I’ve lived in states where people are frugal – a polite word for stingy, greedy, lazy or money grubbing. These folks often thought grazing forage into the ground was economical.
However, letting livestock graze forage into the soil:
- Reduces forage quality consumed, as livestock are forced to eat stems and dead leaves,
- Exposes small ruminants to parasites,
- Reduces the tonnage of forage produced, because the leaves are all gone and plants must use reserves to begin regrowth which slows the entire process and reduces yields,
- May damage wildlife habitat, and
- Can reduce total livestock gains.
So I ask “Do you mow your yard really short? If they say “Yes.” Then I ask, “Why?”
They always say “So I don’t have to mow so often.” Then I say, “So you graze your pastures so short so you don’t have to . . . .?” I’ve seen the light come on many times and they answer “Graze so often!”
Photosynthesis is the only mechanism to feed the plant regardless of what the fertilizer fellow says. The minerals, water, and air are just raw materials. Enough leaf surface should be left on the plants we want to keep to allow them to feed themselves through regrowth. There is no “bank bailout” or “too big to fail” in the plant world. If plants use all their reserves to regrow new leaves, only to have them repeatedly eaten off, then the plant goes bankrupt and dies. But there’s more! I challenge my customers to mow as HIGH as their lawn mower will go on part of the yard where their spouse won’t mind or split one pasture into many paddocks and try that first. The response from those who’ve taken the leap has always been positive, except for the one who didn’t understand about rest and letting the plants regrow and then re-grazed in just a few days.
You Reap What You Grow
Grass roots grow down at least as far as the leaves are high. By leaving more grazing height, the plants have access to moisture and nutrients far longer than their short peers. Letting forages rest appropriately is perhaps “The Key” to good management.
My youngest son plays football and is so good that in his freshman year, he played running back and safety in junior varsity games on Tuesday nights, and varsity games on Friday nights. A few weeks into the season, he was hurt. Why? He never had time to recover between games to rebuild the damage from the games.
The same goes for forages; if they are grazed (especially if they are grazed short), experience extreme weather-related stress (drought), or have pest issues, then they need adequate rest to regain 5-7 complete leaves before being grazed again. This allows forage to store up reserves in the roots and stem through photosynthesis, and perhaps even make seeds for new little plants to replace the ones who died from old age or disease.
point 2. parasites need moisture and moderate temperatures to survive on pastures. over grazing and too short results in conditions NOT conducive to their survival, soil temperature gets too hot and there is too little moisture.
Proper grazing and residual is perfect for parasite hatch & survival. Imagine that, the parasite lifecycle evolved to match growth/recovery of forages so they are ready to be ingested at the L3 larval stage. . . . For all it many advantages for managed grazing, residual/rest/recovery, parasite control is not among them.
Parasite control IS a benefit of managed grazing. Many farmers take advantage of this and many articles/books/research papers have been written on it.
Sorry for the negative outburst. We can probably gain from keeping in mind what Gene reminds us of: that hot dry conditions are death to parasites. By managing for the conditions that set-back parasites when it is right we can add another tool to the toolbox. Thanks for reminding us to be open-minded and work with nature when we can. I AM impressed by how perfect the parasite lifecycle is adapted to its host.
That rotational grazing would reduce parasitism on pasture was a very popular misconception started 25 years ago when the grazing renaissance began that was quickly proven inaccurate. It ignored the lifecycle of the parasite.
If we are moving livestock every day or so we get a very uniform distribution of manure. Nematodes are not highly mobile, when was the last “why did the nematode cross the road” joke that you can remember? They stay relatively near the manure in which they eggs were deposited.
Uniform utilization = uniform distribution of parasites.
Given the choice, livestock will naturally avoid grazing the forage re-growing around their own dung. Doing so they avoid re-infecting themselves with species of nematode. The grazing manager often desires to reduce selection, forcing livestock to re-infect themselves with L3 stage nematode. Sheep will readily graze forage regrowth around a old cow pie, and cattle likewise readily grazing around areas with more sheep manure. Many nematode are species specific, cow parasites don’t impact sheep and vice versa. The exception being haemonchus contortus which impacts both.
The nematode eggs shed on pasture do not all hatch at the same time so can be like hard seed, they will be dormant for a longer period. Those that do hatch and develop through the L3 stage can still live on pasture if the conditions are right for an additional 2-3 weeks. Extending the rest period helps, but does not eliminate the parasite from the pasture, the ‘dormant” eggs that did not hatch initially will continue to hatch over time.
The grazier needs to figure out an IPM strategy and ways to interrupt the life cycle of the parasite.
I agree with everything you are saying as it is directly from the studies/articles/papers I mentioned in my first post. The reason I felt compelled to reply quickly was that the original comment basically promotes overgrazing as a parasite reduction strategy and this could lead people down a bad road.
We have a bad problem with Barber Pole worms on the Gulf Coast and left to graze unmanaged or even loosely managed the sheep drop dead and the calves don’t grow. We try for 45 day rests for sheep and generally are able to graze calves in between depending on “the weather” this is working for us with very limited use of wormers. Unfortunately the worms are always going to be there. Selection for resistant stock is going to be key as more resistant worms evolve. Thanks for the dialogue.
Good comments and I love when these articles begin a discussion. I’ve been in Iowa the last 17 years and a rest of 90 days+ based on research by Iowa State will break the parasite cycle for barber pole worms. Flies are different. When I worked near Houston I never ran into people with small ruminants and the cattle had as many issues with mosquitos as they did with anything else. The idea overlays onto others: High stock density and fast moves are great if rest is adequate. Low stock density is okay in some cases but can lead to pastures with lower quality forage – see buffet line article. Pasture and Rangeland must be managed differently. I am also assuming an effort to maximize profit more than maximize production, since they are seldom equal.
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