Doctor of Philosophy (PhD)


School of Animal Science

Document Type



Gastrointestinal nematode (GIN) parasites cause extensive damage to small ruminants, and Haemonchus contortus is a major concern to production worldwide. With the development of GIN resistance to anthelmintics, alternative strategies for control are needed. The major component of this study compared two strategies for effect on animal health and changes in GIN population. One flock of ewes and lambs (Strategy 1, S1) employed targeted selective treatment (TST) with an anthelmintic based on FAMACHA score, and one flock (Strategy 2, S2) employed sericea lespedeza (SL) supplement feeding and TST with copper oxide wire particles (COWP) based on FAMACHA score. S1 ewes/lambs were supplement fed a concentrate ration and were dewormed with levamisole/albendazole combination when FAMACHA© was 4/5. The S2 ewes/lambs were supplemented with SL pellets and were dewormed with COWP when FAMACHA© was 4/5. FEC for S2 ewes/lambs remained consistently lower and PVC higher than for the S1 ewes/lambs. There were fewer dewormings for S2 lambs than S1 lambs and no ewes needed to be dewormed. Weight gain for S2 lambs was consistently less than S1 lambs. It was also noted that S2 lambs had less coccidia than S1 lambs. To follow up on a possible reason for the poorer production of S2 lambs, a trace mineral panel was done on the ewes/lambs and it was noted that S2 animals were very deficient in molybdenum (Mo). A study was done to evaluate Mo supplementation on weight gain and results indicated a slight improvement. Upon supplementation with Mo, Mn, Se and Zn serum concentrations of all increased but did not achieve normal values nor did it impact weight. S2 lambs had fewer coccidia counts than S1 lambs. Control lambs received Purina® Honor® Show Lamb™ and treatment lambs were fed SL pellets. Lambs were inoculated with 50,000 oocyst over a 3 day period at the beginning of the study. Lambs in the treatment group had lower FEC and coccidian counts than the lambs in the control group. SL was effective in the prevention and control of coccidiosis as well as in reducing GIN infection.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Miller, James