Osama Alsheblak*(1) and Khaled Alnajjar(2)
(1). Animal Wealth Administration, General Commission for Scientific Agrcultural Research GCSAR, Damascus, Syria.
(2). ACSAD, Damascus, Syira.
(*Corresponding author: Eng. Osama Alsheblak. E-Mail: email@example.com).
Received: 03/09/2018 Accepted: 15/10/2018
This study was carried out at AL-Yadoda Research Station, Daraa Research Center, GCSAR, to analyze weight data of local cattle (Akshi, Shami and Golani). 101 heads of calves were weighted in several ages (birth, one and half month, three months, six months, twelve months and eighteen months) during the period from 2009 to 2011. The general liner model (GLM) was used to characterize the growth curve using growth function and to study non-genetic effects on growth traits. The analysis of variance was used to study the effect of gender, birth year, breed and interaction between gender and breed on growth traits, and Duncan test was used to compare means. Results showed that the real weight of local cow sets, from birth, 1.5-month, 3-months, 6-months,12-months and 18-months were (23.0±0.46), (40.25±0.51), (64.26±1.03), (110.8±2.24), (216.43±3.91), (277.82±1.97) kg, respectively, while expected means weight according to growth function were (23.48±0.38), (39.25±0.53), (65.69±0.74), (110.07±1.09), (184.66±1.76), (310.17±3.24) kg, respectively. Growth function constants a, b were analyzed and the estimates of growth function a, b were (14.07) kg, (0.56) kg, respectively and the value of coefficient fitting model was R2=0.98. This study proved that function is fitting to growth curve of local cattle sets in southern Syria from birth to 18-months age. Results of variance analyze showed non-significant effect of gender on (a) and (b) coefficients, model fitting to weigh increase (R2), and no-significant differences found between males and females for these coefficients. Results of variance analyze showed non-significant effect of birth year on (a) and (b) coefficients, model fitting to weigh increase (R2), and no-significant differences found between study years for these treats. Results of variance analyze showed a significant effect of breed on (a) and (b) traits, model fitting to weigh was increased (R2), and significant differences found between local cow groups (Akshi, Shami and Golani). This study proved that function was fitting to describe growth curve of local cow groups in south Syria from birth up to 18-months old, although a little number of parameters (a, b) which can be explained biological and this is very important for selection besides to some non-genetic factors effect such as (gender, year birth and breed) on growth traits.
Keyword: Local cattle groups, Growth curve, Breed, Syria.
Full paper in Arabic: PDF