Achieving and maintaining cow productivity when using pasture for the primary forage source requires constant management. While no single daily decision is highly critical, the accumulation of decisions made will affect pasture quality, quantity, and milk production.
Items like body condition scoring, paddock planning, forage sampling and analysis, and pasture topdressing also need to be kept in mind. These decisions should be made in the context of a larger forage feeding plan that provides alternatives should pasture be in short supply or present in excess.
Just as a weekly pasture walk is useful in planning current grazing/ harvesting decisions for the coming week, a planning walk throughout the pasturing season is likewise useful. The following suggests some items to keep in mind with each decision making period.
These guides are made in the context of grass management. The goal is to maximize quantity and quality of pasture forage. Recognizing that grass growth/day takes place THREE TIMES AS FAST at 4-6" in height vs. 2" in height, then grazing a paddock should be avoided until grass has reached the grazing height of 6-8". Supplemental forage is recommended to allow paddocks to reach the desired grazing height.
Nutritionally and economically this strategy makes the most sense. If supplemental forage and grain is not fed and paddocks with shorter grass are grazed, there is 1) less forage produced from the pasture and 2) when the pasture runs out, harvested forage must be fed anyway. More supplemental concentrates and forage will be needed than if the ration continued to contain some pasture with its higher protein and energy content.
Calendar of pasturing events
Last of April: Start cows on some of the pasture land that is early and drained if grass has started to grow. Hold back some paddocks to be the first full height plots to be grazed. These will start the "official" grazing season on your farm.
Avoid the pitfall of grazing all the proposed pasture at the start in case there is a cold wet spring (like this year and some past years). Feed supplemental forage rather than graze the first "official" paddocks too soon.
Early May: Ungrazed paddocks should be coming "on line" for grazing. The start of the "official" grazing period will be very highly weather dependent. Once on schedule, rapidly maturing paddocks should remain ungrazed and harvested for later feeding.
Late May: The "official" grazing season with paddocks at 6-8" in height will have started by now. Be prepared to harvest any excess growth should the weather turn warm so that paddocks can be returned to the rotation and be part of the "desired" maturity for grazing. The abundance of pasture at this time and its high quality allows for the highest ratio of milk to grain feeding. About 7-8# of corn meal/minerals will support 60# of 4.0% milk and 14-15# about of 80# milk.
Early June: Paddocks are in full swing with enough forage both for grazing and harvesting. Haylage, baleage and hay are the best options. That feed may be needed in late summer and the winter. Clipping and not harvesting should be done if that is the only option. Begin the process of topdressing paddocks most recently grazed. Take samples of early June pasture for forage analysis.
Late June: The character of grass growth begins to change. Even at the desired pasture grazing heights, there may be less energy and protein present. Follow the bulk tank shipments very closely. Milk shipped may begin to drop. Cow condition may begin to drop, unnoticeable at first. Most successful grazers begin to increase the amount of corn meal or other pasture designed concentrates at this time. Continue to machine harvest paddocks too mature for grazing.
July: Summer grasses and clovers are here; the spring grasses have gone dormant. Paddock recovery is slower; more land is needed for grazing. It is a better strategy to allow for full paddock recovery by stretching the available grazing with supplemental forage if the next paddocks are not ready.
This strategy best uses the protein and energy of pasture to supplement the lower protein and energy content of harvested forages. It is nutritionally and economically better to keep some pasture in the ration than to be nearly out of pasture and have to rely almost exclusively on stored feed. Sample summer pasture for forage analysis.
Pasture may only provide a to ½ of the cows' forage needs. Supplemental forage and concentrates containing both corn meal and protein sources will be needed. Rations for 60# 4.0% milk supplemented with corn silage or low protein hay will need about 15# of a 14% CP grain equivalent and for 80# about 25#. Check cow body condition.
August: If your land is dry, chances are that you are feeding a lot of stored feed. Certainly with the drought we had last year even normally heavier lands were dry and not growing any grass. Line up some corn silage, hay or haylage for the winter feeding if you have had to feed all your stored feed during the summer. Recheck cow body condition.
September: With the arrival of cooler, wetter weather, the cooler season grasses return and pasture regrowth can be somewhat quicker than the summer. Because cool weather is approaching, it may be possible to begin to "stockpile on the stem" some forage for November grazing. Because the weather is cooling and not heating up as it does in the spring, grasses will not mature as they did in June and will be higher in available energy. Recheck body condition.
October: Cool weather has arrived again and grass growth has slowed and will essentially stop toward the end of the month. If rain and warmth have been sufficient, stockpiled pasture will be available for the end-of-the-month grazing.
Forage growth in the Fall is not significant enough to provide a surplus for harvesting. All of the Fall growth will be needed for grazing on most farms. Pasture may only provide 1/3 or less of the cows' forage needs during this time.
November: Grass is not growing any more in New England, but if any excess pasture growth has carried over into the month, it may provide some grazing for a couple more weeks. Quality will be retained until cold weather starts to kill the grass. Pasture intake drops and is ended with any significant snow cover.
Grazing does require grass and cow management, timely decision making, anticipation of expected and unexpected seasonal changes and suitable records for success. Develop a grazing calendar that is appropriate for your farm.
Note: Graze grass plants while still vegetative before they reach reproductive stem elongation.
Sidney J. Lyford, Jr.,
Dept. of Veterinary and Animal Sciences
University of Massachusetts Amherst
Crops, Dairy, Livestock News. Vol. 1:2, Summer 1996
Last updated: 3/17/05.