- [Voiceover] Excellent, it's my pleasure
to introduce our next speaker, Dr. Kim Cassida
who is the Forage Grazing specialist
at Michigan State University and she'll be presenting on
cover crops, forages, and grazings.
So please help me welcome Dr. Cassida.
(applause)
- Good morning, I was invited here to be the,
I don't know, maybe the black sheep of the group
and talk to you a little bit about animals
and how your cover crops could be used as forage crops.
And I get the question a lot since I've been at Michigan
about four years now and I'm constantly asked by people
if they can use their cover crops as forages.
And my reply to that is
that all forages are cover crops, alright.
I get my PhD in the early 90's working with Brassicas,
which at that time were considered a forage.
Now they're a cover crop.
A lot of these concepts are not new.
They're new in their use in use in row crops.
But in terms of how we address using these
for animal production, we've known
a lot of this stuff for a long time.
I would also present to you the concept
that all cover crops are forages.
And this should be a review of
what you've already learned this morning.
Because I think almost every speaker has pointed this out.
We tend to think of our livestock as being these
four footed creatures here and our traditional definition
of forage if the edible parts of plants
that are harvested that can provide feed for animals.
Which is great if you're only considering your animals
to be the four footed kind but as we've learned today
we have all kinds of other little animals
that live in the soil that we also need to feed.
And you need to consider those two elephants
that are underground as well as your
traditional types of livestock.
So what forages can we use as cover crops?
We have got a huge history of plants
that if you look back in the literature
over the year have been used for forages
that are currently being used as cover crops.
(laughter) We'll get to the end here eventually.
There's probably more than this but I got tired of
putting boxes on the slide.
I think that's the last one okay.
There's a lot that we could use.
So why do people think that these plants
cannot be used as cover crops?
There's a number of things that
come into that reasoning and probably the first one is.
Oops and I didn't fix that did I?
Oops, sorry.
Is insurance, so that is not a scientific problem okay.
That's been pointed out I think a couple of times.
Maybe that was yesterday.
But we have rules that regard,
that relate to how you have to manage your
cover crops if you're in a crop insurance program right.
And up until recently the very concept that you could
harvest your cover crop for any reason
was a little bit foreign.
So a few years ago the NRCS, FMA, and FSA
got together and kind of came up with some guidelines
about what we could do to get around that problem.
So they have concluded, you can find the guidelines
at this website, but they have concluded
that it is okay to graze or harvest your cover crops.
As long as it doesn't interfere with your
specific crop policy that you have.
So what I always tell people in that regard
here's what you need to do.
So work with your insurance agent.
I can give you guidelines but that's
the person that's gonna decide whether or not
you get any money so that's really the person
you have to keep happy, not me.
But with that in mind it is generally possible
to harvest your cover crop for use
either as a harvested forage or for grazing
as long as that is happening somewhere
in the middle of the growth period.
So you're gonna have regrowth on the cover crop
to maintain your ground cover and
the other reasons that you are growing it.
Where it gets a little bit more questionable is
when you get into the termination phase.
Because the approved methods for termination
include frost or natural kill, chemical application,
crimping, rolling, tillage, or cutting.
You notice grazing is not on that list.
They do not consider grazing to be
an approved method for termination.
And the reason for that is that is that
they don't feel that you can guarantee
that a grazed field is dead and they are right.
You can not guarantee that a grazed field is dead
because of the way animal graze.
They are not gonna eat every single plant in the field.
But there are ways around that.
If exceptions are possible under the new technology
or acceptable deviation policy,
and that would be based on your individual farm records
and the testimony of two experts who will back you up.
Whether it's worth it to go through that process
for the termination is up to the individual farm.
But no problem in the middle of the cropping period.
Another question that comes up a lot
with the use of harvesting of our cover crops is
is that gonna cause soil compaction?
Because we know that one of the big advantages we get
from our cover crops is their improvement of soil properties
and if you're gonna cancel that out
by running over the field with heavy equipment
or a lot of animals then that obviously is not desirable.
And the answer to that is, sometimes you can get
surface compaction if animals are present
when the field is wet or if equipment
is run over the field when it's wet.
So the pretty easiest solution to that is
don't have animals and equipment
on the field when it's wet.
Another thing that research has demonstrated
with that problem is that if you are in an area that freezes
your freeze thaw cycle will tend to alleviate
the surface compaction and minimize the problem.
So some of the other things that you can do
to help minimize that risk is to use no till.
You start out with soil that in better condition
that can hold up your animals to begin with.
