Are You Ready to Put Cows on Pasture?

You may be ready to see green grass and be done with winter, but are our pastures ready? Before the ground thaws (unless sloped) is a good time to fertilize or apply soil correctives to the paddocks that didn’t get tended to last fall. It is time to check fences,  and as it warms and greens up, water lines, lane condition, and pasture stand.

Evaluate The Stand

How did it come through the drought and winter? Are there bare spots? Are the species desirable with a diversity of both cool and warm-season grasses along with some legumes? Do we need to inter-seed into an existing stand or does it need a complete renovation? Maybe we need to consider putting in an annual crop that can give us some fast, high-yielding forage.

Alfalfa hay fields also need to be evaluated; you should sample six random areas of each field.

The guidelines for stems per square foot are as follows:

  1. More than 54 stems: no yield reduction.
  2. 40 to 54 stems per square foot: keep the stand, but expect some yield reduction.
  3. Less than 40 stems: consider replacing the stand because yield reduction will be significant.

It is also a good idea to dig up some plants and split the root lengthwise to evaluate the crown and tap root. You want to see a nice white or cream color. In a healthy stand, you should have fewer than 30% of the plants showing discoloration or rot of the crown and taproot.

Transition to Pasture Gradually

Moving cows to pasture, as with all feed changes, dairy cows – especially high-producing cows – need to be adjusted to pasture slowly. Ideally, this change in diet would take place gradually over a week’s time to reduce the chance of off-feed problems, bloat, and a decrease in milk production. Hungry cows should not be allowed to go on pasture. Feed cows first, turning them out to pasture full (include some dry hay in this). Start by allowing one hour of access to pasture the first day and increasing the time allowed on pasture each consecutive day.

Lush growing pastures are usually high in potassium and low in magnesium, so be sure that the diet you are feeding your cows is over 0.32 % magnesium to reduce the risk of grass tetany (magnesium deficiency). In early spring, well-managed pastures are high in crude protein, and low in effective fiber, averaging well over 20% protein. Cows may even consume a higher level if they are selective grazers. High-quality pasture provides too much degradable and soluble protein raising the blood urea levels which is reflected by a higher MUN level in the milk. So it is important to balance the cow’s diet with some starch from grain and or corn silage to optimize rumen fermentation. Based on trials and research, it’s worth considering feeding a 1:4 grain to milk ratio to support production over 60 lbs and maintain body condition.


“The farther the cows have to travel for water the less they will drink and milk production will suffer.”


Provide adequate Sulfur, plus RUP (bypass protein) along with highly digestible fiber by-products such as soy hulls or beet pulp to enhance rumen fermentation and maintain milk production and components. Grazing cows also have a higher maintenance need because of the added activity of grazing and moving from barn to paddock. Adding products like Midwestern BioAg’s PYK or Bio-Vet‘s Generator Elite or Generator Ultra would be beneficial.

Let’s not forget water which is an essential nutrient needed for all animals. The farther the cows have to travel for water the less they will drink and milk production will suffer. Ideally, clean water (i.e. cleaned daily) should be available within 200 – 300 feet at all times, with a maximum travel of 500 feet.

If providing free-choice minerals on pasture, locate the mineral feeders between the water and feed supply A dairy cow generally grazes for 6 – 9 hours per day. Because of her need to ruminate and rest she seldom grazes over 9 hours per day. The number of bites per minute does not vary much, ranging from 55 – 65 bites per minute. Thus dry matter intake from pasture is controlled by the size of the bite, which is directly related to the stand height and density being grazed. One study of forage intake on rye grass showed that in the spring when the growth was very lush, cows averaged 60 bites per minute over an 8-hour period and were able to consume 31.7 lbs of dry matter daily. In the fall, cows averaged 65 bites per minute over 9 hours of grazing and were only able to consume 19.6 pounds of dry matter.

Grazing Management Recommendations 

During the hottest months, cows will not graze during the hottest times of the day (late morning and afternoon). You may have to consider changing your schedule to allow cows to graze during the early morning and late evening hours. Provide shade or keep the cows in and feed them TMR during the heat of the day along with providing fans and sprinklers to reduce heat stress.

When to move animals can be a little tricky and you get better at it with time. You need to look at what is happening daily (a tape measure or pasture measuring stick is helpful). How much are they eating? Look at the next paddock, look at the previous paddock and consider the weather and growing season. At some point, you may have to skip a paddock (make hay on it) to get the animals back on more nutritious forage. As a general rule, do not graze below 4 inches. This protects the growing point of grass, and also leaves more leaf area to capture solar energy and increase photosynthesis. This allows faster recovery without depleting reserve carbohydrates.  With more canopy, there is less drying out or baking of the soil. Another benefit of leaving a higher crop is that you have less parasite infestation possibly reducing the need for dewormers.

The key to maximizing profitability in a grazing herd is the amount of high-quality forage where intake is maximized along with supplemental concentrates being fed, and supplementing other forages when pasture quality or intake is limiting.

For help in feeding a well-managed and balanced diet or planning your fertility needs, see your Midwestern BioAg Consultant.