- It is accepted that dairy cows can live up to 20 years in captivity.
- In reality, dairy cows generally live 5 years.
- Their short longevity seems to be due to a physiology transformed by human selection, and by the fact that they are very generally killed as soon as they can no longer produce milk in sufficient quantities.
- It is certain that the life of dairy cows is as it is currently because they are exploited for their milk.
Walker’s Mammals of the World – A reference book on the biology of mammals, which talks about the longevity of cows.
Dairy cows trapped between performance demands and adaptability – An article studying the increase in milk productivity of dairy cows over time, and that observes that this occurred at the expense of the longevity of cows that decreased over the same period of time.
Haute performance et longévité… une combinaison gagnante! – An article describing the relationship between the productivity and the longevity of dairy cows in Quebec, and which contains detailed statistics on the causes of their death.
La vie des vaches laitières est trop courte – An article about the longevity of dairy cows in the “organic” production sector in Switzerland.
Dairy cows, and their life cycle
Dairy cows are cows that are exploited to produce milk. Their milk can then be transformed into butter, cream, cheese, other so-called “dairy” products, or included in many industrial preparations in the form of milk powder. As with humans, cows do not constantly produce milk: they must first give birth to a calf before they start producing it.
Thus, the lifecycle of a dairy cow consists of a period of childhood when the cow is still too young to be fertilized or give birth; then, it alternates between insemination (artificial or by bulls), gestation, and lactation. This cycle usually ends when the cow is no longer fertile, or when it no longer produces enough milk; it is then often sent to the slaughterhouse, as are also the majority of the calves to which it will give birth [1,2].
Therefore, as the desired product in a dairy cow – cow’s milk – does not directly imply the death of the latter, it is sometimes difficult for those who do not know the life in the farm to understand if the consumption of cow’s milk is ethical or not. This article will deal with a part of this question.
The ethical question of the longevity of dairy cows
Today, the morality of the consumption of cow’s milk is strongly discussed in the media and in the public sphere . In addition to the fact that so-called vegetable milks are becoming more and more present in supermarkets, social networks allow the sharing of numerous videos questioning the way in which dairy cows are treated.
One of the questions associated with the ethics of cow’s milk consumption is based on the longevity of dairy cows. Because the production milk production does not directly imply the death of the cow which produced it, it is then possible to imagine that dairy cows can enjoy a long life on the farm, in comparison with their sisters that are sent more quickly to the slaughterhouse to be transformed into meat (less than 36 months; see ).
But do dairy cows really enjoy a long life? And how old could they be if they were not exploited for their milk? These two questions go to the very heart of the ethical problems that can arise from the consumption of cow’s milk, at a time when it is no longer necessary for human survival; but these questions makes us delve into a sometimes sparse literature in order to find reliable information on the subject of the longevity of dairy cows. This article will limit itself to this question, while another will explore the living conditions that dairy cows experience during their short life .
The life time of a dairy cow, according to science and according to farmers
To our knowledge, no experiment or observation has been carried out to date in the scientific literature regarding the longevity of dairy cows, if they were not sent to the slaughterhouse. The figure which generally comes up in the discourse of farmers and biologists is 20 years. Lindsay Ferlito, a “regional specialist in dairy products” in the United States of America, says that dairy cows can have a life expectancy of up to 15 to 20 years . An article by Albert de Vries, professor at the Department of Animal Sciences at the University of Florida, states that “the natural longevity of cows has been reported to be 20 years, where they die of old age” . Another article by A. Sawa et al. dating from 2013 indicates that the “natural” longevity of cows is 18 to 20 years . In addition, a thesis in veterinary medicine carried out at the University of Montreal, in Quebec, indicates that “a cow could live 20 years before dying of old age” . Finally, in a reference work on the mammals of the world (Walker’s Mammals of the World), it is possible to read that cows have a lifespan which can exceed 20 years “in captivity” . The oldest cow ever observed in the world, named “Big Bertha”, lived until the age of 49 .
Despite the variations in these figures, and even though they are not associated with a protocol or with a particular scientific source, it seems justified to us to accept the age of 20 years as the “natural” longevity of dairy cows when they are not slaughtered. It is important, however, to cast doubt on the meaning of the word “natural” in this sentence: it is indeed impossible to know whether a cow would routinely survive for 20 years if it was in “the wild”, namely in a natural environment where she is not in captivity. It thus seems that the figure of 20 years of longevity corresponds to an age when dairy cows usually die of old age if other causes (predation, disease, famine) have not led to their death before, which would be more easy in captivity. This point is important to address, in order to compare this “natural” longevity with the average lifespan of cows exploited for their milk from a moral angle.
Regarding the average lifespan of exploited dairy cows, it seems to be much shorter than the 20 years of their “natural” life expectancy. Numerous documents from the scientific literature, government reports, company reports or even farmers attest to this. These documents can relate to different races, and different places in the world.
