RESUMO -Registros de 6.674 pesos de bovinos da raça Nelore nascidos entre 1975 e 1990 em duas fazendas no Estado da Paraíba foram utilizados para estudar efeitos ambientais e estimar parâmetros genéticos das características ganhos em peso diário do nascimento aos 205, dos 205 aos 365 e dos 365 aos 550 dias de idade. Os efeitos ambientais foram estudados usando-se o programa SAS ® . O modelo incluiu o efeito aleatório de touro e os efeitos fixos de ano-mês-sexo, fazenda e idade da vaca como covariável linear e quadrática. Os componentes de (co)variância usados para estimar os coeficientes de herdabilidade direta e materna foram obtidos pelo Método da Máxima Verossimilhança Restrita, usando o programa MTDFREML sob modelo animal. Todos os efeitos incluídos no modelo foram significativos, exceto o efeito de fazenda para o ganho diário do nascimento à desmama. As médias estimadas foram de 0,575 ± 0,089, 0,231 ± 0,114 e 0,283 ± 0,110 kg para ganhos em peso diário do nascimento aos 205, dos 205 aos 365 e dos 365 aos 550 dias de idade, respectivamente. As herdabilidades estimadas para efeito direto foram de 0,12, 042 e 0,21 e, para efeito materno, de 0,29, 0,00 e 0,00, na mesma ordem. Os coeficientes de herdabilidade indicam que a seleção baseada no ganho em peso pós-desmama até um ano de idade pode proporcionar considerável ganho genético.Palavras-chave: bovinos de corte, crescimento, Nordeste do Brasil, parâmetros genéticos Genetic and Environmental Effects on Nellore Cattle Growth in ParaibaABSTRACT -Records on 6,674 Nellore cattle weight, born from 1975 to 1990 in two farms located in Paraiba State were used to study environmental effects and to estimate genetic parameters for average daily gains from birth to 205 days, from 205 to 365 days and from 365 to 550 days. The SAS ® program was used to study the environmental effects. The model included the random effect of sire and the fixed effects of year-month-sex, farm and age of the cow at calving as linear and quadratic covariate. The (co)variance components used to estimate direct and maternal heritabilities were obtained by Derivative Free Restricted Maximum Likelihood using the MTDFREML program, under an animal model. All effects used were significant, but the farm effect for pre-weaning daily gain. The estimated means for average daily gains were 0.575 ± 0.089, 0.231 ± 0.114 and 0.283 ± 0.110 kg for pre-weaning daily gain, daily gain from 205 to 365 days and daily gain from 365 to 550 days of age, respectively. The heritabilities estimated for direct effect were 0.12, 0.42 and 0.21 and for maternal effect were 0.29, 0.00 and 0.00. The estimates of heritability show that selection based on daily gain from 205 days to yearling could allow considerable genetic gain. IntroduçãoO Brasil, por apresentar grande extensão territorial e considerável efetivo de população bovina (aproximadamente 150.276.778 cabeças -Anualpec, 1999), dispõe de condições suficientes para suprir as necessidades internas de demanda, como também contribuir de maneira significativa para a export...

