TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR, College Station, Texas BULLETIN NO. 664 NOVEMBER 1944 THE TOXICITY OF THE RIPE FRUIT OF BLACKBRUSH OR TARBUSH (FLOURENSIA CERNUA) FOR SHEEP AND GOATS by FRANK P. MATHEWS i ALQRAR Y , Division of Veterinary‘? AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS GIBB GILCHRIST, President E29-l144-3M-L180 [Blank Page in Original Bulletin] _ ,/‘ '.\ i Serious losses in sheep and goats as a result of grazing the ripe fruit ;of Ijlgzgilgnsiamcernua lIRVFlIEEIT observed on three ranches during the months of January and February. The characteristic pathological alterations were inflammation, ulceration and perforation of the gastro- ‘ intestinal tract due to the presence of’; some intense irritant. In all cases the animals. had been subjected to considerable handling and p were quite hungry when they gained access to the plant. When L sheep and goats have continuous" access to the plant and are not i’! subjected tohandli/ng during the winter monthsjthere is no evidence é that i‘ parifiloifthe plant is grazed in suflicient amounts to cause toxic effects. The plant has not been associated with similar losses i in cattle. i ._ The toxicity of the ripe fruit was demonstrated by experimental ~ feeding to sheep and goats“ In this work a marked variation in the ’ susceptibility of different i ividuals was observerLas well as a nar- row margin between a sl' htly toxic andii/lethal dose of the material. l \ . Losses is ~ can be avoided by preventing hungry a; animals from gain’ g access to the plant during the winter months. There is no evi nce that the green leaves constitute a hazard to livestock. ,/ _ _ ' »-\ 7- '” f/lii h»? -» k i\\ % ‘~\ / MM. t, Qucw/v dc ~ . a. ( i,’ "=\ K i .1 3/» v ' x‘? _‘ i ‘i fiiiii,» Aw m/ ~> , _ . V‘ ~ ‘V. to the pyloric orifice. ‘standing facts were presented. First, extensive grazing of the fruit of the ‘jplant; second, no other forage to which suspicion could be directed in the ilackbrush thicket, and third, in all probability many of the dead sheep had not ranged beyond the blackbrush thicket, thus excluding "the possi- bility of obtaining some toxic plant in some other part of the pasture. With this evidence it was obvious that the blackbrush was the cause, ilaowever, experimental feeding tests were desired and a small batch of {athe fruit was collected and fed to a sh-eep the next day. The sheep died that night; it was the first animal to be employed in a series of experi- gents which have been conducted with ripe fruit during the past four years. The results of these investigations are reported in this publication. BOTANICAL DESCRIPTION AND DISTRIBUTION* , Flourensia cemua DC. is a very branching and leafy shrub, 1-2 meters (thigh, with the aromatic bitterness and odor of hops. Its leaves are alter- nate and entire, dull-colored, obscurely veiny, ovate to oval, 17-25 mm. long and 6.5-11.5 mm. wide. Its heads are rather small, ‘usually no more than one ‘cm. long, yellow-flowered, without ray-flowers, nodding, solitary in the leaf jlxils, and form long leafy infiorescences. The involucre, the cup in which the head is seated, is shorter than the disk and is of 2 or 3 series of ‘llanceolate erect imbricated bracts with some of the outer foliaceous and ireading ones passing into leaves. The achenes, the 1-seeded dry fruit, I compressed, narrowly oblong-cuneate, callousi-mazrgined and very ous. The pappus is of 2 subulate awns, one from each angle of the a ncate summit of the achene, occasionally with some smaller awns or les, the 2 awns unequal, half the length of the achenes and not sur- fpassing the villous hairs. ‘By V. L. Cory, Range Botanist, Texas Agricultural Experiment Station, Sonora, Texas. In the initial investigation of the outbreak near Allamore three out- p "fruit, and a few dead leaves. Most of the collections were made durif ' feeding tests on the same individual varied between 38 days and on 8 BULLETIN NO. 664, TEXAS AGRICULTURAL EXPERIMENT STATION At least seven other species of Flourensia occur in Mexico, but n the one species grows in the United States. In Mexico this species occu‘ from Nuevo Leon to Sonora and in the United States it occurs from- a... Texas to Arizona, the eastern boundary probably occurring in Andre_ Martin, Glascock, Reagan, Crockett and Val Verde Counties. While usua l known in the United States as “tarbush,” in Texas it is more commo called “blackbrush,” which is unfortunate since another and quite a ferent native plant of the State is known commonly by no other nai than “blackbrush.” Our Flourensia is common and abundant on d Q plains, mesas and low foothills, often occupying large areas and formi a distinctive vegetation type. In northern Mexico the leaves and hea‘ of this plant are sold in the drug markets under the name of “hojas_ or “hojasen” and are taken in the form of a decoction for indigestion. I