Resumo: O objetivo deste trabalho foi avaliar a utilidade de um subconjunto de 18 polimorfismos de nucleotídeo único (SNPs) para a certificação das raças de ovinos Crioula Brasileira, Morada Nova (MN) e Santa Inês (SI). Dados de 588 animais foram analisados com o programa Structure. Em 82% dos casos, observou-se designação racial correta com confiança acima de 90%. A maioria dos casos de designação incorreta de raça foi observada em MN e SI. Portanto, apesar de o subconjunto de 18 SNPs ter confiabilidade elevada, ele não é suficiente para a inequívoca certificação das raças estudadas, principalmente das deslanadas. É necessário o desenvolvimento de um painel mais preciso para uso amplo em certificação racial.

Abstract: The objective of this work was to evaluate the usefulness of a subset of 18 single nucleotide polymorphisms (SNPs) for breed identification of Brazilian Crioula, Morada Nova (MN), and Santa Inês (SI) sheep. Data of 588 animals were analyzed with the Structure software. Assignments higher than 90% confidence were observed in 82% of the studied samples. Most of the low-value assignments were observed in MN and SI breeds. Therefore, although there is a high reliability in this subset of 18 SNPs, it is not enough for an unequivocal assignment of the studied breeds, mainly of hair breeds. A more precise panel still needs to be developed for the widespread use in breed assignment.

Resumen Antecedentes: La falta de información sobre estructura poblacional es una de las principales barreras para el desarrollo de programas de mejoramiento genético y conservación de los recursos zoogenéticos. Objetivo: Caracterizar la estructura poblacional de la raza bovina Crioula Lageana (Bos taurus) para evaluar su diversidad genética. Métodos: Una base de datos con información de 1.638 animales Crioula Lageana (Bos taurus), recogidos durante 38 años, fue analizada utilizando el programa ENDOG v.4.4. Resultados: El tamaño efectivo de la población varió de 72,53 en las generaciones completas a 143,90 en las generaciones máximas. La endogamia y la relación media de los coeficientes fue 0,34 y 0,91%, respectivamente. El número efectivo de fundadores y antepasados fue de 29 y 28 animales respectivamente, y sólo diez antepasados fueron responsables del 50% de la variabilidad genética de la población. El intervalo promedio de generación fue de 5,84 años en la línea paterna y de 7,70 en la línea materna. El índice estadístico de Wright’s F indica una baja distancia genética entre los subconjuntos en relación con la población total (Fst = 0,0015), entre los individuos con respecto a su subpoblación (Fis = -0,0027), y entre los individuos en relación con la población total (Fit = -0,0012). Conclusión: El análisis de la población indica que a pesar del pequeño número de animales con origen conocido y la considerable pérdida de variabilidad genética por el uso constante de pocos toros y el mismo valor del número de fundadores y antepasados, la población mostró un buen manejo genético, baja endogamia, baja diferenciación genética entre las subpoblaciones y probablemente un tamaño efectivo adecuado de la población.

Abstract Background: The lack of information on population structure is one of the main obstacles to develop breeding and conservation programs for animal genetic resources. Objective: To characterize the population structure of Crioula Lageana cattle breed (Bos taurus) in order to assess its genetic diversity. Methods: Database with information of 1,638 Crioula Lageana animals, collected during 38 years, was analysed using the ENDOG v.4.4 program. Results: Effective population size ranged from 72.53 in complete generations to 143.90 in maximum generations. Inbreeding and Average Relatedness coefficients were 0.34 and 0.91%, respectively. The effective number of founders and ancestors were 29 and 28 animals, respectively, and only ten ancestors were responsible for 50% of the genetic variability of the whole population. The average generation interval was 5.84 years in the paternal line and 7.70 in the maternal one. Wright´s F statistics indicated low genetic distances between subsets in relation to the total population (Fst = 0.0015), between individuals with respect to their subpopulation (Fis = -0.0027), and between individuals in relation to the total population (Fit = -0.0012). Conclusion: Analysis of the population indicated that, despite the small number of animals with known parentage and considerable loss of genetic variability by the constant use of a few sires, and same value of number of founders and ancestors, the population showed good genetic management, low inbreeding, low genetic differentiation among subpopulations, and probably adequate effective population size for breed preservation.

