent increases in selection response. Difference in breeding values between selection with OGC algorithm and by EBV only was 8%, however, rate of inbreeding was controlled by 47% after 20 generation. These results indicate that the OGC algorithm can be used effectively in long-term selection programs.

Division of Animal Science, Gyeongsang National University, 501, Jinjudae-ro, Jinju-si, Gyeongsangnam-do, 660-701, KoreaABSTRACTThis study estimated the genetic parameters of growth-related traits from 11-month-old olive flounder(Paralichthys olivaceus) base population in which wild and cultured broodstocks were introduced. The heritability of body weight, total length, body height, body shape, and condition factor of the base population was estimated to be 0.754, 0.753, 0.789, 0.438, and 0.369, respectively. Genetic correlations between body weight and total length, between body weight and body height, and between total length and body height were 0.969, 0.960, and 0.960, respectively, showing highly positive correlation. Genetic correlations between body weight and body shape, between total length and body shape, between body height and body shape were 0.403, 0.344, and 0593, respectively, showing low negative correlation. Overall, olive flounder might be an appropriate selective breeding species with the high heritability of the traits in an 11-month-old population.(Key words : Olive flounder(Paralichthys olivaceus), Growth-related traits, Genetic parameter, Heritability, 11-month-old)

El objetivo fue analizar el pedigrí de cuatro ganaderías mexicanas (Los Encinos=ENC, Montecristo=MCR, Fernando de la Mora=FMO y San José=SJO) a través de estimaciones de parámetros poblacionales tales como el tamaño de población base, tamaño efectivo, número de ancestros, aportaciones porcentuales e intervalos generacionales. Además se analizó el efecto de la consanguinidad sobre el comportamiento de los animales (tienta y lidia al caballo y al torero) con un modelo animal que consideró como efectos fijos a grupo contemporáneo (año-época de nacimiento-sexo, el efecto de sexo sólo en tienta) y las covariables lineales de edad y consanguinidad del individuo; los efectos aleatorios fueron el valor genético del individuo y el error. Los pedigríes incluyeron de 3246 a 8279 animales nacidos entre 1904 y 2006; la información de comportamiento data de 1978 a 2006, variando de 202 a 2776 observaciones. Las consanguinidades promedio variaron entre 2,4% y 12,9%, con máximos individuales de 47,7% en MCR y de alrededor de 40% en las otras ganaderías. El número de ancestros como proporción de la población de referencia en MCR fue 12,3%, mientras que en FMO, ENC y SJO representaron 17,7%, 27,8% y 34,0%, respectivamente. Tres animales explicaron 50% del pedigrí en MCR y 13 o menos en las otras ganaderías. Los tres ancestros de MCR explicaron 22,6% y 20,2% del pedigrí de SJO y ENC, respectivamente. Las ganaderías MCR, SJO y ENC tienen un origen común. Las tendencias anuales de consanguinidad fueron negativas en ENC y SJO (-0,13±0,02 y -0,25±0,02, respectivamente; p

The objective of this study was to evaluate the effect of different defoliation frequencies on winter forage production and nutritive value of improved populations of Dactylis glomerata L. Four entries: (a) base population, (b) selected plants from mass honeycomb selection (MHS), (c) selected plants from pedigree honeycomb selection (PHS), and (d) selected plants from pedigree honeycomb selection using the combined criterion CC = x 2 (1 ‐ CV)/CV (PHS(CC)) were tested under four defoliation frequencies: (1) frequent, (2) moderate, (3) infrequent, and (4) control. Dry matter (DM) production under the frequent and moderate defoliation frequencies was 17% and 7% respectively more than under infrequent defoliation in the first year. However, in the second year, DM production under infrequent defoliation was 41% and 46% higher than under frequent and moderate defoliation, respectively. The DM production of the selected populations (b, c and d) of D. glomerata consistently exceeded that of the base popu...

Objetivou-se, com este trabalho, avaliar o comportamento do coeficiente de endogamia e do limite de seleção considerando população-base selecionada. Utilizou-se o programa GENESYS para a simulação do genoma constituído de uma única característica quantitativa com valor de herdabilidade igual a 0,40, população-base, população inicial e populações sob seleção. Foram consideradas três gerações distintas como gerações bases, gerações zero (G0PB), três (G3PB) e sete (G7PB). As populações foram selecionadas a partir dos valores genéticos obtidos pelo melhor preditor linear não-viesado (BLUP) e com base no desempenho individual, sendo considerados: a) dois tamanhos efetivos de população (Ne1 = 38,09 e Ne2 = 88,88) e b) dois sistemas de acasalamentos dos reprodutores selecionados (reprodutores acasalados aleatoriamente - RAA e exclusão de irmãos completos - EIC). Os parâmetros avaliados foram: coeficiente médio de endogamia, percentagem de locos fixados favoravelmente e limite de seleção. A não-utilização da população-base verdadeira (G0PB) subestimou os coeficientes de endogamia. As populações que utilizaram as gerações três e sete como base apresentaram as mesmas taxas de fixação de alelos favoráveis e os mesmos valores do limite de seleção das populações que consideraram a G0PB. Objective was to evaluate the behavior average inbreeding coefficient associated to the selection limit considering selected population as base population. GENESYS program was used for simulation of the genome (one trait of h2 = 0.40), base population, initial population and populations under selection. Three different generations were considered as base generations, zero (G0PB), three (G3PB) and seven (G7PB). Populations were selected based on best linear unbiased predictor (BLUP) and on individual phenotype in which were considered: a) two effective population sizes (Ne1 = 38.09 and Ne2 = 88.88) and b) two mating systems (random mating - RAA and exclusion of full sibs - EIC). Evaluated parameters were: average inbreeding coefficient, fixation of favorable alleles and selection limit. Selected populations considered as true base population resulted in underestimated inbreeding coefficient. Populations that used generations three and seven as true base population presented the same rates of fixation of favorable alleles and the same values for selection limit as those of populations that considered G0PB.