EXPERIMENTAL PROCEDURE The ripe fruit was collected from six different areas, one in Hudspe three in Brewster, one in Pecos, and one in Reeves Counties. The fruit " :__’_ stripped from the branches, thus the material fed consisted of ch d the month of January. Force feeding was required with all animals. Q daily dose was divided into two equal parts, one part was given in -[ morning, the other in the afternoon. The animals employed in the few feeding tests had been given their regular feed of alfalfa the eveni preceding their introduction into the investigation. This method r», later modified by subjecting the animals to 24 and later 48 hour fasti“ periods before administering the first dose of the fruit. A total of a sheep and 15 goats were employed in the investigation. Six of these Fl mals were used in two or more feeding tests. The elapsed time betwee year. Feeding Ripe Fruit for One Day The results of this method of feeding are summarized in Table 1. Ampl, proof of the toxicity of the fruit of this plant is to be obtained from glance at this table as it will be observed that 11 out of a total of ‘i: animals were killed in this phase of the investigation. The smallest amoun of the plant which was capable of producing fatal results was found be a little over 0.9 per cent of the body weight for sheep and 0.9 per ce l for‘ goats. However, it will be observed that in some animals larger -..f produced little or no toxic effects. The apparent contradiction in such M sults was first encountered while testing the toxicity of material collect from different areas and at that time was considered a variability in toxicity of the plant in different regions but further investigation dis? closed that this represented a variation in the susceptibility of differen individuals, a subject which will be considered later. Beginning with goa No. 117 and proceeding to the bottom of the table it will be observed that. TOXICITY OF RIPE FRUIT OF BLACKBRUSH FOR SHEEP AND GOATS 9 Table 1. Results of feeding the ripe fruit of Flourensia cernua to sheep and goats for one day ' Per cent Animal Weight Pounds of body Results Number Lbs. fed weight 100 0.7 0.85 Off feed two days; recovered 8O 0.7 0. 875 Sick five days; killed for autopsy 115 1.1 0.954 Died within 48 hours 100 1.0 1.0 Died within 48 hours 95 1.0 1.052 Off feed 24 hours; recovered 75 0.9 1.226 No ill effects ' 95 1.5 1.577 Died within 18 hours 70 0.5 0.714 Very sick for 6 days; recovered 85 0.68 0.8 Off feed 3 days; recovered 70 0.6 0.857 Off feed two days; recovered 70 0.61 0.871 Off feed one day; recovered 60 0.54 0.9 Died within 24 hours 65 0.6 0.923 Died within 48 hours 70 0.65 0.928 Off feed one day; recovered 75 0.75 1.0 Died within 48 hours 55 0.55 1. Died within 24 hours 85 0.85 1.0 No ill effects 90 0.9 1.0 Died within 48 hours 75 0.75 1.0 Died within 24 hours 95 0.95 1.0 Died within 48 hours 65 0.7 1.076 Died within 24 hours i fatal results were obtained with all but one animal. Since these tests in- Wclude material collected from four different areas it is evident that the i location of the plant is of minor importance. The one exception, goat No. . 111, is a good example of a resistant animal. No variation in the toxicity of the plant from year to year was observed as Goats 117, 127, and 131, ‘ were fed material collected from the same area in 1942, 1943, and 1944. Feeding Ripe Fruit for Two or More Days The results of this method of feeding are summarized in Table 2. The ‘ object of this method was to prolong the life of susceptible animals by Vthe administration of slightly smaller doses or in the case of resistant -, animals to overcome the resistance by repeated doses, thus providing the additional time which must be required for the necrosis of the abomasum Tto develop. By this method we were able to delay the fatal termination an average of about 54 hours, which was evidently not sufficient time for , this condition to develop. For a two-day feeding period the smallest total T amount required for fatal results was between 1.5 and 1.6 per cent of i, the body weight, an amount considerably in excess of that required when l the feeding was confined to a single day. Since the final results were much the same in both cases the toxic effects appear to be determined by the i, amount of the plant ingested during the first 8 to 18 hours. Range ob- . servations tend to support such a conclusion as the grazing of the plant ‘f’. was confined to a few hours and probably did not exceed 24 hours in a any case. By the end of 24 hours suflicient toxic effects must have oc- curred to produce a loss of appetite and thus prevent further ingestion of the plant under range conditions. 