Assertion failure when using UISearchDisplayController in UITableViewController

Try using self.tableView instead of tableView in dequeueReusableCellWithIdentifier:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"BreedCell"];

    //Create PetBreed Object and return corresponding breed from corresponding array
    PetBreed *petBreed = nil;

    if(tableView == self.searchDisplayController.searchResultsTableView)
        petBreed = [_filteredBreedsArray objectAtIndex:indexPath.row];
    else
        petBreed = [_breedsArray objectAtIndex:indexPath.row];

    cell.accessoryType  = UITableViewCellAccessoryDisclosureIndicator;
    cell.textLabel.text = petBreed.name;

    return cell;
}

This code works pretty well

Note

If you have custom height cells, do not use

[self.tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

Use this instead

[self.tableView dequeueReusableCellWithIdentifier:CellIdentifier];