South Texas ranchers are scrambling to relocate cattle from massive flooding spawned by Tropical Storm Harvey, with many hauling livestock up to the north of the state while others rush to move the animals to higher ground nearby.
About 1.2 million cattle are located in a 54-county disaster area drenched by Harvey, which made landfall as a hurricane last weekend.
With more torrential rain in the forecast, ranchers are expressing worry that some animals could perish despite efforts to save them.
Texas leads US states in cattle and cotton production.
An estimated $US150 million ($A189 million) worth of cotton has been lost as the storms ripped the bolls off plants and left white fibre strewn across fields.
Texas Gulf Coast export terminals that handle about a quarter of US wheat exports also remained shuttered.
Of immediate concern to ranchers were cattle stranded by high water infested with venomous snakes, fire ants and alligators, said Hollis "Peanut" Gilfillian, a cattle rancher in Winnie, Texas, about 100km east of hard-hit Houston.
"We're in gator country," said Gilfillian, adding that nearly every pond on the ranches in his area contain alligators.
"It's not unusual to see an alligator in my backyard or road ditch," he said, but added: "There's plenty other animals that they (alligators) would much rather eat, such as fish, as opposed to trying to go after cattle."
Ranchers had tried to prepare for the storm last week by moving cattle to the nearest hills or trucking them to safety in the north of the state, cattle industry groups said.
Chuck Kiker, who raises cattle on his farm near Beaumont, about 95km northeast of Houston, opted to leave his animals in place but was caught off guard by the storm's severity.
"You can't move animals at this point, so you're kind of stuck because of high water everywhere. There's really no place to move them," he said.
Texas Governor Greg Abbott has declared 54 counties a disaster area.
About 27 per cent of the state's 4.46 million-head beef cow herd is in those 54 counties.
Longer-term concerns for the cattle include foot rot from standing in water or muddy fields for long periods and the risk of disease from mosquitoes.
Heavy rains and flooding closed bulk grain terminals along the Texas Gulf Coast.
On cotton farms, more than 300,000 bales have likely been lost, between cotton yet to be harvested and bales sitting on fields awaiting ginning, according to John Robinson, an agricultural economist at Texas A&M University.
The loss, though a small part of the total US cotton crop of about 20 million bales a year, was devastating for individual farmers.
"The cotton that was where the hurricane hit was affected by the winds, it was blown right off the plant. Some of those fields are obliterated," Robinson said.
"Some of the cotton will still be on the plant but strung out like someone papered your field with toilet paper," he said.
