Ammonia Emissions Below Levels of Concern for Human Health

A question was recently posed to WSU faculty in regard to the concentration of ammonia that might be in dairy barns and if it would present a problem for human health. The short answer is no. A national monitoring study funded by the EPA looked at ammonia emissions in dairy barns across the US. One of the locations studied was in eastern Washington.

Average concentrations of ammonia in the barn ranged between 0.16 to 2.88 pm. These concentrations are significantly below the 50 ppm (averaged over an 8-h shift) permissible exposure limit (PEL) set by the Occupational Safety and Health Administration (OSHA) and the 25 ppm 8-h shift-averaged National Institute for Occupational Safety Health recommended exposure limit (REL) (NIOSH, 2011). The concentrations in the barns also were considerably lower than the NIOSH 15-min REL of 35 ppm. These data indicate that even in the rare event that a farm worker is in the barn for an entire 8-h shift, there should be little safety or health concern from exposure to ammonia.

Amber’s Top Ten Tips: Understanding Group Housing in Calves

Have you considered transitioning your current calf management practices towards a group housing system? I would not be surprised if the thought has crossed your mind at least once. Dairies throughout the country have recently paid more attention to the concept, and why wouldn’t they? With the prospects of reductions in labor expenses and improved animal welfare, this type of system sounds appealing; however, group housing presents its own challenges for successful calf rearing. For now, let’s put aside the financial aspects of group housing and focus on how pair or group housing systems impact calf behavior, health, and growth. The next time group housing crosses your mind, please take the following tips into consideration.

What you need to know about the advantages and disadvantages of pair/group housing in pre-weaned calves:

  1. Social Interactions

    Upon introduction into larger post-weaning groups, pair-housed calves exhibit more (up to 71%) social behavior than calves housed individually.

  2. Aggression Behavior

    In social environments (such as post-weaning groups), calves housed in pairs and groups are 32-60% less aggressive towards other calves than calves housed individually.

  3. Acceptance of Novel Foods

    Group-housed calves are, on average, 50% more likely to begin eating novel foods before individually-housed calves. Why does this matter? Dairies adjust their rations throughout the year (possibly including the addition of unique feedstuffs), in which cows must adapt to diet changes.

  4. Time Spent at Feeder

    Pair-housed calves spend 26-59% more time at the feeder than individually-housed calves.

  5. Visits to the Feeder

    Upon introduction into larger post-weaning groups, pair-housed calves are 42-82% more likely to attend the feed bunk before individually-housed calves.

  6. Heart Rate

    A lower (about 13%) heart rate was measured in pair-housed than individually-housed calves when they were exposed to a novel environment. Why does this matter? An increased heart rate is associated with the physiological stress response, leading to potential detrimental impacts on cow health and production.

  7. Respiratory Disease

    Individually-housed calves are 57-71% less likely to develop respiratory disease than group-housed calves, in general (this is highly dependent on the size of groups).

  8. Antibiotic Resistance

    The odds for antibiotic resistance in E.coli is 50% lower for calves housed individually than calves housed in groups.

  9. Starter Feed Intake

    Pre-weaning starter feed intake is typically higher (about 37%) in pair-housed calves than individually-housed calves. Post-weaning intake also tends to be higher (about 18%) in pair- or group-housed calves.

  10. Average Daily Gain –

    Improved average daily gains have been noticed in pair-housed (14% increase) and group-housed (16% increase) calves over individually-housed calves.

Four calves laying in a group pen.

Let’s Keep It Clean, Folks

Iatrogenic, (eye-AT-ro-JEN-ick), adjective. “Of or relating to illness caused by medical examination or treatment” (The Oxford Pocket Dictionary of Current English, 2009).

Are your medication handling and storage protocols a source of iatrogenic illness on your dairy? With so many uncontrollable factors dairy farmers have to deal with (fuel prices, weather, feed availability, etc.), it may be comforting to learn that a few simple practices can greatly reduce the likelihood of problems resulting from contaminated medications.

The photos used in this article are NOT from Washington State dairies and some are not even from the U.S. Nevertheless, they illustrate breaches in sanitation that can happen anywhere if shortcuts in best practices are taken due to haste, lack of training, or lack of concern about routine preventative measures.

Photo 1a shows an unsurprising source of medication contamination: manure. Controlling external contamination of medications with manure is a good practice for at least two reasons: it reduces the likelihood of transferring fecal organisms into the medication itself (Photo 1b) or other surfaces. Other surfaces include human hands (then water faucets, handles, countertops, etc.), thus putting human health at risk. It is easy to become complacent about surface contamination on dairies—note the coffee mug in Photo 1a—but small actions to improve sanitation may prevent large health problems with animals down the line.

