A suckler cow has one sole unit of output and that is her calf. In dairying, milk is the primary output and the calf is secondary. If the calf dies, the dairy cow is still generating a daily income through milk sales. Profitable suckler cows need to produce a calf every 365 days, or as close to this as possible. This is not easily achieved, but there are a number of suckler producers who do hit this target every year. Having a cow that calves every 12 months is different to a cow that calves every year.