Stay off the wet ground, put your animals out there
to graze while the ground is frozen.
So that they can't compact it.
And probably a very important piece
if you are going to be grazing
is to use managed grazing so that you can control
where the animals are and how long they stand there
so that you can prevent them from really punching up
one part of the field excessively.
And that may mean using a rotational system
or moving your supplement or your water sources around
to keep your animals from congregating in one place.
Another thing that comes up is
you have to be a little bit careful about pesticides.
Both if you may have pesticides that were used on the
previous crop that might have some residuals
that could interfere with the crop that
you're using for forage.
You could have residue still present in the field
from the previous crop that have a
pesticide residue on them that is not legal
for feeding to animals and you may or may not
have used the pesticide on your cover crop itself.
Although probably most of you are not doing that.
So watch your labels.
There's a lot of other things that could go wrong
that make people worried about harvesting
or grazing their cover crop.
One is weeds, and this relates
back to the fact that animals don't completely
kill out the cover crop, and they may have the chance
to go to seed and we don't really want
our cover crops to go to seed if we don't want them to.
Because then they could become
a weed problem in your field.
Some of the species that have potential to do that
include the rye grasses, cereal rye,
hairy vetch, and buckwheat.
Some of our cover crops can accumulate nitrates,
which can be toxic to animals.
And this would include sorghums, small grains, or Brassicas.
And buckwheat has a particular problem
in terms of feeding to livestock in that
it can cause photosensitization of their skin.
So that basically if they have white or pink skin.
They're out in the sun, they get a severe sunburn.
Which is very unpleasant for the animal.
Buckwheat's an excellent cover crop.
But it's one of the very few cover crops that
I don't recommend people use for animals for that reason.
Although you can if you limit it to less than 30%
of the diet it can be manageable.
We have some other things that are only concerns
when the animals are grazing.
They're not so much a problem if you're using hay or silage.
And that includes bloat, some of the cover crops
that can cause bloat include wheat,
annual clovers, medics, and Brassicas.
We typically think of bloat as only occurring
on legume forages but it can occur on
anything that's really rich and lush.
Including some of these grasses and forbs.
Photosensitization can also occur with immature Brassicas.
We have some neurological problems
that occasionally show up when animals are
grazing hairy vetch if they graze it
when seed pods are present on the forage.
And our sorghums and our Sudangrass can cause
prussic acid poisoning in our animals
when they are on pasture.
We have a few problems that are only concerns when you are
feeding the cover crops as hay or silage.
And that would include vitamin K deficiency
with sweet clover which is another
really excellent cover crop that I always
caution people for using for animals.
It's perfectly safe as a pasture.
But if you make hay or silage out of it
and that hay or silage is not perfect you get mold in it.
It contains a factor that can cause tie up vitamin K
in the animal and cause bleeding problems.
And lastly we have a number of our,
or all of our Brassica cover crops
and radishes are a problem if you
want to make hay or silage out of them
because they are extremely wet.
I've actually measured forage rape
in the field at 4% dry matter.
I don't know how the plant stands up at that
but if you try to make hay out of that
I'm pretty sure that would not work.
(laughter) You would have a problem getting it dry enough.
Just a few comments on how grazing a forage
is gonna be different
than harvesting it as a hay or silage.
To begin with, if you have the animals out there
grazing the cover crop you're typically
actually harvesting less of the biomass
than if you went out and cut it, took it off the field.
There's actually very few crops
that remove more nutrients from a field than a hay crop.
That's pretty hard on your nutrient status.
But with grazing you're really recycling most of it.
The animals will recycle typically 50% of the nitrogen
comes back out onto the field and
85% of the P and K will be recycled.
We'll also be leaving a lot of the
biomass itself is still on the field
because the animals won't eat as much
as if you machine harvested it.
They'll probably only eat about 25-75% of what's out there
and the rest will be left as plant residue.
When you return that nutrient onto the field
you're returning it in a different form
than what it came off the field.
So you will be having a lot of that
will be in a more plant available form.
Basically it's manure when it comes back out.
But it will be spatially redistributed on the field.
It's not gonna be put back
in the same spot where it was taken off.
Which is another reason that you need
to be careful to manage the animals.
Because if you let the animals congregate in one spot
what's going to happen there, they're gonna concentrate
the urine and dung in that one spot
instead of distributing it more evenly over the field.
Also hoof traffic is different from wheel traffic.
Hooves are sharper, they tend to
grind plants up a little bit, and there's some evidence
that when you have heavy traffic of animals
over that biomass of the cover crop
you're actually helping it degrade faster
by pulverizing it a little bit.
