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Abstract

Objective

To measure responses of cows to supplemental Se intake in excess of nutritional requirements, but lower than recognized toxic dosages.

Animals

24 healthy adult Holstein cows.

Procedure

Cows were allotted to 4 groups and fed sodium selenite to provide 0, 3, 20, or 50 mg of Se/cow/d for 90 days. Subsequently, the dosage for the group receiving 50 mg/cow/d was increased to 100 mg/cow/d for 28 d. Blood, liver specimens, feces, and urine were obtained at points during the trial.

Results

Serum and blood Se concentrations in groups receiving 20 or 50 mg/cow/d increased over time, compared with controls (P < 0.01). Increasing supplemental Se intake to 100 mg/cow/d further increased serum and blood Se concentrations (P < 0.05). Urine, fecal, and liver Se concentrations increased more markedly in response to treatment than did those of serum or blood. No effect of Se treatment was seen on blood cell counts or serum activities of hepatocellular enzymes. Likewise, neither titer response to rabies vaccination nor lymphocyte blastogenic response to nonspecific mitogens was affected by Se treatment. Objective or subjective physical signs of Se toxicosis were not observed at any Se dosage.

Conclusions

Inorganic Se intakes of up to 50 mg/d for 90 days or 100 mg/d for 28 days by adult Holstein cows do not affect the variables measured.

Clinical Relevance

Intakes of Se as sodium selenite in amounts 10 to 30 times the nutritional requirements are unlikely to cause health problems in adult cows. Urine and feces are good test samples for detection of Se supplementation greater than requirements. (Am J Vet Res 1997;58:760–764)

Free access
in American Journal of Veterinary Research

Objective—

To determine the effect of administration of vitamin E (D-α-tocopherol) on the incidence of retained placenta, metritis, and clinical mastitis during early lactation and on tocopherol concentrations.

Design—

Prospective randomized controlled study.

Animals—

420 Holstein cows

Procedure—

Vitamin E (3,000 mg, IM, once) was administered to 204 cows 8 to 14 days before expected parturition, and 216 control cows were not treated. The number of cows that had retained placenta, metritis, clinical mastitis, displaced abomasum, and clinically apparent acetonemia or hypocalcemia were recorded. Serum concentrations of tocopherol, the tocopherol:cholesterol ratio, and glutathione-peroxidase activity were determined from samples obtained before administration of vitamin E, 7 and 14 days after administration, and at 30 days after parturition from 36 treated and 36 control cows.

Results—

Administration of vitamin E significantly decreased the incidence of retained placenta and metritis (13/204 [6.4%] and 8/204 [3.9%], respectively, for the vitamin E-treated group; 27/216 [12.5%] and 19/216 [8.8%], respectively, for the untreated group) but did not affect the incidence of clinical mastitis. Serum vitamin E concentration was significantly higher in treated than in control cattle at 7 and 14 days after administration, but serum tocopherohcholesterol ratio was significantly higher only at 7 days after administration.

Clinical Implications—

Parenteral administration of a single injection of vitamin E before parturition may decrease the incidence of retained placenta and metritis in dairy cows but will increase serum concentrations for 7 to 14 days after administration. (J Am Vet Med Assoc 1997;211:466–469)

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Serum retinol, retinyl palmitate, and total vitamin A concentrations, and jejunoileal morphology were examined in neonatal calves infected with Cryptosporidium parvum. Group-1 calves served as noninfected controls and, after an adjustment period, were given 50 ml of saline solution iv every 12 hours for 6 days. Group-2 calves were inoculated with 107 C parvum oocysts and, after the onset of diarrhea, were given 50 ml of saline solution iv every 12 hours for 6 days. Group-3 calves were inoculated with 107 C parvum oocysts and, after the onset of diarrhea, were treated with difluoromethylornithine (dfmo, 200 mg/kg of body weight iv, q 12 h) for 6 days. Group-4 calves were naturally infected with C parvum. Jejunoileal biopsy specimens were excised from calves of groups 1-3 at 3 and again at 15 to 16 days of age. During the course of diarrhea and 3 days after saline or dfmo administration, water-miscible retinyl palmitate was administered orally (2,750 μg/kg) to each calf in each group. Cryptosporidium parvum infection was associated with significant (P ≤ 0.05) reduction in postadministration serum retinol, retinyl palmitate, and total vitamin A concentrations in calves of groups 2, 3, and 4. Cryptosporidium parvum infection caused significant (P ≤ 0.05) reduction in villus height. Decreased villus height, villus blunting and fusion, and attenuation of the intestinal mucosa were associated with reduced absorption of vitamin A, as indicated by lower peak postadministration retinyl palmitate concentration in C parvum-infected calves. Intravenous administration of dfmo to group-3 calves did not improve retinol absorption. Vitamin A should be provided parenterally to young calves with enteric cryptosporidiosis in an attempt to avoid depletion of concurrent low liver vitamin A reserves.

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate pharmacokinetics of ammonium tetrathiomolybdate (TTM) after IV and oral administration to dogs and effects of TTM administration on trace mineral concentrations.

ANIMALS 8 adult Beagles and Beagle crossbreds (4 sexually intact males and 4 sexually intact females).

PROCEDURES Dogs received TTM (1 mg/kg) IV and orally in a randomized crossover study. Serum molybdenum and copper concentrations were measured via inductively coupled plasma mass spectrometry in samples obtained 0 to 72 hours after administration. Pharmacokinetics was determined via noncompartmental analysis.

RESULTS For IV administration, mean ± SD terminal elimination rate constant, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 4.9 ± 0.6 μg/mL, 30.7 ± 5.4 μg/mL•h, and 27.7 ± 6.8 hours, respectively. For oral administration, mean ± SD terminal elimination rate constant, time to maximum concentration, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 3.0 ± 3.5 hours, 0.2 ± 0.4 μg/mL, 6.5 ± 8.0 μg/mL•h, and 26.8 ± 8.0 hours, respectively. Oral bioavailability was 21 ± 22%. Serum copper concentrations increased significantly after IV and oral administration. Emesis occurred after IV (2 dogs) and oral administration (3 dogs).

CONCLUSIONS AND CLINICAL RELEVANCE Pharmacokinetics for TTM after a single IV and oral administration was determined for clinically normal dogs. Absorption of TTM after oral administration was variable. Increased serum copper concentrations suggested that TTM mobilized tissue copper. Further studies will be needed to evaluate the potential therapeutic use of TTM in copper-associated chronic hepatitis of dogs.

Full access
in American Journal of Veterinary Research