Body Shape Characters Research Articles

Multivariate principal components analysis of the morphostructural traits of West African Dwarf sheep

A study was conducted to determine the interdependence among conformation traits of 178 West African Dwarf sheep and to predict body weight from their independent scores using principal components analysis. Body weight and nine morphostructural traits: height at withers, body length, heart girth, rump height, hip width, chest depth, fore canon bone length, tail length, and ear length were measured. Phenotypic correlation coefficients between body weight and body dimensions ranged from 0.78 to 0.79. Anti-image correlations of the body shape characters showed that partial correlations were low. Two principal components were extracted from the factor analysis with varimax rotation of the inter-correlated traits which accounted for 69.50% of the total variance. The first principal component (PC1) explained 57.70% and second principal component (PC2) contributed 11.70% of the variance. Both PC1 and PC2 could be considered in the selection programme to obtain animals with better conformations using minimal number of measurements.

Shared variability in body shape characters at growing phase of indigenous piglets

Body measurement traits, body length (BL) , rump height (RH), rump length (RL), rump width (RW), shoulder width (SW), wither height (WH), heart girth (HG), and flank length (FL) of 52 piglets of indigenous breed, managed under traditional system were obtained at birth and at weaning, to evaluate the sources of shared variability and efficiency of weight determination. Factor analysis reveals four factors accounting for 89.53% at birth and three factors accounting for 73.52% at weaning. Most common variability in body dimension at birth and at weaning could be accounted for by factors representing general size and RL in both cases. Body conformation “shape” was controlled by common and unique factors at both ages. Amount of variation associated with shape characters increased with advancing age and accuracy of weight estimation decreased with increase in age.

GENETIC PARAMETERS OF BODY WEIGHT AND MEASUREMENTS TRAITS IN BALADI BLACK RABBITS

ABSTRACT: A total of 250 progeny of 17 sires and 58 dams from Baladi Black breed population were used to estimate variance components and heritability of growth traits. Traits studied were individual body weight (BW12), body length (BL12), head length (HL12) and thigh circumference (TC12) all at 12 weeks of age. Single-trait Animal Model (DFREML) was used to estimate genetic variance components, as well as permanent environmental variation. Estimates of variance components were 0.52, 0.96, 0.91 and 0.81 for BW12, BL12, TC12 and HL12, respectively. Heritability estimates were 0.24, 0.36, 0.36 and 0.33 for BW12, BL12, TC12 and HL12 respectively. The proportions of variance due to permanent environmental effect of dams were 0.08, 0.05, 0.10 and 0.12 for BW12, BL12, TC12 and HL12, respectively. Results showed that out of the principal components (PC) calculated, the one represent 68.98 % of the total variance. The PC1 was 68.98 of the generalized variance. Principal component factor scores expound 77 % of the variation in the body weight of rabbits. Conclusively, the use of orthogonal body shape characters (PC1) derived from the principal component factor solution could be more reliable in predicting body weight compared to the use of the original autocorrelated body measurements. This is because multicollinearity of interdependent explanatory variables could lead to false inferences when original body measurements are used as predictors. Key words: Body measurements, multicollinearity, Rabbits, Principal Component Analysis.

Phenotypic characterization of the indigenous chickens <i>(Gallus gallus)</i> in the northwest of Algeria

Abstract. This study was conducted to characterize local chickens in the northwest of Algeria based on some phenotypic traits and to look at prediction of body weight from morphometric measurements (linear body). The results indicated that the predominant comb colour was dark red (77.8 %), followed by light red (22.2 %). Tarsus colour was either white (40.9 %), grey (31 %), yellow (15.39 %), dark (8.05 %), or green (4.51 %). Most chickens (81.7 %) had orange eyes, while 10.37 and 7.92 % had yellow and dark-brown eyes, respectively. The dominant earlobe colour was white (73.96 %), followed by red (16.81 %). The remaining proportion included yellow and red-mottled yellow and black earlobes. Proportions of the adaptive genes were low. Incidences of Na, F, Pti, Cr, R, and P genes were 8.82, 0.45, 1.22, 5.54, 3.35, and 4.7 %, respectively. The calculated gene frequencies ranged from 0.002 to 0.045. Variations were also found in quantitative morphological traits. Sex-associated differences (P < 0.001) were observed in almost all the parameters evaluated with higher values recorded for males. Phenotypic correlations of body weight and biometric traits ranged from −0.13 to 0.88 and −0.15 to 0.97 for males and females, respectively. From the factor analysis with varimax rotation of the intercorrelated traits, three principal components which accounted for 71.6 and 73.2 % of the total variance were extracted in males and females, respectively. Orthogonal body shape characters derived from the factor analysis accounted for 84.3 and 94.2 % of the variation in body weight of males and females, respectively. Information obtained from this study could be useful in an appropriate management, breeding programmes for selection and utilization of Algerian chicken genetic resources.

