Effects of parenteral administration of doramectin or a combination of ivermectin and clorsulon on control of gastrointestinal nematode and liver fluke infections and on growth performance in cattle.
OBJECTIVE
To compare effects of an injectable doramectin preparation with those of an injectable ivermectin-clorsulon preparation on control of gastrointestinal nematodes and liver flukes and on growth performance in cattle.


METHODS
Randomized complete block design.


METHODS
60 crossbred calves.


METHODS
Calves (20/treatment group) were treated with doramectin or ivermectin-clorsulon or were not treated. Fecal samples were collected for nematode and Fasciola hepatica egg counts on day 0 and for up to 140 days after treatment. Cattle were weighed before treatment and at 28-day intervals until day 140.


RESULTS
From day 7 through day 49, nematode egg counts for calves treated with doramectin or with ivermectin-clorsulon were significantly lower than those for untreated control calves. As the study progressed beyond day 56, the percentages of cattle with fluke eggs in their feces increased, but differences in regard to these percentages were not detected among the 3 groups. Average daily gain for the doramectin-treated cattle (0.79 kg/d [1.74 lb/d]) was significantly greater than that for the cattle treated with ivermectin-clorsuIon (0.71 kg/d [1.56 lb/d]); values for both groups were significantly greater than that for the control cattle (0.62 kg/d [1.37 lb/d]).


CONCLUSIONS
Results suggest that doramectin had a greater impact on subclinical gastrointestinal tract parasitism in calves, as demonstrated by growth performance, than did ivermectin-clorsulon. In the Gulf Coast region of the United States, spring-born nursing beef calves may have minimal grazing exposure to F hepatica during the peak fluke transmission period; therefore, mature fluke burdens may be negligible at the beginning of the fall season.
Loyacano
A F
AF
Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, College of Agriculture, Louisiana State University, Alexandria 71302-9306, USA.
Skogerboe
T L
TL
Williams
J C
JC
DeRosa
A A
AA
Gurie
J A
JA
Shostrom
V K
VK
D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology; D004338:Drug Combinations; D005210:Fasciola hepatica / Q000187:drug effects; D005211:Fascioliasis / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D005243:Feces / Q000469:parasitology; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use; D008297:Male; D009348:Nematoda / Q000187:drug effects; D009349:Nematode Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D011897:Random Allocation; D012621:Seasons; D013424:Sulfanilamides / Q000008:administration & dosage / Q000627:therapeutic use; D013997:Time Factors; D015430:Weight Gain / Q000187:drug effects
D000871:Anthelmintics; D004338:Drug Combinations; D013424:Sulfanilamides; D007559:Ivermectin; C015675:clorsulon; C084101:doramectin