Efficacy of intramammary infusion of ceftiofur hydrochloride at drying off for treatment and prevention of bovine mastitis during the nonlactating period.

This study evaluated the efficacy of intramammary infusion of ceftiofur hydrochloride for the treatment of intramammary infections present at the last milking of lactation and for prevention of new intramammary infections during the nonlactating period. Cows were randomly assigned to five treatments (untreated negative control, 125, 250, and 500 mg of ceftiofur, and a positive control group receiving 300 mg cephapirin benzathine). A dose of 125 mg of ceftiofur per mammary quarter was effective for treatment of existing infections present at the time of milk cessation, but only the 500-mg dose of ceftiofur per mammary quarter was effective for both treatment of existing intramammary infections at the time of milk cessation and for prevention of new intramammary infections during the nonlactating period.

A dose-response study of melengestrol acetate on feedlot performance and carcass characteristics of beef steers.

The dose response of melengestrol acetate (MGA) on ADG (kg/d) and gain efficiency (gain/DMI, g/kg) was estimated in beef steers fed a finishing diet under commercial feedlot conditions. Melengestrol acetate is not approved for use in steers as a feed additive. The study design was five blocks of four pens (each pen was assigned a dose of MGA) with 166 to 200 steers per pen. Melengestrol acetate was fed to steers at 0 (n = 899, five pens), 0.1 (n = 900, five pens), 0.2 (n = 899, five pens), and 0.4 (n = 900, five pens) mg of MGA/steer daily. Pens within a block were slaughtered on the same day. Blocks 1 through 5 were fed MGA for 123, 122, 116, 124, and 138 d, respectively. The experimental unit was a pen of steers, and blocking was based on source of steers. The ADG was 1.81, 1.85, 1.80, and 1.83 kg/d for steers fed 0, 0.1, 0.2, and 0.4 mg MGA per day, respectively. For ADG, the dose was significant, but neither linear nor quadratic effects were significant. Compared with steers of the control group, ADG was greater for steers fed 0.1 mg MGA (P < 0.01). Feed efficiencies were 170, 173, 171, and 172 g/kg for steers fed 0, 0.1, 0.2, and 0.4 mg MGA/d, respectively; however, no effects of dose (P = 0.19) or linear (P = 0.21) or quadratic (P > 0.60) effects were observed. There was no evidence for either positive or negative effects of MGA on DMI, hot carcass weight, dressing percent, quality grade, yield grade, back fat thickness, marbling score, longissimus muscle area, and incidence of dark cutter carcasses in response to feeding MGA to steers at doses of 0.1, 0.2, and 0.4 mg daily. The incidence of buller behavior (0.43 to 1.11%) was low and did not permit an accurate test of the clinical observations that feeding MGA to steers decreases the occurrence of buller steers. Melengestrol acetate fed to finishing beef steers produced small improvements in growth performance (ADG, 2.2%) at the 0.1 mg MGA dose, but none of the doses examined produced improvement in carcass quality or yield grade measurements.

Intravaginal progesterone insert to synchronize return to estrus of previously inseminated 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.

Dose determination and confirmation of a long-acting formulation of ceftiofur (ceftiofur crystalline free acid) administered subcutaneously for the treatment of bovine respiratory disease.

