OF GROWTH AND BODY CHARACTERISTICS IN A CROSS BETWEEN MERINOS AND BARKI SHEEP
M. Sc. Thesis
Mohamed H. Fahmy
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.
University, Faculty of Agriculture, Department of Graduate studies,