A divergent, eight generation selection experiment on uterine capacity in rabbits was performed. Rabbit does were ovariectomized unilaterally before puberty, and selected for increased and decreased litter size by ‘best linear unbiased prediction’ using data from up to four parities. Two different analyses were performed to estimate the response to selection. The first was based on least squares analysis; the second was based on Bayesian methods using Gibbs sampling techniques. Three different priors were used for variance components, but these had little influence on the results. Posterior means of heritabilities for uterine capacity, varied from 0.09 to 0.12, and repeatabilities from 0.18 to 0.22. The response to eight generations of selection was symmetrical and led to a divergence of 0.16 young rabbits per generation, which amounts to about 2% of the average litter size of the base population per generation. The pattern of response however, was not linear: a high initial response was followed by a period where little further response was observed, and a final burst of response was obtained during the last two cycles of selection. Analisis Bayesiona de la Respuesta a la seleccion por capacidad uterina en conejos Se llevo a cabo un experimento de seleccion divergente por capacidad uterina en conejos. Las conejas fueron ovariectomizadas unilateralmente antes de la pubertad, y fueron seguidamente seleccionadas para aumentar y disminuir el tamano de camada mediante un BLUP que incluia datos de hasta el cuarto parto. Se realizaron dos tipos de analisis para estimar la respuesta, el primero basado en minimos cuadrados y el segundo en tecnicas bayesianas con la ayuda de muestreo de Gibbs. Aunque tres a prioris diferentes fueron usados para las componentes de varianza, esto apenas influyo en los resultados, pues las medias posteriores para las heredabilidades variarton de 0.09 a 0.12 y las medias de las repetibilidades variaron de 0.18 a 0.22. La respuesta a ocho generaciones de seleccion fue simetrica y condujo a una diverjencia de 0.16 conejos por generacion, lo que representa un 2% de la media de la poblacion base por generacion. La respuesta no fue, sin embargo, lineal: una fuerte respuesta inicial fue seguida de un periodo de estancamiento y una nueva respuesta en los dos ultimos ciclos de seleccion. Eine Bayes Analyse zu Auswirkungen der Selektion auf uterine Kapazitat beim Kaninchen Ein Selektionsexperiment mit divergierender Selektion wurde uber acht Generationen durchgefuhrt. Die Zibben wurden vor der Geschlechtreife einseitig ovarektomiert und auf hohere und niedrigere Wurfgrose uber Best Linear Unbiased Prediction (BLUP) selektiert. Daten von bis zu vier Trachtigkeiten wurden verwendet. Zwei verschiedene Analysen wurden verwendet um den Selektionserfolg zu bestimmen. Die erste basierte auf der Least Square Analyse, die zweite auf der Bayes Methode des Gibbs Sampling. Drei verschiedene Priors wurden in der Varianzkomponentenschatzung verwendet, aber sie hatten wenig Einfluss auf die Endergebnisse. Die a posteriori Ergebnisse fur die Heritabilitaten der uterinen Kapazitat variierten von 0,09 bis 0,12, die Wiederholbarkeiten von 0, 18 bis 0,22. Die Selektionserfolg uber acht Generationen war symmetrisch und fuhrte zu einem Unterschied von 0,16 Jungtieren pro Generation, was ca. 2% der durchschnittlichen Wurfgrose, bezogen auf die Basispopulation je Generation, entspricht. Das Bild des Zuchtfortschritts war nicht linear: nach einem hohen Anfangserfolg wurde eine Periode geringen Erfolges beobachtet und ein Ende des Zuchtfortschrittes wurde in den letzten zwei Generationen erreicht.

Full-sib and selfed (S1) progenies were obtained from sub-populations of ESALQ-PB1, divergently selected for tassel size (T+ and T-) and ear height (E+ and E-), and used for estimating genetic and phenotypic correlation coefficients between traits. The analyzed traits were: EW- total ear weight (g/plant), PH- plant height (cm), EH- ear height (cm), TB- tassel branch number and TL- tassel length. The highest genetic (rG) and phenotypic (rF) correlation was observed for the combination PH x EH, as expected, with average of 0.800 and 0.778, respectively over sub-populations and locations. It is apparent that divergent selection for tassel size did not affect greatly the correlation between PH and EH in the full sib progenies, but in the inbred progenies the correlation was smaller in the sub-population selected for larger tassels. Genetic correlation between PH and EH with tassel traits was always positive but ranged from 0.020 to 0.668 in Piracicaba and from 0.06 to 0.309 in Rio Verde. Genetic correlation between PH and EH with yield (EW) also was positive in the range of 0.087 to 0.503. EH showed higher correlation with EW in relation to PH x EW and differences were larger in the sub-populations divergently selected for ear height. Correlation between tassel traits with other traits was positive in most of instances and a lack of consistency was observed among sub-populations. Generally the coefficients of genetic and phenotypic correlation differed substantially from the estimates in the base population ESALQ-PB1 before divergent selection for tassel size and ear placement. Divergent selection affected the correlation between traits under unpredicted and varying magnitudes. Progênies de irmãos germanos e de autofecundação (S1) foram obtidas de sub-populações de ESALQ-PB1 após seleção divergente para tamanho do pendão (T+ e T-) e altura da espiga (E+ e E-) e utilizadas para estimar os coeficientes de correlação genética e fenotípica entre caracteres. Foram analisados os caracteres: EW- peso de espigas (g/planta), PH- altura da planta (cm), EH- altura da espiga (cm), TB- número de ramificações do pendão e TL- comprimento do pendão. Como esperado, as maiores correlações genéticas (rG) e fenotípicas (rF) foram observadas para a combinação PH x EH, com médias de 0,800 e 0,778 , respectivamente, em várias sub-populações e locais. Aparentemente, a seleção divergente para tamanho do pendão não afetou fortemente a correlação entre PH e EH nas progênies de irmãos germanos, mas nas progênies endogâmicas a correlação foi menor na sub-população selecionada para pendão grande. A correlação genética entre PH e EH com os caracteres do pendão foram sempre positivas mas variaram de 0,020 a 0,068 em Piracicaba e de 0,060 a 0,309 em Rio Verde. A correlação genética entre PH e EH com produção (EW) também foi positiva, na faixa de 0,087 a 0,503. EH mostrou maior correlação com EW em relação a PH x EW e as diferenças foram maiores nas sub-populações que sofreram seleção divergente para altura da espiga. A correlação entre os caracteres do pendão com outros caracteres foi positiva na maioria dos casos e uma falta de consistência foi observada entre sub-populações. Em geral, os coeficientes de correlação genética e fenotípica diferiram substancialmente das estimativas na população base ESALQ-PB1 antes da seleção divergente para tamanho do pendão e posição da espiga. A seleção divergente afetou a correlação entre caracteres sob magnitudes imprevisíveis e variáveis.

Valores genéticos foram preditos usando-se a iteração nos dados em um modelo animal reduzido. O peso corporal, aos 35 dias de idade, de duas linhas de aves de corte foi medido em duas gerações, cujo arquivo de dados consistia de 1044 pais (população-base), 829 progênies-pais e 9039 progênies-não-pais. O número de iterações e o tempo de processamento, para obtenção das soluções das equações de modelo misto via iteração nos dados, foram avaliados por sete critérios de convergência (10¹ a 10-5 ). Seis iterações foram necessárias, com 9 s de tempo, e 158 iterações, com 5 min e 38 s, para se obterem as soluções para os critérios de convergência de 10¹ e 10-5, respectivamente. As correlações entre os valores genéticos preditos foram perfeitas (r=1,00), e não houve diferenças entre as tendências genéticas estimadas pelos critérios de convergência de 10-1 a 10-5. Com base nestes resultados, conclui-se que a iteração nos dados pode ser eficientemente usada em microcomputadores, na avaliação genética animal, sem grande demanda de tempo e memória computacional. Breeding values were predicted by iterating on data using reduced animal model. Body weight at 35 days of age from two lines of meat-type chickens was measured in two generations and data file was consisted on 1044 parents (base population), 829 progeny parents and 9039 progeny non-parents. The number of iterative rounds and processing time for mixed model equations solutions via iterating on data were evaluated using seven convergence criteria (10¹ to 10-5). A total of six rounds of iteration and 9 s of time and 158 rounds and 5 min and 38 s were required to reach the solutions for 10¹ and 10-5 convergence criteria, respectively. The correlation between predicted breeding values were perfect (r=1,00) and there were no significant differences between estimated genetic trends using 10-1 to 10-5 as a convergence criteria. Based on these results, it was concluded that iterating on data could be efficiently used for animal genetic evaluation in microcomputer without great computational requirements.

