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in Journal of the American Veterinary Medical Association

Objective

To compare pregnancy rates, seasonal effects, and economic benefits of 2 estrus synchronization programs for a confinement-housed dairy herd.

Design

Prospective cohort study.

Animals

200 lactating Holstein cows.

Procedure

Cows eligible for breeding were palpated per rectum and randomly assigned to 2 treatment groups during 4 seasonal periods. Cows in one group (Ovsynch) received injections of gonadotropin releasing hormone (GnRH) on day 0, prostaglandin F on day 7, and a second injection of GnRH on day 8. Cows in the other group (PP) that had a palpable corpus luteum were given prostaglandin F. Estrus detection was not performed on the Ovsynch cows, which were artificially inseminated at a predetermined time after the second GnRH injection. Cows in the PP group were observed for signs of estrus, and only those that were detected in estrus were inseminated.

Results

Pregnancy rates and insemination rates were significantly improved for cows in the Ovsynch group, compared with cows in the PP group.

Clinical Implications

The Ovsynch program was an economically advantageous method for controlling reproduction that resulted in pregnancies without the need for estrus detection. (J Am Vet Med Assoc 1998:212:210–212)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine whether there would be detectable antibiotic residues in milk obtained from dairy cattle with papillomatous digital dermatitis (PDD) after topical treatment with oxytetracycline.

Design

Randomized controlled clinical trial.

Animals

28 lactating Holstein cows with PDD.

Procedure

Cows were assigned to 2 treatment groups. Treatment 1 (n = 16) consisted of spraying of PDD lesions with 15 ml of a solution containing 100 mg of oxytetracycline/ml; lesions were sprayed twice daily for 7 days, using a garden sprayer. Treatment 2 (n = 12) consisted of a one-time application of a bandage that consisted of cotton soaked with 20 ml of a solution containing 100 mg of oxytetracycline/ml. Milk samples were obtained before and after treatment and assayed for tetracycline content by use of high-performance liquid chromatography and a commercially available tetracycline screening test.

Results

None of the cows in either treatment group had violative residues of oxytetracycline in milk samples.

Conclusions and Clinical Relevance

Producers treating lactating cows that have PDD, via topical application of oxytetracycline solution at the concentrations reported in this study, have a low risk of causing violative antibiotic residues in milk. (J Am Vet Med Assoc 1999;215:833–836)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine whether exogenous isobutane gas infused into the udders of dairy cattle could be detected ultrasonographically, and if so, what effects volume of gas infused and infusion pressure had on how long after infusion exogenous isobutane gas could be detected.

Design

Randomized block design.

Animals

8 Holstein cows 28 to 32 days after parturition.

Procedure

In each cow, 1 mammary gland was not treated and the other 3 received 1 of 3 treatments by means of intramammary infusion: low volume-high pressure, low volume-low pressure, and high volume-high pressure infusion of isobutane gas. Mammary glands were examined ultrasonographically 1 hour before and 1,3, 12, 24, 36, 48, 72, and 96 hours after treatment.

Results

After intramammary infusion of isobutane gas, bright echoes and associated acoustic shadows were seen ultrasonographically; echoes were no longer seen 72 hours after gas infusion. Percentages of mammary glands in which bright echoes were detected were not significantly different among the 3 treatment groups at any time during the study.

Conclusions and Clinical Relevance

Results suggest that exogenous isobutane gas infused into the mammary glands to enhance the appearance of the udder of show dairy cattle can be readily detected by ultrasonography. (J Am Vet Med Assoc 1999;215:366–368)

Free access
in Journal of the American Veterinary Medical Association

Objective

To test the effectiveness of 3 topical sprays for treatment of papillomatous digital dermatitis (PDD) in dairy cattle.

Design

Prospective field trial.

Animals

48 lactating cows with PDD randomly assigned to 4 groups of 12 cows each.

Procedure

For 3 weeks, cows in each group were treated topically with oxytetracycline solution (100 mg/ ml), acidified ionized copper solution, acidified sodium chlorite solution, or a placebo (tap water). Cows were milked 3 times daily, and at each milking, lesions were washed with a pressure hose and treatment solutions were sprayed on the lesions. Degree of lameness was graded before and after 3 weeks of treatment.

Results

Mean lameness score decreased (ie, cows were less lame) for all 3 treatment groups, but increased for the control group.

Clinical Implications

Daily application of topical solutions was effective in decreasing degree of lameness associated with PDD in cattle tested. (J Am Vet Med Assoc 1996;209:1134-1136)

Free access
in Journal of the American Veterinary Medical Association