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Here’s the Impact of Fencing and Planning on Grazing Days and Profitability

In November I shared thoughts on the economic importance of stockpiling grass. In that article, I made the case for building internal fence on a new property because of the economic value of the grass. Well, we did build the fences even though we were sick of fencing by November! This article covers what happened after we fenced.

You may recall that I estimated about 20 days grazing for 950 dry cows which would equate to ~$34K worth of hay we would not feed. My estimate was a bit off, so let me share the actual results.

Would you like your own chart to help you figure out Standard Animal Units? Click to download this one that Kathy Voth put together for you.

To refresh your memory, the measurement I use to calculate grass harvested is Stock Days per Acre (SDA). It is the amount of forage a 1000lb dry, pregnant cow will consume in one day or about 24lbs of dry matter. Stock Days per Acre is taught in Holistic Management and Ranching For Profit and there are tables to standardize all classes of livestock. The standardized value is called Standard Animal Unit (SAU). For example, a 1300lb dry, pregnant cow has an equivalency value of 1.23SAU. That is to say the 1300lb cow consumes 23% more per day than a 1000lb cow.

Stock Days per Acre (SDA) is similar to bushels of grain per acre if you were a grain farmer. A grain farmer measures how many bushels are harvested from each field. The number of bushels is divided by the number of acres in the field to get bushels per acre. The same can be done by a grazier. First the herd size must be calculated in SAU. Then, multiply by the number of days grazed, and divide by the number of acres in the paddock.

For example, let’s say we had 615, 1300lb dry, pregnant cows that grazed from Nov 20 – 24 on 34 acres.

To calculate SDA’s:  

(615hd X 1.23SAU) X 5days = 3,782SD

3,782SD / 34acres = 111SDA

Therefore, in this example, 111SDA were harvested from the paddock. This is similar to a grain farmer harvesting a certain number of bushels of grain per acre from a particular field. In terms of grain farming though, the farmer does not stop there. Normally a grain farmer will calculate the price per bushel when the grain is sold. Then they will figure out the revenue per acre. Graziers can do the same thing once they know the Stock Days per Acre and what one Stock Day is worth.

During the growing season and up to Oct 31, I use the custom grazing rate for my area to give one Stock Day a monetary value. I use custom grazing rates because it is the operator’s choice whether they custom graze someone else’s animals or graze their own. Starting November 1, I use the value of ‘normal’ winter feeding to assign a monetary value. I use November 1 because I believe most people can graze until the end of October without much planning.

Here is an example from our area:

Custom grazing rate – $1.25/day/pair

1 cow/calf pair (1300lb cow) has a SAU of about 1.8SAU (from the HM table)

Therefore, $1.25/pair / 1.8SAU = $0.69/Stock Day

If we harvested 111SDA from a paddock prior to Nov. 1 with a cow/calf pair, the value of that grass would be: 

111SDA X $0.69/SD = $76.59/ac

If, however, we harvested 111SDA after Nov.1 the value of that grass would be an expression of how much hay it was replacing.

In the case of our ranch this year, it costs about $2.10/day/dry cow to bale graze.

In this scenario, the value of one SD is:  $2.10 / 1.23SAU = $1.71/Stock Day

Which means, that 111SDA of grass after Nov. 1 is worth:  

$1.71/SD X 111SDA = $190/ac

Now let me share the actual results from our new property.

The property is about 520 acres and is half open, half dense willows with some large poplar trees. I estimated that if we crossed fenced the property into seven paddocks, which we did, there would be 20 days of grazing for 950 cows. Once it was fenced, we moved 615 dry cows into the first paddock. We added cows and took some away, finishing with 802 head on January 1st.

We harvested 125SDA to 175SDA in the first six paddocks. Grazing the last paddock was cut short by 15 days because we set out too many bales with net wrap removed. Our concern was for excessive spoilage if it was left out in the field unprotected until next winter.

This dry herd of cows began grazing stockpiled grass on the new property Nov. 20 and finished Jan.1 for a total of 41 days. If you recall, my estimate at the start of November was 20 days. OOPS! I have become quite cautious as the years go by. Last year, I estimated 90+ days of stockpiled grass only to be foiled the second week of December by three feet of snow in two days! This year we did not have excess snow which made the 41 days possible.

Over the course of the 41 days 43,376SD’s of grass was harvested. Since we would have been bale grazing if not grazing, the value of each SD was $1.71. That means we harvested $74,173 ($1.71 X 43,376SD) worth of grass from that property. Our cost to make this happen was less than $9K (fencing materials, labor, and winter water system). I think that is pretty cool!

Another way to look at this scenario is to consider the cost per day to feed each cow. The expense for this property was about $22,000 (rent, fencing, water development).* With the growing season included, we harvested 49,945SD.

To calculate the $/SD:
$22,000 for rent and infrastructure / 49,945SD = $0.44/SD

To find the cost to feed a cow for a day (Nov. 20 – Jan.1):
$0.44/SD X 1.23SAU = $0.54/day

Plus yardage (labour, truck, quad)
$0.54 + $0.05 = $0.59/day/cow


To find out how much was saved by grazing stockpiled grass:

$2.10/day (bale grazing) X 41 days = $86.10/cow

Subtract $0.59/day (stockpiled grass) X 41 days = $24.19/cow

Total savings per cow = $61.91

The season did not start out with much success expected. As mentioned in the November article, my first day at this ranch was May 28 so there wasn’t time to do any real planning. I just knew we had to get the cattle out clipping grass as fast as possible. Somehow it worked out. A cowboy friend of mine would say, “Sometimes every squirrel gets lucky and finds a nut!” I guess we got lucky.

Over all I’m pretty happy with our stock piled grass and the snow conditions allowed us to capitalize on it. The owners seem to be happy as well. In fact, I heard a rumor they want to keep me around for a while. LOL

*I know the fencing and water should be amortized, however, when we first started, every improvement had to be paid for with current revenue, not borrowed money.

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