Resumo Antecedentes: A falta de informações sobre a estrutura da população está entre os principais obstáculos ao desenvolvimento de programas de melhoramento e conservação de recursos genéticos animais. Objetivo: Caracterizar a estrutura populacional da raça bovina Crioula Lageana (Bos taurus) para acessar a diversidade genética da raça. Métodos: Banco de dados com informação de 1.638 animais Crioula Lageana, recolhidos durante 38 anos, foi analisado utilizando EndoG v.4.4. Resultados: O tamanho efetivo populacional variou de 72,53 nas gerações completas para 143,90 nas gerações máximas. Coeficientes de Endogamia e Relação foram 0,34 e 0,91%, respectivamente. O número efetivo de fundadores e ancestrais foram 29 e 28 animais, respectivamente, sendo que apenas dez ancestrais foram responsáveis por 50% da variabilidade genética de toda a população. O intervalo de gerações foi de 5,84 anos para linha paterna e 7,70 para linha materna. As estatísticas F de Wright indicaram uma pequena distância genética das subpopulacoes entre os subgrupos em relação à população total (FST = 0,0015), entre os indivíduos em relação à sua subpopulação (FIS = -0,0027) e entre indivíduos em relação à população total (Fit = -0,0012). Isto indica uma baixa diferenciação genética na população estudada. Conclusão: A análise populacional indicou que, apesar do número pequeno de animais com ascendência conhecida e considerável perda de variabilidade genética pelo uso constante de alguns touros e mesmo valor do número de fundadores e antepassados, a população mostrou boa gestão genética, endogamia baixa, baixa diferenciação genética entre subpopulações e provavelmente adequado tamanho efetivo da população para a preservação da raça.

Resumo: O recente desenvolvimento de painéis de “single nucleotide polymorphisms” (SNPs) distribuídos ao longo do genoma possibilitou a realização de diversos trabalhos com diferentes espécies. O processo seletivo promove o aumento ou a diminuição da frequência alélica (ou gênica) em loci específicos do genoma, além de promover o arrasto dos alelos próximos no cromossomo. Desta forma, são formadas regiões do genoma com o aumento na frequência de determinados alelos na população, o que caracteriza a assinatura de seleção. A detecção destas assinaturas é importante para a caracterização dos recursos genéticos, bem como a identificação de genes ou regiões envolvidos no controle e na expressão de características de importância produtiva e econômica. Os ovinos são uma importante espécie para estes estudos, uma vez que encontram-se amplamente dispersos em diferentes ambientes e apresentam grande diversidade fenotípica. Devido à grande quantidade de dados gerados nas análises genômicas, são necessários métodos estatísticos e programas específicos para a detecção de assinaturas de seleção. Assim, os objetivos deste artigo de revisão são apresentar os principais métodos estatísticos e os programas atualmente utilizados para análise de dados genômicos e a detecção de assinaturas de seleção; descrever os resultados dos recentes trabalhos publicados sobre assinaturas de seleção em ovinos; e discutir alguns desafios e oportunidades nesta área de pesquisa.

Abstract: The recent development of genome-wide single nucleotide polymorphism (SNP) arrays made it possible to carry out several studies with different species. The selection process can increase or reduce allelic (or genic) frequencies at specific loci in the genome, besides dragging neighboring alleles in the chromosome. This way, genomic regions with increased frequencies of specific alleles are formed, caracterizing selection signatures or selective sweeps. The detection of these signatures is important to characterize genetic resources, as well as to identify genes or regions involved in the control and expression of important production and economic traits. Sheep are an important species for theses studies as they are dispersed worldwide and have great phenotypic diversity. Due to the large amounts of genomic data generated, specific statistical methods and softwares are necessary for the detection of selection signatures. Therefore, the objectives of this review are to address the main statistical methods and softwares currently used for the analysis of genomic data and the identification of selection signatures; to describe the results of recent works published on selection signatures in sheep; and to discuss some challenges and opportunities in this research field.

Abstract The first horses were brought to Brazil by the colonizers after 1534. Over the centuries, these animals evolved and adapted to local environmental conditions usually unsuitable for exotic breeds, thereby originating locally adapted Brazilian breeds. The present work represents the first description of maternal genetic diversity in these horse breeds based on D-loop sequences. A D-Loop HSV-I fragment of 252 bp, from 141 horses belonging to ten Brazilian breeds / genetic groups (locally adapted and specialized breeds) were analysed. Thirty-five different haplotypes belonging to 18 haplogroups were identified with 33 polymorphic sites. Haplotype diversity (varying from 0.20 to 0.96) and nucleotide diversity (varying from 0.0039 to 0.0239) was lower for locally adapted than for specialized breeds, with the same pattern observed for FST values. Haplogroups identified in Brazilian breeds are in agreement with previous findings in South American samples. The low variability observed mainly in locally adapted breeds, indicates that, to ensure conservation of these breeds, careful reproductive management is needed. Additional genetic characterization studies are required to support accurate decision-making.

