November 3, 2010 – Manure
can be both a blessing and a curse on many farms. It is a great fertilizer for
the crops, but it also has to be managed diligently from when it comes out of
the cow to when it is spread on the field to ensure that it is all ending up
where it should. From collections systems to storage and spreading there are
many things to consider about manure management, but one benefit to manure is
often overlooked. It is a great indicator of the health of your cows and how
well they are utilizing the diet that is being fed to them.
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}p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; font-size: 16pt; font-family: Times; }div.Section1 { page: Section1; }November 3, 2010 – Manure
can be both a blessing and a curse on many farms. It is a great fertilizer for
the crops, but it also has to be managed diligently from when it comes out of
the cow to when it is spread on the field to ensure that it is all ending up
where it should. From collections systems to storage and spreading there are
many things to consider about manure management, but one benefit to manure is
often overlooked. It is a great indicator of the health of your cows and how
well they are utilizing the diet that is being fed to them.
There is a great deal of
effort put into creating a well balanced ration and presenting it to the cow,
but after that the cow and her rumen microbes are in control and do we really
know what is happening in there? Yes, we know a great deal about how feeds are
digested and utilized, but every farm and every cow are different. Therefore,
the only way to determine how cows on your farm are utilizing your diet is to
look at the manure. Many producers look for loose manure as an indicator that
there might be too much protein in the ration or too many concentrates in
general. Some even look at whether there are corn kernels in the manure.
Identifiable corn in the manure is a good sign that not all the corn in the
ration is being utilized for milk production.
However, not many look
beyond the looseness of the manure or whether there is corn in it. There is
more that can be learned from the manure and it requires that a manure sample
be taken and sent to a lab for analysis. Manure analysis do not need to be done
as often as forage analysis, but looking at it once or twice a year might yield
some surprising information. From an environmental perspective looking at the
phosphorus content of the manure will give you a good idea as to whether the
diet is providing the right amount of phosphorus to the cow. Manure phosphorus
levels should be between 0.55 percent and 0.7 percent in a diet that is meeting
the phosphorus requirements of the cow without providing too much. Manure can
also be analyzed for neutral detergent fiber to determine how well the fiber
portion of the ration is being utilized. Starch is also a great thing to
measure because it will quantify how much of the starch from the corn in the
manure is being excreted.
In order for manure
analysis results to be useful they first need to be taken properly. The general
rule is that 15 percent of a specific group or up to 20 cows should be sampled.
The sample should be of fresh manure, which means palpating cows or obtaining
samples from piles that have recently hit the floor and are not contaminated
with feed or bedding. As with any sampling, it is important that the sample is
representative of the entire group. Samples from all the cows in a group are
mixed together and sub-sampled. The sub-sample is placed in a well sealed
container and shipped overnight to a lab that performs manure analysis, or
should be frozen if not mailed immediately. This analysis can take two to three
weeks to perform. The results need to be interpreted relative to the ration
that specific group was eating at the time of the sampling.
Having done many manure
analysis, I understand that it is not something that folks are eager to do, but
it is another tool that can be utilized on the farm to help ensure that the
ration is being utilized as efficiently as possible.
