PARASITE TESTS 



Lungworm Results 



Fecal sar.ples from eight (37.5%) animals were tested for 

 lungvorm larvae. Three (37.5%) were positive for 

 Dictyocaulus , with an a\'erage of 0.24 larvae per gram (range 

 = .13 -.35). Meagher (1966) reported 3 of 39 (7.6%) animals 

 testing positive for lungworm in the northern herd. 



CONCLUSION 



The northern Yellowstone bison herd tested 54% 

 brucellosis seropositive in 1988-89, within the range of 

 previous tests of this population. More males tested positive 

 than females but the incidence was not age specific. The 

 incidence of brucellosis seropositivity did not indicate 

 adverse effects on reproduction. 



The age structure of this wild bison population was best 

 determined using a combination of field aging and cementum 

 annuli counts. This provided ages for 67% of the harvest. 

 Age structure of the population in 1988-89 was very similar to 

 that determined during reductions carried out in YNP during 

 1964-65. 



The pregnancy rate of 74% was within the ranges 

 previously documented for this population, with the majority 

 of fetuses in utero, females. The prolonged calving season 

 indicated by our data may reflect previous mild winters and an 

 expanding population. 



RECOMMENDATIONS 

 Incidence of the actual brucellosis organism rather than 

 the brucellosis antibody should be determined as part of an 

 attempt to document actual affects on bison and possible 

 transmission to cattle. 



During any future reductions, data should continue to be 

 collected on brucellosis, age, and reproductive parameters for 

 comparative purposes. There should also be a continual 

 surveillance of other diseases and parasites. In addition, it 

 would be of value to record lactation and kidney fat 

 parameters to assess physical condition. If a high priority 

 was placed on collection of biological data, a great deal of 

 important information necessary for making sound management 

 decisions could be obtained. 



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