RESUMO -Dados de pesos aos 205 (P205), 365 (P365) e 550 dias de idade (P550) de três rebanhos da raça Nelore criados no Estado da Paraíba em regime de pasto, no período de 1975 a 1990, foram utilizados. Os efeitos genéticos direto e materno foram estimados pelo Método da Máxima Verossimilhança Restrita aplicada a um modelo animal. Foram incluídos os efeitos fixos de ano-mês-sexo, fazenda e idade da vaca, como (co) variável linear e quadrática. As médias dos quadrados mínimos e respectivos erros-padrão dos P205, P365 e P550 para as três propriedades estudadas foram, respectivamente, 149, 00 ± 22,28 kg, 198,40 ± 38,84 kg, 256,99 ± 55,65 kg; 145,10 ± 21,31 kg, 182,83 ± 30,38 kg, 247,45 ± 50,57 kg e 162,12 ± 14,23 kg, 246,66 ± 23,11 kg, 332,83 ± 35,02 kg. As estimativas de herdabilidade para o efeito genético direto dos pesos aos 205, 365 e 550 dias de idade foram 0,16 ± 0,05, 0,40 ± 0,11 e 0,76 ± 0,25, respectivamente. Nesta mesma ordem, para o efeito materno dos P205, P365 e P550, os valores de herdabilidade foram 0,36 ± 0,05, 0,44 ± 0,15 e 0,01 ± 1,10. As correlações para os efeitos genético direto e materno para P205, P365 e P550 foram, respectivamente -0,70, -0,74, e -1,00. O efeito materno foi importante apenas na fase pré-desmame.Palavras-chave: peso à desmama, pesos pós-desmama, Nelore Heritability of Maternal and Direct Effects of Growth Traits in Nellore Herds atParaiba State, Brazil ABSTRACT -Weight records at 205 (205W), 365 (365W) and 550 (550W) days of age of three Nellore herds raised in Paraíba State from 1975 to 1990, were used in the analyses. Genetic and maternal effects were estimated with the restricted maximum likelihood method, assuming an animal model. There were included the fixed effects of year-month-sex and farm. The linear and quadratic effects of age of dam at calving were included in the model as covariables. The least squares means and respective standard errors for P205, P365 and P550 for three studied farms were, respectively, 149.00 ± 22.28 kg, 198.40 ± 38.84 kg, 256.99 ± 55.65 kg; 145.10 ± 21.31 kg, 182.83 ± 30.38 kg, 247.45 ± 50.57 kg e 162.12 ± 14.23 kg, 246.66 ± 23.11 kg, 332.83 ± 35.02 kg. The heritabilities estimates for genetic direct effect were 0,16 ± 0,05, 0,40 ± 0,11 e 0,76 ± 0,25, for 205W, 365W and 550W, respectively. The heritabilities estimated for the maternal effects of 205W, 365W and 550W were 0,36 ± 0,05, 0,44 ± 0,15 and 0,01 ± 1,10, respectively. The correlations between direct and maternal effect for 205W, 365W and 550W were -0,70, -0,74, and -1,00, respectively. Maternal effects were important only in the pre-weaning phase. Rev. bras. zootec., 30(4):1224-1227, 2001Introdução As características fenotípicas de valor econômico são influenciadas por um componente genotípico que inclui a variância genética aditiva e não aditiva dos genes e um componente ambiental, regulado pela influência temporária ou permanente do meio ambiente. O ambiente materno pode influenciar o crescimento do bezerro tanto na fase pré-natal quanto na fase pós-natal, sendo que nesta última...

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Biodiversity studies are more efficient when large numbers of breeds belonging to several countries are involved, as they allow for an in-depth analysis of the within- and between-breed components of genetic diversity. A set of 21 microsatellites was used to investigate the genetic composition of 24 Creole goat breeds (910 animals) from 10 countries to estimate levels of genetic variability, infer population structure and understand genetic relationships among populations across the American continent. Three commercial transboundary breeds were included in the analyses to investigate admixture with Creole goats. Overall, the genetic diversity of Creole populations (mean number of alleles = 5.82 ± 1.14, observed heterozygosity = 0.585 ± 0.074) was moderate and slightly lower than what was detected in other studies with breeds from other regions. The Bayesian clustering analysis without prior information on source populations identified 22 breed clusters. Three groups comprised more than one population, namely from Brazil (Azul and Graúna; Moxotó and Repartida) and Argentina (Long and shorthair Chilluda, Pampeana Colorada and Angora-type goat). Substructure was found in Criolla Paraguaya. When prior information on sample origin was considered, 92% of the individuals were assigned to the source population (threshold q ≥ 0.700). Creole breeds are well-differentiated entities (mean coefficient of genetic differentiation = 0.111 ± 0.048, with the exception of isolated island populations). Dilution from admixture with commercial transboundary breeds appears to be negligible. Significant levels of inbreeding were detected (inbreeding coefficient > 0 in most Creole goat populations, P < 0.05). Our results provide a broad perspective on the extant genetic diversity of Creole goats, however further studies are needed to understand whether the observed geographical patterns of population structure may reflect the mode of goat colonization in the Americas.

