"Producing the peak yield of 35 litres of milk per day has been compared to a person jogging for six hours, seven days a week." .
As with the farming of several other species, dairy farming in particular has intensified over time. Improved genetics and nutrition have resulted in a 2-3% annual increase in milk production per cow in Western countries . New Zealand dairy cows are typically hooked up to a milking machine twice (or, increasingly, once) a day, and produced, on average, over 4,200 litres of milk annually by 2014-2015. The pressure of full udders can cause substantial discomfort.
This was 18% more than a decade previously . Genetic selection for increased productivity has resulted in the diversion of a greater proportion of biological resources into milk and muscle production, in dairy and beef cattle respectively. This means that less are available for maintenance (which results in many dairy cows being chronically hungry), or for immune function, to support tissue repair, or to respond to stressful stimuli. Unsurprisingly, therefore, rates of some diseases appear to be increasing, including reproductive problems (such as failure to conceive), mastitis (udder inflammation), lameness and metritis (uterine inflammation).
- Velten H. (2007). Cow. London: Reaktion Books.
- Von Keyserlingk MA, Rushen J, de Passillé AM, et al. (2009). Invited review: The welfare of dairy cattle--key concepts and the role of science. J Dairy Sci 92(9), 4101-4111.
- Anon. (2015). New Zealand’s five million milking cows are doing a great job of efficiently producing milk, according to the latest 2014-15 dairy statistics released today. https://www.dairynz.co.nz/news/latest-news/how-now-new-zealand-cow/, accessed 30 Nov. 2017.