If a cow isn't making a profit for you, cull her. That's why you should check performance of each cow in the herd in the fall. Cull cows not producing a calf. Each cow that fails to calve takes the profit from four or more other cows to pay for her annual costs.
Identify open cows in the fall before the start of winter feeding. Pregnancy checking may appear to be expensive, but it's cheap compared to keeping an open cow through the winter.
Physical defects Also check cows for any physical defects that would prevent them from weaning a healthy, heavy calf next year. Identify cull cows and pregnancy check the others before vaccinating, deworming and treating for grubs and lice.
You have to keep cows given these treatments until withdrawal times have passed.
Cull cows that produced a low-quality or lightweight calf. If the calf doesn't sell for enough money to pay for the cow's annual cost and still leave a profit, the cow isn't pulling her weight.
Don't be tempted to give the cow a second chance.