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Re: red maple / now OAK



Cherry, we live in central california where live oaks are common along with
some white oaks and some other varities that are not as common.  i have
been told that acorns can cause abortion in cows and goats.

the site address is:
	http://vet.purdue.edu/depts/addl/toxic/cover1.htm
and i've included below what it says about red oak.


you might also want to check out this one from cornell as they mention
white and black oak also.  it seems that the red oak is the most toxic but
others are also considered to be so too.
	http://www.ansci.cornell.edu/plants/alphalist.html

karen

47. RED OAK 

Quercus rubra 

(beech family) 

TOXICITY RATING: Moderate high. 

ANIMALS AFFECTED: All animals may potentially be affected, but the primary
risk is to cattle. 

DANGEROUS PARTS OF PLANT: Buds (fall), young shoots (early spring),
sprouts, acorns. 

CLASS OF SIGNS: Poor doer, poor appetite, weight loss, diarrhea or
constipation, increased drinking, increased urination, edema, death is
possible. 

PLANT DESCRIPTION: Oaks are trees with leaves that turn brown but hang on
through the winter. In the southwestern U.S., Gambel's oak, shinnery oak,
and post oak frequently cause poisonings. In our part of the country, red
oak has produced problems. Red oak is a large tree of well-drained
woodlands, parks, and home plantings that bears broad-bladed leaves with
deep lobes ending in bristle-tips (fig. 47). The 

fruit is the familiar nut borne in a scaly cup and called an acorn (fig.
47A). 

SIGNS: This discussion refers primarily to cattle, the species most often
affected by oak toxicosis. It also seems that cattle less than 2 years of
age succumb to oak toxicosis more than do older animals, however older
animals are still at risk. Other species at risk include sheep and possibly
deer. Goats and swine are more resistant to poisoning, and horses are
rarely affected (likely due to a unwillingness to consume oak). Pets rarely
consume sufficient quantities to do harm. Many species of oak have been
implicated in the poisoning of livestock, with red and black oak exhibiting
greater toxicity than white oak. 

While short-term acute poisoning by oak has been reported, the most
commonly encountered oak poisoning is of a chronic nature. Oak is most
dangerous early in the spring when the leaves and buds are the highest in
toxicity and when there is little else to eat. The fall is another at risk
period, when acorns and leaves fall and better forage dies back. Therefore,
management plays a key role in preventing oak toxicosis. 

The toxins in oak are called gallotoxins and are converted in the body to
tannic acid, gallic acid and pyrogallol, all of which are very toxic to the
kidney. It is the resulting kidney failure that causes the clinical signs.
Typically, a significant amount of oak needs to be consumed over a period
of time before clinical signs appear. Signs can develop over 2 to 14 days,
or signs may be present with the animals becoming progressively worse over
many weeks. The number of animals affected in the herd can vary greatly,
but of those showing clinical signs, up to 80% may die. Signs of oak
poisoning can include depression, lack of appetite, a gaunt and emaciated
appearance, poor or rough hair coat, dependent edema (fluid buildup under
the skin under the neck, abdomen or on the legs), digestive disturbances
(both diarrhea and constipation have been reported, with mucus covered or
tarry stools), increased drinking, passage of copious amounts of urine
which may contain blood, and death. 

FIRST AID: The most important step is to get the animals back on to
plentiful and nutritious feed, and to limit stress, shipping and handling
during the recovery period. Also, make sure that plenty of fresh water is
always available, since affected cattle cannot maintain their own water
balance very well while recovering. Since this is a long-term chronic
toxicity, there is little in the way of an antidote to relieve signs.
Severely or more chronically affected animals may not recover, but the less
affected animals may, and may return to previous rates of gain and milk
production. A veterinarian will be able to assist in management, and will
be able to assist in emergency measures if large amounts of oak were
recently consumed. Beyond this, treatment is supportive and symptomatic. 

SAFETY IN PREPARED FEEDS: The toxin in oak remains when dry, so no feeds
are safe that contain oak. 

PREVENTION: Oak toxicosis is easily preventable with proper livestock and
pasture management. Animals tend to eat oak only out of necessity,
therefore by providing adequate and nutritious feed in the spring when the
oak leaves bud out and again in the fall when leaves and acorns drop, the
incidence of toxicosis should be minimized or eliminated. 



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