SAO PAULO, Aug 15 (Reuters) - Brazilian meatpacker JBS SA said a fall in grain prices will benefit its pork and poultry businesses globally as it discussed quarterly results with analysts on a conference call on Tuesday.

CFO Guilherme Cavalcanti said JBS estimates gains of $450 million related to lower grain prices until the end of this year, especially corn. That represents a revision from the $340 million guidance the company gave at the end of the first quarter, he said.

JBS reported a second-quarter loss on Monday, citing the negative effects of an over-supplied global chicken market and tighter margins for its beef business in the U.S. related to a cattle supply shortage on its main market.

In relation to beef, management told analysts the outlook is not going to improve soon, which is likely to leave beef processors with capacity they are unlikely to utilize in the U.S.

"There is no doubt in 2024 cattle supplies will remain tight," Global President of Operations Wesley Mendonca Batista Filho said. "There is no doubt companies will operate using less capacity." (Reporting by Ana Mano; Editing by Kirsten Donovan and Jan Harvey)