Curly Calf Syndrome — or Arthro-gryposis Multiplex — is a lethal genetic disorder that results in stillborn calves with bent and twisted spines. So far, all evidence points to it being inherited as a simple recessive trait. In other words, the disorder's phenotypic expression is only expressed if calves inherit the recessive trait from both parents — homozygous for the trait. Since it's a lethal disorder, there should never be a live animal that is homozygous for the trait.

Using what's known as the Punnett Square (Figures 1-2), you can easily calculate the probability of the recessive gene being transmitted if two carrier animals are mated or if a carrier animal is mated to a noncarrier.