Amber’s Top Ten Tips: Cow Behavior and Automated Milking Systems

Interested in automated milking systems? These systems have a lot to offer, but they are not a solution for all dairies. Automated milking systems are an investment. Although several management decisions can determine whether an automated milking system succeeds, understanding cow behavior can also influence a system’s successfulness. Here are some thoughts on how cow behavior may affect the success of an automated milking system:

  1. Stress and milk yield

    When transitioning cows from a conventional system to an automated milking system, milk yield/cow can decrease by 45% during the first 24 hours of the transition, but milk yield should recover within 4 days. Changing a cow’s routine can cause a stress response that suppresses milk letdown. (Jacobs and Siegford, 2012)

  2. Stress-related behaviors during milking

    Vocalization and elimination behaviors occur more frequently when cows are stressed. Although these behaviors increase during milking when cows are transitioning to an automated milking system, vocalizations and eliminations decrease by 84% and 71% within the first 24 hours of the transition. (Jacobs and Siegford, 2012)

  3. Concentrate allocation in automated milking units

    Feeding cows 11 lbs/day versus 1.1 lbs/day of concentrate during milking does not appear to affect the number of voluntary visits to the milking unit. (Paddick et al., 2019)

  4. Automatic feed delivery and cow lying time

    Lying time is important for cows. They will sometimes alter their behavioral patterns by decreasing the amount of time they spend performing other behaviors to allow more time for lying. Feeding cows with an automated feed system 11 times/day versus 6 times/day did not affect the total daily lying time (average of 12 hours/day). (Mattachini et al., 2019)

  5. Use of an automatic herding system

    Engineers from Israel designed an automatic herding system that uses mobile fences to herd cows to the automatic milking unit. This herding system increased milking frequency by 45%, milk yield by 15%, and decreased labor time to fetch cows by 80%. (Drach et al., 2017).

  6. Ratio of cows to automatic milking units

    Milking frequency/cow per day is negatively related to the ratio of cows to automatic milking units. (King et al., 2016)

  7. Feed bunk activity

    With the ability to be milked on their own schedule, cows milked by automatic milking systems typically prefer to eat during the day, avoiding the late evening and early morning hours. It is important to note that environmental stressors, such as heat stress, can affect cow feeding behavior. (Wagner-Storch and Palmer, 2003)

  8. Concentrate content and milking visits

    When compared against a standard concentrate, a barley-oats concentrate fed during milking caused an increase in the number of cow visits to the automated milking unit and a decrease in the number of fetches. (Madsen et al., 2010)

  9. Waiting area

    With the use of control gates, the open waiting area in front of the automated milking unit should be large enough to decrease competition. Dominant cows spend an average of 13 minutes in the waiting area and subordinate cows spend an average of 20 minutes in the waiting area. (Melin et al., 2006)

  10. Automated milking unit exit area

    Cows exiting the automated milking unit require 54% more time to exit the unit if other cows are near the exit gate than if no cows are near the exit gate. (Jacobs et al., 2012)


  • Drach et al. 2017. Automatic herding reduces labour and increases milking frequency in robotic milking. Biosyst. Eng. 155:134-141.
  • Jacobs, J. A., and J. M. Siegford. 2012. Lactating dairy cows adapt quickly to being milked by an automatic milking system. J. Dairy Sci. 95:1575-1584.
  • Jacobs et al. 2012. Dairy cow behavior affects the availability of an automatic milking system. J Dairy Sci. 95:2186-2194.
  • King et al. 2016. Associations of herd-level housing, management, and lameness prevalence with productivity and cow behavior in herds with automated milking systems. J. Dairy Sci. 99:9069–9079.
  • Madsen et al. 2010. Concentrate composition for automatic milking systems-effect on milking frequency. Livest. Sci. 127:45-50.
  • Mattachini et al. 2019. Effects of feeding frequency on the lying behavior of dairy cows in a loose housing with automatic feeding and milking system. Animals 9(121).
  • Melin et al. 2006. Cow traffic in relation to social rank and motivation of cows in an automatic milking system with control gates and an open waiting area. Appl. Anim. Behav. Sci. 96:201-214.
  • Paddick et al. 2019. Effect of the amount of concentrate offered in an automated milking system on dry matter intake, milk yield, milk composition, ruminal digestion, and behavior of primiparous Holstein cows fed isocaloric diets. J. Dairy Sci. 102:2173-2187.
  • Wagner-Storch, A. M. and R. W. Palmer. 2003. Feeding behavior, milking behavior, and milk visits of cows milked in a parlor versus an automatic milking system. J. Dairy Sci. 86:1494-1502.

Nitrate: Know Your Units of Measure

Is it nitrate or is it nitrate-nitrogen? Are the units in percent dry matter (% DM), parts per million (ppm), or milligrams per kilogram (mg/kg)?

Testing for nitrate is common practice by dairy farmers. Soil, crops and water may be tested. The nitrate content in soil is used to estimate the amount of nitrogen that will be available for crop growth. The nitrate content in both forage and drinking water are commonly used to monitor the amount of nitrate-N that cows might consume in order prevent nitrate toxicity.

Nitrate testing can seem straight forward and simple. However, the result might be expressed in different forms, leading to confusion. For instance, let’s start with soil. The recommended soil depth to obtain a sample is 1 foot, or in multiples of 1 foot. It is common for the test result to be reported as nitrate-N and expressed as mg/kg, ppm, or pounds per acre. Most fertilizer guides use nitrate-N as the unit of expression when interpreting soil analyses. What if a test result is expressed as nitrate (NO3) rather than nitrate-N (NO3-N)? If so, a conversion factor is needed.

