Brazilian naturalized goat breeds are adapted to the semiarid conditions prevalent in the Northeast region of the country (which has the largest Brazilian goat heard) and represent an as yet uninvestigated source of genetic diver- sity. Currently, imported goat breeds are crossed with Brazilian naturalized goat breeds, endangering the genetic po- tential of the naturalized breeds. We used 11 microsatellite markers to determine the genetic diversity among imported (non-naturalized) dairy Alpine and Saanen goats and naturalized Brazilian Moxotó goats. We genotyped 292 goats from three herds (one private, one from the University of Minas Gerais and the Moxotó conservation herd from Embrapa Caprinos) and found that the general heterozygosity was 0.6952 for Alpine, 0.7043 for Saanen and 0.4984 for Moxotó goats. The number of alleles ranged from 5 (INRA005 )t o 11 (BM3205), with an average of 7 al- leles per locus in the imported breeds and 3.5 alleles per locus in the Moxotó breed. Mean differentiation between populations was higher for herds (FSTS = 0.0768) than for breeds (FSTP = 0.0263), indicating similarity between the imported breeds and the existence of crosses between them. Nei's genetic distance was highest between the Moxotó breed and the imported breeds. These indicate that further studies using these molecular markers would be fruitful.

Objective: The objective of this study was to estimate the genetic parameters for worm resistance (WR) and associated characteristics, using the linear-threshold animal model via Bayesian inference in single- and multiple-trait analyses.Methods: Data were collected from a herd of Santa Inês breed sheep. All information was collected with animals submitted to natural contamination conditions. All data (number of eggs per gram of feces [FEC], Famacha score [FS], body condition score [BCS], and hematocrit [HCT]) were collected on the same day. The animals were weighed individually on the day after collection (after 12-h fasting). The WR trait was defined by the multivariate cluster analysis, using the FEC, HCT, BCS, and FS of material collected from naturally infected sheep of the Santa Inês breed. The variance components and genetic parameters for the WR, FEC, HCT, BCS, and FS traits were estimated using the Bayesian inference under the linear and threshold animal model.Results: A low magnitude was obtained for repeatability of worm-related traits. The mean values estimated for heritability were of low-to-high (0.05 to 0.88) magnitude. The FEC, HCT, BCS, FS, and body weight traits showed higher heritability (although low magnitude) in the multiple-trait model due to increased information about traits. All WR characters showed a significant genetic correlation, and heritability estimates ranged from low (0.44; single-trait model) to high (0.88; multiple-trait model).Conclusion: Therefore, we suggest that FS be included as a criterion of ovine genetic selection for endoparasite resistance using the trait defined by multivariate cluster analysis, as it will provide greater genetic gains when compared to any single trait. In addition, its measurement is easy and inexpensive, exhibiting greater heritability and repeatability and a high genetic correlation with the trait of resistance to worms.

The objective of this study was to assess genetic diversity among 5 Brazilian (155 animals) and 5 U.S. goat (120 animals) breeds using 23 microsatellite markers. Samples from the United States represented a broad geographic distribution whereas Brazilian samples were from the northeast region. Samples from Boer were common to each country's breed count. Expected and observed heterozygosity among breeds ranged from 0.55 to 0.72, suggesting ample genetic diversity in the breeds evaluated. United States Angora, U.S. Spanish, and Brazilian Nambi ranked highest for allelic richness, averaging 6.1, 7.1, and 6.5 alleles per locus, respectively. Angora and Spanish also ranked highest in private alleles (7 and 9, respectively). Using STRUCTURE, the U.S. Spanish were also found to share a common cluster assignment with Brazilian Nambi, suggesting that progenitor breeds may have been the same and passed through the Canary Islands or Cape Verde in route to the New World. When non-Boer breeds were pooled by country, the effect of the subpopulation compared with total population (F-st) = 0.05, suggesting minor genetic differences exist between countries. The lack of genetic structure among goat breeds when compared with other species (e.g., Bos taurus vs. Bos indicus) suggests goat breeds may exhibit a plasticity that facilitates productivity across a wide range of countries and environments. Taken a step further, the concept of breed for meat goats may not be as relevant for goat production.

The objective of this study was to evaluate live weight and carcass traits, from birth to slaughter, and meat quality of Nellore (NEL), Curraleiro Pé-Duro (CPD), and crossbred (F1) products in the state of Piauí, Brazil. Progenies from CPD, NEL, and their F1 crossbred (½ NEL + ½ CPD), a total of 252, males and females, from birth to 24 months of age, were evaluated in a comparative study in growth performance. The steers were sent to slaughter at 28 months of age and carcasses and meat quality were analyzed. After slaughter, carcass weight, dressing percentage and Longissimus dorsi area (rib eye area) were evaluated; an index was created by the relationship between these measures per hundred kg of chilled carcass produced. To assess meat quality, the shear force, water-holding capacity, color, brightness, pH, and cooking loss were investigated. Results obtained showed that month and year of birth were significant on growth, indicating influence of climatic variables. Nellore offspring was heavier than F₁ and this was heavier than CPD throughout the study period, including the hot and cold carcass. No differences were found in dressing percentage among NEL and F₁, but CPD and F₁ showed a rib eye area and index significantly higher than NEL. The meat from CPD group presented a stronger red coloration than the others, but there was no significant difference in the remaining meat qualitative variables among the three groups. Curraleiro Pé-Duro and F₁ crossbred produce more meat per 100 kg of carcass than Nellore in natural pasture of Piauí State.