A shortage of bovine somatotropin (BST) will force many producers to make management changes.

Dairy managers will need to consider their options, but no "right answer" will fit all farms, says Mike Hutjens, extension dairy specialist at the University of Illinois.

Earlier this year, producers learned that Monsanto, the company that supplies BST, would be cutting back. Starting March 1, current customers will only be able to buy 50 percent of what they bought between December 2002 and November 2003.

Hutjens recommends that producers and managers measure their response against the following criteria:

  • Economics determines the best strategy.
  • Late-lactation cows may drop 15 to 30 pounds of milk per day when BST injections are stopped. Be ready to dry these cows off.
  • If cows in mid-lactation are removed, causing them to drop in milk production – but remaining in the herd, nevertheless – these cows could become overweight, leading to metabolic disorders and health risks in the next lactation.
  • Early-lactation cows may respond to continued BST administration with milk increases of 8 pounds to 12 pounds per day. According to label recommendations, cows should begin receiving BST injections at 57 to 70 days in milk.
  • First-calf heifers may be a group not to inject with BST during the allocation period. In a growing, first-lactation animal, nutrients are partitioned to both growth and milk production. Consequently, heifers may respond less than mature cows.
  • Look for potentially less-responsive animals – especially, cows with health problems – as ones not to inject.
  • Do not extend the interval between injections – from 14 days to 18 days, for example. Cows ramp-up with successive treatments, and pounds of milk can decline between extended injections and not recover to prior levels.