Sperm production and testicular development of broiler breeder males reared on shortened growth cycles

• Published in: Journal of applied poultry research Vol. 21; no. 1; pp. 88 - 94
• Main Authors: Moyle, J. R., Yoho, D. E., Whipple, S. M., Donoghue, A. M., Bramwell, R. K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford University Press 01-03-2012
• Subjects: broiler breeder; sperm production; fertility
• ISSN: 1056-6171; 1537-0437
• DOI: 10.3382/japr.2011-00363

SUMMARY
Feed restriction is an important tool used in the rearing of broiler breeders to control growth and maintain BW. Feed restriction during the growing phase typically provides 60 to 80% less feed than the birds would consume if provided feed ad libitum, resulting in a perceived animal welfare issue. Because males are typically more rigorously feed restricted than females, this is thought to be especially stressful to the growing cockerels. During this time, the reproductive systems of the males are undergoing formative stages, and improper management can have lifelong effects on their reproductive performance. Therefore, the objective of this study was to rear males under feed management programs that would require less severe feed restriction while still rearing replacement breeder males to the recommended target BW of 3.060 kg at 24, 21, 18, 15, and 12 wk of age, respectively. Males were placed at 3-wk intervals so that all males were light stimulated on the same calendar date and at the same time and BW but at different ages. A total of 5 treatment groups were used, based on age of the male at light stimulation. All males were reared in the same light-controlled house at the University of Arkansas Research Farm. Males were light stimulated and testicular development, semen analysis, fertility, and mating activity were recorded for each group of males. To measure semen production, males were housed in individual cages, with 24 males from each treatment group tested. Males light stimulated at 18 wk of age had the highest semen volume (0.46 mL), followed by males light stimulated at 24 (0.31 mL), 15 (0.29 mL), 21 (0.27 mL) and 12 wk of age (0.27 mL), respectively. Sperm count per ejaculate was highest for the males light stimulated at 18 wk of age, followed by males light stimulated at 21, 24, 15, and 12 wk of age, respectively. Males that were 21 wk of age or older at the time of light stimulation responded quicker to light stimulation than did younger males.