RESUMO -Objetivou-se com este trabalho verificar a utilização de 27 microssatélites para caracterização genética das raças caprinas nativas do Brasil. Foram coletadas amostras de pêlos de 332 animais das raças Moxotó (60), Canindé (50), Serrana Azul (55), Marota (68), Repartida (52) Genetic characterization of Brazilian native breeds of goats using 27 markers microsatellitesABSTRACT -This study aimed to evaluate 27 microsatellites for genetic characterization of Brazilian native goats using samples of hair collected from 332 animals of the Moxotó, Canindé, Serrana Azul, Marota, Repartida and Graúna breeds.Twenty-seven microsatellites were selected, amplified by polymerase chain reaction (PCR). The amplified products were submitted to electrophoreses in poliacrylamide gel using an ABI 377XL automatic sequencer. The number of alleles ranged between three (MAF209) and twenty-three (CSSM66). Averages of expected and observed heterozigosity were respectively 0,672 and 0,582. Except for the marker MAF209 (PIC: 0,042), all the analyzed microsatellites were informative. The polymorphism of all microsatellites indicate their hability in identifying genetic variability of Brazilian native breeds of goats.Key Words: goats, genetic conservation, molecular markers, genetic variability IntroduçãoAs raças caprinas nativas do Brasil estão localizadas na Região Nordeste, onde os animais são criados em sistemas extensivo e semi-extensivo para produção de carne, pele e leite. São animais bem adaptados à região semi-árida e resistentes a doenças e parasitas. Porém, são poucos os trabalhos realizados com esses animais, ameaçados de extinção. Para minimizar esse problema, um programa de conservação foi estruturado e uma de suas prioridades é o estudo da caracterização genética desses patrimônios genéticos.Segundo Gama (2004), a variabilidade genética total das espécies é representada pela contribuição das variabilidades inter e intra-raciais. Verifica-se, portanto, a importância de se medir a variabilidade genética dos animais, visto que a conservação dos recursos genéticos está efetivamente relacionada à manutenção das variabilidades inter-racial (evita a extinção das raças) e intra-racial (evita a erosão genética).A caracterização genética com o uso de marcadores moleculares tem demonstrado ser uma ferramenta eficaz para quantificação da diversidade genética de animais domésticos. Os marcadores genéticos são loci que apre-

Goats are important from a socioeconomic perspective for the poor in arid regions, worldwide. Nevertheless, more than half of the local breeds in the world are threatened and have not been fully characterized. The Canindé is one of the main local breeds of northeastern Brazil and, like most, their effective numbers have fallen over the years and needs to be characterized. Many tools are available for assessing the phenotypic profile of a breed and multivariate techniques are important when considering all variables simultaneously. The present study utilized multivariate techniques for phenotypic characterization of the Canindé goat breed from 11 morphometric variables (HL = head length; FW = face width; HW = head width; BL = body length; CG = chest girth; WH = wither height; SRH = sacral region height; CW = croup width; CL = croup length, SP = shin perimeter and ES = ear size) and morphological variables of qualitative character (presence and absence of earrings, horns, beard, abnormal teat number and hair length) collected from herds from different states (populations) in the northeast of Brazil. Multivariate analysis allowed the differentiation and characterization of the evaluated individuals, HL, FW, WH, SRH and BL variables were the most important to define the phenotypic profile of the studied populations. Examined whether spatial organization of individuals was assessed in each state of the Brazil demonstrated considerable diversity of phenotypes within breeds from the different states. These data could be used successfully in a conservation breeding programme.

Brazilian goat breeds are believed to derive mainly from animals brought by Portuguese settlers since the 16th century. We used microsatellite markers in a sample of 436 animals to study genetic variability and differentiation of the six Portuguese (PT) and six Brazilian (BR) goat breeds currently recognized in the two countries. These breeds were also compared with an outgroup represented by a sample of Alpine (ALP) goats. The effective number of alleles and allelic richness were slightly higher in PT than in BR breeds. The global F(ST) was nearly 0.11 when PT and BR breeds were considered, with a mean pairwise F(ST) of about 0.03 among PT breeds, 0.07 among BR breeds and 0.15 between PT and BR breeds. The dendrogram illustrating relationships between populations and the correspondence analysis indicate the existence of two very distinct clusters, corresponding to the countries of origin of the breeds studied, which are nearly equidistant from the Alpine outgroup. The analysis with structure confirmed the separation between PT and BR breeds but suggests that some BR breeds, especially Graúna and Canindé, may share a common ancestry with PT breeds. The divergence observed between PT and BR breeds may result from founder effects and genetic drift but could also reflect the introduction in Brazil of goats originating from other regions, e.g., West Africa.

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