Photoperiod, diet, and method of feeding on reproduction.

Effects of two lighting programs and three methods of feeding on semen production of Large White turkey males were investigated. Lighting programs of 14L:10D and 8L:16D were used during the reproduction period. The feeding programs consisted of: 1) a low protein ration (10% FF) containing 3,250 kcal ME/kg fed ad libitum, 2) a high protein ration (15% FF) fed ad libitum, and 3) a restricted intake high protein ration (15% R). The latter two diets contained 3,000 kcal ME/kg. Body weight, semen volume, and semen quality (sperm and seminal plasma protein concentrations) were measured weekly throughout the reproductive cycle from 26 to 52 weeks. There was no significant difference in the rate of weight gain of turkeys kept on 8L:16D and 15% FF from 16 to 52 weeks compared to those on 14L:10D and 15% FF. Decreasing protein from 15 to 10% and increasing energy levels of the diet decreased consumption significantly (P less than .05) from 16 to 52 weeks of age regardless of the light treatment. Mortality was lowest in the 10% FF and highest in the 15% R. Lighting treatment of 14L:10D significantly (P less than .05) increased semen volume and sperm concentration vs. the 8L:16D regimen. All the groups of males given 8L:16D had an endemic yellow semen syndrome (YSS) characterized by a combination of an elevated seminal plasma protein concentration (an average of 12.85 g/100 ml), abnormal spermatozoa, and numerous macrophages. Previous work is confirmed (Cecil, 1981) that low dietary protein can be used as a means of controlling body weight without any adverse effect on semen production or semen quality of Large White turkey breeder males.