Resumo: O objetivo deste trabalho foi identificar polimorfismo de nucleotídeo único (SNPs) em dados de ressequenciamento dos genes MC1R, ASIP e TYRP1, obtidos de ovelhas Crioulas (Ovis aries) com cores de pelagem distintas. Polimorfismos nos genes ASIP (agouti-signaling protein), MC1R (melanocortin 1 receptor) e TYRP1 (tyrosinase-related protein 1) foram analisados em 115 ovinos, provenientes do núcleo de conservação da ovelha Crioula, da Embrapa. No total, 7.914 pb foram sequenciados por animal, e 14 SNPs foram identificados. Dois ensaios adicionais foram realizados para detectar duplicações e deleções no gene ASIP. Noventa e cinco por cento da variação de cor da pelagem foi explicada pelas interações epistáticas entre alelos específicos dos genes MC1R e ASIP. Evidências sugerem um importante papel das variantes TYRP1 para cor da lã, apesar das suas baixas frequências. O painel de marcadores usado foi eficiente em detectar alelos associados à coloração da pelagem nos animais estudados e, portanto, pode ser usado na implementação de um programa de seleção assistida por marcadores, no núcleo de conservação de ovinos da raça Crioula.

Abstract: The objective of this work was to identify single nucleotide polymorphisms (SNPs) in resequencing data from MC1R, ASIP, and TYRP1 genes derived from Crioula sheep (Ovis aris) with different coat colors. Polymorphisms in the ASIP (agouti-signaling protein), MC1R (melanocortin 1 receptor), and TRYP1 (tyrosinase-related protein 1) genes were analyzed in 115 sheep from Embrapa’s conservation nucleus of crioula sheep, in Brazil. A total of 7,914 bp were sequenced per animal, and 14 SNPs were identified. Two additional assays were performed to detect duplications and deletions in the ASIP gene. Ninety-five percent of the coat color variation was explained by epistatic interactions observed between specific alleles in the MC1R and ASIP genes. Evidence suggests an important role of TYRP1 variants for wool color, despite their low frequencies. The marker panel was efficient enough in predicting coat color in the studied animals and, therefore, can be used to implement a marker-assisted selection program in the conservation nucleus of sheep of the crioula breed.

RESUMO O objetivo deste trabalho foi desenvolver uma metodologia baseada em técnicas de mineração de dados para selecionar os principais marcadores SNP (Single Nucleotide Polymorphism) para as raças de ovinos: Crioula, Morada Nova e Santa Inês. Os dados utilizados foram obtidos do Consórcio Internacional de Ovinos e são compostos por 72 animais das raças citadas, e cada animal possui 49.034 marcadores SNP. Considerando que o número de atributos (marcadores) é muito maior que o de observações (animais), foram aplicadas as técnicas de predição LASSO (Least Absolute Shrinkage and Selection Operator), Random Forest e Boosting para a geração de modelos preditivos que incorporam métodos de seleção de atributos. Os resultados revelaram que os modelos preditivos selecionaram os principais marcadores SNP para identificação das raças estudadas. O modelo LASSO selecionou um total de 29 marcadores relevantes. A partir dos modelos Random Forest e Boosting, foram obtidos 27 e 20 marcadores importantes, respectivamente. Por meio da intersecção dos modelos gerados, identificou-se um subconjunto de 18 marcadores com maior potencial de identificação das raças.

ABSTRACT This study aimed at developing a method based on data mining techniques to select key SNP markers (Single Nucleotide Polymorphism) for the sheep breeds Crioula, Morada Nova and Santa Inês. We gathered data from the International Sheep Consortium of 72 animals belonging to the aforementioned breeds; each animal has 49,034 SNP markers. Whereas the number of attributes (markers) is much greater than observations (animals), the LASSO (Least Absolute Shrinkage and Selection Operator), Random Forest and Boosting prediction methods were used to generate predictive models, incorporating selection methods and attributes. The results revealed that the predictive models selected the main SNP markers for sheep breed identification. The LASSO technique selected 29 relevant markers. Yet from Random Forest and Boosting selected 27 and 20 major markers, respectively. By intersecting the generated models, we could identify a subset of 18 markers with major potential for sheep breed identification.

