Ceftiofur hydrochloride administered at a dosage of 2.2 mg of CE/kg, SC or IM, once daily for 5 days was efficacious for treatment of APM in dairy cows.

An intravaginal progesterone insert (CIDR insert; 1.38 g of progesterone) was evaluated for synchronization of returns to estrus (SR), conception rate (CR), and pregnancy rate (PR) in dairy cows previously artificially inseminated (AI). Healthy, nonpregnant, lactating Holstein cows, > or = 40 and < or = 150 d postpartum at eight commercial farms were used. Cows detected in estrus and receiving AI 2, 3, or 4 d after one injection of PGF2alpha (25 mg) were assigned as either controls (n = 945), or to receive a CIDR insert (n = 948) for 7 d (14 to 21 +/- 1 d after AI). Cows were observed for returns to estrus from 18 to 26 +/- 1 d after initial AI (resynchrony period) and were reinseminated if in estrus. Vaginal mucus on CIDR inserts (97.3% retention) at removal was scored: 1 = no mucus; 2 = clear; 3 = cloudy; 4 = yellow; and 5 = red or brown. Percentage of cows in estrus (SR) during the 3 d after CIDR insert removal was contrasted to the highest 3-d cumulative percentage in estrus for controls. Cows conceiving to initial AI were omitted in calculations of SR, CR, and PR during resynchrony. Mucous scores of 3 or 4 (mild irritation) were observed in 65% of cows and a score of 5 (more severe irritation) was observed in 2%; otherwise, health was unaffected. The PR to initial AI was lower for cows subsequently receiving CIDR inserts than for controls (32.7 vs. 36.7%). The CIDR insert increased SR (34.1 vs. 19.3% in 3 d) and overall estrus detection (43% in 4 d vs. 36% in 9 d) compared with controls. For the 9-d resynchrony period, CR and PR for CIDR-treated (26.7, 12.2%) and control (30.9, 11.1%) cows did not differ significantly. The CIDR inserts improved synchrony of returns to estrus, slightly reduced PR to initial AI, but did not affect CR or PR to AI during the resynchrony period.

Parenteral administration of ceftiofur significantly improved cure rate, milk yield, and rectal temperature in postpartum cows with fever and vaginal discharge or dystocia. These findings provide information to determine appropriate treatment for postpartum cows, which for years has been debated in the dairy industry.

The effect of Mannheimia haemolytica infection on the penetration of ceftiofur and desfuroylceftiofur metabolites into tissue chambers was studied in cattle after subcutaneous administration of ceftiofur crystalline free acid sterile suspension (CCFA-SS). Four tissue chambers were implanted subcutaneously in each of 12 calves. Approximately 45 days after implantation, two chambers were inoculated with M. haemolytica (10(6) colony-forming units per chamber) while the remaining two chambers were inoculated with sterile phosphate-buffered saline. Twenty-four hours after inoculation, CCFA-SS was administered subcutaneously in the middle third of the caudal ear pinna of each calf. Chamber fluid and blood samples were collected at predetermined times for 10 days following dosing and analyzed for ceftiofur and desfuroylceftiofur metabolites by high-performance liquid chromatography. Concentrations of ceftiofur and desfuroylceftiofur metabolites in plasma and tissue chamber fluid remained above a threshold of 0.2 microg/mL for at least 8 days. Infected tissue chamber fluid concentrations of ceftiofur and desfuroylceftiofur metabolites were significantly higher than those in non-infected tissue chamber fluid, which correlated with significantly higher total protein concentration in infected tissue chambers. These results indicate that single subcutaneous administration of CCFA-SS at 6.6 mg/kg can be expected to provide effective therapy of susceptible bacterial infections for a period of at least 1 week.

Mammary secretions, obtained before and after calving, were examined for visual appearance, SCC, and bacteriology as part of a larger study determining the prevalence of IMI in 1588 primigravid heifers. Appearance of secretions was categorized into five groups: thin and watery, honey-like, serumy, milky, or thickened colostrum. Precalving secretions were further characterized as low viscosity (thin and watery, serumy, or milky) or high viscosity (honey-like and thickened colostrum). Postcalving secretions were further characterized as normal (milky, thickened colostrum) or abnormal (thin and watery, serumy, or honey-like). Infected precalving quarters (81%) had low viscosity secretions. Quarters that were uninfected precalving (75%) had high viscosity secretions. Greater than 90% of all postcalving milk samples appeared to be normal, regardless of geographic location, season, or bacterial infection status. Only 77% of the samples from quarters infected with contagious and noncontagious mastitis pathogens had normal appearance. Precalving SCC from bacteriologically negative quarters were lower than SCC from infected quarters. Similarly, postcalving SCC were lower from the bacteriologically negative quarters than from the infected quarters. Infected quarters had higher mean SCC than the uninfected quarters during both pre- and postcalving periods.