On the potential of improving daily milk yield by extending productive lifespan

Summary

Productive lifespan (PL) is a key factor for the sustainability of dairy farming. A long productive lifespan amortizes the rearing costs over a longer period of time and dilutes resource consumption and emissions. In addition, beef and milk production can be combined to a greater extent, which is advantageous in terms of emissions compared to specialized (separate) production of meat and milk. Nevertheless, the productive lifespan of dairy cows has been decreasing across main milk producing countries for many years. We aimed at describing the development of production level, productive lifespan and culling reasons from 1999 to 2019 by analysing herdbook data of 2.60 Mio. cows of the breeds Braunvieh (BV, n= 1.011.192), Swiss Fleckvieh (SF, n= 652.299), Holstein from swissherdbook (HO_SHB, n= 497.467), Holstein from Holstein Switzerland (HO_HOS, n=262.359), Simmental (SI, n=128.920), and Original Braunvieh (OB, n=50.063). We compared the increase in daily lifetime milk yield achievable over an extended PL with the increase in daily lifetime milk yield achieved over time from 1999 to 2019. Average milk yield per day of life continuously increased in all studied breeds, ranging from 7.5±4.1 (SI) to 12.1±5.5 (HO_HOS) kg/d in 2019.
Average length of productive lifespan in 2019 ranged from 3.0±2.1 (HO_HOS) to 3.8±2.8 (SF) years. In contrast to international reports it increased (and stabilized) in all studied breeds, apart from OB where it decreased. Culling rates during first and second lactations were high, ranging from 40 (SF) to 51% (HO_SHB). Main culling reasons were fertility, udder health and leg/ claw problems in pronounced dairy breeds, while insufficient milk production was relevant in dual-purpose breeds. The comparison revealed that increase of daily lifetime milk yield during 20 years had the same size as could be achieved through extension of the PL by 1.3 years. Therefore, efforts to increase the number of completed lactations per cow may be expected to pay off with greater dynamics than the combined developments in selection for milk yield, improved feeding and housing over time.