A identificação de parâmetros/ métricas associados à adaptação ambiental é uma das principais tendências e desafios da pecuária mundial. Desta forma, o objetivo deste trabalho foi avaliar as características de tolerância ao calor de bovinos da raça Nelore e Pantaneiro no ecossistema do Pantanal matogrossense no pico de calor da região. Estes animais foram mantidos por duas horas à sombra (8:00h às 10:00h) e em seguida uma hora ao sol (10:00h às 11:00h). Após a exposição foram analisados parâmetros de frequência cardíaca (FC), frequência respiratória (FR), temperatura retal (TR), temperatura superficial da costela (TSC), temperatura superficial do pescoço (TSP) e temperatura superficial da garupa (TSG). Também foram avaliados a taxa de sudação (TXS), comprimento e densidade de pelos e calculados o índice de tolerância ao calor (ITC). No período estudado, a temperatura ambiental variou de 29,0 a 40,0ºC e a média para umidade relativa foi de 75%. O ambiente teve influência marcante sobre as variáveis fisiológicas, com exceção da FR. A TR e a TXS diferiram significativamente entre os grupos genéticos, sendo da raça Nelore mais elevada em relação à Pantaneira, mas todas dentro dos limites fisiológicos. A análise multivariada mostrou a importância de variáveis como taxa de sudação e comprimento de pelos para adaptação de bovinos na região. Apesar do Nelore vermelho estar separado dos outros dois grupos, foi possível concluir que ambas as raças analisadas apresentaram capacidade de adaptação e tolerância ao calor às condições climáticas do Pantanal e podem ser produzidas de modo sustentável na região.

Identification of parameters/metrics associated with environmental adaptation is one of the main trends and challenges for livestock worldwide. Thus, this study was conducted at Nhumirim Farm, in Nhecolândia, Pantanal, during the month of February, period with highest ambient temperatures. We used five cattle of each genetic group (White Nelore, Red Nelore and Pantaneira) to evaluate characteristics related to heat tolerance. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), skin temperature (ST), sweating rate (SR), morphometric measurements, hair length (HL) and heat tolerance index (HTI) were evaluated. During the study the air temperature ranged from 29.0 to 40.0ºC and the average relative humidity was 75%. RT and ST were highest in White Nelore, followed by Red Nelore and Pantaneira. The average HTI value for the three groups was between 9 and 10, indicating high tolerance. The environment had considerable effect on physiological variables, except RR, RT and SR that significantly differed between genetic groups, with Nelore being higher than the Pantaneira, but all within physiological limits. Multivariate analysis showed the importance of variables such as sweating rate and hair length for the adaptation of cattle in the region. The red Nelore separated from the other two groups. We conclude, therefore, that both zebu (white and red Nelore) and European (Pantaneira) showed adaptability and heat tolerance to climatic conditions of the Pantanal.

Debatemos neste texto como os personagens dos filmes 33 (Kiko Goifman, 2002) e Olhe pra mim de novo (Kiko Goifman, Claudia Priscilla, 2009) manejam o "risco do real" (Comolli, 2008) no desenrolar da realização de tais documentários, sinalizando para a construção de roteiros abertos, ou seja, que chegam ao momento da filmagem sem uma definição prévia do que será registrado como imagem e som nos diversos planos, cenas, sequências. Para tanto, seguiremos as trilhas metodológicas de Aumont e Marie (2009) sobre a "análise fílmica", aproximando-as às noções de "documentário de busca" (Bernardet, 2005) e "leitura documentarizante" (Roger Odin, 2012) para, assim, propormos a busca pela família como uma questão desafiadora nos referidos filmes.

We will discuss in this text how characters of the films 33 (Kiko Goifman, 2002) and Olhe pra mim de novo (Kiko Goifman, Claudia Priscilla, 2009) handle the "risk of the real" (Comolli, 2008) in the course of these documentaries filmmaking, signaling to the construction of open screenplays which arrive at the time of shooting without prior definition of what will be recorded as image and sound in different planes, scenes, sequences. To do so, we follow methodological trails proposed by Aumont and Marie (2009) about "film analysis", bringing them to the notions of " search documentary" (Bernardet, 2005) and "documentary reading" (Roger Odin, 2012) to thus realize the search for family as a challenging issue in the films in question.

