Posilac changes the shape of the standard lactation curve, moving more of the production to later lactation. Persistency of production is improved so the decline in milk production becomes slower than lactations produced without Posilac. Cows can stay profitable for much longer periods of time than they could previously. If producers can have animals spend a larger portion of their lives between peak milk production and drying off and still remain profitable, the lifetime profitability can increase. Other benefits of extended lactations may also include fewer health problems since most health problems occur in the peripartum period.
Nutrition becomes easier, since the greatest nutritional challenge occurs in early lactation.
Delaying breeding should theoretically improve reproductive performance since cows can be in positive energy balance during the maturation of ova released at the time of breeding. Drying off cows that are milking large quantities of milk is more difficult and likely more stressful on the animals than drying off at lower production levels. Extending the lactation cycle in high producing cows can result in cows producing more reasonable levels at dry off time. The true cost of having a calf must include the loss in production caused by the pregnancy, the dry period, and the risk of health problems associated with the peripartum period. More of the lifetime of the cow would be under little or no change situations if the lactation periods were extened.