Mutton is also very extensively used food and sources of mutton are only sheep and goat.
Sheep have a great genetic potential to fulfill the increasing demand of mutton in our country.
Body conformation and features are very important traits in milch, meat and wool animals. In
developing countries, record keeping is at initial level and the records about pedigree and progeny
of individuals are insufficient and do not provide the estimation about genetic parameters.
Therefore, phenotypic information are necessary for the explanation of relationship among linear
type traits and selection is based on these traits. Principal component analysis technique has been
used to identify the body size, body shape, head size and over all body conformation in Zulu Sheep.
Animal conformation and genetic parameters can be measured by using the technique of
phenotypic characterization.
Data on morphometric traits of Thalli sheep were collected from “Small Ruminant
Research and Development Centre, Rakh Khairewala, District Layyah, Punjab, Pakistan” and
Livestock Experiment Station, Rakh Ghulaman, District Bhakkar, Punjab, Pakistan. Different
phenotypic parameters and twenty one (21) morphometric traits were measured on animals of
Thalli sheep. The traits measured were birth weight, body weight, heart girth, body length, withers
height, head length, head width, ear length, ear width, neck length, neck width, barrel depth, sacral
pelvic width, rump length, rump width, tail length, testes length, testes width, scrotal diameter, teat
length and teat diameter. Different phenotypic characters was recorded as body color, body shape,
eye color, head color, fore head color, face color, face structure, chin color, ear color, ear nature,
appendages color, nostril structure, muzzle structure, neck structure, tail color and tail switch.
Summary
174
Weighing balance (digital) was used for determination of body weight and a flexible
measuring tape (tailor tape) was used to record the different body measurements. To avoid
variations among individuals, measurements were taken by the same person. Animals of different
age groups were reared at these research stations. Animals were divided into different groups (A,
B, C, D, E, F, G, H and I) according to their age as 0-3, 4-6, 7-9, 10-12, 13-15, 16-18, 19-21, 22-
24 and above 24 months. Each group was further divided into two sub-groups of males and females
animals. Normality of data were checked against all animals (overall group and separate groups)
and all animals were fallen in ±3SD but two outliers had been removed. Data on morphometric
traits were analyzed statistically for mean, range, coefficient of variation and standard error.
Pearson’s coefficient of correlation among different biometric traits was estimated and data were
generated for principal component analysis (PCA) from the correlation matrix. Regression
equations were developed for the estimation of body weight.
Descriptive statistics (mean, range, standard deviation and coefficient of variation) of body
measurements of overall female were showed coefficient of variations of overall female animals
of Thalli sheep for mostly variables were ranged from 10-20% and coefficient of variations of birth
weight and body weight were 22.38% and 25.75% respectively. Coefficient of variations of male
animals of Thalli sheep for linear body measurements were ranged 08-25% and tail length had
high coefficient of variations as 26.89%. Male animals of all age groups are heavier than females.
Correlation coefficients of morphometric traits of overall females and males of Thalli sheep
were highly positive and significant (P≤0.01) among withers height, body length, heart girth, head
length, head width, ear length, neck length, neck width, rump length, rump width, barrel depth,
sacral pelvic width and body weight. Withers height, heart girth and body length were observed to
be significantly correlated with each other as well as with live body weight of all age groups.
Summary
175
For overall female animals, two principal components were extracted with eigenvalues
9.005 and 1.558 and 56.279% and 9.740% variances for PC1 and PC2 respectively and their
cumulative variance was 66.020%. For overall male animals, three principal components were
extracted with eigenvalues greater than 1 and PC1 showed high variance 57.516% and PC2 and
PC3 had variances as 12.184% and 7.022% respectively and their cumulative was components
76.721%. In all age groups which has been studied, withers height, body length and heart girth
have high values in commonalities as well as in component matrix. PC1, PC2 and PC3 showed
maximum variations in almost all age group studied.
Regression equations developed to estimate of live weight of all age groups were indicated
that almost all equations had variables withers height, body length and heart girth.
Conclusion:
From findings of present study, it was concluded that body measurements (Withers height,
body length and heart girth) had high correlations with each other and with body weight in almost
all age groups. Principal component analysis of morphometric traits was showed that most of
variation explained by PC1 and in some groups, PC2 and PC3 had also more effects.
Commonalities were higher which showed that all the variables were important but PC1 had high
values for withers height, body length and heart girth and maximum variance. This indicated that
morphometric traits are very important for selection of genetically elite animals. Morphometric
traits can be used to estimate the body weight in the field conditions, where weighing balance is
not usually available. However, further research is needed to investigate the relationship among
different morphometric traits in other breeds of goats, sheep and other livestock breeds like cattle,
buffalo, camel and horse of the country.