Percorrer por autor "Navas, D."
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- Classification and morphological characterization of native Portuguese cattle breeds using numerical taxonomyPublication . Sobral, M.; Cravador, A.; Navas, D.; Roberto, C.; Reis, Clara; Lima, M. B.A morphological study was carried out to characterize eight Portuguese cattle breeds by the application of numerical taxonomic methods.
- Growth hormone AluI polymorphism analysis in eight Portuguese bovine breedsPublication . Reis, Clara; Navas, D.; Pereira, M.; Cravador, A.A total of 195 bulls of eight Portuguese beef cattle breeds (Alentejana, Arouquesa, Barros , Maronesa, Marinhoa, Mertolenga, Mirandesa and Preta) were genotyped for the GH AluI polymorphism by the polymerase chain reaction and restriction length polymorphism (PCRRFLP). The genotype and gene frequencies for each breed were determined and shown to be quite variable among the breeds. The overall gene frequencies for L and V were 0.759 and 0.241, respectively. The relation between the bGH-AluI polymorphism and growth performances was ascertained in 168 of the animals analysed. According to our results there is a significant association between the genotypes LL and LV of the bGH and the average live body weight of the animals of the breeds Alentejana, Marinhoa and Preta.
- Identification of descendants of an extinct bovine population from the Algarve region of Portugal using numerical taxonomy analysis of morphological traitsPublication . Sobral, M.; Roberto, C.; Navas, D.; Palmilha, Isabel; Lima, M. B.; Cravador, A.The morphology of a sample of four bulls and 43 cows, presumed to be descendants of the extinct cattle breed ‘Algarvia’ (AG), was used to assign their relationship with animals from other Portuguese autochthonous breeds – Arouquesa (AR), Barrosa˜ (BA), Cachena (CA), Marinhoa (MA), Maronesa (MO), Minhota (MN), Mirandesa (MI), (only bulls), Alentejana (AL), Garvonesa (GA), Mertolenga (ME) and Preta (PR). Standard numerical taxonomic methods were applied to a set of 183 (cows) and 170 (bulls) traits, to derive average pairwise taxonomic distances among the sample of 257 cows and 76 bulls. Distance coefficients (morphological index of distance) ranged from 0.22 to 2.62 (cows) and from 0.49 to 2.13 (bulls). Unweighted pair group method using arithmetic averages (UPGMA)-based phenograms and a principal coordinate analysis showed that bulls were highly clustered and cows showed a tendency to cluster according to their geographical and breed origin. The AG population grouped together with GA, AL, ME and MN breeds in the Red Convex group. The average taxonomic distance among breeds was 1.02, the highest being 1.39 (ME versus BA) and the lowest being 0.64 (MA versus AR). The approach allowed for the identification of a phenotypically differentiated set of animals, comprising 19 cows and four bulls representative of the AG breed, and which can be targeted in further studies aiming at the recovery of this extinct breed.