Gordon W. Brumbaugh

Bacteriology of preserved stallion semen and antibiotics in semen extenders

Three experiments were conducted to evaluate the effects of different antibiotics in a milk-glucose semen extender on motility of equine sperm and elimination of bacteria following storage of extended semen in vitro. In Experiment 1, 7 antibiotics were compared: amikacin, gentamicin, streptomycin, potassium penicillin, sodium penicillin, ticarcillin, and polymixin B. In Experiment 2, 3 antibiotic treatments were compared: potassium penicillin G, amikacin, or a combination of potassium penicillin G and amikacin. In Experiment 3, 3 antibiotic treatments were compared: potassium penicillin G-amikacin, ceptiofur, and a combination of ticarcillin and clavulanic acid (Timentin). Control treatments (antibiotic-free extender) were included in each experiment. Six motility variables were evaluated: percentage of motile sperm; percentage of progressively-motile sperm; percentage of rapidly-motile sperm; mean curvilinear velocity; mean average path velocity; and mean straight-line velocity. In Experiment 1, mean percentages of motile, progressively motile and rapidly motile sperm were lower (P < 0.05) in semen exposed to polymixin B then in other treatments. Mean average-path velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control or ticarcillin. Mean straight-line velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control, streptomycin or ticarcillin. Semen samples containing gentamicin, amikacin, streptomycin, or potassium penicillin were more effective (P < 0.05) at eliminating bacterial growth than those samples containing polymixin B. Semen samples containing gentamicin were also more effective (P < 0.05) at eliminating bacterial growth than those samples containing ticarcillin or sodium penicillin. In Experiment 2, mean percentage of rapidly-motile sperm, and mean curvilinear, average-path, and straight-line velocities were greater (P < 0.05) for potassium penicillin-amikacin than values for all other treatments. In 2 of 3 stallions, an effect of treatment on percentage of motile sperm was detected (P < 0.05). For one stallion, mean motility of potassium penicillin-amikacin was greater (P < 0.05) than that of all other treatment groups. For another stallion, mean motility of the control was lower (P < 0.05) than that of the other treatments. Following storage, potassium penicillin (16/18 [89%]) or potassium penicillin-amikacin (17/19 [94%]) were more effective (P < 0.05) at controlling aerobic and anaerobic bacterial isolates in semen specimens than was amikacin (10/18 [56%]). In Experiment 3, a difference among treatment groups for motility variables was not detected (P < 0.05). No bacterial growth was recovered in antibiotic-treated semen, with exception of Micrococcus sp. (2 colonies) which were isolated from one semen specimen treated with ceptiofur.

PHYSIOLOGIC RESPONSES OF ACCLIMATIZED OR NON-ACCLIMATIZED MATURE REINING HORSES TO HEAT STRESS: I. HEART RATE, RESPIRATION RATE, LACTATE, RECTAL TEMPERATURE, CORTISOL AND PACKED CELL VOLUME

Abstract An experiment was conducted utilizing twenty mature Quarter Horses to establish physiologic responses to reining training under conditions conducive to heat stress. Ten of the horses were acclimatized to ambient conditions [30°C, 80% relative humidity (RH)] for 28 days while the other ten were acclimatized simultaneously to 20°C and 50% RH in an air-conditioned facility. On day 28 standard exercise testing (SET) 1 was conducted in ambient conditions (30°C, 80% RH) for both groups of horses and was repeated on day 30 and day 32 of the protocol. Heart rate and plasma lactate concentration revealed that galloping circles, spinning and stopping were more taxing maneuvers for the unacclimatized horses on day 28. However, these differences were less significant on day 30 and were not observed on day 32 indicating that it took the horses approximately five days to become acclimatized to ambient conditions. Respiration rate and rectal temperature were higher in the cool-treated horses during rest and the recovery period on day 28. These differences were only seen in the early stages of recovery on day 30 and totally disappeared on day 32. Packed cell volume was lowest in the cool-treated horses on day 28 during the SET and most of the recovery period, which is likely reflective of the absence of a substantial amount of sweating on the first day of acclimatization. This difference was still present, however, less apparent on day 30 and completely absent on day 32. Plasma cortisol concentrations were significantly higher during recovery in the cool-treated horses on day 28 and day 30, but they were not different on day 32.

Treatment of diarrhea of neonatal calves.

