At 4/18/2004 06:58 AM, Vaughan Jones wrote:
>> > Be careful grazing soy beans if seed
>>> is formed because the beans can be
>>> toxic unless heated.
>
>FWO replied -
>>Nope, not true, at least not for dairy cows.
>
>The question was re lambs not cows. See below.
Hi Everyone,
Soybeans contain a trypsin-inhibitor which causes problems with monogastric
animals such as birds and pigs and humans. Ruminants are not affected by
this inhibitor because the rumen microbes detoxify it when the beans are
fermented in the rumen. Cattle, sheep, goats, deer -- are all safe from
this problem.
The unprocessed beans, however, do contain lots of fat -- around 20% on a
dry matter basis -- and if sheep or cattle consume a lot of them, then they
would be receiving a diet that was rather high in fats. In the rumen, too
many unprotected fats (unlike MegaLac and other products) can cause some
problems. Loose fatty acids are toxic to certain bacteria -- particularly
the fiber digesters. If those microbes are affected, then the rate of fiber
digestion in the rumen is reduced. In turn, this slows down the rate of
stuff leaving the rumen, which in turn reduces feed intake. Not exactly a
pathological problem to the animal, but it will reduce performance. (That's
why the protected fat products were developed).
>>Second, I'm searching for scientific information (papers) about lambs
>>grazing soybean pasture.
>> Here in Uruguay (South America) we have many farmers fattening lambs in
>> different types of pasture like white clover, ryegrass, etc.
>
>If some beans get knocked to the ground, go mouldy and are licked up later
>by lambs not only can they get mould problems, but also listeriosis from
>the soil.
>
>Parts of Uruguay have a moist climate so mould forms quickly even in the pod.
>
>Grazing soys is not like feeding dried ones.
Morrison's "Feeds and Feeding" has as section on using soybeans for
pasture. Apparently, the use of soybeans for pasture was a common practice
years ago. He mentions that it has a rather short season. I think that he
was talking about grazing the green well-grown plants before they set seeds.
>Calves have died in Canada from eating unheated soy beans.
The use of soy protein in some milk replacers and creep feeds can cause
severe allergenic problems in pre-ruminant calves and lambs, and will
sometimes cause death. Some companies substitute soy protein for casein in
their milk replacers because of cost. Heat processing does not denature
these antigens. However, there are some commercial soy products that have
been specially treated to remove the problem antigens, so not all soy
protein is a problem in milk replacers and creep feeds.
Best regards.
Woody
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Woody Lane, Ph.D. |
Lane Livestock Services | voice: 541-440-1926
240 Crystal Springs Lane | fax: 541-440-1007
Roseburg, OR 97470 | email: wlane@rosenet.net
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