Lindsay Ferlito indicates in the article cited above that dairy cows live “4 to 6 years” . In an article published in 2009 in the journal “Science of food and agriculture”, W. Knaus writes that cows generally remain below the 4 lactations threshold (4 cycles of impregnation, gestation and lactation) before dying in the USA, in Germany, and Austria . A lactation cycle typically lasting 1 year , this amounts to around 5-6 years of life for dairy cows, by taking into account the infantile period when they are still infertile. Knaus also describes that Holstein cows in Austria live on average for less than 4 years . The official website of the dairy farmers of the province of Alberta in Canada indicates that a dairy cow lives on average 5 years, including 2 of preparation before it can start to produce its milk . In addition, Albert de Vries indicates in an article cited above that the longevity of dairy cows is 4.8 years in the USA .
Other sources seem to support an average of 5 to 6 years of life for dairy cows. Thus, A. Sawa et al. indicate in their 2013 article that cows are killed between 4.5 and 6.6 years of age in Poland, and that the situation is similar in Germany . In Quebec, a report by Valacta (a center of expertise on dairy products) shows that in the province, the average age of the last calving (last calf born before their death) was four years and one month in 2006; but that this average age decreases to 3 years and 11 months in high production herds . Denis Haine’s thesis in veterinary medicine indicates that “In Canadian dairy herds, 30 to 40% of cows are culled each year […], at an average age varying between 5 and 6 years” . With regard to the so-called “organic” agriculture, an article on the “bioactuality” site written by two professionals in the field describes that Swiss dairy cows reach on average 5 to 6 years “before leaving the production process”, which echoes the figure of Denis Haine .
Some sources, however, present slightly higher figures, depending on the country and the breed of dairy cow considered. Thus, a synthesis from FranceAgriMer, a French national institution for agriculture, states that “Except in special cases, a dairy cow is reformed general (killed) at the age of 8” . In addition, the website of the company “Prim’Holstein France” (dedicated to genetic expertise on cows of the so-called “holstein” breed) indicates that “Prim’Holstein” cows live on average 5 years and 52 days ; montbéliardes (another breed of French dairy cow), 5 years and 247 days; and the Norman race, 5 years and 89 days . It should be noted that the “Prim’Holstein” breed cow is very widespread in France.
A last point to remember is that all of these figures relate only to the average age at which cows exploited for milk are killed or die; but they do not concern the average age at which the calves that come with the impregnation of the cow are killed. The calves, mostly killed to produce meat when they are not used to replace dairy cows that die or that go to the slaughterhouse , can be slaughtered from the age of 2 days, up until 3 months .
Why is the life of dairy cows so short?
Two main factors seem to explain the reason why dairy cows have such a short life in the world of dairy production: their biology, associated with their role as a means of milk production.
In the article by W. Knaus, he describes a relationship between the productivity (in milk) of dairy cows and their longevity which seems to have been observed many times in the scientific literature . Thus, where the productivity of dairy cows in the USA only increased from 1950 to 2007, almost quadrupling, their longevity has only decreased over time. Knaus indicates that this is due to the fact that the increase in milk productivity of cows by human selection has taken place at the expense of other biological functions of theirs .
We can thus observe in an article taken from a symposium organized by dairy producers in Quebec that 31% of cows are “culled” (killed) due to reproductive problems; that 30% are killed due to illnesses; 9% due to milk production problems; and that only 9% of cows die by undetermined cause . These figures and causes are verified by other sources for other countries in the world [15,20]. It is therefore easy to understand from these statistics that dairy cows do not usually die on their own, but are killed for the simple reason that they can no longer produce enough milk (usually because their lower fertility poses a problem for farmers). As the increase in their milk productivity comes at the expense of their ability to avoid getting sick and to remain fertile, it becomes easy to explain why dairy cows do not live long. As a tool of production, it becomes pointless – and even expensive – for any dairy producer to keep the cow alive when it no longer fulfills “its role” on the farm. She is then killed.
This cynical equivalence between the “productive life” of a cow (the period when it produces enough milk) and its life in general is visible in all the sources linked to milk production, within the vocabulary used [1,7,17,19]. For example, in a document published by the Holstein Cow Association of Canada, it says “While some cows can live much longer, the normal productive life of a Holstein cow is six years” . The sentence therefore clearly associates productive life and lifespan.
Dairy cow: a life not so peaceful as it seems.
In an era where the consumption of cow’s milk is sometimes associated with acts of animal cruelty, the longevity of dairy cows seems to reinforce the idea that their lives are not easy. The selection of dairy cow breeds to increase their milk productivity seems to have left them with a fragile physiology that makes them susceptible to falling ill easily [11,20]. But on top of that, their status as a mean of production inevitably seems to link their destiny to their capacity to produce milk in sufficient quantity to be a competitive mean of production; which can be perceived as unethical.
