UNIV. OF FL LIB. 
 DOCUf 
 
 MENTS DEFT. 
 
 A. I. 32. 
 
 1 
 
 U.S. DEPOSITORY 
 
 c_ 
 
 Issued May 20, 1918. 
 
 United States Department of Agriculture^'-*!^ 
 
 BUREAU OF ANIMAL INDUSTRY. JT^O ••**"* * # *v5f - 
 
 JOHN R. MOHLER, Chief of Bureau. 
 
 OAK POISONING OF LIVE STOCK. 
 
 «w 
 
 By C. Dwight Marsh, Physiologist in Charge of Poisowous JUaAlTmestigation^' 
 A. B. Clawson, Physiologist, and Hadleigh Maesh, yeflgfc^tSli*- Tft****^-^ 
 
 Pathological Division. 
 
 *"*„*!*'* 
 
 PREVALENCE. 
 
 For some years there have been reports of poisoning of live stock 
 b} oak leaves on the western stock ranges. These reports have come 
 mostly from Colorado, Utah, Texas, and New Mexico. 
 
 In the mountains of Utah there is a very distinct oak zone between 
 the altitudes of 5,500 and 8,000 feet, in which the species known as 
 Quercus gambellii is the principal form of vegetation. When the 
 cattle go to the summer range they graze through this zone at the 
 time when the young leaves of the oak are appearing, and again late 
 in summer they frequently come down from the higher ranges and 
 stay in the oak zone, eating largely of the leaves. It is generally 
 said that most of the cases of so-called oak poisoning occur in the 
 spring, when the animals are eating the buds and young leaves. 
 
 In Texas and New Mexico cattle are said to be poisoned by the 
 " shinnery " oak, Quercus havardi, in the early spring. In the Texas 
 shinnery country the cattle are kept in pastures where the vegetation 
 consists mainly of shinnery, mesquite, bear grass (Nolina), sage, 
 grama grass, and a few weeds. Of these plants the shinnery is the 
 first to begin growing early in the spring. 
 
 Reports from stockmen in regard to oak poisoning have been some- 
 what contradictory, and the matter has been made a subject of special 
 investigation for the last three years with the field experimental 
 work in Utah and Texas. The subject has proved to be one of con- 
 siderable difficulty, requiring many experimental feedings. While 
 there are still some doubtful points, it is considered that the work is 
 now fairly complete from the practical side, and a technical report 
 is in preparation. Inasmuch as it may be some time before this 
 technical report appears, and as it is important that stockmen should 
 have all available information as soon as possible in order to reduce 
 their losses, it has seemed wise to issue a concise preliminary paper 
 giving the main results of the investigation. 
 
 55952°— 18 
 
ANIMALS POISONED. 
 
 The losses from oak in America seem to be confined to cattle, 
 although there have been unconfirmed reports of the poisoning of 
 sheep. No cases of the poisoning of horses are known. 
 
 . 
 OAK THE CAUSE OF THE TROUBLE. 
 
 It has been definitely proved that the cause of this illness is the 
 oak. This has been shown experimentally in Utah and Texas, and 
 doubtless would be equally true for other localities. 
 
 In Utah the usual time for the cases to occur is in the spring when 
 the cattle are driven to the summer range. They frequently pass into 
 the oak zone so early that the grass has not started, so that there is 
 little for them to eat except the oak. Many of the animals have come 
 from dry feed, are greedy for green material, and naturally eat 
 largely of the young oak leaves. Similar conditions obtain in Texas. 
 At the time when the shinnery oak begins to put out leaves there is 
 practically nothing else on the range for the cattle to eat, and by 
 necessity they devote themselves to it. It has been shown by observa- 
 tion that they do not eat shinnery by preference, but will take grass 
 more readily if any is to be found. 
 
 OAK NOT NECESSARILY INJURIOUS. 
 
 While it has been shown that illness may result from eating oak 
 brush, it does not follow in all cases. The number of cases of sick- 
 ness is comparatively small, although in some localities in the early 
 spring oak leaves are about all that the animal can get to eat. In 
 the shinnery country the annual loss is estimated at 3 per cent, which 
 indicates that comparatively few of the cattle suffer from their oak 
 diet. If the animals feed exclusively or nearly exclusively on oak, 
 some of them may be affected, but many will go through the season 
 with no serious harm. It has been found experimentally that if a 
 small quantity of hay is added to the daily ration, no harm results 
 from the oak feeding. With a certain quantity of other material 
 oak may be considered as good forage. As a matter of fact, cattle in 
 Utah frequently come off the oak ranges in the fall in fine condition. 
 
 SYMPTOMS. 
 
 Perhaps the most noticeable symptom is the extreme constipation. 
 The feces are passed infrequently, are dark and hard, consisting at 
 times largely of mucus, and sometimes are bloody. This condition 
 of constipation may be followed by diarrhea. 
 
 The animal becomes gaunt, its coat rough, its nose dry and cracked. 
 The attitude is peculiar, the head being extended forward. Appetite 
 

 is lost and weakness increases until the case is ended by death. The 
 temperature and respiration are normal. 
 
 These symptoms appear after rather prolonged feeding upon the 
 oak, not less than about a week. The animals may die in two weeks 
 or they may linger for an indefinite period. 
 
 In the autopsies the congested condition of the interior of the 
 intestine and sometimes of the fourth stomach is most noticeable. 
 
 TREATMENT OF OAK CASES. 
 
 From the fact that oak cases are constipated, it is evident that any 
 treatment relieving this condition would be helpful. Epsom salt 
 might be used in pound doses, or it could be given in the water, in 
 small quantities, in localities where the cattle are watered at wells. 
 
 It is evident, however, from what has been said, that the sensible 
 thing is to prevent trouble by proper feeding. If cattle are turned 
 upon an oak range when there is little other vegetation, some loss 
 must be expected. There is no doubt that in some localities cattle 
 are admitted to the summer range too early. In such cases it would 
 be more profitable, in the end, to feed a little longer and use the 
 range only after the grasses have had a fair start. The exact time 
 when this should be done can not be determined in advance but should 
 be fixed each year after an actual examination of the range. 
 
 If cattle are confined in pastures containing oak, care should be 
 taken that the diet is not exclusively oak. It has been found that as 
 small a quantity as 3 pounds of alfalfa hay daily, with the oak, will 
 provide a maintenance ration for a 2-year-old steer. 
 
 WASHINGTON : GOVERNMENT PBINTINC. OFFICE I 1918 
 
UNIVERSITY OF FLORIDA 
 
 3 1262 08925 9583