June 2008

Victor Shelton, NRCS Grazing Specialist

I had three “dry” rains over the weekend, which was good for me because I had hay down, but the down side might be that this could be the start of our dry season.  Plan ahead, don’t overgraze, and allow for extra rest after grazing and especially after haying.  If you are going to plant any summer annuals and have at least 60 degree soil temperatures – better get to it.

Some people, with my wife at the lead, would probably say I’m a little strange at times, but I’m not afraid to get my hands or my boots dirty to get the real story.  This was exactly the case one day as I walked a pasture with a producer and his wife and I was ribbed by the Mrs., when I not only raked my boot through a cow pile, but got down close and dug through it with a stick.

I’ve probably watched too many episodes of CSI, but inquiring minds really must know and in this case, what is the cow really getting out of this pasture?  The output can tell us a lot about the input and this simple assessment won’t cost you anything except perhaps washing your boots and scrubbing your hands before you eat.

Let me pull back for a second, I’m heading down the lane a little too fast.  OK, I want to start talking first about the forage quality.  I’ve discussed in the past good reasons to rotate livestock and one of those reasons was to maintain good nutritional value in the forage.  Forage quality is important because it influences milk production on those lactating cows that are supporting a calf, and is critical in meeting the goals of average daily gain for growing animals.  Keeping the forages as vegetative as possible for as long as possible should be top priority!  In other words, don’t let it even think about going to seed.

Where am I going with this?  You can tell a lot about what is going on in the pasture, especially with forage quality by taking a good look at the manure.  The dairy folk have been doing this for a long time using it as a tool to help them adjust their TMR or paddocks even to the extreme of running it through sieves to separate out different particle sizes….anybody want that job?  It gives us though a really good evaluation of the cow and her diet and provides an idea of how well the rumen is functioning.

In a well working rumen, there should be enough total fiber to maintain rumination.  The mat of fiber in the rumen retains the forage for more complete digestion.  It must be in balance and we have to give some credit where due and here it lies with the cow herself.  If she has a choice, she will consume a mixture that will maintain that mat.  Have you ever taken the time to watch a cow in the early spring once they have been turned out into new grass?  She will be out there grazing for about 3 days and then, based on forage quality and how much dry residue is left from the previous year, she is very likely to start hitting every fence row looking for old mature roughage and will even eat tree limbs, etc. to get it.  If this is really what she is doing, then you could go up to the side of this cow and give a push and hear a sloshing sound…better from the side than from the rear…don’t stand to close behind her under these conditions; consider yourself warned!  At this time of year, especially if there is little or no dry residue left from the previous year mixed into the sward, the forage quality is typically very high in crude protein and moisture.  It is under these conditions you can win the bet that that cow would probably even eat straw if available; perhaps a good story for a “Ripley’s Believe It or Not”.

I’m getting sidetracked again.  Sorry about that.  Rumination and digestion by microbes break down forages in the rumen.  If the cow does not eat enough fiber to maintain that mat, both for rumination and rumen function, the forages can pass through the rumen too quickly and be under digested.  If this is happening, milk production and average daily gain can suffer.  Back to the manure, looking at it can tell you a few things.  The softer the stool, generally the higher the quality of forages they are grazing…within limits.

Extremely soft or just plan “loose” manure is a good indicator of very high forage quality but as mentioned above, you can get too much of a good thing.  Those really soft piles…splatters, can easily be 22-28% crude protein with digestibility in the 80’s…it is really moving!  This is wonderful feed if we can just slow it down a bit.  Grazing turnips is a good example of a high moisture, high protein forage that really needs some dry matter as a side dish to balance the rumen and maintain that mat.

True “piles” indicate then that forage quality is lower and probably more like in the range of 6-8% crude protein with moderate total digestible nutrients.  This type of manure usually indicates a declining forage quality and is more maintenance quality at this point.  Look at the manure of cows that were trying to survive on some of the hay and stalks fed last winter, quality was certainly lacking in some cases.  They were often consuming more mature forages including the stalks, so there is an increase in structural carbohydrates consumed.  This type of “feed” stay in the digestive track longer, more moisture is removed and so it ends up as harder material.

The happy range is that nice smooth textured manure…yeah, I’ve looked at way too much manure.  This manure will have a crude protein range from 12-20% with digestibility in the 60’s and 70’s.  I believe it was R.L. Dairymple who actually broke manure quality down into categories, four or five if I remember right, which I did not keep in my mind, but I think I remember the descriptive word of what he thought the ideal patty should look like; pudding.  At this stage, quality of the forages consumed is well balanced and stays in the rumen long enough to allow good absorption of nutrients and thus good performance.  If it is almost liquid, then some roughage, i.e. fiber is beneficial to slow down the process.  If it is hard and piling high, then the addition of protein may be warranted or improved pasture management practiced. 

So, what can we take home from this? 

• Manure evaluation is a quick and easy assessment of forage quality.
  • Pudding like ~ just right, good performance potential
  • Liquid ~ very high CP, low fiber, potential performance problems
  • Piled high and deep ~ low CP, high fiber, lower performance
• Leave some forage residue behind to improve fiber content of early spring grazing and improve performance.
• Maintain forages during the growing season in a vegetative stage as much as possible to maintain that forage quality remembering to allow adequate time for rest between grazing periods and maintaining minimum grazing heights.
• Allow the livestock some forage choices and diversity to help them balance out their nutritional requirements.

Until next time, watch closely where you walk and keep on grazing!

Keep on grazing!