Broilers that survived unilateral pulmonary artery occlusion and lived to maturity comprised the first generation (GEN1) of an ascites-resistant line. Progeny from the GEN1 line previously were shown to tolerate fast growth and cool temperatures with a 50% lower incidence of ascites than chicks from the breeder pullet line serving as the base population for the resistant line. In the present study, progeny from the GEN1 line were subjected to unilateral pulmonary artery occlusion, and survivors were reared to breeding age to serve as the parent stock for the second generation (GEN2) ascites-resistant line. In two experiments (EXP1 and 2), chicks were reared separately by sex but were mixed by line within environmental chambers, where they were grown as rapidly as possible and exposed to cool (14 C) temperatures from 17 to 49 d of age. In EXP1, the ascites incidences in the base population, GEN1, and GEN2 lines, respectively, were 31% (48/157), 15% (8/52), and 4% (3/69) for males and 10% (13/128), 11% (5/46), and 3% (1/36) for females. In EXP2, the ascites incidences in the base and GEN2 lines, respectively, were 44% (71/163) and 6% (7/110) for males and 12% (19/155) and 0% (0/92) for females. The final BW for nonascitic broilers did not differ across lines in EXP1. In EXP2, the final BW was lighter for nonascitic GEN2 males (2,915±43 g) and females (2,382±17 g) than for nonascitic base population males (3,088±42 g) and females (2,493±22), respectively. Right:total ventricular weight ratios were higher for ascitic than nonascitic broilers, confirming the primary role for pulmonary hypertension in the pathogenesis of ascites. These experiments demonstrate ongoing improvement in the ascites resistance of progeny from broiler breeders that, for two consecutive generations, have survived the rigorous selection pressure imposed by unilateral pulmonary artery occlusion.

Merino lines that were divergently selected from the same base population from 1986 to 2009 for their ability to rear multiples were assessed for dag score in autumn and spring, breech wrinkle score, and crutching time. Animals in the Low (L) line had higher dag and breech wrinkle scores and took longer to be crutched than High (H) line contemporaries. Expressed relative to H line least squares means, means of L line individuals were respectively 54%, 65%, 42% and 40% higher for autumn dag score, spring dag score, breech fold score, and crutching time. Gender effects for dag score were inconclusive, as ewe hoggets were more daggy than rams in autumn, with an opposite trend in spring. Shearer (n = 6) also affected crutching times, with an almost twofold difference in mean crutching time from the quickest shearer (27.7 ± 3.1 seconds) to the slowest shearer (49.4 ± 3.7 seconds). The inclusion of dag score and breech wrinkle score as linear covariates in an analysis on crutching time eliminated the effect of selection line. It thus seems that the quicker crutching times of H line animals may be related to line differences for dag score and, to a lesser extent, for breech wrinkle score.Keywords: Reproduction, selection lines, shearing time, wrinkle

A study was conducted to determine BW, feed intake, feed efficiency, and carcass composition changes following 51 generations of selection for high 4-wk BW in Japanese quail. Quail lines utilized were the P line selected for high 4-wk BW on a normal 28% CP diet and the unselected base population (C line) from which the P line originated. Body weight, feed intake, and feed efficiency data were collected daily from 1 to 28 days, whereas percentage carcass water, ash, protein, and total lipid data were obtained at 0, 4, 7, 10, 14, 21, 28, 42, and 56 days of age. Body weights of P line quail were significantly (P.05) larger than BW of C line quail at all ages with the greatest deviation occurring at the age of selection. Feed intake was significantly greater in the P line and paralleled BW increases. When feed intake was adjusted for differences in BW, P line quail consumed less feed per gram of BW than C line quail and adjusted feed intake declined with age after Week 1. The P line quail had superior feed efficiency compared with C line quail from 1 to 13 days of age with the greatest deviation immediately posthatch. Carcass composition determinations revealed significant (P.05) age and line effects. Both percentage ash and protein increased from hatch to 14 days and thereafter remained constant. However, percentage water and total lipid demonstrated contrasting responses to increasing age; percentage water declined whereas percentage total lipid increased. The P line quail had less carcass water and protein, but had more lipid.(ABSTRACT TRUNCATED AT 250 WORDS)

The effectiveness of selection for hen-days without beak-inflicted injuries was studied. The base population was known to have a high incidence of beak-inflicted injuries when pullets' beaks were intact. Data from the foundation stock yielded nonsignificant family heritability estimates ranging from .05 to .17, depending on length of the test period (varying from 16 to 28 to 16 to 40 wk of age) and number of six-hen cages per family (one to three). Selection was practiced on sire family groups of either 30 or 36 pullets. Birds used for selection were housed six birds per cage and had intact beaks. The criterion of selection was mean hen-days without beak-inflicted injuries from 16 to 40 wk of age. Three selected and three unselected strains were involved. After two generations, mean hen-days without beak-inflicted injuries from 16 to 40 wk of age were 164.8 and 155.3 for selected and unselected stocks, respectively, yielding a realized family heritability of .65 ± .13 (SE). Selection did not appear to alter the relative frequency of beak-inflicted injuries by body regions affected; about 30% of all injuries involved the vent-cloacal area. Egg production traits were measured also. No differences were detected in Generation 1, but selected pullets had higher hen-housed rates of lay and egg mass in Generation 2. It is tentatively concluded that stocks having high levels of cannibalism when kept with intact beaks can benefit from selection against beak-inflicted injuries when evaluated by techniques similar to those used in the present study.

A divergent selection experiment for carcass leanness in Texel-Oxford sheep was established to examine the differences between genetically lean and fat animals derived from the same base population. The selection criterion was designed to change body composition without a corresponding change in live weight, using an index of ultrasonic backfat depth and live weight at 20 weeks of age. The index was constructed using estimates of genetic and phenotypic parameters, which were available at the start of the experiment in 1985. The difference between the high and low lines, after 3 years of selection, for the selection index, live weight at 20 weeks of age, ultrasonic backfat and muscle depths was 0·59,1·30 kg, -0·76 mm and 0·88 mm respectively. The estimated difference for carcass lean and fat weight was 0·72 kg and -0·04 kg respectively with 13·5 g/kg and -13·8 g/kg for carcass lean and fat proportion. The realized heritability for the selection index, estimated from the regression of cumulative response on cumulative selection differential was 0·42, with a standard error of 0·25, after taking account of genetic drift. The selection index heritability, estimated with residual maximum likelihood (REML) methodology, was 0·46 (s.e. 0·14). REML heritability estimates for live weight at 20 weeks of age, ultrasonic backfat and muscle depths were 0·20 (s.e. 0·13), 0·35 (s.e. 0·14) and 0·43 (s.e. 0·14) respectively.

1. After 5 generations of selection on income minus food cost between 21 and 40 weeks of age (SECR), a correlated genetic improvement of 14.5% and 16.3% of the base population mean could be observed for income minus food cost between 41 and 60 weeks (IF60) in two lines of laying hens. The total responses up to 60 weeks amounted to 17.2% and 17.3% of the base population mean. A heritability of 0.30 for IF60 and a genetic correlation of 0.61 between SECR and IF60 were estimated. 2. The correlated relative genetic responses for 5 traits of the period between 41 and 60 weeks of age for the two lines were: 4.3% and 5.2% in egg number, 5.8% and 7.4% in egg weight, 8.4% and 10.8% in egg mass, ‐2.7% and ‐0.6% in body weight at 60 weeks, and ‐5.2% and ‐6.3% in food efficiency. 3. The estimated heritabilities of these 5 traits from the whole data set were 0.36, 0.75, 0.34, 0.71 and 0.17. The estimated genetic correlations between SECR and the same 5 traits were 0.30, 0.46, 0.61, ‐0.22 and ‐0.49. 4. A high ...

