BackgroundAmerican Creole cattle presumably descend from animals imported from the Iberian Peninsula during the period of colonization and settlement, through different migration routes, and may have also suffered the influence of cattle directly imported from Africa. The introduction of European cattle, which began in the 18th century, and later of Zebu from India, has threatened the survival of Creole populations, some of which have nearly disappeared or were admixed with exotic breeds. Assessment of the genetic status of Creole cattle is essential for the establishment of conservation programs of these historical resources.Methodology/Principal FindingsWe sampled 27 Creole populations, 39 Iberian, 9 European and 6 Zebu breeds. We used microsatellite markers to assess the origins of Creole cattle, and to investigate the influence of different breeds on their genetic make-up. The major ancestral contributions are from breeds of southern Spain and Portugal, in agreement with the historical ports of departure of ships sailing towards the Western Hemisphere. This Iberian contribution to Creoles may also include some African influence, given the influential role that African cattle have had in the development of Iberian breeds, but the possibility of a direct influence on Creoles of African cattle imported to America can not be discarded. In addition to the Iberian influence, the admixture with other European breeds was minor. The Creoles from tropical areas, especially those from the Caribbean, show clear signs of admixture with Zebu.Conclusions/SignificanceNearly five centuries since cattle were first brought to the Americas, Creoles still show a strong and predominant signature of their Iberian ancestors. Creole breeds differ widely from each other, both in genetic structure and influences from other breeds. Efforts are needed to avoid their extinction or further genetic erosion, which would compromise centuries of selective adaptation to a wide range of environmental conditions.

Genetic diversity in and relationships among 26 Creole cattle breeds from 10 American countries were assessed using 19 microsatellites. Heterozygosities, F-statistics estimates, genetic distances, multivariate analyses and assignment tests were performed. The levels of within-breed diversity detected in Creole cattle were considerable and higher than those previously reported for European breeds, but similar to those found in other Latin American breeds. Differences among breeds accounted for 8.4% of the total genetic variability. Most breeds clustered separately when the number of pre-defined populations was 21 (the most probable K value), with the exception of some closely related breeds that shared the same cluster and others that were admixed. Despite the high genetic diversity detected, significant inbreeding was also observed within some breeds, and heterozygote excess was detected in others. These results indicate that Creoles represent important reservoirs of cattle genetic diversity and that appropriate conservation measures should be implemented for these native breeds in order to minimize inbreeding and uncontrolled crossbreeding.

Resumo -O objetivo deste trabalho foi estudar a influência de fatores ambientais e genéticos nas características fenotípicas de búfalo (Bubalus bubalis) das raças Carabao, Jafarabadi, Murrah e Mediterrâneo e do tipo Baio. Os dados foram analisados usando-se o procedimento GLM do SAS (Statistical Analysis System), cujo modelo estatístico incluiu os efeitos fixos de ano e mês de nascimento, ordem de parto e sexo do animal. As médias encontradas para as variáveis foram: peso ao nascer de 32,79 kg (de 32,22 a 34,71 kg), peso da fêmea adulta de 514,31 kg, primeiro intervalo entre partos de 501,30 dias (de 483 a 564 dias), período de serviço de 191,30 dias (de 86 a 191 dias), idade ao primeiro parto de 1.088,03 dias (de 1.040 a 1.156 dias) e intervalo entre partos de 380,32 dias (de 373 a 392 dias). O grupo genético dos machos teve influência significativa nas características estudadas, exceto no peso da fêmea adulta. O sexo do bezerro influenciou o peso ao nascer e idade ao primeiro parto. A ordem de parto influenciou o peso ao nascer, período de serviço e intervalo entre partos. O ano e mês de nascimento influenciaram todas as características estudadas. As médias das características produtivas nas populações de bubalinos criadas na Região Amazônica demonstram que a espécie encontra-se adaptada àquelas condições, constituindo-se em uma alternativa para os criadores.Termos para indexação: Bubalus bubalis, idade ao primeiro parto, intervalo entre partos, fatores ambientais. Phenotypic characterization of national Brazilian buffalo breeds and Baio typeAbstract -The objective of this study was to verify the influence of environmental and genetic factors on buffalo (Bubalus bubalis) of the Carabao, Jaffarabadi, Mediterranean, and Murrah breeds and of the Baio type, utilizing the GLM procedure of SAS (Statistical Analysis System). The mean birth weight was 32.79 kg (from 32.22 to 34.71 kg), mature female weight was 514.31 kg, first calving interval was 501.30 days (from 483 to 564 days), service period was 191.30 days (from 86 to 190 days), age at first calving was 1,088.03 days (from 1,040 to 1,156 days) and calving interval was 380.32 days (from 373 to 392 days). Sire group significantly affected all traits studied, except mature female weight. Calf sex affected both birth weight and age at first calving. Calving order affected birth weight, service period and calving interval while year of calving significantly affected most traits studied. The productive characteristics studied on the buffalo populations raised on the Brazilian Amazon show that this species is well adapted to those harsh conditions and that it can be considered as an alternative for breeders.Index terms: Bubalus bubalis, age at first calving, calving interval, environmental factors.(1) Aceito para publicação em 26 IntroduçãoEstima-se que o aumento do rebanho bubalino mundial seja de 10% ao ano, refletindo o crescente interesse mundial por esta espécie (Vale, 1988, citado por Sampaio Neto et al., 2001. Mattos (1992) relatou que a população bubalina no ...