Problem: Medication contamination with manure.

Solution: For medications commonly used cow-side that can be kept at environmental temperatures, consider keeping them in a washable plastic flip-top cooler to keep them clean.

Storing medications according to the manufacturer’s label instructions is critical. Upon arrival or purchase of any medications or vaccines, storage instructions on the label should be followed immediately. Only draw up or mix enough vaccine that can be administered within 30 minutes; remaining vaccine and/or un-mixed components should be kept according to label instructions (usually cool) until use. Keep thermometers in medication storage areas and monitor storage temperatures regularly; do not purchase vaccines over-the-counter if the business’s refrigerator temperature is not within vaccine label parameters (Troxel et al. 2009).The vaccines in Photo 2 were left at room temperature overnight, rendering them useless and a waste of money.

Two vaccine vials sitting on a counter with syringes piercing the cap.
Photo 2. Vaccines left at room temperature. Photo courtesy of Dr. Anita Varga.

Problem: Improper vaccine storage temperature.

Solution: Unless using them within 30 minutes, keep vaccines stored as instructed on the manufacturer’s label.

Photo 3 depicts medications kept in a refrigerator—they have been protected from dirt and manure (yay!) but the refrigerator was not working (boo!). Photos 2 and 3 also illustrate another all-too-common sanitation no-no: leaving a needle and syringe inserted into a medication bottle top for a prolonged time. Dust and other debris can enter the syringe chamber and contaminate it. Also, the rubber stopper top is not able to “repair” itself from the needle’s insertion. Many individual needle insertions can weaken a rubber stopper, leave large holes that can permit contamination, and even send small rubber fragments into the medication. Using a “nurse needle” (see below) is a practical way to protect the integrity of a rubber stopper medication top and address sanitation concerns.

Several bottles of medications stored with syringes piercing their caps.
Photo 3. Leaving needle and syringe inserted into medication. Photo courtesy of Dr. Paul Biagiotti.

Problem: Leaving needle and syringe inserted into medication bottle for prolonged periods.

Solution: use a nurse needle for each session of medication use and never leave needles in bottle top rubber stoppers for prolonged times.

Steps to Keep New Medications Sterile

  1. Flip metal, plastic or foil cover up but do not detach.
  2. Clean top of rubber stopper with alcohol.
  3. Crack open and insert a new nurse needle into medication top, retaining plastic cap (Photos 4a, 4b, 4c); do not remove the nurse needle from the rubber stopper top until the last dose is drawn up for a group of similar treatments of the same medication or vaccine.
  4. Attach a new syringe to the nurse needle and draw up the required dose of medication or vaccine.
  5. Detach filled syringe from nurse needle and leave nurse needle in top of bottle.
  6. Cover nurse needle hub with the plastic cap while injecting cattle.
  7. Use a new needle for each individual animal.
  8. When it is time to refill the syringe, use the nurse needle still in the medication top: attach same syringe to nurse needle, draw up dose(s), detach syringe from nurse needle, leave nurse needle in medication top, attach new needle to syringe, inject next animal, repeat.
  9. The nurse needle can be used for an individual animal injection after the last syringeful of medication or vaccine has been drawn into the syringe.
  10. If possible, fold metal, plastic or foil cover down to original position to protect medication bottle’s rubber stopper until next use. A protective cap of aluminum foil or plastic wrap could also be applied and rubber-banded in place.

Save the plastic hub after opening needle and use it to cover nurse needle while not in use.

Not everyone who works on a dairy farm has previous experience with livestock medications, including proper care, handling, and storage (Photo 5). Correct use of medications should be part of all new worker training and presented by someone fully aware of all aspects of sanitation and correct use. Through effective training and modeling of correct behavior, sanitation practices can easily become habits for new workers.

Photo 5. Lack of attention to the importance of proper medication handling and storage. Photo courtesy of Dr. Terry Wollen.

Problem: Lack of attention to medicines and their importance, handling, and storage.

Solution: teach employees about the crucial role medications play in animal health and train them about proper medication handling and storage.

Proper medication handling, storage, and use will save money, reduce product contamination, increase the likelihood of treatment success, and reduce iatrogenic illnesses. Dairy farms are busy enough without having to treat problems that could have been prevented through simple sanitation practices.


  • Troxel, T.R., and B.L. Barham. 2009. Case Study: The Temperature Variability of Refrigerators Storing Animal Health Products. Professional Animal Scientist 25:202-206.