Grazing Bites

by Victor Shelton,

Retired NRCS Agronomist/Grazing Specialist 

 I was recently at a pasture ecology workshop in Southern Indiana and there was a lot of discussion about the weather and its impact on pastures this year. For most of the area east of the Mississippi River there was a lot of forage growth, and it came on fast.

Most of those same areas have had a lot of rain. Prolonged rainfall and saturated soils create anaerobic conditions, leading to nitrogen losses through denitrification, leaching and reduced uptake. Grasses are highly affected, while legumes may lose some nitrogen-fixing ability.

Saturated soils and nitrogen loss place significant stress on cool-season forages, weakening root function, reducing nutrient uptake, and slowing growth. In response to this stress, many cool-season grasses may shift into reproductive mode earlier than normal, going to seed sooner as a survival mechanism. While this helps the plant reproduce, it leads to lower forage quality, reduced regrowth and more stemmy, less digestible feed. This spurred a fair amount of discussion at the workshop about how you should manage this grass gone wild.

Timely grazing starts before grasses are in late boot stage, the stage when the seed head is almost ready to emerge from the stem but hasn’t fully developed. If it’s grazed during this time, you will stop most seed head production. This is also true with regard to clipping during this stage of growth. You generally can only graze so much once this begins and when conditions favor or push reproduction because of environmental stresses, it quickly gets out of control.

Moving faster and top grazing can produce comparable results, but it’s hard, if not impossible, to keep the entire farm in that condition through grazing alone. Plan B is almost always clipping. In my experience, clipping can be beneficial for maintaining forage quality. I typically clip most fields at least once, with the best results occurring when it’s done during late boot. That timing not only reduces seed head production for the year but also encourages tillering and regrowth and helps maintain quality. These fields are usually ready to be grazed again in about 30 days depending on fertility, rainfall and stop grazing height.

Timeliness wasn’t in the picture this year, at least not for me and many others. Periods dry enough to even consider doing any clipping were shadowed by minute thoughts on forage harvesting on designated hay fields. Do you mow or clip when there is enough soil moisture to run off the wheels or leave tracks in the field? I don’t want to create or add to any compaction issues – the cows are doing enough pugging in wet areas already. Compacted soils can show their dirty side later on especially if it decides to turn dry.

Now, there’s no argument that clipping pastures won’t improve forage quality and likely help promote new forage growth if done timely but what if it’s not timely? What if it’s already fully mature or at least appears to be? We must consider the cost of the endeavor and the impact on the forages if forced procrastination was present. Most brush-hogs can’t mow high enough to not remove valuable forage and the solar panel if not previously grazed.  So, no matter the time frame, I won’t clip before grazing first, period. We’ve been so wet this year that I hate to admit I’ve not got any clipping done yet – but the brush-hog is hooked up and I’m hopefully progressing by the time you read this. I’m now at 32.95 inches of rain for the year as I write this. The soil has been wetter than I prefer to have a tractor on. That can change quickly though – and it has - drought is always only two weeks away.

Now, that said, if you are trying to build soil organic matter or improve soil health and you are not trying to maximize average daily gain on finishing animals on just forages, then a slightly more relaxed approach is workable. Graze the best and leave the rest. For best results, allocate forages for short grazing periods – ideally less than two days allowing the animals to eat the best and lay down the rest to help improve soil health and increase soil organic matter. These allocations are generally ready to graze again in 45 to 60 days depending on the year.

I’ve been recently asked how those “laid down” pastures compare to tightly grazed fields – i.e., overgrazed. They both appear to be flattened and short in nature and what about stop grazing heights?

When you overgraze, grazing to less than three inches in most cases, you are removing a high percentage of the solar panel for the system, so photosynthesis is tremendously slowed, forage roots die back with self-pruning, energy reserves are reduced, generally less residue is left on the soil surface and the recovery time is extended the closer it was grazed.

If you allocate short moves allowing the ruminants to graze the best and leaving the majority of the rest flattened on the ground, the solar panel isn’t completely removed or disrupted, there is significantly less root dieback, the soil is kept covered with residue, less energy is lost, and regrowth is not impacted near as much as overgrazing.

Sometimes I think there’s a bit too much emphasis on building soil organic matter and soil health. Not that those aren’t important, they are, but I believe it’s more effective to keep the primary focus on the forage with livestock in mind. When managed well, both the forage and the soil will benefit.

If you do have to clip, try and mimic grazing or clip to remove stems and seed head, preferably before they form, which will promote more tillers. Clipping also evens out the stand if done at the right height and will help the livestock to graze more evenly next time around. Haying is the last option and one to be avoided if possible. If it turns dry, that forage will be needed for grazing. Haying pasture might increase your chances of feeding hay earlier and it is almost always better to leave nutrients where they are by grazing than to have to make sure to get them back where they should be.

It’s not about maximizing a single grazing event but optimizing the entire grazing season. Observe, plan ahead and keep on grazing.

Reminders & Opportunities 

Greener Pasture Field Day – Aug. 28, – 6 p.m. RSVP by August 18 by calling 812-482-1171, ext. 3. Presentations on warm season grasses, biochar and gypsum, paddock systems, alternative legumes and nitrogen, and watering systems. 

Please send comments or questions to grazingbites@gmail.com.