1 1 10 BULLETIN NO. 664, TEXAS AGRICULTURAL EXPERIMENT STATION Table 2. Results of feeding the ripe fruit of Flourensia cernua to sheep and goats for two or more days Pounds Per cent Number Total i Animal Weight fed of body days amount Results a number Lbs. daily weight fed fed ‘ S113 115 0.8 0.7 2 1.6 No ill effects S172 75 0.53 0.706 2 1.06 Very sick five days: recovered S173 70 0.53 0.757 2 1.06 Died three days after last dose S130 115 0.9 0.782 2 1.8 Off feed 48 hours; recovered S142 100 0.8 0.8 3 2.4 N0 ill effects S124 8O 0.65 0.812 2 1.3 Died 48 hours after last dose S141 100 1.0 1.0 3 3.0 Died 72 hours after last dose S170 85 1.04 1.223 3 3.12 Off feed two days; recovered G132 6O 0.45 0 75 3 1.35 Sick for five days after last dose; recovered G131 50 0.4 0.8 2 0.8 Off feed 24 hours after last dose; recovered G111 90 0.72 0.8 3 2.16 Off feed two days after last dose; recovered G125 70 0.6 0.805 2 1.2 Died 48 hours after last dose G127 50 0.45 0. 9 4 1 .8 Off feed for 24 hours after last dose; recovered G120 60 0.6 1.0 1 0.6 Off feed after first dose, very sick 0.3 0.5 1 0.3 for five days then began to re- cover; killed for autopsy Individual Resistance In 1942 the ripe fruit was collected from three different areas devoted to sheep ranching and in which no evidence of loss from this source could be obtained. The three collections were fed to Sheep 142, Goat 111, Table 2, and Sheep 170, Table 1, with little or novtoxic effects. These results sug- gested a variability in ‘the toxicity of the plant in different areas, how- ever, continued investigation proved that we had demonstrated a variation in resistance of the individual and not a variation in the toxicity of the plant. Goat 111 was used in three experimental feedings; in 1942 very slight toxicity was obtained from an amount equivalent to 0.928 per cent of its body weight, in 1943 three daily feedings equivalent to 0.8 per cent of the body weight produced the same effects and in 1944 no ill effects were obtained from feeding an amount equivalent to one per cent of the body weight of the same material that proved fatal in the same size dose for Goat 131 (Table 1). Sheep 170 was off feed but not apparently sick after receiving an amount equivalent to 0.85 per cent of its body weight in 1942; in 1943 it received three daily doses each representing 1.223 per cent of its body weight with but slight toxic effects. Sheep 175 and 176 showed little or no toxic effects as a result of receiving over one per cent doses, whereas an amount equivalent to 0.954 per cent of the body weight proved fatal for Sheep 130. In this case two different batches of fruit were used, but the material fed Sheep 175 and 176 was the same batch that proved fatal for Goat 131, thus demonstrating its toxicity. Further evidence in regards to individual resistance is to be observed in Goats 125 and 127 (Table 2). Goat 125 was killed with two doses, each representing 0.805 per cent of the body weight, whereas Goat 127 withstood four daily doses, each TOXICITY OF RIPE FRUIT OF BLACKBRUSH FOR SHEEP AND GOATS 11 Fig. 1. Flourensia cernua, a single bush in the foreground and an extensive thicket in the background. Fig. 2. A branch of the plant showing leaves and blooms. BULLETIN NO. 664, TEXAS AGRICULTURAL EXPERIMENT STATION 12 representing 0.9 per cent of the body weight. A true evaluation of the re- sults on Goat 127 is confused by the fact that it was later killed with a slightly larger dose (Table 1) which introduced another factor, namely, a narrow margin between a slightly toxic and lethal dose of the plant. A narrow margin between slightly toxic and lethal doses must be i taken into account in an interpretation of the results as a whole, and especially in connection with individual resistance. In this connection Sheep 130 (Table 2) showed but slightly toxic effects after being fed a dose equal to 0.782 per cent of the body weight for two days, and 41 days later an amount equal to 0.954 per cent of the body weight of the. same material constituteda lethal dose (Table 1). Similar results were obtained with Goat 121 in which the feeding of 0.871 per cent of the body weight produced but slight toxic effects and one equal to 1.076 per cent of the body weight of the same material was found to be a lethal dose. In these two animals the short interval of time between the two feedings might indicate a carry-over of the toxic effects from the first to the second feed- ing, however, the results with Goats 127 and 131 appear to exclude such a possibility. Goat 127 (Tables 1 and 2) showed but slight toxic effects from four 0.9 per cent doses in 1942 and was killed with one 0.923 per cent dose one year later. In addition Goat 131 withstood two doses representing 0.8 per cent of the body weight in 1943 and was killed one year later as a result of feeding an amount equal to one per cent of its body weight for one day. The batch of fruit which proved fatal in either case did not ap- pear to be any more toxic than that fed the previous year, as in the case of Goat 131 the same material was fed to Sheep 175 and 176 with but