The Life of a Modern Dairy Cow
The modern dairy cow’s life bears little resemblance to that of her wild relatives. Every aspect of her life is manipulated to maximise milk yield, inevitably at the expense of her health and welfare.
“The dairy cow is exposed to more abnormal physiological demands than any other class of farm animal”, making her “a supreme example of an overworked mother”.
John Webster, Emeritus Professor of Animal Husbandry at Bristol University’s Clinical Veterinary Science Department (7,8)
Milk Production: Due to Pregnancy
Cows are mammals who, like us, produce milk in their mammary glands to feed their young. They therefore must give birth to a calf in order to produce milk and must be re-impregnated every year to keep that milk supply going (7, 8). Most dairy heifers are impregnated for the first time when they are between 14 and 28 months old, giving birth to their first calf nine months later (31). Farmers aim to get cows impregnated as early as possible to reduce the time and cost of keeping a cow that can’t be milked (31).
Most dairy herds in the UK are now artificially inseminated (AI) as this is much cheaper than keeping a bull and allows farmers to select the sire from a variety of breeds. AI is, in fact, a very lucrative business, with the dairy farming sector split between farms which produce milk and farms which produce semen (32). The use of more invasive practices such as multiple ovulation therapy and embryo transfer is increasing steadily in the UK and the rest of Europe (33).
Fate of the Calves
Although a cow would naturally suckle her calf for nine months to a year, calves born on dairy farms are taken away from their mothers within a few days of birth (8, 29) – so that we can drink the milk that was meant to nourish the calf. A strong mother/infant bond is formed between cow and calf within the first few hours of birth, making their separation extremely traumatic (34). Both the cow and calf bellow and show obvious signs of distress when they are separated, often continuing for several days, leaving those within earshot in no doubt that it is a harrowing experience for both (8, 30, 34). The cow will be re-impregnated two to three months after the calf is removed and forced to endure this emotional suffering again and again, every year until she is worn out (31, 35). Professor John Webster describes the removal of the calf as the “most potentially distressing incident in the life of the dairy cow” (35). The fate of dairy calves is discussed in the chapter “Calves – Unwanted By-Products”.
Simultaneous Lactation and Pregnancy: A Huge Physical Burden
Because she is re-impregnated while still lactating from the previous pregnancy, a dairy cow spends seven months of every year simultaneously pregnant and producing large quantities of milk. This enormous physical demand requires her to eat over four times more food per day than a beef cow at pasture (8). Her average milk yield will be around 25 litres a day (1, 36) but for some cows it can be up to 50 litres a day – this means seven to 14 times more than a calf would drink, so her whole body and udder in particular is forced to work unnaturally hard (37). In addition, a calf would normally feed five to six times a day so that the maximum amount of milk in her udder at any one time would be around two litres (37). But on most dairy farms a cow is milked only twice a day, allowing milk to accumulate in the udder and can force her to carry around 20 litres of milk or more (7). This greatly enlarges the udder and leads to lameness in her hind legs and predisposes her to mastitis (a painful infection of the udder) (8).
Her only rest from this demanding workload is during the last month or two of her pregnancy when she is ‘dried off’ in preparation for calving – then the whole cycle starts again (38). This ‘dry period’ lasts between two months and three weeks before birth and its main aim is to give the cow’s udder a little bit of time to heal and regenerate before she starts to be milked again (38). Predictably, this gruelling cycle takes its toll on her body:
“…a depressing number are culled after only two to three lactations because they are worn out, either through complete loss of body tissue (emaciation), or breakdown of the udder tissues, or chronic lameness.”
Professor Webster (37)
The problems of malnutrition, lameness and mastitis are discussed further in ‘Suffering in Silence’, page 22. Because of the huge pressure this puts on the cow’s body, the average dairy cow in the UK completes less than four lactations (31) – that means that around the age of six, she is slaughtered because she stops being profitable (either because of low milk yield, infertility or diseases that would require costly treatment) (5, 31).
The dairy cow’s physical problems are compounded by being kept indoors for six months of the year. The majority of dairy herds in the UK currently graze from April to October and spend the rest of the year housed indoors in cubicle units (3, 39). However, there’s an increasing number of dairy farms in Britain that have adopted a zero-grazing system where cows spend their entire lives indoors (3, 8). This is discussed in the ‘Intensification and Zero-grazing’ chapter, page 29.
As a result of the switch from British Friesians, who average 550kg, to Holsteins, who average 700kg, as the dominant dairy breed, many cows now simply do not fit in the cubicles and their hind legs protrude into the slurry passage behind them, while some find the cubicles so uncomfortable that they choose to lie in the slurry covered aisles instead (5). The social hierarchy within the herd can also contribute to problems in indoor housing units as lower ranking cows often choose not to use cubicles next to dominant cows and instead lie in the aisles or slurry passage (5, 40).
Whilst indoors, cows are fed a diet of silage (wet, fermented grass) and high protein concentrate (a mixture of cereals, rape meal, sunflower meal, maize and soya) (8). Wet silage causes wet manure and the resulting poor hygiene conditions contribute to mastitis and lameness (8) – these conditions are described below.
High protein concentrates cause a build up of toxins in the cow’s system which often cause the severely painful condition laminitis (inflammation of the tissue which lies below the outer horny wall of the foot) (8, 41, 42). When there’s too much concentrate in the diet or too much of it is fed at once, it causes lactic acid accumulation which leads to a change in metabolism and a change in bacteria in one of the stomachs (rumen). This condition is called acidosis – which means there’s too much acid in the body, more than the body can cope with. When lactic acid is absorbed into the bloodstream it upsets the cow’s metabolism and affects blood circulation reducing blood supply to the feet (41). And because the increased acidity of the rumen also kills some of the bacteria that naturally live there, their decay produces toxins which are absorbed into the blood stream and can cause permanent damage to blood vessels (41).
For all of her hard work and suffering, the dairy cow is sent to the slaughterhouse as soon as her milk yield drops. Modern dairy farms are about maximising profit and minimising overheads. Worn out cows endure a gruelling journey to market where they are sold to fattening (finishing) farms, before being sent to the slaughterhouse – ending up in ‘low quality’ beef products such as pies, burgers, soups and baby food.
DairyCo even has a dairy herd culling calculator online enabling farmers to count their herd’s cull rates (43). It states these reasons as the main and most common reasons for culling dairy cows: infertility, mastitis, lameness and poor milk production. The same website also contains a ‘finishing calculator’ (44) that allows farmers to calculate the price estimate of a cow’s carcass when they’re planning to slaughter her.
For details on cattle slaughter methods in the UK, please see Viva!’s Sentenced to Death report.