Enterotoxigenic Escherichia coli, Salmonella spp, and Giardia duodena are causes of diarrhea of neonatal calves that may be treated by specific antimicrobial or antiprotozoal therapy. Treatment to correct physiologic abnormalities resulting from diarrhea is most successful because the causative agent does not have to be identified prior to treatment. Some agents, such as orally administered antimicrobials, kaolin-pectin, and parasympatholytic drugs, have detrimental effects that make them inappropriate for treatment of diarrheic calves.

Effectiveness of two fluoroquinolones for the treatment of chronic respiratory disease outbreak in broilers

1. Chronic respiratory disease (CRD) caused by Mycoplasma synoviae in association with Escherichia coli is the disease most frequently encountered in poultry in Mexico. 2. Differences of antimycoplasmal activity, pharmacokinetics and cost among fluoroquinolones were the impetus for this clinical evaluation of efficacy of enrofloxacin and norfloxacin-nicotinate in broilers with CRD. 3. A total of 99,600 broilers, naturally infected with M. synoviae and E. coli, were treated with enrofloxacin (10 mg/kg/d for 3 d) (n = 49,800) or norfloxacin-nicotinate (20 mg/kg/d for 3 d) (n = 49,800). 4. Based on survivor analysis, there were no significant differences of efficacy of the 2 drugs. Survivor probabilities were above 0.99. 5. These results indicate that enrofloxacin and norfloxacin-nicotinate are efficacious for treatment of CRD. Questions remaining to be answered by other studies include: public health concern about the use of fluoroquinolones for the treatment of CRD; clinical superiority of one of these drugs on the basis of an attribute other than antimicrobial activity, such as cost:benefit ratio or ability to prevent bacterial resistance. 6. Clinical efficacy is not a relevant variable in assessing whether norfloxacin-nicotinate or enrofloxacin should be used for the treatment of CRD associated with E. coli in broilers.

Growth of yearling fillies fed alfalfa or soybean meal

Summary Sixteen Quarter Horse yearling fillies were used in a 112-day randomized block experiment to determine the comparative efficacy of alfalfa hay protein to support growth in young horses. The yearlings were divided into two groups of eight and paired according to weight and age, with one yearling from each pair randomly allotted to each diet. Group 1 was fed a diet of coastal Bermuda grass hay and concentrate. The corn-based concentrate was supplemented with soybean meal such that the total diet for group 1 contained approximately 13% CP. Group 2 was fed a diet that also contained approximately 13% CP and consisted of alfalfa hay and a similar concentrate without soybean meal. Yearlings were fed the diets in a 60:40 grain-to-hay ratio, and intakes between members of each pair were equalized. The calculated digestible energy density in both final diets was approximately 2.85 mcal/kg, and the protein:calorie ratio for both diets was approximately 45 gm/Mcal. Body weight, body length, heart girth, wither and hip heights, as well as forearm, gaskin and cannon bone circumferences were measured every 28 days. Rump fat thickness was measured ultrasonically every 28 days. Physical measures of growth were similar for horses eating each diet (P>0.05). Also, blood urea nitrogen was similar for horses eating each diet (P>0.05) and was not reflective of differences in nitrogen metabolism. The fillies fed the SBM-supplemented diet retained more nitrogen more efficiently than did fillies fed the alfalfa diet (P

Use of bethanechol and metoclopramide in horses with duodenitis/proximal jejunitis: 13 cases (1987–1993)

Abstract All horses diagnosed with duodenitis/proximal jejunitis (DPJ) at the Texas Veterinary Medican Center between January 1, 1987 and July 1, 1993 were included in a retrospective study to evaluate the therapeutic and prognostic value of bethanechol and metoclopramide as gastrointestinal prokinetic drugs in horses with DPJ treated at our clinic, and to compare the clinical outcome of horses with DPJ treated with these drugs and those with DPJ that were not treated. During the study period, 70 horses diagnosed with DPJ were admitted to the clinic. Of these 70 horses, 18(25.7%) were treated with bethanechol, metoclopramide, or both; 13 of the 18 treated horses received more than one dose of either drug. No adverse effects of treatment with these drugs were noted. A precise therapeutic plan and clinical benefit of bethanechol, metoclopramide, or both coul not be determined from this retrospective study. The use of these gastrointestinal prokinetic drugs in horses with DPJ appeared to have prognostic value. Horses that did not respond to treatment with these gastrointestinal prokinetic drugs within 24 hours were not discharged alive.

Serologic response to Mannheimia haemolytica in calves concurrently inoculated with inactivated or modified-live preparations of M haemolytica and viral combination vaccines containing modified-live bovine herpesvirus type 1

OBJECTIVE To assess the serologic response of calves to inactivated and modified-live (ML) Mannheimia haemolytica (MH) preparations given alone and concurrently with combination viral vaccines containing ML bovine herpesvirus type 1 (BHV-1). ANIMALS 642 calves seronegative for BHV-1. PROCEDURES In experiment 1, 192 calves received 1 of 3 MH preparations alone or concurrently received 1 of 3 MH preparations and 1 of 4 combination viral vaccines. In experiment 2, 450 calves received 1 of 4 MH preparations alone or concurrently received 1 of 4 MH preparations and 1 of 5 combination viral vaccines. Pretreatment and posttreatment blood samples were processed to obtain serum, which was analyzed to detect concentrations of antibodies against MH leukotoxin and BHV-1. RESULTS In experiment 1, antibody titers against MH leukotoxin in calves receiving MH and ML virus vaccine appeared decreased, albeit nonsignificantly, compared with titers for calves receiving MH preparations alone. In experiment 2, all groups (except for 1) concurrently receiving an MH preparation and viral vaccine had a significant decrease in antibodies against MH leukotoxin. In both experiments, there was a significant decrease in the number of calves responding to MH leukotoxin when ML viral vaccine was coadministered. CONCLUSIONS AND CLINICAL RELEVANCE Coadministration of ML BHV-1 and MH preparations interfered with the serologic response to MH leukotoxin in calves seronegative for BHV-1. Serologic response to MH leukotoxin may be substantially improved in seronegative calves when MH vaccination is delayed until after calves have received a dose of ML BHV-1 vaccine.

Adverse Drug Reactions and Interactions in the Horse

Drugs undergo extensive evaluation before they are marketed. The occurrence of adverse reactions, however, may be so rare that thousands of patients must receive the drug before reliable data are available. It is necessary that veterinarians be informed about the drugs they use, be able to recognize drug-associated complications, know how to evaluate the patient for evidence of drug-associated toxicity, report adverse effects of drugs to the respective manufacturers, and be prepared to provide medical support and antidotal treatment (if it exists) for a patient if toxicosis occurs.

Pharmacologic and Alternative Therapies for the Horse with Chronic Laminitis

This article deals with treatment of the chronically foundered horse. The first section of this article is focused on aspects of the traditional pharmacologic approaches to management of digital pain and sepsis, dietary management, and thyroid supplementation. A second section introduces the concepts, principles, and agents that are used in homeopathic treatments for laminitis. Lastly, a third section of this article reviews the use of acupuncture and traditional Chinese medicine approaches to treatment of chronic laminitis.

Effect of tilmicosin on chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages

OBJECTIVE To evaluate chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages (AM) exposed to tilmicosin. ANIMALS 12 healthy calves and 12 healthy pigs. PROCEDURES Lungs were obtained immediately after euthanasia; AM were collected by means of bronchoalveolar lavage and density gradient centrifugation. Chemotactic activity was evaluated by exposing AM to lipopolysaccharide or macrophage inhibitory peptide during incubation with tilmicosin. Phagocytic activity was evaluated by incubating AM with tilmicosin for 24 hours and then with tilmicosin-resistant Salmonella serotype Typhimurium. Bactericidal activity was evaluated by incubating AM with tilmicosin (0, 10, or 20 microg/ml for bovine AM; 0 or 10 microg/ml or 10 microg/ml but washed free of tilmicosin for porcine AM) and then with Mannheimia haemolytica (bovine AM) or with Actinobacillus pleuropneumoniae or Pasteurella multocida (porcine AM). RESULTS Tilmicosin had no significant effects on chemotactic or phagocytic activities of bovine or porcine AM. The time-course of bactericidal activity was best described by polynomial equations. Time to cessation of bacterial growth and area under the time versus bacterial number curve were significantly affected by incubation of AM with tilmicosin. CONCLUSIONS AND CLINICAL RELEVANCE Results show that bactericidal activity of bovine and porcine AM was enhanced by tilmicosin, but not in proportion to the reported ability of AM to concentrate tilmicosin intracellularly. With or without exposure to tilmicosin, the time-course of bactericidal activity of bovine AM against M haemolytica and of porcine AM against A pleuropneumoniae or P multocida was too complex to be reduced to a simple linear equation.