Lactation starts at the birth of the calf and continues until weaning in beef cattle, and usually about 60 days before the next calving in dairy cattle. These are the norms. Usually beef calves are weaned at or around 205 days. The goal is to achieve a 12 month calving interval. With soime high milking dairy cows they don't breed them to calve but every 18 months to two years.
> When does lactation start ? Is it
> after the birth of the calf? Is it
> for 305 days ?