Effect of Erythromycin and Gentamicin on Abomasal Emptying Rate in Suckling Calves

More movement with manure: increased mobility of erythromycin through agricultural soil in the presence of manure

Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K = 8.01 × 10-2 L/mg; qmax = 1.53 × 10-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K = 1.99 × 10-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics.

Effects of parenteral administration of tylosin and ivermectin on abomasal emptying rate in healthy suckling lambs by use of nuclear scintigraphy

Abomasal hypomotility is one of the important causes of neonatal mortality in small ruminants. Various pharmaceutical agents have been studied to address this problem in large ruminants. The aim of this study was to determine the effect of parenteral administration of tylosin and ivermectin on abomasal emptying rate in neonatal suckling lambs. Abomasal emptying rate was assessed using nuclear scintigraphic method in 10 healthy female Iranian fat tailed Ghezel lambs. Each lamb was tested three times, once as a control (1 ml of saline 0.9%, IM) and twice after the injection of tylosin (17.6 mg/kg, IM) and ivermectin (200 μg/kg, SC) in a crossover study. Based on radiopharmaceutical counts, remnant activity in abomasums at 90 min were 48.3 ± 3.5, 45.6 ± 7.5 and 41.6 ± 2.9% in control, tylosin and ivermectin groups, respectively. Administration of tylosin (p = 0.049) and ivermectin (p = 0.045) to lambs, significantly caused faster abomasal emptying rate compared to control. Evaluating the ROIs revealed that the half emptying time (T_1/2) in control, tylosin and ivermectin groups were 67.1 ± 8.6, 62.6 ± 14.2 and 54.3 ± 9.9 min, respectively. These difference between all groups, statistically were significant (p = 0.026). However, the clinical efficacy of abomasal emptying rate facilitating by tylosin or ivermectin administration in lambs remains to be determined.

Interactions between erythromycin, flunixin meglumine, levamisole and plant secondary metabolites towards bovine gastrointestinal motility-in vitro study

Continued ingestion of plant secondary metabolites by ruminants can provoke pharmacological interactions with pharmaceutical agents used in animals. As some drugs and phytocompounds affect smooth muscle activity, the aim of this study was to verify the possible interaction between selected pharmaceutical agents and plant secondary metabolites towards bovine gastrointestinal motility. The interactions between phytocompounds-apigenin, quercetin, hederagenin, medicagenic acid-and medicines-erythromycin, flunixin meglumine and levamisole-were evaluated on bovine isolated abomasal and duodenal specimens obtained from routinely slaughtered cows. The obtained results confirmed the contractile effect of all three drugs used solely. Hederagenin and medicagenic acid (0.001 μM) enhanced the contractile effect of levamisole. Hederagenin additionally increased the impact of erythromycin. Both saponins (100 μM) showed synergistic effects with all tested pharmaceuticals. Apigenin and quercetin (0.001 μM) intensified the contractile response induced by erythromycin and levamisole. Moreover, both flavonoids (100 μM) showed an antagonistic interaction with all tested drugs which in that situation were devoid of the prokinetic effect. To conclude, plant metabolic metabolites such as saponins and flavonoids are potent modifiers of the effect of drugs towards gut motility. The synergy observed between phytocompounds and selected medicines can be beneficial in the treatment of cows with hypomotility disorders.

Effect of orally administered cisapride, bethanechol, and erythromycin on the apparent efficiency of colostral IgG absorption in neonatal Holstein-Friesian calves

Objective

To evaluate the effect of orally administered cisapride, bethanechol, and erythromycin on the absorption of colostral IgG in dairy calves.

Animals

Twenty‐four healthy neonatal Holstein‐Friesian calves.

Procedures

Calves were randomly assigned to one of the following treatments: 0.9% NaCl solution (2 mL, PO; negative control); erythromycin lactobionate (20 mg/kg BW, PO; anticipated to be a positive control); cisapride (0.5 mg/kg BW, PO); bethanechol chloride (0.5 mg/kg BW, PO). Calves were fed 3 L of pooled bovine colostrum containing acetaminophen (50 mg/kg) by suckling and oroesophageal intubation 30 minutes after each treatment was administered. Jugular venous blood samples were obtained periodically after the start of feeding and plasma total IgG, protein, acetaminophen, and glucose concentrations determined. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration.

Results

Oral administration of cisapride facilitated the absorption of colostral IgG and protein. The effect of cisapride on abomasal emptying rate could not be evaluated because cisapride appeared to interfere with acetaminophen metabolism. Based on the total IgG and total protein concentration‐time relationships, the beneficial effects of cisapride appeared to occur early after oral administration and were transient.

Conclusions and Clinical Importance

Additional studies appear indicated to characterize the effect of cisapride dose on the magnitude and duration of its effect on facilitating the absorption of colostral IgG and protein. Identification of a nonantimicrobial method for increasing abomasal emptying rate, such as cisapride, will potentially provide a practical and effective method for facilitating transfer of passive immunity in colostrum‐fed dairy calves.

Treatment of calf diarrhea: antimicrobial and ancillary treatments

Adjunct treatment of diarrhea should be routinely undertaken in all calves with systemic signs of illness, manifest as fever, inappetance, or lethargy. Ancillary treatments with documented efficacy in undifferentiated calf diarrhea include parenteral administration of antimicrobials with a predominantly gram negative spectrum of activity, parenteral administration of non-steroidal anti-inflammatory agents such as meloxicam and flunixin meglumine, and continued feeding of cow's milk. Halofuginone and azithromycin have efficacy in calves with diarrhea due to Cryptosporidium parvum, and their administration should be considered in calves documented or suspected to have cryptosporidiosis.