Hormonal modulation of the physiologic responses of calves infected with Eimeria bovis.
OBJECTIVE
To determine whether an estradiol-progesterone (EP) growth implant would have an effect on febrile responses and on the catabolic component of Eimeria bovis infection.


METHODS
27 Holstein bull calves.


METHODS
Calves were assigned to treatment groups as: control (n = 5), EP implant (EP, n = 5), E bovis-inoculated (coccidia: C, n = 7), pair fed (n = 4), or EP plus E bovis-inoculated coccidia (EP/C, n = 6) groups. Calves were provided subcutaneous EP implants at 8 weeks of age, and were inoculated with 2 x 10(5) oocysts of E bovis at 11 weeks of age. Body weight was measured on postinoculation day (PID) 0, 14, and 28. Rectal temperature and food intake were determined and fecal samples were collected daily from PID 15 to 28. Blood samples were collected on PID 24 for analysis of CD2+, CD4+, and CD8+ antigens and plasma insulin-like growth factor I concentration. Blood samples were collected at 15-minute intervals for measurement of pulsatile growth hormone release.


RESULTS
Group-EP/C calves had fever for 2 days versus 5 days for group-C calves (P < 0.05). These calves had diarrhea for fewer days than did their group-C counterparts (P < 0.05). Fibrinogen and glucose values were high in group-C (P < 0.05) but not group-EP/C calves. The latter had positive weight gain from PID 14 to 28, whereas group-C calves had weight loss (P < 0.05). Plasma insulin-like growth factor I concentration was reduced by infection (P < 0.05). EP-treated noninfected calves had increased numbers of CD2+, CD4+, and CD8+ blood mononuclear cells (P < 0.05).


CONCLUSIONS
EP has a protective effect in calves infected with E bovis. This may relate to changes in immune function induced by EP.


CONCLUSIONS
Treatment of calves with EP could offer some protection against the often severe wasting and debilitation associated with E bovis infection.
Heath
H L
HL
Department of Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849, USA.
Blagburn
B L
BL
Elsasser
T H
TH
Pugh
D G
DG
Sanders
L G
LG
Sartin
E A
EA
Steele
B
B
Sartin
J L
JL
D000818:Animals; D001831:Body Temperature; D001835:Body Weight / Q000187:drug effects; D002417:Cattle; D002418:Cattle Diseases; D003048:Coccidiosis / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary*; D004343:Drug Implants; D004435:Eating; D004539:Eimeria; D004958:Estradiol / Q000008:administration & dosage / Q000627:therapeutic use*; D005243:Feces; D005334:Fever; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism; D013007:Growth Hormone-Releasing Hormone; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D011374:Progesterone / Q000008:administration & dosage / Q000627:therapeutic use*; D011863:Radioimmunoassay; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D015430:Weight Gain
D004343:Drug Implants; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone