Longevity impact on sustainability and welfare

Abstract

Recently, there have been increased discussions about both sustainability and longevity in the dairy industry. Sustain­ability has a goal of minimal use of resources (land, air, water, etc.) per unit of milk (and meat) produced. Longevity is deter­mined solely by the replacement rate. Dry matter intake (DMI) is a proxy for resources used in dairy production. Because the dry matter intake for maintenance metabolism is relatively constant, more milk components per cow per day will dilute maintenance. If we assume older cows will produce more milk, then increasing the longevity of the herd is an important com­ponent of sustainability. However, the impact of age on milk yield can be overestimated. The objective here is to examine the relationship between milk production and successive lacta­tions in a convenience sample of herds, with some inference to sustainability.