Chicken lines that were either resistant or susceptible to ascites syndrome were developed by using a hypobaric chamber to induce the disease. Birds were reared in a hypobaric chamber that simulated high altitude by operating under a partial vacuum, which thereby lowered the partial pressure of oxygen. Ascites mortality data from birds reared under hypobaric chamber conditions were used to select siblings to be used for breeding. The response to selection for the susceptible (SUS) and resistant (RES) lines of chickens was very rapid from the base population, which exhibited an incidence of ascites of 75.3%. Extremes in the incidence of ascites were observed in generation 8, with line SUS exhibited an average incidence of ascites of 95.1%, and in generation 9, with line RES exhibited an average incidence of ascites of 7.1%. The incidence of ascites in the relaxed line remained relatively stable and currently has a general incidence of ascites of 60%. The heritability estimates ± SE for ascites were estimated to be 0.30 ± 0.05 and 0.55 ± 0.05 for lines SUS and RES, respectively. Changes in the incidence of ascites appeared to be associated with livability. By generation 10, selection for ascites in line RES increased livability by 11.5 d, whereas in line SUS, livability was decreased by 8 d. Although divergent selection for ascites resulted in a reduction in d 42 BW for both the SUS and RES lines, the SUS line was approximately 163 g heavier than the RES line. Negative genetic correlations between ascites and the right ventricle:total ventricle (RV:TV) ratio were observed in both the SUS and RES lines; however, no significant change in the RV:TV ratio was observed for birds reared under normal conditions in either line. The current data raise questions about the validity of using the RV:TV ratio as an indicator trait in a selection program designed to reduce the incidence of ascites. Overall, direct selection for resistance to ascites by using sire family performance appeared to be an effective means of reducing the incidence of ascites. However, simultaneous selection for BW should be applied to counterbalance the losses in correlated BW.

Clonal families from a broad genetic base population in the Potato Breeding Program at the Universidade Federal de Lavras (UFLA), Brazil, were used in this trials. Twenty-five families were assessed in a 5 x 5 triple lattice design. Each plot consisted of 30 clones distributed in three rows of ten plants. Tuber yield per plant, percentage of large tubers, mean weight of large tubers, mean medium-sized tuber weight and tuber specific gravity were measured. Three hundred experiments were simulated varying the family sizes from three to 90 clones. The coefficients of experimental variation (CVe), the coefficients of genetic variation (CVg), heritabilities for family mean and the CVg/CVe ratio were estimated. Genetic parameters were stabilized with family sizes as small as six clones, depending on the trait. This indicates that the families can be adequately represented by a small sample of clones. Using the maximum curvature method it is possible to conclude that approximately 30 clones would be sufficient to represent each family, even for traits with the highest CVe. The genetic variance within family was greater than the genetic variance among families for all traits, indicating a favorable potential for within family selection. The correlation coefficients of the family means with the 5%, 10%, 15% and 20% best clones from each family, considering the five traits assessed, were always high, meaning that within the best families generally are the best clones. Foram utilizadas famílias clonais, obtidas pelo programa de melhoramento de batata da UFLA, representando ampla gama de materiais genéticos. Avaliaram-se as 25 famílias no delineamento látice triplo 5 x 5. Cada parcela foi composta por 30 clones distribuídos em 3 linhas de 10 plantas. Foram avaliadas a produção de tubérculos por planta, a porcentagem de tubérculos graúdos, o peso médio de tubérculos graúdos, o peso médio de tubérculos médios e o peso específico de tubérculos. Foram simulados 300 experimentos variando-se o número de clones da cada família de três a noventa. Estimou-se os coeficientes de variação experimental (CVe), os coeficientes de variação genética (CVg), as herdabilidades e relação CVg/CVe. Os parâmetros genéticos se estabilizaram a partir de famílias contendo seis clones, dependendo da característica avaliada. Este resultado indica que a representatividade das famílias pode ser feita com um número pequeno de clones. Empregando-se o método da curvatura máxima sugere-se que as famílias poderiam ser representadas por aproximadamente 30 clones, mesmo para os caracteres com maior CVe. A variância genética dentro de famílias foi maior que a variância genética entre famílias para todos os caracteres, indicando um potencial favorável à seleção dentro de famílias. Os coeficientes de correlação entre as médias das famílias e os 5%, 10%, 15% e 20% melhores clones de cada família, considerando-se as cinco características avaliadas, foram sempre altos, significando que as melhores famílias possuem, de modo geral, os melhores clones.

Data were recorded for birth weight, birth coat score and weaning weight of between 2018 and 4235 Merino lambs born over a 17-year interval from 1986 to 2002. The resource population was divergently selected from the same base population since 1986, either for (H line) or against (L line) maternal multiple rearing ability. Direct additive genetic variances - expressed as a ratio of the total phenotypic variance (h2, direct heritability) - were estimated at 0.12 + 0.03 for birth weight, 0.70 + 0.05 for birth coat score and 0.13 + 0.04 for weaning weight. Maternal genetic variance ratios (m2) were estimated at 0.23 + 0.04 for birth weight and 0.10 + 0.04 for weaning weight. It was not significant for birth coat score. Maternal permanent environmental variance ratios (c2) for the respective traits amounted to 0.08 + 0.03 for birth weight, 0.04 + 0.02 for birth coat score and 0.08 + 0.03 for weaning weight. No consistent phenotypic or genetic differences in favour of either line were found for birth weight or birth coat score. Compared to L line lambs, phenotypic means for weaning weight were heavier in favour of H line lambs from 1995. This trend was confirmed by divergence in yearly averaged direct breeding values in the H and L lines. Expressed as percentage of the overall phenotypic mean for weaning weight, genetic changes amounted to +0.23% in the H line and -0.26% in the L line. A corresponding maternal genetic trend amounting to -0.19% of the overall phenotypic mean for weaning weight was found in the L line, while no maternal genetic change could be discerned in the H line. Divergent selection for multiple rearing ability thus did not influence birth weight and birth coat score, while the correlated response in weaning weight was favourable. Keywords: Direct heritability, Genetic trends, Maternal heritability, Parameter estimation, Smoothing splines South African Journal of Animal Science Vol.33(4) 2003: 248-256

No período de 1999 a 2001, a população de milho CPATC-3 foi submetida a três ciclos de seleção entre e dentro de progênies de meios-irmãos, em dois municípios de Sergipe, visando obter estimativas de parâmetros genéticos, para posterior verificação do comportamento da variabilidade genética em relação ao peso de espiga. Em cada ciclo foram avaliadas 196 progênies de meios-irmãos, em blocos ao acaso, com duas repetições, com recombinação das progênies superiores dentro do mesmo ano agrícola, de modo a se obter um ciclo/ano. Foram observadas diferenças altamente significativas entre as progênies que podem ser obtidas da população-base, em todos os ciclos de seleção, o que evidencia a presença de variabilidade genética entre elas. As magnitudes dos parâmetros genéticos mostraram que a população CPATC-3 possui variabilidade genética suficiente, a qual fornece perspectivas de aumentos subseqüentes de produção de espigas que, associadas ao bom rendimento apresentado, tornam essa variedade importante alternativa para a agricultura nordestina. From 1999 to 2001, the maize population CPATC-3 was submitted to three selection cycles among and within half sib families in two sites of Sergipe State in order to obtain genetic parameters estimates and to verify the behavior of the genetic variability for ear weight. In each selection cycle, 196 half sib families were evaluated in a completely randomized block design with two replications per local and the recombination of the best families within the same agricultural year was made. The results showed highly significant differences among the families from the base population and for all selection cycles, evidencing the genetic variability presence for ear weight. The genetic parameters estimates showed that the maize population CPATC-3 presents genetic variability for increasing ear weight and offers good perspectives to continue the breeding program.

