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  • Author or Editor: E. A. Sartin x
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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Excess production or long-term administration of glucocorticoids is detrimental to longitudinal growth in people and rats. A portion of this effect is attributed to cortisol inhibition of growth hormone (gh). Glucocorticoid effects are usually studied in subjects under long-term treatment with synthetic, more potent glucocorticoids, and, to the authors' knowledge, have not been examined in domestic animals. We sought to examine the effects of cortisol infusion on gh release in sheep. Cortisol infusion into castrated, male Suffolk sheep (1 to 1.5 years old) caused a significant (P < 0.0001) increase in cortisol concentretion. Basal gh release was not affected over the 4-hour period of infusion. Growth hormone-releasing hormone administration stimulated gh release in both groups (P < 0.001); however, the control group had a greater response to growth hormone-releasing hormone than did the cortisol infused group (P < 0.0001). These results were duplicated in cultured sheep pituitary cells. Cortisol inhibition of gh release may be mediated via enhanced somatostatin release, owing to a direct inhibition of somatotrope function, or a combination of both mechanisms. Because of effects of stress and disease in increasing cortisol concentration, additional study of the mechanisms for cortisol inhibition of gh release in sheep needs to be performed.

Free access
in American Journal of Veterinary Research

Abstract

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.

Animals

27 Holstein bull calves.

Procedure

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 × 105 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.

Clinical Relevance

Treatment of calves with EP could offer some protection against the often severe wasting and debilitation associated with E bovis infection. (Am J Vet Res 1997;58:891–896)

Free access
in American Journal of Veterinary Research

SUMMARY

Neospora caninum-induced abortion is a major production problem in the dairy cattle industry in the United States and worldwide. Abortions attributable to naturally acquired N caninum infection also have been observed in pygmy goats. We studied experimentally induced infections with N caninum in pregnant pygmy does to determine whether abortions attributable to N caninum infection would occur after inoculation. Seven pregnant pygmy does (1 control doe and 6 inoculated with N caninum) were studied. The control doe remained clinically normal throughout the study and delivered 2 healthy kids. Abortion, fetal death, and stillbirths were observed in some pregnant does inoculated with N caninum. Two pregnant pygmy does inoculated with N caninum early in gestation (day 51) had fetuses that died and were aborted, or died and were reabsorbed. Neospora caninum tachyzoites and lesions were observed in the brain, spinal cord, and heart of aborted fetuses; parasites also were isolated from the placenta. Four additional pregnant pygmy does (2 inoculated at mid-gestation [day 85], and 2 at late gestation [day 127]) did not abort after inoculation. However, 1 doe inoculated during midgestation delivered a stillborn fetus that had died about 1 week prior to parturition. This kid was congenitally infected with N caninum. Neospora caninum was isolated from the placentas of all inoculated does examined. Neonatal neosporosis was not observed in live-born kids, nor were stages of N caninum isolated from any live-born kid. Does did not undergo abortion or have congenitally infected kids when they were rebred and evaluated for neosporosis.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate effects of treatment with a pulsed electromagnetic field (PEMF) on healing of open and sutured wounds, clinicopathologic variables, and CNS activity of dogs.

Animals

12 adult female Beagles.

Procedure

Open and sutured wounds were created in the skin of the trunk of the dogs. Dogs were divided into 2 groups. One group received PEMF treatment and 1 group served as untreated (control) dogs. The PEMF-treated dogs received treatment twice a day starting the day before surgery and lasting through day 21 after surgery. Wounds were evaluated by use of tensiometry, planimetry, laser Doppler perfusion imaging, and histologic examination. Clinicopathologic variables and electroencephalographic tracings were also evaluated.

Results

Use of PEMF treatment resulted in significantly enhanced epithelialization of open wounds 10 and 15 days after surgery. Five days after surgery, wounds of control dogs had a negative value for wound contraction, whereas PEMF-treated wounds had a positive value. The PEMF treatment did not cause significant changes in short-term planimetric, perfusion, tensiometric, histologic, clinicopathologic, or electroencephalographic results.

Conclusions

The PEMF treatment enhanced wound epithelialization in open cutaneous wounds and provided indications of early contraction without significant short-term changes in other variables. (Am J Vet Res 1998;59:1177-1181)

Free access
in American Journal of Veterinary Research