Perspectives on pasture versus indoor feeding of dairy cows.

The dairy industry in many regions of the world has moved towards a high-input/high-output system maximising annual milk production per cow, primarily through increasing concentrate-based total mixed rations fed indoors year round, as opposed to allowing cows to feed on pasture. Pasture-based dairy systems in regions like New Zealand and Ireland are oriented towards maximum milk yield per unit of pasture, which has led to Holstein strains that are 50 to 100 kg lighter, exhibit a higher body condition score, and produce roughly half the annual amount of milk as compared to their Holstein counterparts kept in confinement in North America and Europe. Freedom from hunger might not be guaranteed when high-yielding dairy cows are kept on pasture without any supplemental feed, but at the same time no access to pasture can be considered an animal welfare concern, because pasturing is generally beneficial to the animals' health. On pasture, lighter-weight dairy cows with a medium milk production potential have proven to be superior with regard to feed efficiency and fertility. The year-round indoor feeding of high-yielding dairy cows with total mixed rations containing substantial amounts of human-edible crops from arable land puts global food security at risk and fails to utilise the evolutionary advantages of ruminants.