INHERITANCE
OF GROWTH AND BODY CHARACTERISTICS IN A CROSS BETWEEN MERINOS AND BARKI SHEEP
IN THE
M.
Sc. Thesis
Mohamed
H. Fahmy
SUMMARY
Seven
body measurements in addition to body weight were taken 106 lambs of four breed groups born during
the period from November 1st, 1961 to first of February 1962 at Ras El-Hekma
Desert Research Station, to study the growth of these breed groups during their
first year of life. The groups studied were two pure-breeds; Hungarian Merino
and local Barki, and two crosses; Merino rams x Barki ewes and MerinoBarki rams
x Barki ewes. Only single male and female lambs were used in the study as the
number of twins was too small.
The measurements used in this study
were, height at withers and hook, length from shoulder to hook, depth at chest,
width at shoulder and hook, circumference at heart girth and body weight. All
these measurements were taken every fortnight during the first two months and
every four weeks until the 52nd week of age.
The lambs involved in this study were kept in separate pens
and received the same feeding and management, as the rest of the flock.
The
following results were observed from this study.
1 -
The Merino x Barki and the backcross lambs generally exceeded the two parental
breeds in all measurements and body weight, the backcross being superior to the
other groups.
2 -
The Merino lambs were markedly slower in growth than all the other groups.
3 -
Barki lambs tended to grow at a steady rate through-out the period of
observation.
4- All the measurements showed heterosis in the
two crosses. The highest heterosis was
observed
in body weight and were 108.3%, 115.8% and 112.3%, 108.2% in MerinoBarki and
backcross males and females respectively.
5 -
Male lambs generally exceeded females. Sex difference was a significant source
of variation in all the measurements studied except heart girth.
6 -
Sex differences of the MerinoBarki group were comparatively smaller than those
of the other breed groups; this result was explained by the “homogametic
heterosis" theory.
7 -
Merino lambs tended to be born longer than the lambs of the other three groups,
but this character was not maintained.
8 -
The correlations between body weights and different measurements at weaning and
yearling ages were positive and highly significant.
9 -
The regression coefficient estimates show that it may be possible to predict
the yearling weights and measurements from those obtained at weaning.
Ain Shams
University, Faculty of Agriculture, Department of Graduate studies,