Use of Antibiotics against Bacterial Infections on Dairy Sheep and Goat Farms: Patterns of Usage and Associations with Health Management and Human Resources

Abstract

The objectives of the study were (a) to describe the patterns of antibiotic usage against four major clinical problems and (b) to evaluate factors that were associated with their use on small ruminant farms. Sheep and goat farmers mostly administered the antibiotics to animals at the dose prescribed (80.4%) and observed the necessary withdrawal period (98.7%), but fewer farmers (22.3%) weighed the animals to calculate their bodyweight before antibiotic administration. For the treatment of clinical mastitis, oxytetracycline, penicillin and streptomycin were the antibiotics used more frequently; 2.03 different antibiotics were used per sheep flock and 2.06 per goat herd, most frequently administered in injectable forms (88.8% of farms). In cases of abortion, oxytetracycline was administered more frequently; 1.12 different antibiotics were used per sheep flock and 1.03 per goat herd. In 94 farms (21.2%), routine administration of antibiotics was performed to newborns; oxytetracycline and ampicillin were administered more often. For the treatment of pneumonia in newborns, oxytetracycline, penicillin and tulathromycin were used more frequently; 1.33 antibiotics were used per sheep flock and 1.29 per goat herd. For the treatment of diarrhoea in lambs and kids, oxytetracycline, amoxicillin and penicillin were the antibiotics used more frequently; 1.34 antibiotics were used per sheep flock and 1.59 per goat herd. Results of multivariable analyses indicated 16 variables associated with the various outcomes for usage of antibiotics for the treatment of the above clinical problems. Of these, 11 variables were associated with the farmers: education of farmers was significant for three outcomes; the age, the experience, the professional involvement and farming family tradition of farmers and the daily period spent at the farm were each significant for one outcome.

Comparison of the Efficacy of Intramammary or Injectable Antibiotic Administration against Staphylococcal Mastitis in Ewes

“…When comparing the two routes, no difference was found in the recession of the clinical signs of the infection. This can possibly explain the preference for using injectable products for the treatment of clinical mastitis; in a recent study, it was reported that in 89% of sheep farms in Greece solely the injectable form was employed for the treatment of clinical mastitis [ 11 ]. In this respect, it should also be noted that the administration of the antibiotics by the injectable route would cost 30% less than administration by the intramammary route: 2.8 € versus 4.0 €, respectively (based on current retail prices of the products in Greece), which can also play a role in the selection by the prescribing veterinarians.…”

“…It is noteworthy that in an extensive study performed recently an association was found between the route of the administration of the drugs for the treatment of clinical mastitis and the somatic cell counts and total bacterial counts in the bulk tank milk of the farms: 0.393 × 10 6 cells mL −1 and 309 × 10 3 cfu mL −1 , respectively, in farms where treatment was performed by the intramammary route, versus 0.743 × 10 6 cells mL −1 and 1413 × 10 3 cfu mL −1 , respectively, in farms where treatment was performed by the injectable route [ 11 ]. The results of the current experimental study fully align with that evidence from the field.…”

“…Papers on the antibiotic susceptibility of bacterial isolates recovered from cases of mastitis have also been published [ 7 , 8 , 9 ], as this is important for the implementation of the correct treatment regimes. Furthermore, the determinants for the treatments (i.e., factors taken into account for decisions regarding the therapeutic strategies) followed in cases of mastitis have also been studied [ 10 , 11 ].…”

“…Treatment of the infection requires the administration of antibiotics [ 10 ]. Most frequently, oxytetracycline, penicillin, and streptomycin were found to have been administered [ 11 ]. However, the small number of products licensed specifically for use in sheep leads to high rates of extra-label use of antibiotic products [ 10 ].…”

Antimicrobial and Methicillin Resistance Pattern of Potential Mastitis-Inducing Staphylococcus aureus and Coagulase-Negative Staphylococci Isolates from the Mammary Secretion of Dairy Goats

“…A major public health concern is the emergence of methicillin resistance in staphylococci worldwide [ 14 ]. Taking into account the routine use of β-lactams as mastitis treatment in dairy goats, this practice may facilitate the emergence of methicillin-resistant staphylococci in the produced milk and dairy products [ 15 ]. In several studies, S. aureus and CoNS strains resistant to one or more antimicrobials and even multi-drug resistant (MDR) strains have been isolated from goat milk collected from individual animals with [ 13 , 16 , 17 , 18 ] or without mastitis [ 19 , 20 ], with a high frequency of resistance to various members of the β-lactams groups commonly observed.…”