Authors : J.S. Rwuaan, P.I. Rekwot, P.A. Abdu, L.O. Eduvie, B.O. Omontese and J.A. Obidi
Abstract: Fifty 20 weeks old Shikabrown (SB) cocks consisting of 22 red and 28 white SB cocks were purchased from the National Animal Production Research Institute Shika. The cocks were fed on a diet of layers mash with 18% crude protein, 95.6% dry matter, 17.1% crude fibre and 3% nitrogen. About 25 cocks consisting of 8 red and 17 white SB cocks selected on the basis of body weight and antibody titres were infected with 0.2 mL of 106.0 EID50 of velogenic Kudu 113 strain of Newcastle disease virus intranasaly and orally. About 25 cocks consisting of 14 red and 11 white SB cocks served as control. Cloacal temperatures, body weights and semen samples of both control and infected cocks were taken weekly for 6 weeks. The semen was evaluated for volume, colour, motility, concentration, percentage live spermatozoa and percentage total spermatozoa abnormalities. Semen colour was graded as creamy (1 = very good); milky (2 = good) and watery (3 = poor). There was no significant difference in the cloacal temperatures and body weights of control and infected red and white SB cocks. The infected red and white cocks had slightly higher cloacal temperatures than the control. The semen volume of infected red cocks showed a general increase over that of the control red cocks. The semen volume of the control white SB cocks was significantly higher than that of the infected white cocks. The white SB cocks had higher semen volume than the red SB cocks. The red SB cocks had slightly better semen colour than the white SB cocks. The control white cocks had higher spermatozoa motility than the infected white cocks while the infected red cocks had higher spermatozoa motility than the control red cocks. The white SB cocks generally had better spermatozoa motility than the red cocks. The spermatozoa concentration of the control white cocks was consistently higher than that of the infected white SB cocks; the reverse was the case with the red cocks where the spermatozoa concentration of the infected red cocks was higher than that of the control red cocks. The white cocks had better spermatozoa concentration than the red cocks. The control white SB cocks had significantly (p<0.05) higher percent live spermatozoa than the infected white cocks. Similarly, the infected red SB cocks had lower percent live spermatozoa than the control red cocks. The control white SB cocks had significantly (p<0.05) higher percent live spermatozoa than the control red SB cocks. The infected red and white SB cocks had higher percentage total spermatozoa abnormalities than the contol red and white cocks. It can be concluded from this study that the white SB cocks had better semen quality than the red SB cocks; the non-infected SB cocks had better semen quality than the infected SB cocks. It is recommended that white SB cocks be used for breeding purposes and that breeder cocks should be routinely vaccinated against Newcastle disease to ensure that the level of antibodies is high enough to prevent adverse effect on semen quality.
J.S. Rwuaan, P.I. Rekwot, P.A. Abdu, L.O. Eduvie, B.O. Omontese and J.A. Obidi, 2010. Semen Characteristics of Vaccinated Shikabrown Cocks Challenged withn Velogenic Newcastle Disease Virus. Research Journal of Poultry Sciences, 3: 43-47.