Previously, evaluation of the first 2 wk of daily growth velocity with an artificial neural network (ANN) provided an effective noninvasive approach for predicting the susceptibility of broilers to pulmonary hypertension syndrome (PHS). This study was conducted to define the minimum number of days of growth data and the type of ANN required for the best prediction of PHS susceptibility. Four experiments were conducted in which broilers were weighed daily at 0800 h. In Experiment 1, Hubbard male broilers were reared to 50 d of age, with 13 developing PHS and 33 remaining normal (N), for a PHS:N ratio of 13:33. In Experiment 2, ANAK broilers were exposed to cool temperatures (16 to 17 C) from 17 to 42 d of age, resulting in a PHS:N ratio of 16:46 for males. In Experiments 3 and 4, Hubbard male and female chicks from a base population and a PHS-resistant line were exposed to cool temperatures from 17 to 42 d (Experiment 3) or 49 d of age (Experiment 4). The PHS:N ratios were 40:68 for males and 6:96 for females in Experiment 3 and 26:91 for males and 10:58 for females in Experiment 4. Four ANN, back propagation (BP3), Ward back propagation (WardBP), probabilistic (PNN), and general regression (GRNN), were evaluated for their ability to predict PHS in the shortest number of days based on daily growth velocities (BWd+1-BWd). A 100% prediction of PHS and N birds was considered the criterion of success. Starting with 14 d of data, each ANN was trained on daily growth velocity, and the number of predictive days was reduced with each run of the ANN. The best ANN was a GRNN, which correctly diagnosed PHS and N male broilers on 4 and 6 d of growth velocity data for Experiments 1 and 2, respectively. The results were poorer with the BP3, WardBP, and PNN. The diagnostic ability of the neural network was not consistent over all four experiments. In Experiment 2, a minimum of 6 d was required for 100% PHS detection for males. In Experiment 3, the best diagnostic value for males was 93% PHS detection and 100% N detection at 15 d. For females, the 100% PHS detection occurred at a minimum of 8 d. In Experiment 4, males had 100% PHS and N detection at a minimum of 11 d. Females had a 100% PHS and N detection at a minimum of 10 d. An attempt to build a single neural network that would detect PHS susceptibility in Hubbard (Experiment 1) and ANAK (Experiment 2) broilers was unsuccessful. The application (validation) of neural networks between experiments also was not successful (data not presented). However, these studies demonstrate that within a breed or line reared under similar selection pressures for ascites, a GRNN based on the first 14 d of growth velocity can detect, with at least 93% accuracy, broilers susceptible to PHS.

Previous research has shown that a line (F) of turkeys selected long-term for increased 16-wk body weight was more susceptible to challenge with washed Pasteurella multocida than a randombred control line (RBC2), the base population of F. A previous study also indicated that the mortality of the F line following challenge with P. multocida was similar to that of sire lines from two of the three major primary breeders. The purpose of the present study was to compare the resistance of the sire line from the third major primary turkey breeder (C) not previously studied with that of the F and RBC2 lines to determine whether there is variation in resistance among the sire lines from three major primary breeders. The sire lines from all three primary breeders were used in the production of commercial turkeys. Body weights of the F line were greater than those of the C line at the time of challenge with P. multocida. Both the C and F lines were heavier than the RBC2 line. The birds were challenged at 6 wk of age with a field isolate of washed P. multocida (1.2 x 10(7) organism per bird of capsular serogroup A and somatic serotype 3,4). Mortality was recorded daily for 14 d. Mortality following challenge with P. multocida was higher in the F line than in the C line, and both large-bodied lines had higher mortality than the RBC2 line. Based on the present results and those published in the literature, there may be variation in resistance among commercial sire lines from the three major primary breeders.

The effect of long-term genetic selection on physical quality and composition of eggs was determined by analyzing eggs acquired from Agriculture Canada: Ottawa Control Strain 5 (CS5) from a 1950 base population, 7 (CS7) from a 1958 population and 10 (CS10) from a 1972 population. Eggs from the HN "Nick Chick" current commercial strain (CCS) were also included. Eggs were collected monthly over a 62-wk laying period and analyzed for egg, albumen, shell and yolk weight; albumen protein, solids and pH; percentage yolk solids and fat; Haugh units; and specific gravity. Significant (P0.05) differences found between strains included a progressive increase in weight of eggs from the CS5 to CCS. Although the eggs increased in size, no significant differences were found between strains for specific gravity or percentage shell weight. Yolk weights of eggs from the strains examined did not differ. However, the percentage of yolk found in current strain eggs was significantly lower (P0.05), with a subsequent higher percentage albumen due to the increase in egg size of the CCS. Haugh units were significantly higher in the CS10 and CCS strains than in the other strains. No significant differences between strains were seen in albumen protein, solids, pH, or yolk solids. Mean percentage yolk fat assay values for eggs from the CS5, CS7, CS10, and CCS strains were 33.08, 32.68, 32.84, and 32.40, respectively. Percentage yolk fat values obtained from CCS were significantly lower (P0.05) than those obtained from the other strains. The results from this study indicate that genetic selection has produced larger eggs containing a lower percentage of yolk while overall egg quality has been maintained or improved.

This paper presents a general expression to predict breeding values using animal models when the base population is selected, i.e. the means and variances of breeding values in the base generation differ among individuals. Rules for forming the mixed model equations are also presented. A numerical example illustrates the procedure. Cet article présente l’expression générale pour prédire les valeurs génétiques par le modèle animal quand la population de base est sélectionnée, c’est-à-dire quand cette population est un mélange de sous-populations à moyenne et variances génétiques différentes. On présente les règles de construction des équations du modèle mixte. La procédure est illustrée par un exemple numérique.

1. Heritabilities and genetic correlations in the base population of a closed strain of Muscovy duck, moderately selected for body weight at 10 weeks of age, have been estimated from the data of 9 successive generations for the following traits: male and female body weight at 10 and 18 weeks of age (BW10m, BW18m, BW10f, BW18f) and length of the 8th primary feather at 10 weeks of age (F110m, F110f). 2. Multivariate REML with an animal model was used, pooling data from the 9 generations (3283 and 3289 male and female offspring respectively). The same trait expressed in male and female was considered as 2 different traits. 3. The 8th primary feather was longer in females than in males by 6% to 22% at 10 weeks of age. Body weight was heavier in males than in females by 42% to 58% at 10 weeks of age and by 57% to 75% at 18 weeks of age. 3. The heritability estimates for body weight traits showed moderate values, being a little higher for females than for males at the same age, increasing with age from h2=0.24 at BW10m to h2=0.43 at BW18f. 4. The heritability estimates for feather length showed that a greater response would be obtained in selection for male feather length (h2=0.37) than for female length (h2=0.14). Both have high genetic correlations with body weight so they could be indirectly improved. 5. Heritabilities of the difference in body weights between males and females at 10 weeks (h2=0.07) and 18 weeks of age (h2=0.10) were small, as well as for feather length (h2=0.10). It would probably be difficult to modify sexual dimorphism in body weight through selection. 6. Genetic correlations between BW10m, BW18m and BW10f, BW18f were respectively r(g)=0.77 and r(g)=0.80. They were larger for body weight at the same ages between males and females, r(g)=0.90 (r(g)=0.88 between F110m and F110f). Body weight in males and females at the same age should be better considered as 2 different traits in a selection programme. 7. The cumulated predicted genetic gains expressed per unity of the genetic standard deviation (sigma(g)) over the 8 generations of selection were 1.3 sigma(g) and 1.4 sigma(g) respectively for the BW10m and BW10f. The predicted correlated responses were 1.2 sigma(g) for body weights at 18 weeks of age, 0.9 sigma(g) and 0.7 sigma(g) for F110f and F110m respectively.

