(09/09/20) SOUTHWEST LOUISIANA — Hordes of mosquitoes pushed out of the marsh by Hurricane Laura continue to menace livestock.
“The population just exploded in the southwest part of the state,” said Jeremy Hebert, LSU AgCenter agent in Acadia Parish.
Spraying programs in several parishes have made a big difference. “The spraying has dropped the populations tremendously. It’s made a night-and-day difference,” Hebert said.
Jimmy Meaux, AgCenter agent in Calcasieu and Jefferson Davis parishes, said mosquitoes remain a severe problem, but spraying programs have started to control the pest.
Hebert said he has talked to several cattle owners who have lost as many as eight head. He also heard of three mosquito-related deaths of horses.
AgCenter regional livestock specialist Vince Deshotel said cattle confined in small holding pastures were starting to show signs of stress made worse by the heat and increasing insect populations. Cattle deaths from mosquitoes are widespread.
“I lost a bull Friday night,” Deshotel said.
He said he met four other cattle producers during the weekend who were having to dispose of carcasses.
Several parishes are conducting mosquito spraying by airplane, and that is providing some relief.
Dr. Craig Fontenot, an Evangeline Parish-based veterinarian, said livestock mortality has been widespread. One cattle producer lost 20 head, Fontenot said, and a penned deer operation lost 13 of 100 deer.
Reports of bulls succumbing to mosquitoes have been reported, and it’s common to hear of herds losing four to five head of cattle. “There’s a lot on the verge of dying,” Fontenot said.
The swarms seemed to lessen in the past few days, but now some cows are having spontaneous abortions from the stress.
The swarms of the insects drain blood from livestock, and the animals keep moving to ward off mosquitoes and become exhausted. “They can’t get enough oxygen,” Fontenot said.
He said it seems mosquito numbers have decreased.
Cattle owners have been spraying their pastures to give their cattle a couple of days of relief.
AgCenter extension veterinarian Dr. Christine Navarre said products are available to control the pests on livestock.
“Basically, there are many products that can be applied to the animals, either in a spray, spot-on or with back rubs,” she said. “It will depend on what is available locally and what works for the situation.”
The products must be used exactly according to label, “and if it is used on a food-producing animal, it must be approved for that species,” she said.
Repeat applications may be needed, but only if the label says that is safe.
Using fans could benefit individual animals, and coverings could be useful, but those coverings could also cause heat stress, Navarre said.
Any nutritional supplements should be given under the direction of a veterinarian. “Good general nutrition and managing other stressors such as heat and transport are the best medicine,” she said.
Horses with coverings to protect them from mosquitoes graze in a pasture at Iowa, Louisiana. Photo by Bruce Schultz/LSU AgCenter
A load of dead cattle in Evangeline Parish. Livestock deaths from mosquitoes have been occurring throughout southwest Louisiana. Photo by Dr. Craig Fontenot
Mosquitoes feed on a cow. Photo by Dr. Craig Fontenot