Resumo -O objetivo deste trabalho foi estimar componentes de variância e parâmetros genéticos, incluindo correlações genéticas, fenotípicas e herdabilidade das características produtivas e reprodutivas de búfalos na Amazônia brasileira. As estimativas de herdabilidade (h 2 ) das características variaram de 0,04 a 0,05 no primeiro intervalo entre partos, de 0,0 a 0,26 no intervalo entre partos, e de 0,0 a 0,25 no período de serviço, refletindo grande influência ambiental. Na idade ao primeiro parto, a herdabilidade variou de 0,12 a 0,38. Em relação ao peso ao nascer, a raça Murrah foi a que apresentou a mais alta h 2 (0,62). As correlações genéticas variaram de 1,00 a -1,00. Foram negativas as correlações genéticas entre idade ao primeiro parto e peso da fêmea adulta (-0,12 a -1,00 dependendo da raça), assim como as correlações entre período de serviço, peso ao nascer e peso da fêmea adulta (0,01 a -1,00). O efeito de ambiente permanente (c 2 ) variou de 0,000 a 0,155. Somente no intervalo entre partos para a raça Jafarabadi pode-se considerar que houve c 2 significativo (0,458). O efeito materno (m 2 ) no peso ao nascer variou de baixo a médio, nas raças Carabao, Jafarabadi, Mediterrâneo e Murrah (0,11, 0,17, 0,37, 0,04, respectivamente).Termos para indexação: correlações genéticas, herdabilidades, índices de produção e reprodução. Genetic parameters of production and reproduction traits of buffaloes in the Brazilian AmazonAbstract -The aim of this study was to estimate genetic parameters, including genetic and phenotypic correlations as well as heritabilities, for production and reproduction traits of buffaloes in the Brazilian Amazon. Heritability estimates varied from 0.04 to 0.05 for FCI (first calving interval), 0.0 to 0.26 for CI (calving interval) and 0.0 to 0.25 for SP (service period), reflecting high environmental variation for these traits. For AFC (age at first calving) the heritabilities varied from 0.12 to 0.38. The Murrah breed showed the highest heritabilitiy for BW (birth weight) (0.62). Genetic correlations varied between 1.00 and -1.00 depending on the traits. There were negative genetic correlations between AFC and MFW (mature female weight) (-0.12 to -1.00 depending on breed) as well as between SP, BW and MFW (0.01 to -1.00). Permanent environment effects of the traits were low (0.000 to 0.155) and only that for CI in the Jafarabadi breed could be considered significant (0.458). Maternal effects for birth weight were low to medium (0.11, 0.17, 0.37 and 0.04 for Carabao, Jaffarabadi, Mediterranean and Murrah, respectively).