Inbreeding coefficients are calculated routinely for all animals included in national genetic evaluations for yield traits. The base population for inbreeding is defined as animals born during 1960. Animals with unknown parents are assumed to have inbreeding coefficients that are equal to the mean of coefficients for animals with known parents born during the same year. Mean inbreeding coefficients reached .03 to .04 for recent years, and coefficients for some animals exceeded .50. The annual increase in level of inbreeding was highest for Milking Shorthorns, but the rate of change of that increase was greatest for Holsteins. Accounting for inbreeding in calculation of the inverse of the relationship matrix had only a small effect on evaluations. For Jersey, the maximum change in breeding value was 73 kg of milk for cows and 40 kg of milk for bulls with > or = 10 daughters. Estimates of inbreeding depression were similar across breeds for production traits and were -29.6 kg of milk, -1.08 kg of fat, and -.97 kg of protein per 1% of inbreeding for Holsteins. In January 1994, the USDA began considering the percentage of inbreeding when calculating inverses of relationship matrices, the largest matrix representing over 20 million Holsteins; this inbreeding percentage was released to the dairy industry for bulls.

Two experiments were conducted to determine the protein requirement of quail lines (P and T) following selection for increased 4-wk BW under normal-protein (28% CP) and low-protein (20% CP) diets, respectively. Quail progeny from Generation 39 breeders were fed diets containing 18, 21, 24, and 27% CP from 0 to 5 wk of age in Experiment 1, whereas in Experiment 2, quail progeny from Generation 79 breeders were fed diets containing 18, 21, 24, 27, and 30% CP from 0 to 4 wk of age. Quail from the unselected base population (C line) were also included in both experiments. Significant line, diet, and line by diet interactions were present in both experiments. At 2 wk of age, T line quail were significantly (P < .05) larger than P line quail across diets, whereas by 4 wk, BW of P line quail were significantly larger than those of T line quail. Across dietary protein levels, quail receiving diets containing 24% CP or higher were significantly larger than those receiving the 18 and 21% CP diets. Quail in both the P and C lines had larger BW with increasing protein levels and an apparent protein requirement between 24 and 27% CP. However, quail in the T line showed no BW response to increased protein levels, indicating that long-term selection for increased BW on a 20% CP diet had altered the protein requirement in this line.(ABSTRACT TRUNCATED AT 250 WORDS)

Fearfulness was measured as latency to recover from induced tonic immobility using White Leghorn hens from a population originated by crossing three different strains selected for egg number and egg weight. Realized heritability was calculated in a single generation selection experiment with eight replicates, each consisting of 76 40-wk-old females from which 21% were selected for decreased tonic immobility duration. A randomly selected control population was maintained for each replicate. Separately from this experiment, fear differences between ages and sexes were investigated at 1, 2, 4, 8, 12, 16, 20, 24, 28, and 32 wk. The realized heritability (.32 +/- .10) indicates that induced tonic immobility should respond to selection. It was numerically higher than the estimate calculated by half-sib analysis of variance in the base population (.18 +/- .07); the logarithmic transformation did not yield higher heritability estimates. Crossing effects were evaluated in two different crossbreds, i.e., Leghorn x Castellana and Buff Prat x White Prat, which suggested important negative heterotic effects for this fear-related trait (-31% and -54%, respectively). Significant (P < .05) quadratic and cubic variation between 1 and 32 wk of age was obtained in females and males, respectively; the involvement of these age effects make it difficult to generalize about realized heritability for tonic immobility. Tonic immobility increased from 32 to 72 wk. Differences between the sexes were apparent, males showing longer tonic immobility durations than females except in the postjuvenile period before sexual maturity, suggesting a relationship between this trait and hormonal changes.

Divergent selection resulted in Merino lines that differ markedly for reproduction. These lines were selected from the same base population from 1986 to 2009. Selection was initially based on maternal ranking values for reproduction in both ewe and ram progeny. The maternal ranking scores were augmented by breeding values from a single-trait repeatability model since 2003. The site and severity of flystrike were recorded for mature breeding ewes in the flock from 2007 to 2009. The following details were captured: animal number, site of the strike (body or breech) and the severity of the strike (1 = mild to 5 = severe). Breech strikes amounted to 92.1% of all strikes and this trend was consistent across years. High-line ewes were less likely (P < 0.05) than low-line ewes to be suffering from breech strike. Ewes that suffered from breech strike during a reference year were more likely to be struck again during subsequent years, when compared with contemporaries not affected by breech strike in the reference year. When breech strike and body strike were assessed in a joint preliminary analysis, it seemed that body strike was generally more severe when diagnosed than breech strike. It was concluded that Merino sheep selected for improved reproduction for >20 years were less likely to be affected by breech strike than contemporaries selected for low reproduction.

SUMMARYA theoretical analysis of open nucleus breeding systems, in which there is some introduction of breeding females to the sire breeding nucleus, is presented. Numerical analysis of a discrete generation model shows that the rate of genetic gain may be increased by 10 to 15% by opening the nucleus when selection intensity in females is low. In sheep and beef cattle breeding the optimal structure would be to have about 10% of the population in the nucleus, to get half of the nucleus female replacements from the base population, and to use all nucleus-born females not needed as nucleus replacements for breeding in the base population. The genetic gain, however, is not very sensitive to variation in these parameters. The rate of inbreeding in such an open nucleus would be about half that in a closed nucleus of the same size.

Direct selection for grain number per spikelet, grain number per ear, or weight per grain was more effective than selection for yield per se as indicated by direct responses and realised heritabilities. Yield per plant did not show any response to direct selection. The base population for selection was 40 F3 lines of each of 2 crosses, derived by intense and fairly effective single plant F2 selection for these yield components. F3 line selection for grain number per spikelet gave positively correlated responses for most yield components and yield per plant at 2 planting densities in Hilgendorf × Oroua and at the higher density in Kopara × Oroua. Although grain number per ear and weight per grain compensated for each other, selection for grain number per ear in Kopara × Oroua resulted in positively correlated responses in yield components (except weight per grain) and yield per plant at high density. Selection for weight per grain in both crosses gave significant increases in yield/m-2 at low dens...

One cycle of divergent sib selection, for or against abdominal fat weight, combined with within-family selection for body weight, was performed in a population of a commercial female grandparent line (White Rock type). Chicks from the first generation (S1 G1) of high-fat (HF) and low-fat (LF) selection lines were raised in three different environmental and climatic conditions. A second generation (S1 G2) of the selection lines was obtained by within-line selection for body weight only. The HF line had about 60% more abdominal fat than the LF line in all three environments. The realized heritability of this trait was calculated to be .73, almost identical to the heritability estimated from the base population. The LF line mean body weight was between 1% and 5% lower than that of the HF line. This difference was not significant and it was almost abolished in S1 G2, after both lines were selected for body weight only. The difference between lines in abdominal fat weight was increased to 80% in S1 G2. It can be concluded that reduction in abdominal fat weight was not associated with a decrease in body weight. Selection for body weight, in a line previously selected against abdominal fat, did not reverse the reduction in fat. The difference between the HF and LF lines had the same magnitude in both sexes and under different environmental conditions that increase or decrease fat deposition.

