Effect of the northern fowl mite, ornithonyssus sylviarum (Canestrini and Fanzago), on white leghorn roosters

Abstract

The effects of the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), on body weight, reproductive potential and hematology of White Leghorn roosters were studied. Mean body weight was approximately 100 g. less for the mite infested roosters than for the uninfested roosters 4 weeks after they were infested with the northern fowl mite. Both groups increased in weight throughout the 26 weeks of the test but the differences in weight remained. Reproductive potential studies showed that after moderate populations of mites (101-1,000 mites/rooster) were observed, the volume of seminal fluid decreased. Four weeks before the test ended, one half of the infested roosters produced an average of less than 0.1 ml. of seminal fluid per week while the other half showed a decrease of 0.07 ml. in volume of seminal fluid produced when compared with the controls. Sperm concentration of mite infested roosters increased as the volume of seminal fluid decreased but was not statistically different from the controls. Motility and live/dead ratios of sperm did not show significant differences. Serum testosterone levels were statistically different between mite infested and control roosters. Hematology studies showed the greatest decrease in RBC and PCV occurred from the 4th to the 8th weeks when infestations were initially increasing rapidly. Mean Hemoglobin concentrations for the infested birds were consistently lower but not statistically different from the controls. No specific anemia could be attributed to mite populations as all hematological values were within normal ranges.