By Victor Shelton, Natural Resource Conservation Service State Agronomist/Grazing Specialist
Generally, by the first of June, most cool-season forages have peaked their growth and quite often have reached about two thirds of their production for the year. Clippings taken support that theory. Unfortunately, there just haven’t been enough warm sunny days for this to occur this spring until just recently.
With this being a major pivoting point for the growing season, it is usually a decent gage of stocking rate and grazing efficiency. If you are short of forage at this time of year, then the stocking rate is too high, unless you happen to be in a drought area. I don’t know of anywhere where that is an issue right now.
Think about this for a moment. If you are short on forages at the peak of the cool-season forage season, then where will you be when it turns hot and dry? The old soap box talks start getting a little bit old. You need to maintain the forage solar pane, to keep the plant growing, producing and maintaining sufficient live roots that are able to go down after moisture and nutrients. A short vegetative top means short roots. The combination of short roots, lack of sufficient soil cover allowing increased evaporation, and lack of adequate rest between grazing periods just doesn’t work out well once it turns hot and dry. Maintaining cover and sufficient live green leaf is a good place to start for that contingency plan.
Stop grazing heights for most cool-season forages needs to be 3 to 4 inches, e.g. tall fescue and orchardgrass. Bluegrass and perennial ryegrass both tolerate closer grazing than taller species, but they are also not very productive during hot and dry weather. Stop grazing height is the shortest forage left standing, not the tallest. So, if you want to leave a stop grazing of at least 4 inches, then the stand will appear taller than that with a fair amount at 6 inches or better. If the tallest forage out there is 4 inches, then your actual stop grazing height is probably only 1.5 to 2 inches! Good stop grazing heights increase animal intake, support forage regrowth and root development, and improve drought tolerance.
Earlier I mentioned that we haven’t had enough warm, sunny days. If you keep an eye on growing degree days, we are behind. At mid-May, we were 24% to 40% behind the average. Forages, row crops, and even gardens have been impacted.
Plant growth is highly influenced by the ambient temperatures but also very dependent on adequate moisture and photosynthesis. Adequate moisture without enough heat units or sunshine are just not the same. Photosynthesis probably has less impact on yield as compared to its impact on energy for the plant and for what consumes it. Those soluble carbohydrates in the forages are highest after good sunny days. This variability can even be tracked in a normal day with values peaking in the afternoon and lowest in the early morning. Numerous days with little or no sunshine can, therefore, impact forage quality, mainly energy. Too many cloudy rainy days can impact energy of forages. The sun better get busy!
When grass is stressed, its first defense or survival mechanism is usually to produce seed. Rotate livestock quickly to keep pastures under control and clip if needed to maintain quality. If it starts getting too far ahead of the livestock, go back and graze the first paddock again as soon as it’s ready and stockpile or cut the skipped field for hay. Just don’t get too aggressive. It’s easy to cut more hay than needed and if the site can be grazed, you are usually better off doing so rather than moving nutrients around and burning fuel.
Quite a bit of hay was cut in early June. Weather conditions are generally more favorable and it’s a point in time for most cool-season forages where there is a happy balance between forage quality and quantity. Forage quality is usually higher before the boot stage of grasses and that quality usually starts going south as the forages start maturing. That boot stage is prior to any seed head emergence. Some “hay” varieties of grasses, especially orchardgrass, tend to want to go to seed early and quite often before weather allows you to even think about making any hay. Varieties that are mature later are better for grazing and hay, as far as I’m concerned, because they are slower to go to seed, maintain quality longer and tend to be able to keep vegetative longer. When you keep it vegetative longer, you have a better solar panel, higher quality for longer periods, and it helps buy you some time.
It is now a good time to think about planting sorghum-sudangrass and or millets which can provide excellent forage for summer grazing. Brown mid-rib (BMR) varieties offer higher energy and are certainly placed higher in desirability by grazing livestock than non-BMR varieties. These are best seeded in early June for summer grazing. The key advantage of the millets is the lack of prussic acid and associated problems that occur under extremely droughty conditions or later after being frosted.
Brassicas and warm-season grass annuals can offer a means for livestock producers to supplement and/or improve summer forage during the normal slump period and can also provide some cheap insurance. If you have a crop field that happens to be fenced and was planted to wheat last fall, then a summer annual mix might be a better choice over double crop soybeans, especially if you need forage. The value of that quality forage can be better on the pocketbook and less risky than soybeans. There are some increasing opportunities for assistance with annuals for grazing within a cropping system, but they are not a substitute for maintaining good quality forage. Contact your local NRCS office for more information.
I should also mention something about perennial warm-season grasses, e.g. switchgrass, big bluestem, and Indiangrass. They also help fill that summer slump period when cool-season grasses really slow down. The warm-season forages thrive and produce well even under hot dry conditions. The stop grazing height on them is no shorter than 6 inches and they would really prefer to be closer to 10 inches. They usually out produce most cool-season grasses and will end up being one of your favorite forages once you go through a drought year with them on the farm. I used to recommend that at least 15% to 20% of the system should be warm-season perennials. That percentage could easily be doubled on most farms.
If you are grazing warm-season forages during the hot summer days, your cool-season forages are getting that much-needed rest and will provide more grazing opportunities and days later in the year. When livestock prices are challenging, the livestock need to work for you more than you are working for them. Keep inputs low. Remember, it’s not about maximizing a grazing event, it’s about maximizing the grazing season. Stay well and keep on grazing!