tulathromycin and Body-Weight

The objective of this study was to evaluate one strategy for control (metaphylaxis) of bovine respiratory disease, with and without co-morbidity with otitis media, in dairy heifers at a commercial development facility. Individual heifers were the experimental unit. At weaning, 1 of 3 experimental treatments (gamithromycin, tulathromycin, or no medication) was randomly assigned to 1,567 heifers from 11 different dairies. Gamithromycin was administered to 631 heifers, tulathromycin was administered to 621 heifers, and no medication was administered to 315 heifers (negative control). Heifers were then commingled and penned according to body weight. Each pen contained heifers from each group, and periodically, larger numbers of heifers were penned together. All heifers were observed for the subsequent 42 d and treated according to protocols prescribed for the facility. Morbidity due to respiratory disease was less for heifers medicated with gamithromycin than for heifers medicated with tulathromycin. Morbidity due to respiratory disease was less for heifers medicated with gamithromycin than for heifers in the negative control group. Fewer heifers medicated with either antimicrobial were subsequently treated because of co-morbidity with otitis media. Mortality was not different among the treatment groups. Heifers medicated with either antimicrobial had greater average daily gain than did heifers in the negative control group.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Cattle; Cattle Diseases; Disaccharides; Female; Heterocyclic Compounds; Macrolides; Morbidity; Otitis Media; Random Allocation; Respiratory Tract Diseases; Weaning

Preweaning respiratory disease continues to have a substantial effect on the current and future productivity of dairy replacement animals. Establishing an effective treatment plan for the preweaned calf may have a significant effect on well-being and lifetime productivity by limiting any early development of chronic disease. The primary objective of this study was to examine the efficacy of treatment with tulathromycin (TUL) or enrofloxacin (ENR) on the risk of re-treatment, with a secondary objective of investigating the effect of disease and subsequent treatment choice on average daily gain (ADG). A total of 1,141 Holstein heifers from 4 farms were observed and systematically scored for evidence of respiratory disease from birth through weaning or the time of death. At the time of diagnosis, calves were randomly and blindly allocated into 2 treatment groups. The overall incidence of respiratory disease was 60.9%. In the univariable analysis, the incidence of re-treatment between 7 and 10d of initial therapy for calves treated with ENR was greater than that in calves treated with TUL (27.6 vs. 21.2%). After adjusting for farm ID, clinical score at first treatment, and weight at first treatment, the odds of re-treatment were 1.5 times higher for calves treated with ENR than with TUL. The percentage of calves that required more than one re-treatment was higher for calves that received ENR compared with those that received TUL (9.3 vs. 4.1%). We observed no difference in ADG between calves treated with ENR or TUL, and no difference in ADG between calves that were treated for respiratory disease and those that were not treated for respiratory disease. Appropriate drug therapy for preweaning respiratory disease may have an important role in reducing the odds of re-treatment during the preweaning period.

Topics: Animals; Anti-Infective Agents; Bacterial Typing Techniques; Body Weight; Cattle; Disaccharides; Enrofloxacin; Female; Fluoroquinolones; Heterocyclic Compounds; Linear Models; Logistic Models; Respiratory Tract Diseases; Treatment Outcome; Weaning

Remote delivery devices (RDD) are used by some to administer antimicrobials (AM) to cattle when treatment by manual injection is logistically difficult. However, it is not clear that the pharmacokinetics (PK) of AM administered by RDD is comparable to that for AM administered by injection; thus, it is not certain that cattle treated by RDD experience equivalent AM effect. Fifteen crossbred beef steers (body weight [BW] = 302.5 ± 21.7 kg) were used in a three-way crossover study to determine the PK of tulathromycin following administration with RDD in the BQA injection triangle. Cattle were treated by each of three methods at 2.5 mg of tulathromycin per kg of BW with a 60 d washout period between treatments: 1) subcutaneous injection of tulathromycin (SC), 2) treatment by RDD delivered by air pump projector (AIR, Pneudart, Model 178B) at 4.5 m distance, and 3) treatment by RDD delivered by CO2-powered projector at 7.5 m (CO2, Pneudart, Model 176B). Blood was collected prior to injection and at various points up to 552 h post-administration, pharmacokinetic data were analyzed as a mixed model using animal as a random effect and method of administration, order of administration, and their interaction as fixed effects. Plasma creatine kinase (CK) was measured before treatment and at 24 h after treatment to determine the degree of muscle injury resulting from each treatment. Three darts administered by AIR did not discharge (20%; 95% CI = 4% to 48%); and results from these steers were excluded from analysis. Maximum plasma concentration (718, 702.6, and 755.5 µg/mL for SC, AIR, and CO2, respectively) and area under the concentration-time curve (17,885, 17,423, and 18,796 µg • h/mL for SC, AIR and CO, respectively) were similar and not significantly different between methods of administration. There was an effect of time (P = 0.0002), period (P = 0.0001), and interaction between method of administration and study period (P = 0.0210) on plasma concentration of CK. However, method of treatment (P = 0.6091), interaction between method and time (P = 0.6972), interaction between period and time (P = 0.6153), and 3-way interaction between method, period and time (P = 0.6804) were not different. Results suggest that PK of tulathromycin following delivery by RDD can be similar to subcutaneous injection; however, failure of RDD to discharge after delivery by some types of projectors can cause an important proportion of cattle to fail to receive drug as expected.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Cattle; Cross-Over Studies; Disaccharides; Drug Delivery Systems; Heterocyclic Compounds; Injections, Subcutaneous; Male

Bovine respiratory disease (BRD) is a major concern when raising replacement heifers because of the high incidence and long-term effects of this disease, such as decreased growth and increased time to first calving. The objective of this study was to determine the effect of tulathromycin (TUL) treatment at postweaning movement on the incidence of BRD in dairy replacement heifers. A total of 1,395 heifers were enrolled between November 2006 and June 2007 at a commercial heifer-raising facility. Calves were randomly assigned either to treatment with TUL or to a positive control group treated with oxytetracycline (TET). Calves treated with TUL were 0.5 times (95% CI: 0.4 to 0.7) less likely to be treated for BRD in the 60 d following enrollment than calves treated with TET. For calves that had no history of BRD in the pre-enrollment period, TET calves weighed 4.9+/-0.5kg less than TUL calves after 6 wk in group housing. If calves were treated for BRD in the pre-enrollment period, there was no treatment effect on growth. Calves with clinical BRD in the 60 d following movement weighed 7.9+/-0.6kg less than calves without BRD after 6 wk in group housing. Treatment with TUL at the time of movement to group housing had a beneficial effect on the health and performance through the prevention of BRD in dairy calves with no prior history of the disease. Moreover, BRD after movement to group housing after weaning had a significant effect on the growth of dairy calves.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Bovine Respiratory Disease Complex; Cattle; Dairying; Disaccharides; Female; Heterocyclic Compounds; Oxytetracycline; Random Allocation; Weaning