Vamos a discutir en este texto como los personajes de las películas 33 (Kiko Goifman, 2002) y Olhe pra mim de novo (Kiko Goifman, Claudia Priscilla, 2009) manejan el "riesgo de lo real" (Comolli, 2008) en el transcurso de la realización de esos documentales que señalizan para la construcción de guiones abiertos, es decir, que llegan al momento de la toma sin una definición previa de lo que va a ser registrado como imagen y sonido en diferentes planos, escenas, secuencias. En términos metodológicos, seguiremos las proposiciones de Aumont y Marie (2009) sobre "análisis fílmico", acercando también nociones como "documentales de búsqueda" (Bernardet, 2005) y "lectura documentarizante" (Roger Odin, 2012), propondo por último la búsqueda de la familia como una question desafiante en estas películas.

The identification of regions that have undergone selection is one of the principal goals of theoretical and applied evolutionary genetics. Such studies can also provide information about the evolutionary processes involved in shaping genomes, as well as physical and functional information about genes/genomic regions. Domestication followed by breed formation and selection schemes has allowed the formation of very diverse livestock breeds adapted to a wide variety of environments and with special characteristics. The advances in genomics in the last five years have enabled the development of several methods to detect selection signatures and have resulted in the publication of a considerable number of studies involving livestock species. The aims of this review are to describe the principal effects of natural/artificial selection on livestock genomes, to present the main methods used to detect selection signatures and to discuss some recent results in this area. This review should be useful also to research scientists working with wild animals/non-domesticated species and plant biologists working with breeding and evolutionary biology.

Brazilian goats are generally kept in small herds and extensive rearing systems, mainly in the northeastern region of the country. Despite production improvement in recent years, the lack of pedigree control has affected genetic progress. This study aimed to validate a panel of 16 microsatellites for parentage testing in locally adapted and commercial goats breeds raised in Brazil, as well as to compare its efficiency with the panel recommended by the Brazilian Ministry of Agriculture, Livestock and Supplies (MAPA) in 2004. The number of alleles and expected heterozygosity (He) per marker ranged from four to 18, and from 0.051 to 0.831, respectively. Using all markers, 100% of parentage cases of the validation dataset were resolved with a strict confidence level of 95%. The 16 microsatellites panel showed adequate exclusion power (99.99%) and identity accuracy (99.99%). Suggestions for improvement of the marker panel endorsed by MAPA are provided.

A genealogical analysis of registered Pantaneiro horses was carried out with 3647 males and 6794 females. Of these animals, 50.66% had identified sires and 48.86% identified dams. The number of pedigrees increased over the generations, with higher registration of parents of sires than dams. Two municipalities are responsible for almost 70% of all registers: i) Poconé (Mato Grosso State), where the headquarters of the breeders association is located and ii) Corumbá (Mato Grosso do Sul State), where EMBRAPA Pantanal conducts its research. The mean inbreeding was 0.04% and average relatedness was 0.13%. Mean generation interval was 8.20 years. There is moderate to high genetic differentiation between farms (15% of total genetic variation) while between municipalities there is little differentiation. Wright's fixation statistics were calculated and F IS (inbreeding coefficient of individuals relative to the subpopulation) values indicate some heterozygosity between farms but not municipalities, with overall F IT (inbreeding coefficient of individuals relative to the total population) close to zero. The municipalities with the highest number of animals (Poconé and Corumbá) import relatively fewer sires (45 and 67% respectively). Genetic indices from genealogical data on the Pantaneiro horse population show that inbreeding is under control.Future breeding plans should include germplasm exchange between municipalities. The conservation program for the Pantaneiro horse has been shown to be successful but careful planning is needed in the future to avoid inbreeding and changes in important breed traits given the increasing interest in the use of the breed in sporting competitions.

Fine mapping of quantitative trait loci (QTL) from previous linkage studies was performed on pig chromosomes 1, 4, 7, 8, 17, and X which were known to harbor QTL. Traits were divided into: growth performance, carcass, internal organs, cut yields, and meat quality. Fifty families were used of a F2 population produced by crossing local Brazilian Piau boars with commercial sows. The linkage map consisted of 237 SNP and 37 microsatellite markers covering 866 centimorgans. QTL were identified by regression interval mapping using GridQTL. Individual marker effects were estimated by Bayesian LASSO regression using R. In total, 32 QTL affecting the evaluated traits were detected along the chromosomes studied. Seven of the QTL were known from previous studies using our F2 population, and 25 novel QTL resulted from the increased marker coverage. Six of the seven QTL that were significant at the 5% genome-wide level had SNPs within their confidence interval whose effects were among the 5% largest effects. The combined use of microsatellites along with SNP markers increased the saturation of the genome map and led to smaller confidence intervals of the QTL. The results showed that the tested models yield similar improvements in QTL mapping accuracy.

