Complex sentence: Downer cows are encouraged to get to their feet and have a much greater chance of recovery if they do, though if they cannot, some have survived as long as 14 days and were ultimately able to get back on their feet.
Split into simpler sentences: Downer cows are encouraged to get to their feet and have a much greater chance of recovery if they do. If unable to rise, some have survived as long as 14 days and were ultimately able to get back on their feet.