Thus, even if dairy cows were not killed when their bodies were no longer able to produce enough milk, it is unclear whether their physiology would support their lives until the age of 20, as announced in many sources. But if this was the case, the exploitation of dairy cows generally implies maintaining their lives at a quarter of these 20 years, which seems far from the image of a long and peaceful life.
Of course, it is impossible to know whether the life of dairy cows would be long and peaceful if they were released “in the wild”, or in a natural environment after their period of exploitation. However, without exploitation, most of these cows simply would not exist, because the maintenance of their large number is only due to their economic importance. Thus, the territories dedicated to their food, the vast majority of which could be freed, would then be populated by wild animals with very different living conditions. However, it remains certain that the life of cows as a means of milk production is short; and that if theirs is not, there remains that of the calves that they must constantly give birth to in order to continue producing the cow’s milk that humans consume.
- D. Haine, Réforme des vaches laitières au Québec, Université de Montréal, 2016. https://papyrus.bib.umontreal.ca/xmlui/bitstream/handle/1866/18586/Haine_Denis_2016_these.pdf?sequence=4.
- See our article on the killing of veals for the production of cow milk (Soon to come !), (n.d.).
- C. Newkey-Burden, Dairy is scary. The public are waking up to the darkest part of farming Chas Newkey-Burden, The Guardian. (2017). https://www.theguardian.com/commentisfree/2017/mar/30/dairy-scary-public-farming-calves-pens-alternatives.
- J. Sheridan, P. Allen, J. Ziegler, M. Marinkov, M. Suvakov, G. Heinz, Guidelines for slaughtering, meat cutting and further processing, FAO, 1991.
- See our article on the life conditions of dairy cows (Soon to come !), (n.d.).
- Life cycle of cows can vary, NNY360. (2016). https://www.nny360.com/artsandlife/life-cycle-of-cows-can-vary/article_385c667b-d42c-5b67-becc-be170581829d.html.
- Cow longevity economics: The cost benefit of keeping the cow in the herd, Milkproduction.Com. (2013). http://www.milkproduction.com/Library/Scientific-articles/Management/Cow-longevity-economics-The-cost-benefit-of-keeping-the-cow-in-the-herd/.
- A. Sawa, M. Bogucki, S. Krężel-Czopek, W. Neja, Relationship between Conformation Traits and Lifetime Production Efficiency of Cows, ISRN Veterinary Science. 2013 (2013) 4. http://dx.doi.org/10.1155/2013/124690.
- R. Nowak, Walker’s Mammals of the World, 6th edn.’, Johns Hopkin s University Press, Baltimore, Maryland. (1999) 1550–1565.
- Oldest cow ever, Guinness World Records. (n.d.). https://www.guinnessworldrecords.com/world-records/70843-oldest-cow-ever/.
- W. Knaus, Dairy cows trapped between performance demands and adaptability, Journal of the Science of Food and Agriculture. 89 (2009) 1107–1114. https://doi.org/10.1002/jsfa.3575.
- H. Foundation, Milking and Lactation, (2017).
- How long does the average dairy cow live?, Alberta Milk. (n.d.). https://albertamilk.com/ask-dairy-farmer/how-long-does-the-average-dairy-cow-live/.
- C. Blais, R. Roy, S. Lafontaine, Améliorer la longévité des vaches, est-ce vraiment payant?, Le Producteur de Lait Québécois. (2007). https://www.agrireseau.net/bovinslaitiers/documents/valacta_lplq_2007-12_longevite.pdf.
- N. Schmid, T. Pliska, La vie des vaches laitières est trop courte, BioActualites.Ch. (2018). https://www.bioactualites.ch/actualites/nouvelle/la-vie-des-vaches-laitieres-est-trop-courte.html.
- FranceAgriMer, La dynamique des troupeaux laitiers français à l’approche de la fin des quotas, 2013. https://www.franceagrimer.fr/content/download/22294/183352/file/SYN-LAI-1-Sortie%20des%20quotas%20laitiers.pdf.
- Prim’Holstein France, Longévité comparée des races laitières, (2009). https://primholstein.com/2009/longevite-comparee-des-races-laitieres/.
- Meat processing – Labels and standards, Encyclopedia Britannica. (n.d.). https://www.britannica.com/technology/meat-processing.
- G. Lehoux, Haute performance et longévité… une combinaison gagnante!, in: 33e Symposium Sur Les Bovins Laitiers, Drummondville, 2009: p. 25.
- P.A. Oltenacu, D.M. Broom, The impact of genetic selection for increased milk yield on the welfare of dairy cows, Animal Welfare. 19 (2010) 39–49.
- La race Holstein, Holstein Canada. (n.d.). https://www.holstein.ca/Public/fr/%C3%80_propos/L%E2%80%99industrie_laiti%C3%A8re_canadienne/La_race_Holstein.