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SUMMARY

Five castrated male llamas (mean body weight, 94 kg) were studied in an energy balance trial to determine maintenance energy requirement of llamas. Llamas were fed a 50% oat hay-50% pelleted concentrate diet (2.43 Mcal of metabolizable energy/kg of diet dry matter) at approximately 1.6% of body weight (bw). An 8-day total collection digestion trial was used to determine fecal and urine energy losses. Heat production and methane emissions were determined via indirect respiration calorimetry-measurements on each llama fed at the same level of intake as during the digestion trial and subsequently on days 3 and 4 of a period of nonfeeding. Fecal, urine, and methane energy losses of the llamas fed near-maintenance intake were 32.5, 3.5, and 7.1% of gross energy intake, respectively. The postabsorptive metabolic rate, commonly called nonfed (fasting) heat production, was 59.3 kcal/bw 0.75. Using a linear relation between postabsorptive and maintenance energy requirement and efficiency of energy use below maintenance of 0.702, metabolizable energy requirement at maintenance was determined to be 84.5 kcal/bw 0.75.

Free access
in American Journal of Veterinary Research

Summary

Zoometric measurements and bioelectrical impedance analysis were evaluated as methods of body composition determination in healthy cats. Zoometric and impedance measurements were taken on 22 anesthetized adult cats of various ages, genders, breeds, and body weights. The cats were then euthanatized. The bodies were processed through a tissue homogenizer and free-catch specimens were taken, freeze-dried, and analyzed for total body water, protein, fat, potassium, and ash content. Stepwise regression analysis was implemented to identify statistically significant relationships between the chemically determined dependent variables (total body water, protein, potassium, fat-free mass, fat mass, and percent body fat) and the zoometric measurements, with or without bioelectrical impedance analysis. Statistical analysis revealed high correlations between the dependent variables and the corresponding predicted values of those variables. Body weight alone was a poor predictor of body composition in these cats. On the basis of these findings, we suggest that zoometric and bioelectrical impedance measurements may serve as practical, noninvasive, simple, and accurate methods for estimating body composition in domestic cats.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether cattle exposed to heat stress alone or heat stress while consuming endophyte-infected fescue (EIF) have lower wholeblood (WB) concentrations of glutathione (GSH).

Animals—10 Simmental cows.

Procedure—Cows were sequentially exposed to thermoneutral (TN; 2 weeks; 18 C, 50% relative humidity [RH]), heat stress (HS; 2 weeks; alternating 4-hour intervals at 26 and 33 C; 50% RH), and heat stress while consuming EIF (10 µg of ergovaline/kg/d; 2 weeks; HS + EIF). Blood samples were collected after each period and tested for GSH and oxidized glutathione (GSSG) concentrations.

Results—Feed consumption was similar when data were analyzed for time points at which WB concentrations of GSH or GSSG were determined. However, significant effects of treatment, cow, days exposed to heat, cow-by-treatment interaction, and treatment-bydays exposed to heat interaction were detected when data were considered simultaneously. Mean ± SD hematocrit for TN, HS, and HS + EIF were 35.3 ± 3, 33.3 ± 2, and 37.1 ± 3%, respectively. Mean WBGSH concentrations for TN, HS, and HS + EIF were 3.2 ± 0.65, 2.7 ± 0.62, and 2.4 ± 0.56 mmol/L of RBC, respectively. Reduced WBGSH concentrations were associated with reduced feed intake during the later part of each heat period.

Conclusion and Clinical Relevance—Decreased GSH and increased GSSG concentrations were evident during heat stress, especially when cattle consumed EIF. These were associated with reduced feed intake during heat stress. Heat stress, reductions in feed intake, and thermoregulatory effects of EIF may induce oxidative stress in cattle. (Am J Vet Res 2002;63:799–803)

Full access
in American Journal of Veterinary Research

Objective

To evaluate efficacy and nephrotoxicity of amphotericin B lipid complex used for treatment of dogs with naturally developing blastomycosis.

Design

Prospective clinical trial.

Animals

11 dogs with blastomycosis.

Procedure

All dogs were treated with an amphotericin B lipid complex. Two dogs received a cumulative dose of 8 mg/kg of body weight, 1 received a cumulative dose of 10 mg/kg, and 8 received a cumulative dose of 12 mg/kg.

Results

The 2 dogs that received a cumulative dose of 8 mg/kg and 1 of the dogs that received a cumulative dose of 12 mg/kg had a relapse of blastomycosis within 30 days after treatment. Seven of the remaining 8 dogs were clinically free of blastomycosis 6 months after treatment. One dog died of an unrelated cause 5.5 months after treatment, but did not have clinical signs of blastomycosis at the time of death. There were not any adverse clinical effects attributable to drug administration in any of the dogs in this study, and none of the dogs developed clinical signs of renal disease or failure.

Clinical Implications

Amphotericin B lipid complex was a safe and effective treatment for blastomycosis in these dogs. (J Am Vet Med Assoc 1996;209:2073–2075)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate fecal shedding of Cryptosporidium parvum from California cow-calf herds with respect to age, geographic region, temporal effects, and association with watery feces.

Animals

Cows and calves from 38 beef cow-calf operations.

Procedure

Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Associations between age, geographic region, month of collection, watery feces, and likelihood of shedding C parvum were evaluated.

Results

3.9% of cattle were shedding C parvum oocysts. Prevalence of shedding among calves ranged from 0 to 13%, and was 0.6% among cattle ≥ 12 months old. The odds of shedding C parvum among 2-month-old calves were 41 times greater than among cattle > 4 months old. The odds of shedding C parvum among cattle tested in May were 8.7 times greater than among cattle tested during June, July, or August. The odds of infected individuals having watery feces were 3 to 4 times greater than for noninfected individuals, but the etiologic fraction was only 8 to 9%.

Conclusions and Clinical Relevance

Substantial fecal shedding of C parvum by cow-calf herds was limited to calves 1 to 4 months old, with low prevalence detected in older animals. Risk of contamination of watersheds with C parvum was limited to those periods when young calves were in the herd. Although the odds of having watery feces were greater for animals infected with C parvum than for noninfected animals, the low etiologic fraction suggests that most calves with watery feces were not infected with C parvum. (Am J Vet Res 1999;60: 420-425)

Free access
in American Journal of Veterinary Research