The current drought in Texas and Oklahoma is having a damaging impact on crop and livestock producers. Drought can have a negative impact on the health of cattle, especially if they are not in great condition to begin with.
Floron Faries, Jr., DVM, MS, Texas AgriLife Extension Service, Texas A&M System, says drought can create numerous health situations in cattle. An obvious impact is that cattle can’t get enough to eat, and cattle get thin malnutrition/starvation, range ketosis (hypoglycemia in thin/nursing cows under stress), grain aflatoxin poisoning from stressed corn and sorghum, and lumpy jaw/woody tongue from irritated mouths and tongues due to eating sharp or dry forages.
Cattle of course get dehydrated during droughts because of high salinity in tanks. Faries says >10,000 PPM will reduce water intake and high salt intakes can cause neurological signs.
Drought-stressed cattle suffering from heat, malnutrition and dehydration can exhibit low fertility, low milk production, abortion, dystocia, retained afterbirth, uterine prolapses and immunosuppression.
Cattle that are already sick and facing drought conditions can be highly stressed and experience immunosuppression, germ recrudescence, germ shedding, low immunity, low response to vaccines and contact exposure of pathogens.
Drought can cause downers and dead cattle from malnutrition, laminitis and polioencephalomalacia from low protein/low roughage/high sulfate diets, grain diets without roughage, downer cows attempting to stand and cattle with ankles that remain flexed or knuckled over.
Cattle can die from grain aflatoxin poisoning of stressed corn and sorghum with >600 PPB of aflatoxins. Plant nitrate poisoning can occur during drought in stressed corn, sorghum and Johnson grass containing >1% nitrates. Plant cyanide poisoning can also occur in stressed sorghum and Johnson grass. And in times of reduced forages, animals can resort to eating poisonous plants. Soil-borne issues such as clostridial pathogens and anthrax can also occur during periods of drought and can be fatal to cattle.
There are post-drought issues as well in terms of cattle health. Faries notes that after rains move in post-drought, plant cyanide poisoning can still be a problem. Fog Fever (pulmonary emphysema and edema) can cause toxic reactions in the lungs after the consumption of lush, green grass in the spring or fall. Rains can also stir up clostridial pathogens and anthrax from dry soil.
If producers have lost or liquidated cattle due to drought and are restocking, they need to keep animal health in mind with purchased cows and bulls which can carry easily-spread diseases such as Johne’s disease, neosporosis, vibriosis and trichomoniasis.