; of which $6,000,000, to remain available until expended, shall be for the National Veterinary Stockpile; of which up to $1,500,000, to remain available until expended, shall be for the scrapie program for indemnities; of which $2,500,000, to remain available until expended, shall be for the wildlife damage management program for aviation safety: Provided, That of amounts available under this heading for wildlife services methods development, $1,000,000 shall remain available until expended: Provided further, That of amounts available under this heading for the screwworm program, $4,990,000 shall remain available until expended