Kind of working it into contact with the soil surface.
Lastly the main difference is that
grazing requires animals okay.
It also requires fence, water, and a different set
of management skills than a lot of farmers have.
And this creates a problem because
in our current agricultural systems
a lot of our farms that are using cover crops
are pure row crop farms and they no longer have animals.
And a lot of times the farms where the animals are
don't really have a whole lot of row crops
where they might put out a cover crop.
So this creates a bit of a dilemma.
We have a large group of farmers in Michigan
that are actually working around this problem
by actually working together as
a community with their neighbors.
So if you have a row crop farmer next to a livestock farmer
they'll actually work out a deal
where the livestock farmer can put
their animals out on the cover crop.
And this particular picture is
actually a sheep flock that belongs to our
small ruminant specialist at Michigan State.
But there's some, hard to see it in this picture,
but there's some movable plastic net fence
in the background so this field
that belongs to his neighbor is actually not fenced.
So Dr. Ehrhart brings in the fence himself.
This is a portable system that runs
off of battery charger with a solar panel.
And these sheep are trained to it.
And he just puts this fence up
and walks the sheep down the road,
or you could take them on a truck,
and leave them out there until they have,
basically leave them out there until
the cover crop is completely grazed down.
And this is a combination of
forage turnip, radish, and oats.
Although about all you can see right here
in the oats is the, or in the picture is the oats.
So if you're looking for an ideal characteristics
for a cover crop that could be a good forage
these are the traits that I look for.
I'm looking for something that's a fast growing
vigorous seedling because usually we're trying to do this
in a short window of opportunity.
It needs to reach harvest-able biomass within 60 days.
Again we've got a short window.
It should not self seed.
It needs to have acceptable nutritive value
for whatever type of animal it is
that we're planning to feed it to.
It needs to have a manageable toxicity risk.
I mentioned a lot of problems.
But a lot of those we can manage.
As long as we're aware of them.
It needs to regrow after harvest.
Because if we're going to meet
our cover crop criteria for crop insurance,
right, it's gotta grow back after we graze it.
It needs to be easy to terminate.
A lot of times, at least in the northern part
of the mid-west, if you pick one that will winter kill
you can pretty much solve that problem.
And it needs, if you wanna make it into hay or silage,
it needs to have acceptable preservation characteristics
for that purpose, which would rule out the Brassicas.
Some of the cover crops that work really well
as forage crops in the northern part of the mid-west
include the Brassicas, the sorghums, and small grains.
We have a long history of how to manage those.
We know how to grow them.
We know how to graze them
or harvest them to our best purpose.
One of the really good opportunities we have
to fit something in to our systems in, Michigan anyway,
is looking at the window of opportunity
after wheat comes off in July.
We have about a 60-90 day window
that we could grow a cover crop
and be able to harvest it as a forage.
The wheat belt extends, well a lot of us
could take advantage of this.
This is a little bit of data from Dale Mutch
in Michigan and this just shows a wheat field
that had been frost seeded with red clover.
We have a lot of people in Michigan that do that already.
And they just decided to mow half of this field.
Took the red clover off, so they have
a not mowed half and a mowed half,
and this is what it looked like the next year.
They actually had more vigorous regrowth
of the red clover on the mowed half.
This does not surprise me as a forage scientist
because we know that when you defoliate a plant
you cause it to drop roots, alright.
That's it's response to having leaf tissue taken off.
It will also drop roots roughly proportionally to match.
But then it will grow them back
at the same time as it's growing back leaf.
So theoretically we would expect
that this actually should be pumping
more organic matter into the soil system
than if you did not defoliate that plant.
And in the case of red clover we're probably
also adding more nitrogen which actually showed up.
When they looked at nitrogen credit
under the clipped red clover was 94 pounds per acre
versus 88 pounds where they did not clip it.
That was a significant difference.
And they went in the following year
and planted some organic corn varieties.
And actually found for several of the varieties
that they actually had significantly better corn yield
where they had clipped the clover
and removed some biomass than when they had left it alone.
We're in the middle of a study right now
where we are looking at that particular system.
We're looking at what kind of forages
could you put in after wheat that would
serve a cover crop benefit as well as
being harvest-able as forage.
So our system is a two year rotation
where the first year is winter wheat harvested in July.
In this particular system we are
leaving the straw in the field.
We then plant a cover crop as soon as we can get in
there after the wheat comes off.
And we take half of those cover crops off.
And we harvest them for forage
after about 60 days after we planted them.
We're chopping them for haylage
and we're leaving the other half alone.
