A Survey on Antibiotic Usage in Dairy Herds in Pennsylvania

Abstract

A survey was conducted (July 2001 to June 2002) on antibiotic usage of 113 dairy herds from 13 counties in Pennsylvania. Fifty percent of dairy farms surveyed maintained antibiotic treatment records. Only 21% of dairy producers had written plans for treating sick animals. Thirty-two percent of dairy producers sought veterinarian advice before administering antibiotics and on most farms (93%), antibiotics were administered by the owner/manager or designated herdsman. Twenty-four percent of the dairy producers said they always completed the course of antibiotic treatment. Any extra-label use of antibiotics was administered only on the guidelines of a veterinarian on majority of the farms. Comprehensive records from 33 dairy farms indicated that antibiotic usage was largest for calves with enteritis (36%) followed by pneumonia in calves (25%) and foot rot in cattle (16%). Twenty-four antibiotics including beta-lactams, spectinomycin, florfenicol, and tetracyclines were used on these farms. Beta-lactam antibiotics were used mostly for dry cow therapy, clinical mastitis, and on some farms for pneumonia and metritis. On 18% of the dairy herds surveyed, ceftiofur was used in an extra-label manner to treat mastitis in lactating cattle. On 70% of farms, calves were fed medicated milk replacers containing oxytetracycline and neomycin. The results of this study suggest that antibiotics are used extensively on dairy herds for both therapeutic and prophylactic purposes. Beta-lactams and tetracyclines were the most widely used antibiotics. There is considerable variation in the management practices associated with antibiotic use on dairy farms. It is anticipated that the findings of this survey will permit developing new strategies for prudent use of antibiotics on dairy herds.

Methicillin-resistantStaphylococcus aureus(MRSA) in food production animals

“…In addition, although this has not been substantiated by evidence, the small timescale in which LA-MRSA has attained these different species and has spread to different countries suggests that LA-MRSA can spread easily. As β-lactam antibiotics, β-lactamase-sensitive as well as -stable, are among the most frequently used antibiotics for treatment of mastitis and also tetracyclines, macrolides and aminoglycosides are often included in the treatment or prevention schedule (162,163,164), the typical resistances LA-MRSA exhibits against these antibiotics might cause serious problems for treatment of mastitis. Because risk factors (repeated or enduring contact with a contaminated source) and transmission routes (the milking machine and hands of the farmer) for the spread of normal mastitis-causing S. aureus are likely to be the same for spread of LA-MRSA, future research might want to focus on these topics.…”

Cezayir’de İnek Mastitislerinden İzole Edilen Stafilokokların Antibiyotik Direncinin Fenotipik ve Moleküler Yöntemlerle Belirlenmesi

“…Besides to their resistance to all types of beta-lactam antibiotics, MRSA strains illustrate resistance to other antimicrobial agents, also used for treatment and prevention of mastitis [60] . Susceptibility tests showed here a wide variety of nine different resistance patterns among the isolates.…”

Phenotypic and genotypic antimicrobial resistance of staphylococci from bovine milk

“…Antimicrobials are commonly used for control of bacteria causing mastitis on dairy farms (Sawant et al 2005), but resistance to β-lactams, macrolides and lincosamides (ML antibiotics) have been reported in staphylococci from the milk of cows with mastitis (Luthje and Schwarz 2006, Sawant et al 2009). Tetracyclines are widely used in veterinary medicine, in livestock rearing, in agriculture and in human medicine.…”