Date of Graduation


Document Type


Degree Name

Master of Science in Animal Science (MS)

Degree Level



Animal Science


Thomas A. Yazwinksi

Committee Member

Michael Looper

Second Committee Member

Jeremy Powell

Third Committee Member

Charles Rosenkrans

Fourth Committee Member

Andrew Fiddler


Biological sciences, Cattle, Co-species grazing, Haemonchus, Nematodes, Parasitology, Sheep


The existence of anthelmintic resistance is not singular in parasite species, host species or geographic region. It has become a problem of worldly stature, especially when considering sheep nematodes. Recommendations have been modified from chemical-based control to multipart, managerial intervention. Compared with nematodes of cattle, the worldwide resistance of sheep nematodes to anthelmintic remedies is much more pronounced and urgent. As the resistance to essentially all anthelmintic classes approaches a cautionary level, the implementation of non-chemical controls has grown increasingly essential. Six-6 to 8 month old Holstein steer calves, six-5 month old Katahdin ram lambs and eight-5 month old Suffolk X Rambouillet lambs were dewormed and inoculated with either cattle-source infective nematode larvae or sheep-source infective nematode larvae. Fecal egg counts (FEC) were followed until necropsy at 39 and 40 days post inoculation. The total mean FEC were highest amongst the hair and wool sheep groups, respectively, which were inoculated with both sheep-source and cattle-source nematodes. The low fecal egg output by treatment group 1 shows that using cattle as models for the sheep-source nematodes can keep the fecundity of the nematodes low; however, caution should be taken before implementation. The host specificity of Haemonchus spp. seems to be a minimal factor in nematode fecundity.

Appendix pdf.pdf (1417 kB)