Using a Brody equation in describing the growth curve of newborns resulting from local and imported straws for Friesian bulls in the countryside of Deir Ezzor

Abstract

The research was conducted to describe the growth curve of local cows newborns resulting from grading. We used /96/ local graded cows and they were divided into two groups: /48/ cows inseminated with imported Spanish Friesian straws and /48/ cows inseminated with local Friesian straws produced from Al-Ghazlaniya Center in Ghouta of Damascus. A Brody equation was used to estimate growth landmark in math sample y(t) = α - (α – w0) e ^{(- b * t):} w0 (birth weight), b (weight gain over time). The results showed a significant (p≤0.5) superiority in the relative weights of offspring from the imported straws compeer with the newborns from local straws from birth to six months, this is due to the phenomenon of hybrid power. Also the results showed that the expected weight values for newborns resulting from imported straws which were a significant higher (p≤0.5) in comparisan with the newborns from local straws during the study period, as it reached the local straws (48.22, 86.49, 116.45, 187.72) kg, respectively. While the imported straws (67.01, 100.84, 131.46, 231.93) kg, respectively. In both groups, the value of the coefficient of determination (fitness coefficient) was (R ² = 0.98). This study demonstrated that the use of Brody'sequation is suitable for describing the growth curve of improved local cow calves, and it is useful in predicting birth weights early, thereby selecting well-grown offspring based on a high fitness coefficient (R ²)