الفهرس 
Materials and mithodsOnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
This study was carried out at farm of faculty of agriculture Zagazig university (Banha Branch), during period from April (2000) to April (2002).
A number of 9 cow bulls (Friesian X Balady) and 5 buffalo bulls, kept under the Egyptian farm condition and the economic system of feeding and management were allowed to have an available ration containing corn silage, rice straw and concentrate.
The present study was designed to study the effect of age and individuality on body dimensions, libido, semen characteristics and level of plasma testosterone in cow and buffalo bulls.
The obtained results can be summarized as follows:
1-Age of both cow and buffalo bulls had highly (P < 0.01) effects on their body weight and all body measurements studied at more than 24 months of age group-while its effects on sexual desire (libido) and all semen characters studied traits were found in bulls aged 19-24 months of age (P < 0.01) in cow bulls. While aged 13-18 months recorded the best results in buffalo bulls.
2-Cow bull No. 9 had the highest significantly mean values in all body measurements studied. However, they were mostly for buffalo bulls No. 4 and 5 (P < 0.01).
3-Bulls differed among themselves in sexual desire (Libido) as well as, in their semen quality studied traits. Thus, cow bull No. (6) had the best mean values in S.V; M.M; P.L.S,
SUMMARY 104
Ma.A and M.A traits and was good in S.C. However, buffalo bull No. (3) had the highest results in M.M; PLS; SC; sperm abnormalities and also good result in S.0 traits.
4-Either age groups or bull individuality had no significant effects on cow and buffalo bulls plasma testosterone levels. But in general, they were higher at puberity than after it and this study recorded that average of 1St ejaculation in cow and buffalo bulls were 17 and 20 months respectively. 5-Correlation coefficients:
a)Body dimensions were found to be positively and high significantly (P < 0.01) correlated with each other in both cow or buffalo bulls and generally ranged between (0.69) to (0.96) in cow bulls and between (0.50) to (0.97) in buffalo bulls.
b)Obtained results revealed low positively and insignificantly correlations between body dimension and R.T. in either cow or buffalo bulls, except with B.L. trait (-0.083) in cow bulls and with each of B.W; H.G; B.L. and F.L. trait in buffalo bulls, and ranged from (-0.168) to (-0.049).
c)Obtained correlation coefficient values between body dimensions and each of semen studied traits, as well as, plasma testosterone levels in both cow and buffalo bulls, were generally low, negatively or positively correlated, except between S.C. and all dimension traits. They were significantly and ranged from (0.390) to (0.613) (P < 0.01) in cow bulls, while were significantly (P < 0.05)
negative between age and S.0 (- 0.425) and between H.G and T.L. (-0.295) in buffalo bulls.
d) There was significantly (P < 0.01) and positively correlations between P.L.S and each of M.M. (0.688) and I.M. (0.870), as well as between M.M and I.M (0.720) and negative correlations between Mi.A and both M.M. (-0.332) and I.m (-0.300) in cow bulls. However, there were significantly (P < 0.01) and positively correlations between M.M and each of I.M (0.715); P.L.S. (0.615) and S.0 (0.430). Also between I.M and both of P.L.S (0.875) and S.C. (0.587) and between S.0 and P.L.S. (0.580). However, was only negatively (P < 0.01) between S.C. and Mi.A. in buffalo bulls. But correlations between other traits were generally insignificant either positive or negative in buffalo bulls.
e) Correlation coefficients between sexual desire and levels of plasma testosterone hormones were insignificant low in cow bulls (-0.171) and (-0.095) in buffalo bulls.
0 Estimated correlation coefficient values between sexual desire (R.T) and different semen quality traits were generally, low and insignificant in cow and buffalo bulls. While, were mostly negative in cow bulls and approximately equals in buffalo bulls.
g) In general, correlation coefficient values between studied semen quality characters and plasma testosterone levels in both cow or buffalo bulls were low and not significant
Age of both cow and buffalo bulls had highly (P < 0.01) effects on their body weight and all body measurements studied at more than 24 months of age group-while its effects on sexual desire (libido) and all semen characters studied traits were found in bulls aged 19-24 months of age (P < 0.01) in cow bulls. While aged 13-18 months recorded the best results in buffalo bulls.
Cow bull No. 9 had the highest significantly mean values in all body measurements studied and bull No. 6 in libido and semen quality studied traits. However, buffalo bull No. 4 & 5 in body weight and measurement traits and bull No. 3 in libido and semen quality traits, which were significant (P < 0.01) in all body measurements and only in semen concentrations trait. While both age and individuality has no significant effects on plasma testosterone level in either cow or buffalo bulls.
Obtained correlation coefficients values between B.W and body measurements and between each other as well as between body measurements and libido, semen quality traits and between each other, were generally positive and high. However, they were low and negative between body measurements and semen quality and libido and plasma testosterone levels in both cow and buffalo bulls.