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Drug residues and clearance time in sick animals

By RORY LEWANDOWSKI OSU Extension Wayne County Published: June 10, 2017 5:00 AM

One important aspect of responsible livestock management is to care for sick animals. In some instances, this may require the administration of drugs to help alleviate pain, promote healing and return the animal to health.

Depending upon the illness, injury and treatment regimen, the animal may no longer fit into the production system and the livestock manager must make a decision to send the animal to slaughter.

In that case, livestock managers need to consult the drug label for information about the withholding period or withdrawal time necessary from the time drug treatment has stopped until the animal can enter the slaughter channel.

The goal is to allow time for the drugs to clear the animal's system and to prevent drug residues in the food chain.

Recently I read an interesting article, "User Beware: Drugs Take Longer to Clear in Sick Animals" on the bovine veterinarian online website. The entire article is available online at http://ow.ly/KFg730cd29R, but I want to summarize some important points that livestock producers should be aware of.

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The central point was healthy animals are routinely used to determine label withdrawal times. However, drug clearance in sick and/or diseased animals can take longer than the withholding period stipulated on the drug label. Livestock producers should consider this when animals that have been sick and treated with drugs are being culled and sent to slaughter. Although the focus of the article was on dairy cows, the principles apply across livestock species.

Some other good points brought up in the article include:

-- Route of administration affects drug clearance. An example was given of a particular drug with a correct administration to the base of the ear that allowed residues in meat to clear in 13 days. However, that same drug given as an intramuscular injection required a withdrawal time of 90 days and if administered subcutaneously, the withdrawal time was 140 days.

-- Record keeping is critical when treating sick animals with drugs. Record the date, time, specific drug and route of administration. Keep notes on whether the animal recovered or needed repeat treatments.

-- Euthanasia may be the better option for cattle treated extensively and repeatedly with drugs rather than allowing them to enter the food stream.

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-- Livestock producers should work with their veterinarians to develop antibiotic treatment protocols and withdrawal periods.

-- Employees should receive training that allows them to competently administer drugs, identify treated livestock, keep records and calculate withdrawal times.

Recommendations for late-planted soybeans

Our persistent wet weather has resulted in delayed and prevented planting. This week Laura Lindsey, OSU Extension wheat and soybean production specialist, provides the following management recommendations for late-planted soybeans:

Row spacing. The row spacing for June planting should be no greater than 7.5-inches, if possible. Row width should be narrow enough for the soybean canopy to completely cover the inter-row space by the time the soybeans begin to flower. The yield benefit of narrow rows increases as planting date is delayed to later season.

Seeding rate. Higher seeding rates are recommended for June plantings. Data from previously conducted seeding rate trials suggest seeding rates between 200,000-225,000 seeds/acre when planting the first half of June.

Relative maturity. For June planting dates, plant the latest maturing variety that will reach physiological maturity before the first killing frost.

This is to allow the plants to grow vegetatively as long as possible to produce nodes where pods can form before vegetative growth is slowed due to flowering and pod formation. The recommended relative maturity ranges for northern Ohio are 3.2-3.8 for June 1-15 planting dates, 3.1-3.5 for June 16-30 planting dates and 3.0-3.3 for July 1-10 planting dates.

Revised Ohio Agronomy Guide Available

The recently revised, 15th edition of the Ohio Agronomy Guide, bulletin 472 is now available at the Wayne County Extension office. The newly revised edition contains updates to the previous publication and this edition contains three new chapters, Considerations for Using Cover Crops, Conducting On-Farm Research and Precision Agriculture.

These chapters are in addition to the chapters on Climate and Soil, Soil and Water Management, Soil Fertility, Corn Production, Soybean Production, Small Grain Production, Forage Production, Multiple Cropping and Pasture and Grazing Management. The cost of the new Ohio Agronomy Guide is $15.75. Contact the Wayne County Extension office at 330-264-8722 for more information.

Rory Lewandowski is an OSU Extension Agriculture & Natural Resources educator and may be reached at 330-264-8722.


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