|Elsasser, Theodore - Ted|
Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/5/1997
Publication Date: N/A
Citation: Interpretive Summary: Low level infection costs producers as well as consumers due to increased management input to control infection. Management strategies have been sought to reduce the incidence of disease as well as to reduce the duration of disease and the intensity of clinical symptoms. If the intensity and duration of disease response in farm animals could be shortened, the production losses associated with commensurate decreases in growth and feed efficiency would be drastically cut. Recently chromium has been demonstrated to impart beneficial effects on immune function in animals. In the present study we fed low levels of a chromium supplement to calves and measured the effect of this treatment on their response to a viral challenge. Although calves responded with the usual variety of clinical symptoms (fever, etc), there were no significant effects of treatment of young calves with chromium on the duration and magnitude of the physiological response to the disease. The data suggest that in calves, simple addition of chromium may not protect against the symptoms of viral infection.
Technical Abstract: Twelve Holstein bill calves (6 to 8 wk of age) were fed ground corn, commercial calf protein supplement, and ad libitum grass hay. Treatments were delivered in a topdressing of either high chromium ( Cr ) yeast product (1 ppm ) in a SBM carrier (Chromium; n=6) or only SBM carrier (Control; n=6) Following 53 d of treatment, all calves were fitted with jugular vein catheters, and blood samples collected every 4 h into EDTA -containing tubes. Twenty-four hours later, all calves were inoculated intra nasally with bovine herpesvirus ( BHV -1, 1 x 10E7 plaque-forming units in each nostril). Serial blood samples collection continued at 4-h intervals for 6 d. Plasma was harvested, immediately frozen in liquid N, and stored at -20 C. Individual rectal temperatures and urine samples were collected at the same time each day. Rectal temperatures were not affected by Cr treatment, but were elevated ( P<0.05 ) on d 2, 3, 4 and 5. Treatment with Cr did not affect secretion of ACTH and cortisol of plasma TNF , although clear circadian variation in ACTH and cortisol were in evidence. Lymphocyte proliferation responses to mitogen and neutrophil bactericidal function also were not affected. In conclusion, the supplementation of Cr from high Cr yeast did not alter stress responses of calves experimentally inoculated with BHV -1.