slight toxic results. The number of animals involved does not permit definite con- clusions, but the average results for the four animals show that the difference between a slightly toxic and a lethal dose was equal to 0.15 per cent of the body weight. In considering the results of the investigation as a whole it is probable that this figure is not far from correct. Feeding Green Leaves The results obtained by feeding the green leaves were not as conclusive as one would desire. For some reason there was a tendency to choke the animal while engaged in the force feeding, probably due to the resinous, sticky nature of the boli. The feeding was further handicapped by regurgi- tation during the course of the feeding; a chain of events which nearly always results in some injury to the pharynx. One per cent doses were fed to three animals, Goat 131 receiving one dose, Goat 129 two doses and Sheep 141 three doses on consecutive days. The two goats were off feed for about two days, probably due to pharyngitis, but the sheep de- veloped no indication of toxicity. As all three animals were later killed with ripe fruit it is evident that the failure to produce toxic effects was not due to resistance on the part ofthe animals. zI I! TOXICITY OF RIPE FRUIT OF BLACKBRUSH FOR SHEEP AND GOATS 13 SYMPTOMS Loss of appetite was considered as evidence of but slight toxicity, especially when this was the only symptom observed and existed for a period not to exceed 72 hours. In such cases the usual, lively attitude was presented with no evidence that they were actually sick. When the loss of appetite prevailed for more than three days there was a listless attitude, grinding of the teeth, the nostrils were clogged with mucus, the general attitude being that of_very sick animals. The respiration was normal with the exception of expiration which was accompanied by a sort of grunt. Although evidence of very sick animals prevailed for five or six days evidence of improvement appeared within the course of a few hours and complete recovery within a few days thereafter. In the acute, fatal cases the first symptom noted was salivation, followed within two to four hours by slight muscular twitching, groaning and grinding of the teeth. There was a slight arch to the back and a tucked-up appearance of the abdomen, movement was avoided if possible and the animals re- mained on their feet until a short time before death. Little or no struggle accompanied the final stages. The symptoms thus noted are in accord with those observed under range conditions. PATHOLOGY Death within the first 48 hours after feeding on the toxic fruit was as- sociated with a marked inflammation of the abomasum and the first foot or two of the duodenum. It is rare to find such an extreme congestion as that observed in the mucosa of these organs; hemorrhage had un- doubtedly occurred but could not be detected with the unaided eye. There was marked congestion of the liver and kidneys with albuminous degen- eration in some cases. In the case of Sheep 141 there was a slight thicken- ing of the mucosa of the abomasum which presented a bluish-red appear- ance. It was easy to visualize necrosis of the mucosa had death been de- layed another 48 hours in this animal. No additional lesions were observed in the acute fatal cases. Sheep 163 and Goat 120 had been quite sick for five days but began to eat on the sixth day. They were killed for post mortem examination on the seventh day since it was evident from past experience that such cases were on the way to complete recovery. Upon autopsy, extensive ulceration of the abomasum was found in both animals but all inflammatory reaction of the fourth stomach and duodenum had subsided. There was ample evi- dence that the ulcers were undergoing healing which probably would have been complete within the next two weeks. No other lesions were observed in these cases. Microscopic examination revealed marked congestion and hemorrhage in the mucosa of the abomasum and duodenum. In Sheep 141 an occasional shallow area of necrosis was found which involved the epithelium and sup- porting connective tissue but did not extend into the gastric pits. Marked 14 BULLETIN NO. 664, TEXAS AGRICULTURAL EXPERIMENT STATION congestions of the liver and kidneys and variable but constant albuminous degeneration were observed in all acute cases. Fatty changes were found in the livers of two animals. Active regeneration of the epithelium around the ulcerated areas of the abomasum in the two animals which were killed for autopsy indicated that recovery was in progress and would have been complete in a short time. There was no additional pathology in these two cases. ' DISCUSSION From the first investigation it was obvious that the fruit of this plan‘. is toxic and under certain conditions may cause serious losses in both sheep and goats. During the course of the experimental work many