Is There Any Effect by Dietary Diatomaceous Earths in the Control Of Gastrointestinal Nematodes?
L. NUTI1, B. JOHNSON1, D. MCWHINNEY1, N. ELSAYED2, J. THOMPSON2, T. CRAIG.*2 1INTERNATIONAL DAIRY GOAT CENTER, PRAIRIE VIEW A&M UNIVERSITY, PRAIRIE VIEW, TX,2COLLEGE OF VETERINARY MEDICINE, TEXAS A&M UNIVERSITY, COLLEGE STATION, TX, USA
A pasture trial was run using 79 pregnant/lactating goats of four different breeds. The pastures had been grazed by the combined flock prior to the beginning of the trial and all of the does were treated with oral ivermectin at a dose averaging 0.4 mg/kg during the preparturient phase of gestation.
The does were blocked by breed and randomly assigned to one of four treatment groups. The treatment group was then confined to a single pasture for the duration of the trial. The 16week trial began during the first week of March 1999. The does had begun kidding in early February and continued until mid April. All does produced one or more kids. All goats were fed 1.36 kg/head/day of a 12% protein concentrate in addition to access to the pasture. The feed was placed in three troughs/pasture.
The treatment groups were 1) no treatment, 2) 0.4 mg/kg oral ivermectin at weeks 1, 4 and 7, 3) 0.4 mg/kg oral ivermectin at week 1, plus diatomaceous earths (DE) (Agrisafe Corp) in the concentrate, and 4) DE in concentrate. Weekly fecal examinations and hematocrits were taken from each doe. If an individual doe's packed red cell value (per) fell to less than 20, or the McMaster egg count was greater than 4,000 strongyloid eggs per gram (EPG) the doe was treated with 0.4 mg/kg ivermectin the following week and was considered to be a non-survivor.
No differences were detected among the treatment groups based on egg counts or packed cell volumes. However, the estimated survival of individuals (maintained PCV > 20 or EPG < 4000) in any of the treatment groups (2, 3 and 4) was statistically greater than for the control group. After the initial few weeks of the trial, it became obvious that ivermectin was only marginally effective in lowering nematode egg counts. Haemonchuswas the only genus seen by copro culture. The survival rate on the Boer goats was higher than other breeds across treatments. Feeding DE at 2.5% of the concentrate ration was equal to a marginally effective anthelmintic in controlling parasitic disease.