Not touched to be a more conventional type of cover crop.
And then in the second year
we are growing corn for grain
to see what affect that has, what affect the harvesting
of the cover crop had on corn.
And the cover crops that we selected
for this system, we had our control, was red clover.
Which is already being used again in Michigan a lot.
And that was frost seeded so it was in a little bit longer.
All the rest of these were planted after wheat harvest.
And these were selected based on the criteria
that we expected we were gonna be planting in July
when we expected it to be hot and dry.
So we were looking at some warm season plots or plants
that we thought would be successful
under those growing conditions.
And we also were looking at several legumes because
we wanted to get nitrogen fixation into the system.
Unfortunately what happened in the two years
that we have done this is that we had unusually cold
wet weather in the summer so we really
didn't achieve a hot and dry July.
Which really disadvantaged our warm season plants.
We also thought, in hindsight, we were treating this more
as a pure cover crop system so we did not fertilize
after the wheat came off.
Now we know from our management standards
for using annual forages in the past
that typically we would like to feed them a little bit
if we wanted to boost their growth
to get rapid forage production.
So we think in hindsight that a little bit of fertilizer
out here at cover crop planting
might have boosted this a little bit.
Because we were overall disappointed with the yields.
Typically I tell people if you don't have
at least a ton of forage dry matter
in the field it's probably not worth it
to run your equipment over the field to harvest it.
Economically speaking that's probably just not worth it.
So our red clover that was frost seeded
we hit that target, and we did get the oats and peas.
And the Sudangrass managed to hit the target in one year.
And the rest of the things were rather disappointing.
But we think that is because of the unusual weather mostly.
We also looked at forage quality of these materials.
And the top graph here is relative forage quality.
Which is a calculated value that assesses
several different characteristics of the forage
to see what it's relative value would be.
And the best one that we had was the oat/pea cover crop
followed by, well you can read those.
Our red clover remember had the highest yield.
It also had the lowest quality.
That was probably because it was in full bloom
at the time that we harvested it.
But interestingly we found when you looked at crude protein
down here, and these are ranked in the same order
as the top chart, but we did see a little boost
in protein for the annual alfalfa cover crop.
Even though there was very little of it
present in the plot.
So what that indicates, to me anyway,
is that you can get a boost with a very small amount
of cover crop actually present.
All of these plots had a lot of volunteer wheat in them.
With the exception of the oat, peas,
and the warm season grasses where the wheat didn't survive.
Wheat is also a cover crop and it's
a very high quality cover crop.
and it undoubtedly contributed to the
high nutritional value of the plots
that had a lot of it in there.
Oops, these are just markers for what we would consider
excellent quality to be.
So we were adequate.
We weren't excellent, but we were adequate.
Then we looked at the corn yields next year.
We did not see any depression in corn yield
due to taking off a harvest of haylage.
Corn yields were the same pretty much across the board.
So that shows us that we did not interfere
with our cover crop benefits by harvesting.
Now the last but little piece of data that I wanna show you
is a study that we're also in the middle of
where we are looking at high energy cover crops
for finishing of grass-fed beef.
One of the limitations we have in a grass-fed beef system
is that when you're trying to put that
last little bit of fat on the animal
before it goes to harvest that
often happens in the following year.
And we don't have our traditional forages,
our perennial grasses are not high enough in quality
at that time of year.
So we had the idea to try some of these
forage Brassica small grain mixes that are
very high in nutritional value
to see if we could get that last
little bit of finish on these animals.
And so we have three systems we're looking at.
One is our traditional pasture.
One is a simple mixture of oats and forage rape.
And then a more complex mixture of oats
and basically two kinds of Brassicas,
field peas and Italian rye grass.
And when you look at the forage quality
that we got from this system we're actually
seeing excellent forage quality
of our Brassica mixtures.
40% NDF is considered dairy quality forage.
It needs to be 40% or less
so our complex mixture was even better.
Our biomass was also greater in the fall of the year
on our cover crop mixtures than it was
on our traditional pasture.
So how did our animals perform?
We found when we looked at the hot carcass weight,
because we actually sent these animals to slaughter
at the end of the trial and looked to see
what the carcass characteristics
and the meat quality is going to be.
The complex mix animals had the heaviest carcasses.
And they also had the highest dressing per cent.
Which is indicating to us that those cover crop mixes
are actually much more effective than a traditional pasture
at this time of year for getting good animal performance.
That we can get acceptable performance
with these grass-fed animals.
And that is the end.
I may, probably don't have time for questions.
(applause)