Table 1. Conversion between nitrate (NO3) and nitrate-nitrogen (NO3-N)
To convert To Multiply by
Nitrate (NO3) Nitrate-nitrogen (NO3-N) 0.22
Nitrate-nitrogen (NO3-N) Nitrate (NO3) 4.43

The reason for this conversion is that nitrate molecule weighs 62 grams per mole; the nitrogen content of nitrate is 22.5% of the total weight of the molecule. (Source: R. Smith and M. Cahn, July 30, 2012, retrieved from on June 5, 2019).

A value of 6.9 mg/kg of nitrate-N would be 6.9 × 4.43 = 30.6 mg/kg nitrate.

Let’s start with soil. For dairy forage crops, the recommended soil sampling depth is typically one foot. Most commonly, the test result is reported as nitrate-N and expressed as mg/kg. The lab may also convert the result to pounds per acre. Most fertilizer guides use nitrate-N as the unit of expression when interpreting soil analyses.

An example of conversion of soil test nitrate-N is shown below. This example is from a commercial soil test lab that used a conversion factor of 3.5 to convert mg/kg to lbs/acre. The conversion factor of 3.5 assumes that a one acre-foot sample of soil weighs 3.5 million pounds (3.5 lb per acre-foot = 1 ppm). A very common factor to use is 3.5.

Table 2. Concentration of Nitrate-N in Soil
Depth Nitrate-N (mg/kg) Nitrate
inches mg/kg lbs/acre mg/kg lbs/acre
0-12 6.9 24.26 30.6 107

Can a soil sample be taken at a depth of 0 – 6 inches and the results be translated to a depth of 0 – 12 inches or one foot — NO!

The attempt to use a 6 inch soil sample to represent a 1 foot sample will either over or underestimate the corresponding value for the 1 foot sample.

As an example of underestimating the amount of nitrate-N in one ft of soil with a six inch soil sample, if a sample were obtained from the first 6 inches in the fall after it had started raining, the nitrate in soil may have been pushed to the 7 – 12 inch depth and not accounted.

As an example of overestimating the amount of nitrate-N in one foot of soil with a six inch soil sample, if fertilizer had just recently been surface applied and had not been distributed within the top foot of soil, the nitrate in the top six inches would result in an overestimation of nutrients available to the crop.

All Forms of Nitrogen

The other form of nitrogen available for crop growth is organic nitrogen found in soil organic matter. During a growing season, some of the organic nitrogen present in soil organic matter (OM) will become available for plant growth due to the biological activity in the soil. If the top foot of soil weighs approximately 3.5 million pounds, as previously noted, a soil with 5% OM has 175,000 pounds of OM present in the top foot. For soils up to 5% OM, approximately 20 pounds of nitrogen will become available to the crop for each percent OM. Thus a 2% OM soil will provide approximately 40 pounds of plant available nitrogen per acre each year and a 5% OM soil will provide 100# per acre.

Washington’s Natural Resources Conservation Service (NRCS WA) has supplements to the national Agricultural Waste Field Management Handbook, or AWFMH, Table 11-9.

The table below, taken from an actual soil test, shows the accounting of nitrogen from three sources, nitrate-N, N from OM, and N from ammonia-N. In this soil sample, there was a total of 67 pounds of tested N with 7 pounds of ammonia-N, and 38 pounds of N in OM (1.9 × 20 = 38) and 22 pounds of nitrate-N.

Table 3. Example Soil Test Report
Ammonium-N mg/kg 2.3 7
Organic Matter W.B. % 1.9 ENR: 38
Depth Nitrate-N Sulfate-S Moisture
inches mg/kg lbs/acre mg/kg inches
0 – 12 6.9 22 9  
Totals 6.9 22 9  
Sum of Tested N: 67 lbs/acre N

Analyzing a forage sample or water sample for nitrate follows the same logic as discussed for soil.

Table 4. Guidelines for Limits of Nitrate in Feeds and Water
Percent (%) NO3 on 100% dry matter (DM) basis Comment
Original Source: Hoard’s Dairyman August 25, 1970.
Less than 0.44% (4,400 ppm) Safe
0.44 to 0.88% (4,400 to 8,800 ppm) Generally safe when fed balanced rations. Best to limit to half of the total dry ration for pregnant animals. In addition, be sure water is low in nitrate.
0.88 to 1.5% (8,800 to 15,000 ppm) Limit amount to less than half of total dry ration. Be sure water is safe. Be sure ration is well fortified with energy, minerals, and vitamin A.
Over 1.5% (15,000 ppm) Potentially Toxic – do not feed
Table 5. Guide of Use of Water with Known Nitrate Content
PPM of NO3 Comment
Original Source: Hoard’s Dairyman August 25, 1970.
Less than 44 Generally regarded as safe for all animals and humans
44 to 88 Questionable or risky for humans, especially children and pregnant women. Safe for livestock unless feed also has high levels.
88 to 176 Considered unsafe for humans. Might cause problems for livestock, especially swine and poultry.
176 to 440 Unsafe for humans and risky for livestock. Be sure feed is low in nitrates and be sure as well balanced ration is fed. Fortify ration with extra vitamin A.
440 to 880 Dangerous and should not be used. General or nonspecific symptoms such as poor appetite are likely to develop. Water apt to be contaminated with other foreign substances. When allowed free-choice to cows on a good ration, acute toxicity not likely.
Over 880 Don’t use. Acute toxicity and some death losses might occur in swine. Probably too much total intake for ruminants on usual feeds.