Sex and the Single Cow
Reproduction is at the heart of the dairy industry as cows must give birth to calves in order to produce milk. This aspect of the cow’s life is extensively manipulated.
Very few dairy cows in the UK mate naturally. The majority are impregnated by artificial insemination (AI), which involves restraining the cow so she can’t move and passing a catheter through the cervix of the cow and depositing the semen in her uterus (45).This is an uncomfortable, stressful experience for the cow which can result in injury if carried out by an untrained or inexperienced person (40). According to The Veterinary Surgery (Artificial Insemination) Order 2010, artificial insemination is one of the procedures non veterinarians are permitted to carry out (46). The criteria for being legally allowed to do this are: aged 16 years or over, have never been convicted of an offence relating to the welfare of animals, carrying out artificial insemination as part of an approved course or has successfully completed an approved course. AI training courses take place on working farms, using live animals for practice.
Artificial insemination is so widespread because it is cheaper to purchase frozen sperm than to feed and look after a bull. It also allows the farmer to choose from a variety of breeds to sire the calves. It is common practice for farmers to use semen from dairy breeds such as Holstein/Friesian for 50 per cent of their inseminations and semen from beef breeds such as Charolais or Hereford for the other half (32, 47). This ensures a regular replacement of ‘good milkers’ for the herd as well as a number of dual purpose calves who can be sold for beef production (32). However, male calves who have been sired by a dairy breed are of little use on a dairy farm as they do not produce milk. They are also of little use to a beef farmer as they do not put on muscle in the same way that beef breeds do. Male dairy calves are simply unwanted by-products of dairy production and of around 500,000 born every year, about 100,000 are killed on farms shortly after birth (48, 49). In 2011, over 11,000 male dairy calves were exported live mostly to European countries for veal production and 360,355 remained in the UK to be killed within a few months (49). The fate of dairy calves is discussed further in ‘Calves – Unwanted Byproducts’ page 16.
In 1999, the largest British AI company Cogent (50) began selling Holstein semen which was sorted to pre-determine the sex of the calf. It was the first breeding company in the world to offer sexed semen commercially. The sexed semen, they claim, gives an average result of 90 per cent female sperm and 10 per cent male sperm, allowing farmers much greater control over the cow’s reproduction (50). However, sexed semen is more expensive and not used by many farmers due to its high cost (51, 52).
Invasive embryo technologies have been used in Europe for years. To ensure that ‘high quality’ cows produce more offspring than is naturally possible, embryos are removed from their wombs and transferred into ‘lower quality’ cows who serve as surrogate mothers (40). Embryos can either be collected directly from the ‘donor’ cow or can be produced in vitro (in a test tube) with ‘donor’ cow eggs retrieved through ovum pick-up (33). Embryo collection: ‘high quality’ cows are given a treatment to increase ovulation and then artificially inseminated in the usual manner (45). The resulting embryos (usually between seven and 12) are flushed from her uterus using a catheter type instrument (45). As this procedure takes place a week after oestrus (ovulation), the uterus is more difficult to penetrate than during artificial insemination and can result in bleeding and sometimes even uterine rupture (45). The procedure is so painful that UK law requires the use of an epidural (53).
Ovum pick-up: unfertilised eggs are collected from ‘donor’ cows by a needle inserted through the wall of the vagina and into the ovary (53). According to Defra:
‘Repeated epidural injections are necessary for this procedure and they can cause welfare problems for the animals, such as severe pain in the tailhead and lower back’. (53)
Surrogate cows receiving the embryos, whether direct from the ‘donor’ cow or from in vitro fertilization, are artificially brought into heat (45). A ‘gun’ is then used to insert the embryo high into the uterus, a procedure requiring great skill which can only be acquired with practice (45). The use of an epidural is compulsory (53).
Over the past decade the use of rectal ultrasound to detect pregnancy has become common on British dairy farms (40). This involves inserting a long probe (about the thickness of a finger) into the cow’s rectum until it lies over her uterus (40). Careless insertion or removal of the probe can damage the rectal tissue and internal organs, causing great pain (40). Both the Royal College of Veterinary Surgeons (RCVS) and the Government’s Farm Animal Welfare Council (FAWC) have expressed concerns over nonveterinarians performing the procedure (5). Despite these concerns Defra still permit non-veterinarians to carry out per rectum ultrasound (54).
Concerns have been raised by the FAWC and the Food Ethics Council (FEC) over the use of embryos or semen from large cattle breeds in smaller recipient cows who will have difficulty giving birth to them (40, 45). This mismatch can result in severe injuries to the cow during calving, including internal haemorrhage, nerve paralysis and pelvic fracture (45, 55). According to the National Animal Disease Information Service (NADIS) calving difficulties are the cause of 46 per cent of ‘downer cow’ cases – when a cow is unable to stand up – on British dairy farms (55).
‘Downed’ cows require immediate attention to prevent injuries, which may only be temporary, from causing permanent damage (40). A cow may ‘go down’ because of temporary nerve paralysis caused by calving difficulties or simply fatigue from her gruelling workload, but if left recumbent for several hours permanent damage can be caused to her legs, specifically nerves and muscles (due to her 700kg body cutting off the blood supply) (51, 56). Several different types of lifting gear are used to get ‘downed’ cows on their feet again. These include (56):
- Tail lift
- Hoists clamped to the cow’s hip bones
- Inflatable bags
- Flotation tanks
However, if used incorrectly all the above can do more harm than good to the cow (56).
Hobbles and shackles are also commonly attached to the hind legs of cows who have suffered muscle or nerve damage during calving and would not be able to stand unaided. If the farmer were to cull a cow who was injured during calving he would lose the large quantity of milk which she was about to produce. Injured cows are therefore often forced to carry on, even when in pain, for seven to eight months until their milk yield drops and they are killed.
Dairy cows impregnated with large continental beef breeds such as Belgian Blue, Charolais or Limousin are sometimes unable to give birth naturally and must undergo caesarean section (37, 40). In order to prevent the need for this major surgery, farmers using large continental breeds to sire calves may induce calving before the cow reaches full-term (40), which obviously causes enormous stress to the cow and calf.