The objective of this work was to determine and confirm an effective dose of ceftiofur crystalline free acid sterile oil suspension (CCFA-SS, 100 mg ceftiofur equivalents (CE)/mL], a long-acting single-administration ceftiofur formulation, for the treatment of the bacterial component of bovine respiratory disease (BRD). Study 1 was a dose determination study that used an intratracheal Mannheimia haemolytica (Pasteurella haemolytica) challenge model to evaluate single-administration doses of CCFA-SS at 0.0, 1.1, 2.2, 3.3, 4.4 or 5.5 mg CE/kg body weight (BW) for the treatment of BRD. Data from this study were used to select doses for field testing in three multi-location clinical studies. In Study 2, the efficacy of a single administration dose of CCFA-SS at 4.4 mg CE/kg BW was compared with a negative control for the treatment of naturally occurring BRD in feedlot cattle. Treatments were administered when uniform clinical signs of BRD were present. Study 3 used a design similar to Study 2, and compared single-administration doses of CCFA-SS at 3.0 or 4.4 mg CE/kg BW with the positive-control tilmicosin (Micotil(R) 300 Injection, Elanco Animal Health) at 10 mg/kg BW. Study 4 compared the efficacy of single doses of CCFA-SS of 1.1-8.8 mg CE/kg BW with tilmicosin at 10 mg/kg BW. A total of 1176 cattle were included in these clinical studies. In Study 1, a dose of 4.55 mg CE/kg BW was determined to be effective. This was rounded to 4.4 mg CE/kg for field testing. In Study 2, a single dose of CCFA-SS at 4.4 mg CE/kg BW had a higher treatment success rate on day 14 (61%) than negative controls (26%, P < 0.01). However, in Study 3 this dose was judged to be at the beginning of an efficacious dose range for the treatment of BRD when compared with tilmicosin. In Study 4, day 28 treatment success rates were higher for CCFA-SS at 4.4-8.8 CE/kg BW than for tilmicosin (P=0.002) or the noneffective CCFA-SS dose of 1.1 mg CE/kg BW (P < 0.001). Based on decision criteria for Study 4, the effective dose was determined to be 4.4-5.5 mg CE/kg BW. These clinical studies demonstrated that a single dose of CCFA-SS (100 mg CE/mL) administered subcutaneously (s.c.) in the neck at 4.4-5.5 mg CE/kg BW is an effective treatment for BRD in feedlot cattle. However, this route of administration is no longer being considered for this formulation because of the ceftiofur residues that are present at the injection site for extended periods of time.

Multilocation trial of ceftiofur for treatment of postpartum cows with fever.

OBJECTIVE: To evaluate the effect of ceftiofur for treatment of postpartum cows with fever. DESIGN: Multilocation randomized complete block design trial. ANIMALS: 330 cows. PROCEDURE: Cows with rectal temperature > or = 39.5 C (103.1 F) during the first 10 postpartum days were randomly assigned to a treatment (ceftiofur; 1 mg/kg [0.45 mg/lb] of body weight daily for 3 days) or untreated control group. Cure (no additional or alternative antimicrobial treatment used, rectal temperature < 39.5 C, and no other concurrent clinical signs of disease when evaluated at 9 or 10 days after enrollment), milk production, and rectal temperature were evaluated. RESULTS: Ceftiofur-treated cows were significantly more likely to be cured than control cows (56.0 vs 28.9%, respectively), with an odds ratio of 3.14 when vaginal discharge (a factor with moderate interaction with treatment) was present at enrollment. Among cows that had an abnormal calving (a significant interaction factor), treated cows had first milking yield 2.27 kg (5 lb) greater than control cows. Treated cows had a significantly greater reduction in rectal temperature (1.19 C [2.14 Fl), compared with control cows (1.04 C [1.87 F]). CONCLUSIONS AND CLINICAL RELEVANCE: 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.

Ceftiofur hydrochloride: plasma and tissue distribution in swine following intramuscular administration at various doses.

Twelve mixed-breed swine (26.5-42.5 kg) received three daily intramuscular (i.m.) doses of 14C-ceftiofur hydrochloride. Three males and three females, received 6.76 +/- 0.83 mg of 14C-ceftiofur free acid equivalents (CFAE)/kg body weight (b.w.)/day, while the other group received 4.41 +/- 0.97 mg.CFAE/kg b.w./day. The swine were slaughtered 12 h following the last dose. Total dose accountability for the 6.76 mg dose was 91.44 +/- 16.11% (72.51% in urine; 12.63% in faeces). For the 4.41 mg dose, accountability was 100.35 +/- 20.45% (82.48% in urine; 12.85% in faeces). Within the tissues used for residue monitoring, the highest concentrations were observed in the kidneys (10.68 and 6.33 micrograms.CFAE/g for the 6.76 and 4.41 mg doses, respectively), followed by the injection sites, lungs, liver and muscle. In a separate study, twelve mix-breed swine (23.1-39.7 kg) received 14C-ceftiofur hydrochloride at 3.08 mg.CFAE/kg b.w. once daily for 3 days. Two males and two females were slaughtered at either 12, 72 or 120 h after the last dose. Total dose accountability for the 3.08 mg dose was > 83% (> 68% in urine; > 13% in faeces). In swine slaughtered 12 h after last dose, residue concentrations closest to the safe concentrations were observed in the kidneys (3.62 micrograms.CFAE/g), followed by the injection sites, lungs, liver and muscle.

The visual appearance and somatic cell count of mammary secretions collected from primigravid heifers during gestation and early postpartum.

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.