From the same base population of Romney ewes in 1971, two flocks were generated by mating and subsequentl y backcrossing ewes to either average-merit rams from the Waihora Romney Breeding Scheme of the Department of Lands and Survey (Rotorua), or to rams from commercial sources normally available to the Department. The Waihora and Commercial flocks were managed separately only during mating and from lambing to tailing. Physical and financial records of the two flocks over the period 1979-85 were compared. Mean litter size (lambs born per 100 ewes lambing) was 121.9% for Waihora ewes and 110.2% for Commercial ewes (P < 0.01). Flock differences in ewe fertility and lamb survival tended to be small, but performance levels were higher in the Waihora flock. Mean net reproductive rates (lambs weaned per 100 ewes present at lambing) for the Waihora and Commercial flocks were 105.2 and 92.3%, respectively (P < 0.01). Over all years combined, 59.1 % of wether lambs drafted for slaughter were from the Waih...

Carcass composition of turkeys from a long-term growth-selected line (F), a subline (FL) of F selected only for increased shank width, and a randombred control population (RBC2) that served as the base population for F, were compared. Birds of both sexes were killed at 16 wk of age in the fifth and sixth generations in Line FL. A commercial sire line (C) was also included in the sixth generation. Body weight increased at comparable rates in F and FL males through the 5th generation of selection in Line FL, but the BW of FL males was significantly smaller than that observed in F males in the 6th generation. Body weights of FL females were significantly lower than BW of F females in both the 5th and 6th generations, resulting in a significant line × sex interaction. A similar interaction was also observed in both generations in the actual weight of most leg bones, leg muscles, and breast muscles. When expressed as a percentage of live BW, most of the latter line × sex interactions were not significant. Genetic increases in shank width of the FL line were associated with increases in the relative weight of all leg bones measured and drumstick muscles. This may have contributed to the improved walking ability consistently observed in FL males relative to that of F males. In general, genetic increases in BW in Line F were associated with a decreased amount of relative support (leg muscles and leg bones) in comparison with that observed in Line RBC2. These results support the hypothesis that a portion of the leg problems observed in large-bodied turkeys are attributable to an inherent weakness of body support structures resulting from the slower growth of these structures relative to that of total BW.

Genetic evaluation by BLUP requires knowledge of the inverse numerator relationship matrix among breeding values. When pedigree information is complete, the true relationship matrix can be determined and an exact inverse found. When pedigree information is incomplete, an exact inverse of an approximate relationship matrix is obtainable. The usual algorithm for the inverse numerator relationship matrix may be derived assuming each unidentified parent to be a different base population animal.

It is shown that a commonly used method of calculating cumulative selection differentials in experiments where generations overlap is biased, and consequently leads to biased estimates of realized heritability. In one example, the heritability was underestimated by about one-fifth. Since genetic variation in a given progeny crop may be increased by genetic differences between parental age groups, realized heritability estimated by regression may not agree with base population estimates. An alternative form of analysis is proposed to allow for this effect.

1. Data from 16 inbred lines derived by three generations of full sib mating from a common outbred base population were used to estimate genetic correlations between body weight, abdominal fat content, follicle number, liver weight, egg weight and egg number using between‐line variances and covariances. 2. High genetic correlations were found between body weight, fat content and egg weight. Low genetic correlations were found between follicle number and all traits other than egg weights. 3. Theoretical expectations and low correlations within lines led to the conclusion that environmental correlations among the traits considered were very low.

Genetic differences in body fat, body weight, follicle number, and egg production were found among six inbred lines of White Leghorn hens derived from a common outbred base population. High positive genetic correlations of body fat with body weight were found between inbred lines as well as between inbred parents and line-cross progeny. Heterosis of fatness, body weight, egg production, egg weight, and liver weight were observed. Large follicles and liver weight were unaffected by inbreeding and crossing of lines.

SUMMARYThe possible use of superovulation and embryo transfer in selection programmes in cattle is investigated theoretically, in terms of both rates of response and inbreeding.In a selection programme for growth rate, it should be possible to achieve about twice the response of a conventional performance testing programme, so that 400-day weight, for example, could be increased by 16 rather than 9 kg per year.The improvement of reproductive performance by the use of laparoscopy to measure the natural ovulation rate of animals over several oestrous cycles followed by superovulation of selected animals is investigated. The rate of progress is dependent upon the incidence of twin ovulations in the base population and is unlikely to exceed 0·6% per year unless the initial frequency is 8% or more.

The ontogeny of plasma growth hormone (GH) was determined within and between genetically-related turkey lines selected for differential growth rates. Blood samples were obtained at weekly intervals from hatching through 195 days of age from male and female poults of a slow-growing, randombred line (RBC-2), representing the base population, and a fast-growing line selected over 20 generations from RBC-2 for increased 16-wk body weight (F). Growth rate of the F line exceeded that of RBC-2 during the very early (0 to 14 day) posthatch period (P less than .05), but was not different from that of the RBC-2 line by 77 to 195 days of age. Males of both lines were larger than females at all ages (P less than .05). Plasma GH increased from hatching until 2 wk of age and declined thereafter in both lines. Differences between overall plasma GH concentrations of the lines were not observed during the 0 to 14 day period, but concentrations were higher (P less than .05) in RBC-2 than F birds thereafter (21 to 195 days of age). Plasma GH concentrations initially (0 to 14 days) were higher in females than in males for both lines (P less than .05), but thereafter (21 to 195 days) declined more rapidly and averaged lower overall in females than in males (P less than .05). Correlations between measures of GH and growth rate within lines over age were strongly positive (r = .83 to .93; P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Data has been presented on the loss of alleles from populations of small fixed size. Emphasis has been placed on the effect which the allele frequency distribution and the interlocus distribution of heterozygosity will have on the pattern of allelic loss. Rare alleles are rapidly lost during the initial sampling period, and continue to be lost for several generations following the establishment of small population size. The nonequilibrium nature of the process of loss of genetic variability is stressed. The rapid loss of rare alleles and the preservation of intermediate and high frequency alleles will result in (1) heterozygosity declining much more slowly than allele number, and (2) the establishment of genetically similar populations when sampled from the same base population.

SUMMARYThe Israeli procedure for measuring sire breeding values and genetic progress due to selection is described. The estimate of sire breeding value has two components, the current contemporary comparison (CC) and an adjustment for the average genetic deviation of the contemporaries from the original base population. The combined value is called the cumulative difference (CD). For practical purposes the CD was found to be free of the time trends observed for CC, and the residual variances of the two measures were approximately equal. The relative genetic level in any given time interval was measured by the average CD of all sires used during the period October 1964 o t January 1971 in Israel. The analysis indicates that essentially all of the progress in 122-day FCM yields was due to sire selection, whereas 60% of the progress in 305-day FCM yields was due to selection and 40% to improved management.

