4 
Brisket Disease 
all of tlie forest reserves since these are usually found at high 
altitudes. It seems not to occur in the San Luis Valley to 
any extent, but is frequent on the ranges adjacent to that 
territory. In fact it has been seen in practically every part 
of the State where many cattle are maintained above an alti¬ 
tude of 8,000 feet. 
The disease is known definitely to exist in Wyoming and 
New Mexico but so far lias not been diagnosed in any other 
state or country. One. report of its occurrence in Montana 
lias not been verified. It is said by competent authority not 
to exist in the Alps of Switzerland. 
ANIMALS AFFECTED 
Cattle of all ages are susceptible, even calves as young 
as one month often showing well marked symptoms. In fact 
many calves die from the disease when the owners do not 
recognize the ailment. 
CAUSE 
It seems to have been demonstrated that the cause lies in 
failure of acclimatization to extreme altitudes. The maladv 
• •/ 
is far more prevalent in animals that are shipped in from low 
altitudes. In the case of calves, those that are sired by low 
altitude bulls are much more susceptible. The higher the alti¬ 
tude the more prevalent is the disease and the shipping of 
affected animals to lower levels will in a majority of the cases 
effect a cure. All of these observations clearly indicate that 
the altitude is the chief factor. In order to eliminate the 
food as a factor the Station shipped six affected animals to 
Fort Collins (altitude 5,000 feet) and fed them on South Park 
hay after arrival. (This disease is very prevalent in South 
Park, altitude 9,000 to 10,000 feet.) Four of these animals 
recovered, while two died. Since the two which died arrived 
in a moribund condition, and one of them died within 24 hours 
after arrival, it is not believed the food could have been re¬ 
sponsible for their death. 
The disease does not appear to be contagious, since only 
a small percentage of animals is ordinarily affected. The 
work of the Station has never revealed a micro-organism that 
could in any way be a causative factor. Transmission ex¬ 
periments resulted negatively in the two instances tried. 
It is the belief of those who have investigated the disease 
that the lack of oxygen, the exhausting labor involved in 
grazing over the mountains, and the severe climate, all result 
in over-strain of the heart in some individuals, which leads to 
the generalized dropsy that has been called brisket disease. 
