ABSTRACT The objective of this study was to evaluate the morphology and biometrics of female Amiata donkeys reared in four different areas of southern Tuscany, Italy, to determine the differentiation degree of animals. Four southern Tuscan areas were investigated: two mountainous zones (East and West Amiata) and two flatter areas (Coastal area and Siena surrounding). Morphology and biometrics of adult female Amiata donkeys were collected to determine the homogeneity of the population. Primitive coat markings typical of the breed (shoulder and leg stripes) were found in Amiata donkey. Jennets from Siena surrounding were more dolichomorphic, while West Amiata individuals were smaller. The Principal Component Analysis and the Discriminant Analysis separated the Siena surrounding jennets from the other populations. This result was confirmed through the heatmap representation. The biometrics found in this research confirm that Amiata donkey is a small-medium sized breed suitable for different purposes.

Dados da Associação Brasileira de Criadores de Zebu (ABCZ), correspondentes a 2977 bezerros da raça Nelore, nascidos no período de 1976 a 1994 e criados em regime de pasto em 11 fazendas dos Estados do Piauí e Ceará, foram analisados para estudar o efeito dos fatores de ambiente e estimar as herdabilidades para a característica peso aos 205 dias de idade (peso a desmama). O modelo matemático incluiu os efeitos fixos de sexo, ano, estação e fazenda de nascimento, a covariável idade da mãe e o efeito aleatório de touro. Os componentes de variância usados para estimar a herdabilidade (h²) foram obtidos pelo método da Máxima Verossimilhança Restrita Livre de Derivativa, usando o programa MTDFREML. Os efeitos fixos de sexo, ano e fazenda de nascimento foram significativos e os de estação de nascimento e a idade da mãe ao parto, não-significativos. A média ajustada para o peso à desmama foi de 129,06 ± 1,46 kg (CV=17,6 %). Os machos foram, em média, 12 kg mais pesados que as fêmeas e os animais mais pesados nasceram no ano 1982, com média de peso de 146,54 ± 5,22 kg, enquanto os mais leves nasceram no ano 1979, com média de peso de 114,13 ± 4,51 kg. As diferenças entre as fazendas foram bastante evidentes, e algumas apresentaram médias muito elevadas em relação à média geral. A herdabilidade para o peso a desmama foi 0,48 ± 0,08.

Growth records from Associação Brasileira de Criadores de Zebu (ABCZ), correspondent to a 2977 Nellore breed calves, born from 1976 to 1994 and raised on pasture in 11 herds from Piauí and Ceará states were analyzed to study the environmental factor effects and to estimate the heritability for the traits weight at 205 days of age (weaning weight). The mathematical model included the fixed effects of sex, year, season and herd of the birth, the covariant age of the dam and the random effect of the sire. The variance components used to estimate the heritability (h²), were obtained by Derivative Free Restricted Maximum Likelihood, using MTDFREML program. The fixed effects of sex, year and herd of birth were significant, whereas the season of birth and the age of the dam at calving were not significant. Least squares means for the weaning weight was 129.06 ± 1.46 kg (CV =17.6%). Males were an average, 12 kg heavier than females and the heaviest animals were born in the year of 1982, with a mean weight of 146.54 ± 5.22 kg, while the lightest ones were born in the year of 1979, with a mean weight of 114.13 ± 4.51kg. Differences among herds were evident, and some showed high mean values in relation to the overall mean value. The heritability for weaning weight was .48 ± .08.