The effect of fetal and maternal genotype on embryo survival was studied in two lines of mice from the same base population: line E, selected for high embryo survival, and line CN-, selected for small litter size. Embryos were collected at 3.5 days postcoitus from normally mated donors of both lines and were transferred to the uteri of 2.5-day pseudopregnant recipients from each line. The number of embryos recovered and the proportion of those recovered that had been fertilized were greater in line E donors than in line CN- donors (P < .05). Development into blastocysts was slower for CN- embryos. The proportion of recipient females that were pregnant was higher for line E than for line CN- after transfer of line E embryos (P < .005). The same trend was observed following transfer of line CN- embryos (P < .10). Embryos of both lines showed greater survival when transferred to line E recipients than when transferred to line CN- recipients (P < .005), and, within line E recipients, E embryos tended to survive better than did CN- embryos (P < .10). The results suggest that although the genotype of the embryo may play a role, the maternal genotype has greater influence on embryo survival in the two lines of mice.

Feed intake and feed conversion patterns of meat-type dwarf (dw) and normal contemporaries were investigated in two trials, with the Athens-Canadian randombred line used as the base population. Dwarf chickens consumed significantly less feed than normal ones the first day posthatching and in all subsequent observation periods. The deviation in body weight ratios and feed intake ratios between lines were greatest during week 1. These data indicate that the action of the dw gene is present at hatching and exerts at least part of its influence through feed intake or appetite. Feed conversion ratios (feed/gain) were lower in dwarf birds than in normal birds during week 1, whereas overall differences across 8 weeks were small. The difference in relative growth rate between genotypes was greatest during week 1; by week 4, relative growth rates were similar.

Fleece, liveweight and skin follicle data are presented for 1150 unselected feral female goats mated over a period of 4 years (1981–1983) to 45 unselected male goats, and 1169 of their offspring. Liveweight, down weight, down diameter, length, primary and secondary follicle density and S/P ratio of female adults were 29.4 kg, 53 g, 15.4 μm, 51.4 mm, 2.37 mm −2 , 14.62 mm −2 and 6.17, respectively. The adult males were heavier and had greater down production but follicle densities were lower. Between-animal coefficients of variation ranged from 20 to 65% with the exception of down diameter for which the coefficient was less than 10%. Pregnancy reduced down production by 30%, lactation reduced it by 48% and together they reduced it by 65%. Female progeny of the foundation adults averaged 24.7 kg liveweight, 75.0 g down, 15.5 μm down diameter, 62.2 mm down length, 3.42 primary follicles mm −2 , 23.4 secondary follicles mm −2 and 6.81 S/P ratio, respectively. Males were 14% heavier than females, while down weight and length were slightly, but not significantly, greater. There was no difference between the sexes in down diameter. Differences caused by birth type and age were greatest in their first year. Single-born animals averaged 6.3% heavier than twins and grew 6.6% more down which was longer and coarser (16.3 and 20.6%, respectively). Age differences were significant for all parameters; in particular down diameter increased by 1.1 μm from first to second fleece, 0.7 μm from second to third fleece, and 0.4 μm from third to fourth fleece. Differences in skin-follicle densities between sex, birth type and age groups reflected differences in liveweight.

Summary The theoretical and practical implications of population size on selection programmes are reviewed. Short term responses can be predicted from genetic variances and depend little on the distribution of gene effects and frequencies. The main influence of population size (N) is through selection intensity, and is important only if these are reduced to minimize inbreeding. The variability of short term response is approximately inversely proportional to N. As the time scale increases, the mean and variance of the response can not be predicted accurately from the usual genetic parameters estimated in the base population. The probabilities of fixation of favourable genes and thus the limit to selection from genetic variability in the base population increases with N, but not linearly; only for genes initially rare or of small effect does N substantially influence the limit. The long term response from new variation created by mutation is, however, very dependent on N. The fixation probability of additive or dominant mutant genes initially in single copy is independent of N and the number of mutants and thus response is proportional to N. Although it may be many generations before mutants contribute significantly, their contribution to response may eventually be very large. Resume Effets de la grandeur des populations sur selections a court- ou long terme Les resultats des selections a court terme peuvent etre predits des variances genetiques et dependent peu de la distribution des effets des genes et des frequences. L'influence principale de la grandeur de population (N) est pratiquee par l'intensite de selection et devient important uniquement lorsque celle-ci est reduite pour minimiser la consanguinite. Lorsque les laps de temps augmentent, valeur moyenne et variance de la population de base echouent comme ressource pour la prediction exacte du progres. La probabilite de la fixation de genes favorables et, de ce fait, la limite de selection, augmente avec N, cependant pas lineairement; seulement pour les genes initialement rares ou d'effet mediocre, l'influence de N est importante. Le resultats a long terme de variations nouvelles creees par mutation est tout de meme tres dependant de N. La probabilite de fixation des genes additifs ou dominants est independante de N, de ce fait, le succes est proportionnel a N. Bien que beaucoup de generations sont necessaires pour que les mutantes montrent une repercussion significative, leurs contribution au succes peut finalement etre tres large. Resumen Efecto del tamano de la poblacion sobre seleccion a corto y largo plazo Se revisan implicaciones practicas y teoricas del tamano poblacional sobre programas de seleccion. Respuesta de seleccion a corto plazo, pueden ser predecidas a traves de las varianzas geneticas y dependen poco de la distribucien de frecuencias y efectos genicos. La mayor influencia sobre el tamano poblacional (N), es a traves de la intensidad de seleccion y es importante solo si se disminuye mediante la minimizacion de la consaguinidad. La variabilidad de respuesta a corto plazo es aproximadamente inversamente proporcional a N. A medida que el tiempo transcurre, la media y la varianza de la respuesta, no pueden ser predecidas con exactitud desde los parametros geneticos usuales, estimados en la poblacion base. La probabilidad de fijacion de los genes favorables y por consiguiente el limite de seleccion, desde la variabilidad genetica en la poblacion base aumenta con el N., pero no linealmente solamente para genes inicialmente raros o de pequeno efecto, tiene N una influencia sustancial sobre el limite. La respuesta a la seleccion a largo plazo, debido a nueva variacion producida por mutacion, en comparacion, depende fuertemente de N. La probabilidad de fijacion aditiva o dominante de genes mutantes, es independiente de N y del numero de mutantes, y la respuesta por consiguiente es proporcional a N. Sin embargo, pueden transcurrir muchas generaciones antes que los mutantes contribuyan significativamente, su contribucion a la respuesta puede eventualmente ser muy grande. Zusammenfassung Wirkungen der Populationsgrose auf kurz- und auf langfristige Selektion Kurzfristige Selektionserfolge konnen von genetischen Varianzen vorhergesagt werden und hangen nur wenig von der Verteilung von Genfrequenzen und – wirkungen ab. Der Haupteinflus der Populations-grose (N) wird uber Selektionsscharfe ausgeubt und wird dann wichtig, wenn diese wegen Inzuchtminimierung vermindert wird. Mit zunehmenden Zeitraumen versagen Mittelwert und Varianz der Ausgangspopulation als Hilfsmittel zu genauer Vorherschatzung des Fortschrittes. Die Wahrscheinlichkeit der Fixierung erwunschter Gene und damit die Selektionsgrenze, nimmt mit steigendem N zu, allerdings nicht geradlinig; nur bei anfanglich seltenen Genen oder solchen mit geringer Wirkung, ist der Einflus von N bedeutend. Der langfristige Erfolg durch mutationsbedingte neue Variabilitat hangt dagegen stark von N ab. Die Wahrscheinlichkeit der Fixierung additiver oder dominanter Einzelgene ist von N und von der Zahl der Mutanten unabhangig, so das der Erfolg proportional mit N zunimmt. Obwohl viele Generationen verstreichen mogen bevor Mutanten sich signifikant auswirken, kann ihr Beitrag zum Erfolg schlieslich sehr gros sein.