Possible Clues:

• What cows and icebergs do
• Give birth, as a cow
• Ignore a ''Simpsons'' suggestion
• How cows give birth
• Break off, as a glacier chunk
• Deliver new stock of local vegetables
• Produce new animal and slice it up, say
• Shed an iceberg
• Of ice, to become a berg
• Drop a little lower, keeping length in mind