Application of principal component and discriminant analyses to morpho-structural indices of indigenous and exotic chickens raised under intensive management system

The objectives of this study were to investigate the relationships between body weight and morpho-structural indices to predict body weight from their orthogonal body shape characters using principal component analysis and to morphologically classify the chicken genotypes using multivariate discriminant analysis. Data used were from 273 randomly selected 12-weeks-old indigenous chickens of normal-feathered (NF), frizzle-feathered (FF), naked-neck (NN) and Anak Titan (AT) genotypes. Phenotypic correlation among body weight and most biometric traits ranged from 0.227-0.876, -0.7-0.901, 0.034-0.968 and -0.207-0.849 for NF, NN and AT chickens, respectively. Factor analysis with varimax rotation of interrelated traits revealed three principal components which accounted for 83.1%, 74.4%, 78.8% and 76.5% of the total variance in NF, FF, NN and AT chickens in the order listed. Breast girth, keel length, thigh length, shank length and wing length were found to be the most discriminating variables to separate the chicken genotypes. The longest distance (72.54) occurred between AT and NF genotypes while the shortest distance (4.27) was recorded for FF and NN genotypes. Classification results showed that 85.2% of AT genotype was correctly classified into their source population. However, 22.7% of NF was misclassified as NN, while 33.3% of NN was misclassified as NF chickens. These results suggest that there is high rate of gene flow between these two indigenous chicken genotypes. Information obtained from this study may be considered useful in breed improvement programmes for selection, characterization, conservation and better management of Nigerian indigenous chickens.

Shared variability of body shape characters in adult muscovy duck

In this study body weight and six body measurements namely body length, breast circumference, thigh length, shank length, total leg length and wing length of 150 twenty weeks old male and female Nigeria indigenous muscovy duck, reared under semi intensive system, were subjected to factor analysis. The objectives of the study were to evaluate the main sources of shared variability among body shape characters, to deduce the factors that describe these characteristics and to quantify sex differences in morphometric size and shape in adult muscovy duck. Variation occur in descriptive statistics between male and female traits in favour of the male in almost all traits except shank length. Magnitude of correlation also differ between sexes. Common factor variability in the measured traits in both sexes were accounted for by two factors and are about similar. Body conformation and shape appears to be controlled by common and unique factors. Communalities ranged from 0.671 for shank length to 0.987 for body length.

Changes in sources of shared variability of body size and shape in Egyptian local and New Zealand White breeds of rabbits during growth

Abstract. Correlations between body weight and measurements (body length, thigh circumference, shank length and chest width) at 6, 8, 10 and 12 weeks of age in New Zealand White (NZW), Red Baladi (RB), Black Baladi (BB) breeds of rabbits were studied by factor analysis to disclose the main sources of shared variability, to deduce the factors that describe these characteristics and to quantify breed differences in morphometric size and shape variation during growth. Differences and similarities between NZW and Egyptian rabbit breeds in factors describing variations in size and shape characters are discussed. At marketing age, compared with local breeds (RB and BB), NZW had higher communality (proportion of variance for a variable that is shared in common by other variables) for chest width and lower communality for body weight and other body shape characters. Compared with NZW, Egyptian breeds varied more in size and less in shape characters. Finding indicated that most of the common variability in live performance traits could be accounted for by two factors with the influence of general factor preponderating. Irrespective of breed, the first factor at various ages was interpreted as a general size factor. The second factor varies with breed and stage of development. In NZW, this factor at all ages (6 to 12 weeks) was described as chest width factor. The second factor in RB was designated to chest width (at 6 and 8 weeks) and a shank length at 10 and 12 weeks. In BB, the second factor was designated to chest width (at 6 weeks), a shank length (at 8 and 10 weeks) and to thigh circumference (at 12 weeks). The importance of the general size factor in relation to the second factor (shape) changes with age. The contribution of the general size factor to the total variance decreased with age in both NZW and RB, but it showed irregular pattern in BB. While that of the second factor increased with advancing age from 6 to 12 weeks in RB and from 6 to 10 weeks in NZW.

Sources of shared variability among body shape characters at marketing age in new zealand white and egyptian rabbit breeds

Body measurements (body length, thigh circumference, shank length and chest width) of 311 rabbits representing three breeds, New Zealand White (NZW), Red Baladi (RB) and Black Baladi (BB) purebreds were subject to factor analysis. The objectives of this study were (a) to disclose the main sources of shared variability among body shape characters, (b) deduce the factors that describe these traits, (c) quantify the breed differences in size and shape and (d) predict live weight at marketing age from orthogonal body shape characters. Body conformation 'shape' appeared to be controlled by common and unique factors. The communalities ranged from 0.80 for chest width to 0.99 for thigh circumference and uniqueness (special factors) made the balance. Compared with local breeds (RB and BB), NZW had higher communality (proportion of variance for a variable that is shared in common by other variables) for chest width and lower communality for thigh circumference and body length. Our findings indicated that most of the common variability in NZW body dimensions could be accounted for by factors representing general size and chest width. Corresponding factors in RB were general size and shank length and those in BB were general size and thigh circumference. Independent body shape characters derived from factor analysis accounted for 83.4%, 87.9% and 90.8% of the variation in live body weight in New Zealand White, Red Baladi and Black Baladi, respec- tively. New Zealand White rabbits / Egyptian rabbits / body dimensions / multicollinearity / factor analysis / shared variability