Size and shape analyses in hair sheep ram lambs and its relationships with growth performance

• Published in: Livestock science Vol. 131; no. 2; pp. 203 - 211
• Main Authors: López-Carlos, M.A., Ramírez, R.G., Aguilera-Soto, J.I., Aréchiga, C.F., Rodríguez, H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2010; Amsterdam; New York: Elsevier
• Subjects: animal age; animal development; animal growth; Blackbelly Dorper Katahdin Pelibuey; body conformation; Body measurements; breed differences; Canonical analysis; food animals; Growth performance; lambs; principal component analysis; Principal components; Ram lambs; rams; shape; sheep breeds; weaning; wool; Mexico; Ram lambs; Body measurements; Canonical analysis; Growth performance; Blackbelly Dorper Katahdin Pelibuey; Principal components
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2010.04.001

Data of 12 body measurements from purebred replacement ram lambs of four hair sheep breeds (40 Blackbelly, 40 Dorper, 40 Katahdin and 40 Pelibuey) were analyzed by conventional and multivariate techniques to assess body size and shape differences between them and their relationships with growth traits at the beginning (4.7
±
0.5
months of age) and conclusion (7.6
±
0.5
months of age) of a 90
day performance test carried out in north–central México. Moreover, Pearson correlation analyses were estimated between body measurements and productive traits, and between principal components and productive traits. The body measurements and canonical discrimination analysis revealed marked differences in body size, shape and maturity rate for the four breeds under study, but these differences are consistent with the original purpose of the breeds studied. The measurements of heart girth, abdominal girth, neck girth, loin width, and metacarpus and metatarsus circumference, contribute mostly to the differentiation among breeds both, at the immediate postweaning age (4.7
months of age) and at the end of a 90
d performance test (7.6
months of age). The first three principal components explained between 74 and 88% of the total variance in body measurements. The first component was an indicator of body size and thickness, while the second component was interpreted as an indicator of body shape at the younger age, and of body frame and maturity, at the latter age. Results indicate that lamb body shape and size changed from 4.7 to 7.6
months of age according to breed, individual conformation and age at maturity. Furthermore, body measurements and some specific conformations by breed were correlated with growth characteristics. The information from this study would be the basis of further studies to establish genetic relationships between specific patterns of body conformation and growth traits, for studied breeds.