Ideal Sudan Grazing Height

[Otha]

Let me give ya'll a few details to help understand the situation.
We have planted and fertilized 13 acres of BMR Sudan. 150 lbs of fert once it got 8 inches tall. It is also irrigated. Got the water running right now. We plan to graze it so we can cut more coastal Bermuda for hay. We will rotate the cattle across it. Not sure if they will get moved every day or not. Depends on how tall it is and how hard it is to set the wire up.
So the question is how tall do we let it get before starting to graze? Trying to maximize what the cows can get from it for the summer so I know we need to let it get to a decent height as it will be growing faster but also don't want it to get too tall as I expect that would result in more being trampled.
The other issue is the irrigation. We use water reals, the kind with the big cannon on the end so once the stuff gets to be 3-4 feet tall we wont be able to water it as well without making paths. Our sprinklers are little and the sprinklers only stand off the ground about 18 inches. What we can do is water it very heavy at 3 foot tall and then let it grow for a couple weeks before turning in. Just don't want to go too long without water as it will be hard to catch up if this drought continues.
Oh and there are a few Ace Cow Peas in there but I don't think that really changes anything.

 

[wbvs58]

I think I would start as soon as it gets to a height that the roots hold onto it when they graze. That will depend a lot on your soil. My sandy soil will need a bit more growing to hold onto it.

Ken

 

[Otha]

I think I would start as soon as it gets to a height that the roots hold onto it when they graze. That will depend a lot on your soil. My sandy soil will need a bit more growing to hold onto it.

Ken

Thanks for the advice. Can you explain why you recommend that? So I will understand the full picture a little better.

 

[wbvs58]

I might be wrong, I was hoping others would comment as I don't have much experience grazing a forage sorghum but from my experience with other forage cereals they are good to go once it has a sufficient root system that they don't pull it up when grazing, By grazing it early you keep it growing in the vegetative stage trying to stop it from going to seed.. If it goes to seed and gets tall most will get trampled and flattened.

Ken

 

[Ebenezer]

university recommendation

 

[Allenw]

That's what I was thinking.

 

[callmefence]

I don't graze it much except in the fall I'll graze it out. And it's primarily SS .It does seem to me that when it starts to get bigger than pencil sized stalk it breaks off and gets stomped on worse. Maybe when it starts getting to tall to water graze it down and water would be a good plan.

 

[Otha]

university recommendation

For those that didn't read the article the university of Kentucky recommends grazing at 18-30 inches. It doesn't elaborate on why that is recommended. I would assume that's when the plants have there highest nutritional value. I think I' start grazing around the 30 inch mark and by the time the cows get to the far end it'll be taller. That's one nice thing about using a poly wire. I may leave a little patch to grow tall just to see what happens.

 

[redcowsrule33]

It's because the young plants/leaves have more prussic acid and raises the risk of poisoning.

 

[Otha]

It's because the young plants/leaves have more prussic acid and raises the risk of poisoning.

I understand that's the concern on young plants but I am more so asking what is the ideal height to turn in at for maximum tonnage for the year. I know you don't want it too big but also need to be leaving some leaf when you move them for faster re growth.
I have a neighbor that has been sowing sudan straight into his wheat fields in may and never takes the cows out. The sudan never gets over 6-8 inches tall and starts to spread out kinda like sod grass does. Defiantly not the most efficient mothed but interesting to note he hasn't had any prussic acid problems.

 

[Stocker Steve]

The standard stuff can get 11' to 14' high here. Max tonnage, looks impressive, but the cattle will mostly just eat leaf if it is that course. So your grazing utilization is very low - - perhaps 15 to 20 percent.

Normally we plant SS in a complex mix. We usually take one summer grazing with SS at about 4', and a second grazing after a killing frost. Many of the other varieties in the mix regrow during late summer. SS not so much.

For grazing - - you need to think about timing compared to your perennial pastures, and grazing utilization, NOT max tonnage. So in MN we plant it in June to first graze during the August period when some of our cool season grasses are dormant.

 

[fnfarms1]

From advice and research I've done. Graze it around 30inches back to 12inches and move them to next patch. Keeps from killing it out and growing.