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Thursday, May 26, 2011

Indoor Dairy Farms

There has been much "to do" about a proposal to have indoor dairy farms down in MacKenzie Country in New Zealand.  Many are up in arms about spoiling this beautiful  environment of desert and bunch grass.  Others are concerned about animal welfare and still others about pollution of streams.  I haven't much to say about the spoiling of the appearance of the area.  I'm not even sure if what we see, is the original, pre-human face of this area or it is simply the face that people alive today first saw and hence have become attached to.  However, with respect to problems to do with animal welfare and stream pollution, as Porgy said, "It ain't necessarily so".

I worked for more than a year in two dairy farms in Israel.  Let me first describe how they work. The cows are housed in huge, open sided sheds.  This is necessary due to the high temperatures and almost constant sunshine in the Middle East.  Lengthwise, down the middle of these sheds is a raised cement driveway wide enough for a tractor.  Along both edges of the driveway there is a shallow cement trough with its upper lip level with the roadway.  Outside of the troughs is a fence made of vertical galvanized pipes.  It is constructed so that the cows can put their heads through the bars.  By moving a lever at the end of the fence, their heads are trapped and the cow has to stay there until released.  This is needed because otherwise, dominant cows scoff their own food and then drive weaker cows away and eat their food.

The farmer drives his tractor down the middle of the shed distributing the various feeds that they give the cows.  Feeds consists of waste products from vegetable processing, fruit processing and  brewery waste (lees)* and grass which they grow nearby and harvest with a special cart that both harvests and, with the press of another button, spreads the grass behind the cart when they drive down the roadway in the middle of the shed.  The farmer then sweeps the grass or other feeds into the troughs on both sides of the driveway so that the cows can get at it.

*This is their favorite.  You should see the excitement when they smell the beer wagon  coming.

They milk 3 times a day and in one  Kibutz that I worked at, when I visited last year, they were averaging 45L of milk per cow per day with their prize cow giving 75 L.  In some of the farms they are now installing methane generators using the manure and they can generate more than enough electricity to power the operation with lots of power left over to feed into the grid.  Critical is that they now have almost all the waste from the herd including from the milking parlor to use, making the generation of methane worthwhile.

The biogas is fed directly into the air intake of a diesel engine which runs a generator.  The engine then uses only 10 or 15% as much diesel to set off the biogas as it would running just on diesel

The heat from the diesel generator which now is primarily powered by bio-gas, heats the water for the dairy*.  So what are the advantages of having the cows housed indoors. (I'll leave you to comment on the disadvantages ((yes, I will publish them))).

*The over all energy efficiency of biogas when you generate electricity and utilize the waste heat approaches 75%.

Protection from the Weather
When the weather is harsh, cows are better off inside.  This includes intense heat or cold, flood,  deep snow and muddy conditions after heavy rain.  All these conditions occur at various times in various places in New Zealand.

Control of the manure and Urine
A cow pat*  kills a largish patch of grass and makes the adjacent grass unpalatable to cows.  A full urination in well drained soil will go down through the root zone of the grass into the water table.  Manure, urine and spilled milk are full of energy and shouldn't be wasted by simply applying them to the land.  After energy extraction through methanogenesis, the waste from the methane generator is excellent fertilizer, apparently better than the raw manure.    If cows are kept inside, all their manure and urine plus any wastes from the milking process can be used and don't interfere with grass production.

The material from the methane generator can be spread evenly on the land at the optimal dose rate and at the best time. This eliminates environmental pollution.   Bio gas can be fed directly into a diesel generator.  The electricity can be used in the farm and the excess electricity fed into the grid to generate another revenue stream.  The heat from the diesel generator is  used to directly heat water which is used for cleaning in the dairy and thus, saving the electricity for more important uses.

Of special interest, the generation of electricity for sending to the grid can be done at any time during the day and thus help peak shave.  This is unlike wind or solar-electric which generates when the wind is blowing or the sun is shining.

* Individual deification by a cow is typically the size of a large dinner plate and stays around for weeks until the worms or scarab beetles have broken it down.

Less land needed
Because of all of the above, less land is needed to produce the necessary pasturage for the cows.  More of the farm can be left in riparian zones*.  Cattle do not trample over their food source.  During wet conditions, indoor cattle don't wreck soil structure.  Soil remains healthier and better aerated when it is not trampled by cattle.

*The area adjacent to streams.  For the protection of our water resources, a wide zone along streams should be vegetated and domestic grazing animals should be denied access to this area.

Possibility of using  various waste products for food
With the cows in a shed, it is convenient to utilize a wide variety of waste products from other agricultural processing industries.  Cows, with their huge bacterial processing vats (rumen) are the perfect animals to turn otherwise wasted products into valuable milk.

Cows under closer observation
Cows kept indoors are under the observation of the farmer more of the time than cows that are only seen during milking.  With outdoor farming the farmer only sees the under side of outdoor cows and then only for a short time.  One day, while feeding the cows in Israel, I saw that one of the cows had become asymmetric.  The farmer, seeing this, quickly got a hollow needle from the office, punctured the correct place in the rumen between two of the ribs and let off the gas pressure that would have killed the cow if this hadn't been done.   

Lack of need for Riparian fences
With cows kept indoors, there is no need to fence off riparian zones.  This is a saving to the farmer.

Another model
If one objects to cows being always confined to a shed, one can have an open sided shed where the cows can come when they want to get away from adverse weather conditions.  They can also be fed any supplements in the shed and waste products from other agricultural enterprises and have water available for drinking.  This way a great deal more manure and urine is collected than if the cows only come indoors for milking.  This makes biogas generation worthwhile and eliminates the negative effects listed above of having cows in the fields.

It is clear that cow welfare and environmental protection can gain in many ways when cows are kept partially or completely indoors.  It must be pointed out that this is not always so.  It is possible to make the conditions better for cows indoors than outdoors or with giving the cows a choice but the opposite is possible.  Careful design and operation is necessary.  The devil is in the details.

ps.  Have a look at this article on composting barns.  Makes the idea of indoor dairy farms even more attractive.


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farm sheds nz said...

The concept of indoor dairy farms is really interesting and the fact is that, It will safe the environment as well.