Sexual Dimorphism in the Growth and Morphometric Allometry of the Santandereana Creole Goat Breed in Colombia
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
Simple Summary The Santandereana Creole goat inhabits the department of Santander, Colombia. It is an animal adapted to a rocky, hilly region, feeds on cacti and native grasses, and is part of the culture and tradition and a productive sector for rural communities. To the authors’ knowledge, there are no studies on sexual differentiation in the breed’s growth. A population of 99 animals was studied to evaluate morphometric allometry using 30 linear traits. It was found that sexual differentiation in growth is related to size, with body weight, body length, thoracic perimeter, and horn length being the most discriminating traits. These values were higher in males. Body indexes confirm that the Santandereana Creole goat is an animal with a tendency towards meat production, with larger males and brachycephalic features due to the shape of their heads. The traits that differentiated growth in males and females can be considered of interest for the preservation of the breed and the establishment of genetic improvement programs. plain-language-summary Abstract Animal growth involves changes in size with age and is associated with environmental factors. The aim was to conduct a study of a representative group of the Santandereana Creole goat breed to evaluate morphometric allometry according to sex. A sample of 23 males and 76 females, ranged 8–72 and 8–84 months of age respectively, was studied. Morphometric allometry was evaluated using 30 linear characters. A Mann–Whitney test as
Abstract
Simple Summary The Santandereana Creole goat inhabits the department of Santander, Colombia. It is an animal adapted to a rocky, hilly region, feeds on cacti and native grasses, and is part of the culture and tradition and a productive sector for rural communities. To the authors’ knowledge, there are no studies on sexual differentiation in the breed’s growth. A population of 99 animals was studied to evaluate morphometric allometry using 30 linear traits. It was found that sexual differentiation in growth is related to size, with body weight, body length, thoracic perimeter, and horn length being the most discriminating traits. These values were higher in males. Body indexes confirm that the Santandereana Creole goat is an animal with a tendency towards meat production, with larger males and brachycephalic features due to the shape of their heads. The traits that differentiated growth in males and females can be considered of interest for the preservation of the breed and the establishment of genetic improvement programs. plain-language-summary Abstract Animal growth involves changes in size with age and is associated with environmental factors. The aim was to conduct a study of a representative group of the Santandereana Creole goat breed to evaluate morphometric allometry according to sex. A sample of 23 males and 76 females, ranged 8–72 and 8–84 months of age respectively, was studied. Morphometric allometry was evaluated using 30 linear characters. A Mann–Whitney test assessed right- and left-side differences in horns (length and perimeter) and ears (length and width). A one-way PERMANOVA, using Gower distances, assessed sex differences. Principal component analysis (PCA) using a var-covar matrix identified the most discriminating traits. A one-way ANCOVA, using loadings at PC1, was performed to compare allometric trends between sexes. Differences between sexes were observed in linear traits (= 0.0101) and indices (= 0.0364). No differences were observed between the right and left sides in horns and ears. Differences were observed in size, with body weight, body length, thoracic perimeter, and horn length (right/left) being the most discriminating values reflecting sexual dimorphism of size. The indexes corroborated the larger size of males, especially in relation to skull width, rump length, chest depth, and body weight. Detected differences may reflect variations in the development of skeletal maturity. The indexes confirm that the Santandereana Creole goat is an animal with a tendency for meat production, with larger males and brachycephalic features due to the shape of the head. Discriminatory measures can be considered as parameters of interest for preserving the breed and establishing genetic improvement programs.