The efficacy of gamithromycin did not differ from that of tulathromycin for all outcomes except morbidity rate; calves administered gamithromycin had a higher BRDC morbidity rate than did calves administered tulathromycin. On the basis of the bioequivalence limits established for this dataset, gamithromycin was considered equivalent to tulathromycin for the control of BRDC.

Calves administered gamithromycin had a higher BRDC retreatment rate than did calves administered tulathromycin; otherwise, the clinical efficacy did not differ between the 2 treatments for the treatment of BRDC in feedlot calves.

An increasing concern from both producers and consumers regarding the overuse and misuse of antibiotics leading to the development of antibiotic-resistant pathogens dictates the need for new research objectives. These new objectives should be directed towards exploring different management practices and the use of antibiotic alternative products to treat or prevent disease in cattle and other food producing animals. The main objective of this pilot study was to determine if a bovine immunotherapeutic (Amplimune™) derived from Mycobacterium cell wall fraction (MCWF) decreases the incidence and severity of clinical conditions that require antimicrobial treatments, thus reducing the cost of treatment and improving weight gain in young calves entering the feedlot. Four hundred and eighty (480) Holstein steer calves were transported from a large commercial ranch in New Mexico to a feedlot in California. Twenty-four hours following arrival, calves were randomly assigned to one of three treatment groups (control, MCWF 1 and MCWF 3) and allocated to feedlot pens. Animals in MCWF 1 and MCWF 3 groups received either 1mL or 3mL of Amplimune™ subcutaneously, while the animals in the control group were untreated. For the purpose of the study, metaphylactic use of antibiotics was omitted at the time of arrival. Animals were monitored for 102 days and information on the health status, clinical conditions, treatments and body weights were collected and subjected to further analysis. Groups that received Amplimune™ had 13 and 39 less treated animals compared to controls, resulting in calculated savings of USD 535.84 and USD 1021.36 for the MCWF 1 and MCWF 3 groups respectively. In addition, calves treated with Amplimune™ gained a total of 580lbs. and 1,630lbs. more. Overall, there was a significant beneficial effect observed with regards to morbidity, average weight gain, and medical cost per head for both MCWF groups when compared to controls. Results from this pilot study suggest Amplimune™ as a substitute for antibiotic prophylactic treatment in calves entering feedlot.

The study objective was to determine the disposition of gamithromycin in plasma, peripheral blood polymorphonuclear cells (PMNs), pulmonary epithelial lining fluid (PELF), and bronchoalveolar lavage (BAL) cells in alpacas. A single subcutaneous injection of gamithromycin (6.6 mg/kg) was administered to six healthy adult alpacas. At various time points after administration, gamithromycin concentrations were analyzed via LC‐MS/MS in plasma, PMNs, PELF, and BAL cells until Day 14 post‐injection. Plasma gamithromycin concentrations were measured in all six alpacas; the remaining three body compartments were analyzed in four alpacas. Gamithromycin rapidly concentrated in blood PMNs, BAL cells, and PELF. Shorter Tmax, and lower Cmax, and AUC were observed in plasma than in the other three compartments. Cmax was highest in BAL cells (26001.80 ± 12400.00 ng/ml) and PMNs (2573.00 ± 963.30 ng/ml) compared to PELF (660.80 ± 413.70 ng/ml) and plasma (452.30 ± 196.20 ng/ml). Mean terminal half‐lives were 72.60 ± 14.10 h in plasma, 56.60 ± 10.60 h in PELF, 62.80 ± 85.30 h in PMNs, and 93.60 ± 124.80 h in BAL cells. No injection site reactions occurred. One alpaca developed colic but no other adverse reactions were noted. Overall, gamithromycin was highly concentrated in white blood cells and pulmonary fluids/cells. Clinical utilization of gamithromycin in alpacas should be done with caution until further investigation of potential for colic.

A 75-day study was conducted in 400 beef-production, Holstein-cross calves to determine the effects of administering a single dose of a nonspecific, mycobacterial cell wall fraction immunotherapeutic (Immunoboost®, Vetrepharm, Georgia, U.S.A.) via various routes within the first 24 hours of life.