Weather update: Soybean water stress, poisonous trees

Hope­fully by the time you read this, we will have received some much needed rain­fall. The National Weather Ser­vice is say­ing that most places will get some rain within this next few weeks. They are say­ing that it will not end the drought at this time and the worst hit areas of north­west Ohio may get the least rain­fall where it is needed most.

Symp­toms of Water Stress on Soybeans

Because of the drought con­di­tions and high tem­per­a­tures, soy­beans are exhibit­ing symp­toms of water stress. Accord­ing to Laura Lind­sey, Ohio State Uni­ver­sity Extension’s soy­bean and small grains spe­cial­ist, the dry weather is caus­ing flipped leaves, which expose a silver-green under­side, reflect­ing light. In more severe cases, the outer leaves of the tri­fo­li­ate will close together to reduce the leaf area exposed to sun­light and reduce water loss. Water-stressed soy­beans will grow slower and have smaller leaves com­pared to soy­beans grow­ing with ade­quate soil moisture.

Lind­sey said that soy­bean yield poten­tial is influ­enced by total num­ber of pods per plant, num­ber of beans per pod and seed size. Stress con­di­tions dur­ing soy­bean repro­duc­tion can reduce yield by affect­ing one or more of these yield com­po­nents. Veg­e­ta­tive growth, flow­er­ing, pod devel­op­ment and seed fill­ing stages over­lap allow­ing the plant to com­pen­sate for short peri­ods of stress. Many soy­beans are begin­ning to flower around the county. In a nor­mal year, 60 to 75 per­cent of soy­bean flow­ers will abort, but this num­ber can increase in a stress­ful year. Lind­sey also says that flow­er­ing can occur through the begin­ning of the R5 growth stage (begin­ning seed). If water stress is alle­vi­ated prior to the R5 growth stage, some flow­ers and pods can still be pro­duced com­pen­sat­ing for the flow­ers that were aborted ear­lier. If water stress per­sists, soy­bean yield will be reduced, espe­cially as plants enter the R4 growth stage (full pod). Yield reduc­tions at this time result mainly from reduc­tions in total pod num­ber per plant. “At the R6 growth stage, water stress will cause a reduc­tion in seed size,” Lind­sey said.

Poi­so­nous Trees and Livestock

With the recent storms down­ing a lot of trees, we now have two com­po­nents that cause the threat of live­stock poi­son­ing. Poi­son­ing is most com­mon when graz­ing is scarce, such as peri­ods of dry weather like we have seen this sum­mer. With the scarce pas­ture, veg­e­ta­tion ani­mals will graze plants that they don’t nor­mally eat or trees that may have come down in the pas­ture. Clif Lit­tle, OSU Exten­sion Edu­ca­tor in Guernsey and Noble coun­ties put together a good sum­mery of poten­tial prob­lems with poi­so­nous trees. Below are some symp­toms and trees that Lit­tle encour­ages you to watch for as you inspect your live­stock and pastures.

Among the most deadly this time of year is the wild black cherry. The leaves and twigs of fallen wild black cherry trees are read­ily eaten by live­stock and are poten­tially deadly. The seeds, twigs, bark and leaves of the wild black cherry con­tain a highly toxic com­pound, hydro­cyanic acid. Poi­son­ings most often occur when wilted leaves are eaten, but can also occur when leaves are con­sumed fresh or dry. Cyanide poi­son­ing causes a defi­ciency of oxy­gen reach­ing the body tis­sues. Symp­toms fol­low­ing con­sump­tion appear quickly. Ani­mals may exhibit excite­ment, inco­or­di­na­tion, con­vul­sions, rapid and labored breath­ing. Con­sult your vet­eri­nar­ian imme­di­ately if you sus­pect poi­son­ing. Wild black cherry trees should be among the first to be removed from live­stock graz­ing lands.

Red maple poi­son­ing can result from live­stock con­sum­ing wilted leaves of fallen trees. Dried leaves have been reported to remain toxic for up to 30 days. The cause of tox­i­c­ity is not clearly under­stood how­ever, the pri­mary effects are acute hemolytic ane­mia, methe­mo­glo­bine­mia and Heinz body for­ma­tion in the red blood cells. Symp­toms develop three to four days after inges­tion and may include rapid breath­ing and heart rate, weak­ness, depres­sion, cyanosis and brown­ish dis­col­oration of blood and urine.

The black locust tree con­tains sev­eral toxic com­pounds found in the sprouts, leaves, bark, flow­ers and seed pods includ­ing a gly­co­side (robitin) and phy­to­tox­ins (robin and phasin). Affected ani­mals may exhibit signs of depres­sion, diar­rhea, weak­ness, pos­te­rior paral­y­sis, pupil dila­tion, weak pulse and rapid, irreg­u­lar heartbeat.

Many oak species con­tain toxic tan­nins. Large quan­ti­ties of young leaves, sprouts and green acorns are toxic. Live­stock must con­sume large quan­ti­ties of these plant parts for a period of time before poi­son­ing will occur. These plant tan­nins or their metabo­lites may cause intesti­nal and renal dys­func­tion. Symp­toms appear sev­eral days after the period of con­sump­tion and include abdom­i­nal pain, depres­sion, diar­rhea and blood in urine.

Our state tree the buck­eye tree can and does make cat­tle sick each year. Cat­tle read­ily con­sume fallen buck­eyes. Tox­i­c­ity is attrib­uted to gly­co­sides and pos­si­bly alka­loids. Sprouts and leaves may also be poi­so­nous. Ani­mals exhibit depres­sion, inco­or­di­na­tion, twitch­ing, paral­y­sis and inflam­ma­tion of mucous mem­branes. If caught quickly, treated ani­mals usu­ally survive.

As we clean up from the storm, some peo­ple mis­tak­enly throw branches and clip­pings in to pas­tures. One of the most deadly shrubs to live­stock is the yew. Yews are flat-needled ever­green shrubs with a bright red fleshy cup-shaped berry. The leaves, bark and seeds con­tain alka­loids that affect the ner­vous sys­tem and are toxic green or dry. Poi­son­ings often occur when clip­pings are acces­si­ble to live­stock. Symp­toms include gaseous dis­tress, tremors, diar­rhea, con­vul­sions, dilated pupils, weak­ness and res­pi­ra­tory difficulty.

This com­bi­na­tion of sum­mer drought with high winds and bro­ken trees has cre­ated a per­fect storm for live­stock poi­son­ing. Clean pas­tures and hay fields of these poten­tially harm­ful trees. Lit­tle also sug­gests that you pro­vide addi­tional feed and/or hay when for­age graz­ing is lim­ited and as always, con­sult your vet­eri­nar­ian if you sus­pect poisoning.