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in Journal of the American Veterinary Medical Association

Objective

To determine typical alterations in acid-base balance and serum electrolyte concentrations in cattle grouped on the basis of age, breed type, hydration status, clinical signs, and underlying disease.

Design

Retrospective study.

Animals

632 cattle.

Procedure

Information on blood pH, Pvo2, Pvco2, HCO3 concentration, and base excess (BE) as well as serum or plasma sodium, potassium, chloride, and total carbon dioxide concentrations was obtained. Values for calves (ie, cattle ≥ 1 month old) were compared with values for cattle ≥ 1 month old. Within each age-group, values were compared for cattle grouped on the basis of breed type, previous treatment, and hydration status. Proportions of cattle with various disorders for which values were within, greater than, or less than reference ranges were determined.

Results

BE, pH, and HCO3 concentration were significantly higher and Pvco2 and sodium, potassium, and chloride concentrations were significantly lower among cattle ≥ 1 month old than calves. Base excess and HCO3- concentration were significantly lower among dairy than beef calves. Sodium and potassium concentrations were significantly lower among dairy than beef cattle ≥ 1 month old. A higher proportion of cattle that did not survive had a high anion gap than cattle that did survive. Sodium, potassium, and chloride concentrations were significantly lower among dehydrated cattle than cattle that were not dehydrated.

Clinical Implications

Because certain alterations were consistently found in some groups of cattle, it may be possible to make reasonable predictions of alterations in acid-base balance and serum electrolyte concentrations when laboratory evaluations are not available. (J Am Vet Med Assoc 1998;212:1769–1775)

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in Journal of the American Veterinary Medical Association

Objective—

To determine gross income lost that was attributable to thin cows in a beef cattle herd, to estimate the cost of added nutrition necessary to prevent thin cows in the herd, and to determine the financial outcome of the improved nutritional practices.

Design—

Prospective, observational study.

Animals—

Four hundred twenty-two Santa Gertrudis cows and their calves.

Procedure—

At pregnancy examination in the fall of 1992, cows were assigned a body condition score (BCS), using a scale of 1 (emaciated) to 9 (obese), and the ratio of the productivity of BCS-3 and BCS-4 cow groups (thin cows), compared with the mean productivity of BCS-5 and BCS-6 cows (cows in good condition), was determined. Measures of productivity evaluated included pregnancy rates, weaning weights, and prices per hundredweight of calves. The performance ratios of BCS-3 and BCS-4 cows were multiplied by the mean gross income of BCS-5 and BCS-6 cows to calculate their gross income. This was then subtracted from the mean income of BCS-5 and BCS-6 cows to estimate the amount of lost gross income per thin cow. The cost of a nutritional program that would prevent thin cows in the herd was subtracted from the lost gross income of the thin cows to yield the amount of increased net income that could be generated from a nutritional program that would maintain cows in the herd at a BCS of 5 or 6.

Results—

Cows with a BCS of 3 were 0.48 as productive, and cows with a BCS of 4 were 0.74 as productive as the average of the BCS-5 and BCS-6 cows combined. Each BCS-3 cow generated $215.06 less, and each BCS-4 cow generated $107.53 less gross income than the average gross income of BCS-5 and BCS-6 cows. The added cost of nutrition that would have reconditioned BCS-3 and BCS-4 cows to a BCS of 5.5 was $91.48/BCS-3 cow and $43.67/ BCS-4 cow. Implementation of the reconditioning nutrition program the previous fall would have resulted in an extra net income of $123.58/BCS-3 cow and $63.86/BCS-4 cow, received over a 2-year period. The 262 thin cows in the herd accounted for a total net income loss of $19,897.

Clinical Implications—

The time of pregnancy examination is a strategic intervention point to estimate the past negative economic impact of thin cows and to implement a plan to prevent these losses in the future.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether beef herds could increase profitability by reducing production cost per 100 lb (hundredweight [CWT]; ie, 45.4 kg) of calf through implementation of advice from teams of veterinarians and county extension agents supported by university specialists.

Design—Longitudinal study.

Sample Population—6 commercial cow-calf herds comprising 1,927 cows.

Procedure—Teams of veterinarians and county extension agents provided advice on 25 profitable ranch management practices to herd owners for 3 years. Use of each practice in herds was measured on a scale of 1 to 5 for baseline year 1999. Similar measurements were made at the end of each year for comparison with baseline values. Outcomes were measured by standardized performance analysis.

Results—Mean weaning weight of calves per exposed cow of the 6 herds increased significantly from 1999 (2000, 26.8 kg [59 lb; 17%]; 2001, 49.1 kg [108 lb; 31%]; and 2002, 43.2 kg [95 lb; 27%]). Mean cost per CWT of calf decreased significantly from the 1999 value (2000, −$20.04 [−18%]; 2001, −$33.40 [−29%]; and 2002, −$22.52 [−20%]). Additional profits for the 6 herds were $54,407 in 2000, $135,695 in 2001, and $116,089 in 2002 (3-year total of $306,191). Mean increase in management score of herds was positively correlated with increase in net income and accounted for > 60% of increased profits.

Conclusions and Clinical Relevance—Profitability of beef cow-calf operations can be substantially increased through a team approach by identifying opportunities for improvements in management and helping ranch managers implement profitable practices. (J Am Vet Med Assoc 2004;225:210–220)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine safety, efficacy, and immunogenicity of an intranasal cold-adapted modified- live equine influenza virus vaccine administered to ponies following induction of exercise-induced immunosuppression.

Design—Prospective study.

Animals—Fifteen 9- to 15-month old ponies that had not had influenza.

Procedure—Five ponies were vaccinated after 5 days of strenuous exercise on a high-speed treadmill, 5 were vaccinated without undergoing exercise, and 5 were not vaccinated or exercised and served as controls. Three months later, all ponies were challenged by nebulization of homologous equine influenza virus. Clinical and hematologic responses and viral shedding were monitored, and serum and nasal secretions were collected for determination of influenza-virus-specific antibody isotype responses.

Results—Exercise caused immunosuppression, as indicated by depression of lymphocyte proliferation in response to pokeweed mitogen. Vaccination did not result in adverse clinical effects, and none of the vaccinated ponies developed clinical signs of infection following challenge exposure. In contrast, challenge exposure caused marked clinical signs of respiratory tract disease in 4 control ponies. Vaccinated and control ponies shed virus after challenge exposure. Antibody responses to vaccination were restricted to serum IgGa and IgGb responses in both vaccination groups. After challenge exposure, ponies in all groups generated serum IgGa and IgGb and nasal IgA responses. Patterns of serum hemagglutination inhibition titers were similar to patterns of IgGa and IgGb responses.

Conclusions and Clinical Relevance—Results suggested that administration of this MLV vaccine to ponies with exercise-induced immunosuppression was safe and that administration of a single dose to ponies provided clinical protection 3 months later. (J Am Vet Med Assoc 2001;218:900–906)

Full access
in Journal of the American Veterinary Medical Association