more animals were employed than are generally used to demonstrate the tox-. icity of a given plant. By the experimental feeding of the ripe fruit we produced an acute, fatal condition with death within 18 to 72 hours; also a marked illness for several days followed by recovery, which, in two animals, was found to be associated with ulceration of the abomasum similar to that observed in some cases under range conditions. However, we failed to produce extensive necrosis of the abomasum or a perforated ulcer of the duodenum. It was the failure t0 reproduce these two condi- tions that prompted the continued investigation and the employment of so many experimental animals. The failure to reproduce the complete clinical picture is probably due to one of two factors; first, administration of the exact dose required, and second, inability to reproduce exact field conditions. In connection with the exact dosage it is evident that this would require very careful regulation in view of the narrow margin be- tween slightly toxic and lethal doses. Such an undertaking would require, the expenditure of a large number of animals. In an attempt to reproduce range conditions24 to 48’ hour fasting periods were employed but had no influence on the results. On the ranges the individual seed clusters are grazed one at a time, thus consumption is slower than it is in experimental feeding and probably continuous for a period of 8 to 18 hours, a factor which would be diificult to reproduce by experimental methods. The sur- prising feature in field cases was the length of time an animal could livc with such extensive pathology in the abomasum and duodenum. A common feature in the four outbreaks which have come to our at» tention is extensive grazing of the ripe fruit by hungry animals which gained access to the plant during the months of January and February. On the ranch near Allamore part of the same thicket in which the loss oc- curred extended into another pasture. In this pasture 200 ewes were maintained during the winter without loss, but they were subjected to no handling during the winter. The ewes were observed in the occasional plucking of a head of seed but there was no evidence of extensive grazing as was observed on the other side of the fence where the loss in lambs had occurred. This observation is in keeping with observations on many ranches where blackbrush is a common plant and where no loss has been experienced. ' TOXICITY OF RIPE FRUIT OF BLACKBRUSH FOR SHEEP AND GOATS 15 The results of the experimental work do not definitely determine the ' status of the green leaves, but they are in accord with range observations , which have disclosed no reason for suspecting this part of the plant. There are many ranches in the Southwest where this is a common plant and where poor range conditions are of periodic occurrence. Under poor range conditions the green leaves of this plant may constitute a large part of I the green forage, nevertheless ranchers are able to subject both sheep and g goats to considerable handling and return them to the pasture with no loss. Under such conditions the leaves are grazed but after watching them do so one finds it hard to believe that any animal will consume as much I as one per cent of its body weight over a 24-hour period. There is no evidence to cause blackbrush to be viewed with concern , in connection with cattle ranching as no losses have been encountered ~ which could be associated with the grazing of this plant. The different a grazing habits of cattle, sheep and goats is probably an important factor “in this connection "as the small clusters of seed sticking out from the stem is an ideal presentation of the material for sheep and goats, whereas, in the case of cattle, large quantities of the woody stems would-have to be consumed in order to obtain a great deal of the seed. This type of grazing has never been observed. ~ The toxic principle was not soluble in alcohol as alcoholic extracts did not produce toxic effects in _rats. The extracts contained large amounts of a heavy resinous material and some volatile substance, probably a volatile i oil, the latter material being very irritating to the nasal passages. Much dis- Icomfort is experienced in gathering the plant as a result of the volatile substance, which is evidently the causative agent in severe attacks of hay fever of some individuals, the mere driving by a thicket of the blackbrush I being sufiicient to bring on a severe attack of the disease. CONTROL Never turn hungry sheep or goats into a blackbrush thicket during the months of January, February and March. As the ripening stage of the fruit is hastened by low temperature, December may be included in this 1 period as a result of an early hard freeze. Wind thrashes out the seed by the middle or latter part of March, thus removing the hazard. The green ~ fruit is not grazed. >v .._..,--__