| Popis: |
Thirty-two male Holstein calves were used to investigate supplementation of vitamin E alone or in combination with lasalocid to control coccidiosis. Calves were inoculated with 100,000 Eimeria bovis oocysts at 2 wk of age. Vitamin E-fed calves (n = 16) were given 180 IU of vitamin E once daily. Lasalocid-fed calves (n = 16) were given lasalocid at 99 mg/kg of diet. Feed intakes and fecal scores were recorded twice daily, and BW was recorded weekly throughout the 8-wk study. Packed cell volume was measured during wk 4, 5, and 6, and fecal oocyst counts were measured during wk 2 through 8. Blood and saliva were collected at 24 h and during wk 2, 4, 6, and 8 to measure vitamin E, total Ig, IgG1, IgG2, IgM, and IgA. Four calves from each group were euthanized at wk 8 to examine intestinal pathology. There were no treatment differences for packed cell volume and fecal oocyst counts. Incidence of scours decreased in calves fed lasalocid and increased in calves fed vitamin E. Lasalocid increased BW and grain intake. There was an interaction of lasalocid and vitamin E on growth and intake. Calves fed lasalocid had higher-total Ig levels throughout the study. Control calves had lower IgM levels at wk 8. Calves fed vitamin E alone had increased levels of IgM at wk 8. Plasma IgG1 and IgG2 and salivary IgA levels were not different between groups. Postmortem inspection revealed no intestinal lesions at wk 8. Lasalocid was effective in decreasing severity of coccidiosis, but vitamin E alone was not. |
