During the normal production cycle a cow should be in her best body condition at the time of calving. After calving, the nutritional stress of lactation will cause most cows to lose weight and body condition up to the point of weaning.
Bottomline: it is easier to feed cows for optimum Body Condition Scores (BSC) when they are dry. The (BCS) system is intended to provide a consistent way to quantify relative fatness of cows to serve as a management tool for producers. If cows are to maintain a calving interval of one year, they must bred back within 80 – 85 days after calving.