Purebred sales typically have "terms and conditions" that are published in the catalog. Typically bred heifers have been confirmed bred by a vet. Then they are hauled after the sale (maybe hundreds of miles with other cattle) and can be stressed and challenged with exposure to sick cattle and all sorts of weather changes and things. Generally, the buyer is the new owner as soon as the bred heifer leaves the ring and is responsible for whatever happens. I have purchased bred heifers before and sometimes have one abort. Who should be responsible when the animal is confirmed bred prior to the sale and then aborts later at the new owner's place? I did mention that the heifer aborted and the seller indicated a willingness to make some adjustment, but seems to me that he sold a bred heifer, then I owned her. I did not see that he had any responsibility for my misfortune.
Typical terms for open heifers at purebred sales is that they are guaranteed breeders unless they are shown. Harder to get overfed show heifers to settle. Usually there is a time limit to notify the seller if you cannot get an open heifer bred. Then the heifer must be returned to the seller at the new owner's expense and the seller has a time period (maybe 6 months) to get her bred to a bull at his place. If he gets her bred, then you pick up your bred heifer. If he cannot get her bred, he refunds the purchase price or gives a credit for that amount for use in a future sale. He ships the heifer to slaughter and keeps that money. Again those are typical terms for a purebred sale. But, if there are no terms mentioned or announced at the sale, then it is assumed that there is no guarantee. Then you may be able to work some deal with the seller if the two parties can agree on a settlement. Some sellers will be quick to offer some assistance and some will be hard of hearing. Probably should expect less or no assistance on commercial cattle than purebred ones if there were no announced guarantees. Even if there were terms and conditions stated, some breeders are slow or resistant to comply.
Here are suggested terms and conditions from the simmental association. But only applies if published or announced that cattle sell under the suggested terms.