DEADWOOD, S.D. -

South Dakota Game, Fish and Parks officials say they're concerned about the deaths of five bighorn sheep in the past few weeks, diminishing the herd of 26 animals transplanted last year from Canada.

Regional Wildlife Manager Trenton Haffley says that the first bighorn died Oct. 13 when it fell off a cliff south of Deadwood.

State game officials are most worried about the loss of at least one to a form of pneumonia that can infiltrate a bighorn herd. Lab tests showed the sick ewe had suffered from mycoplasma ovi-pneumonia, a deadly bacterial disease that is often the primary cause of pneumonia in sheep.

The other three deaths occurred to due to a bacterial infection, a drowning and old age.