Three production systems for sheep (Low - L, Medium - M and High - H technology), with increasing technological levels, were studied under conditions in the Center-west of Brazil, to determine economic weights and selection indices of important traits. Receipts and costs were simulated using an economic simulator to calculate the structure of the operational costs. Only characteristics that were responsible for more than 10% of the profit were studied, which included: number of weaned lambs, food consumption (ewe and lamb), weight of carcass and weight of female lambs sold for reproduction. Regardless of the index used (profitability or yield) or system (L, M or H), the economic weights are larger for the number of lambs weaned per ewe. With improvement in the technology used within the production system (H to L) the importance of this trait becomes less important. Lamb growth increased and weight of female for slaughter decreased in importance in higher technology systems. Changes in herd structure had little influence on economic values, whereas (co)variances were important sources of change in selection indices.

In this work, linear body measures were taken and production indices calculated for 100 Cuban Creole goats and 100 crossbred goats in order to aid in the characterization of animal genetic resources in Cuba. Low variation was found for all indices of the Creole goats, showing homogeneity between the groups of animals studied. Most of the functional indices are related to the milk biotype which is in agreement the possible origin of the breed from animals of the Iberian Peninsula and Canary Islands. The crossbreds were more varied, mostly due to undesigned disorganized crossing. These data may help in identifying a commercial niche for the breed and contribute to in situ conservation of the Cuban Creole goat.

Os objetivos neste estudo foram analisar modelos não-lineares para descrever o crescimento em ovinos da raça Morada Nova criados no estado da Bahia e, após a definição do modelo de melhor ajuste, calcular a taxa de crescimento absoluto e avaliar a influência de fatores ambientais (sexo e tipo de parto) sobre os parâmetros da curva. Utilizaram-se dados de pesagem de 40 ovinos, do nascimento aos 385 dias de idade. Os modelos não-lineares utilizados foram: Brody, Von Bertalanffy, Richards, Logístico e Gompertz. Os modelos Von Bertalanffy, Brody e Richards foram os que apresentaram os melhores ajustes e são equivalentes para explicar o crescimento dos animais. A taxa de crescimento absoluto teve acentuado decréscimo na fase pós-desmama, o que indica a necessidade de se adotar um regime alimentar adequado para acompanhar as exigências de nutrientes dos animais nessa fase. Os efeitos ambientais (sexo e tipo de parto) influenciaram significativamente a taxa a maturidade (k), mas apenas o sexo do animal afetou o peso à maturidade (A). Os animais que nasceram de parto simples tiveram peso maior que o daqueles de parto duplo, e estes apresentaram ganho compensatório. Os machos tiveram maior crescimento que as fêmeas, que, por sua vez, apresentaram maior precocidade. A correlação estimada entre os parâmetros A e k foi negativa (-0,65) para o modelo Von Bertalanffy e (-0,71) para os modelos Brody e Richards, e isso indica que os animais mais precoces possuem menor probabilidade de atingir pesos elevados à idade adulta.

The objective of the present study was to evaluate non-linear models to describe Morada Nova sheep herds raised in the State of Bahia and, after defining the best suiting model, calculate the rate of absolute growth and evaluate the influence of environmental factors (sex and type of parturition) on the curve parameters. Weighting data from 40 sheep from birth up to 385 days of age were used. The non-linear models used were: Brody, Von Bertalanffy, Richards, Logistic and Gompertz. Von Bertalanffy, Brody and Richards models presented the best adjustments and were equivalent to explain the growth of the analyzed animals. A remarkable drop in the absolute growth rate was observed after weaning, suggesting that a proper diet should be implemented to supply the nutritional demands of the animals at this stage. The environmental effects (sex and type of parturition) have significantly influenced the maturity rate (k), but only the sex of the lamb affected weight at maturity (A). Animals born from single parturition proved to be heavier than twins which, in turn, presented compensatory gain. The growth of males was higher than of females and the latter presented more precocity than males. Estimated correlation between parameters A and k was negative (-0.65) for the Von Bertalanffy model and for the Brody and Richards models (-0.71) indicating that the most precocious animals are less likely to reach elevated weights when adults.