Till the Cows Come Home

by Philip Walling

  As with many innovations in animal and plant breeding, AI began with a Dutchman, Antony van Leeuwenhoek (1632–1723), a man of many parts, none of them scientifically trained. He was an amateur whose thirst for knowledge led him to discoveries that eluded the conventionally minded establishment. Fascinated by natural history, he trained himself to be an expert grinder of magnifying lenses, the better to observe minutely the things that interested him. Through his lenses he studied the bacteria in his mouth that caused tooth plaque, the minute organisms in water and the structure of blood cells. He described all these in a series of letters he wrote over many years to the Royal Society. Then in 1678 he gave an account of his observation of moving sperm, which he called ‘animalcules’, through a lens he had ground to 270x magnification.

  This knowledge was built on by Lazzaro Spallanzani (1729–99), an Italian priest from Pavia, who in 1784 artificially inseminated a bitch that gave birth to three pups. A hundred years later, Walter Heape (1855–1929), a biologist from Cambridge, reported that AI had been successfully used in occasional experiments to breed rabbits, dogs and horses.

  But serious progress was not made until the beginning of the twentieth century, when a Russian scientist, Ilia Ivanov, achieved international recognition for his work with AI, which he originally undertook to improve Russia’s imperial bloodstock. He harvested sperm from the best stallions, and by 1922 could boast that with AI one superior stallion could sire 500 foals in a year, compared with 20–30 by conventional service. He also experimented with hybridization of different species of domestic animal, creating a zeedonk by crossing a zebra with a donkey; a zubron from a European bison and a cow; and trying (without success) various combinations of rats, mice, guinea pigs and rabbits. However, when his suggestion that it might be possible to cross a human with an ape was met with widespread repugnance, he knew he had gone too far for conservative Orthodox Christian Russia.

  He had to wait for the Bolshevik revolution to give him his opportunity. After Lenin’s death in January 1924, he petitioned the new Soviet regime to allow him a trip to Africa to collect apes for insemination. They gave him exceptional permission to travel abroad and awarded him the huge sum of $200,000 to fund his research. This was at a time when the country was in turmoil, almost bankrupt, and millions of people were starving.

  On his first trip, via Paris, to Guinea, in 1926, he failed to obtain any apes and returned to Paris, where he spent some months with the celebrated Russian émigré surgeon Serge Voronov, originator of the modish monkey gland ‘rejuvenation therapy’, which he claimed could reinvigorate men and spectacularly prolong human life. Its main effect was to separate rich, credulous men from large amounts of their money. During the 1920s and 30s, Voronov made a fortune. He lived in Paris like a prince with his retinue, occupying the entire floor of a hotel, and was lionized for his remarkable but doubtfully effective solution to ‘ageing’ – a euphemism for impotence.

  When Ivanov finally returned to the Soviet Union, he advertised for women who would volunteer to bear a half-man, half-ape foetus. By the time he was ready to inseminate the first of five women who had volunteered, ‘in the interests of science and the motherland’, his only surviving ape, a 26-year-old orang-utan called Tarzan, had suffered a brain haemorrhage. Then, in 1930, Ivanov was arrested in one of Stalin’s periodic purges and exiled for five years to Kazakhstan. Released after a year, his health broken, he suffered a stroke and died soon afterwards.

  But that did not end the Bolshevik regime’s fascination with AI, which they believed could accelerate the spread of ‘desirable traits’ in the population, such as willingness to accept communal living and working, and eradicate the unfortunate human instinct to be competitive and to own property. Through AI, human nature could be changed in consonance with the Marxist plan. Crossing the Russian peasant with an ape might have been a surer way to create Homo sovieticus than waiting for him to accept the Bolshevik utopia.

  By the time I got into farming, AI of cattle had become available almost everywhere in Britain by phoning the nearest Milk Marketing Board AI centre the day before, or early in the morning of the day you needed the cow serving. That was all very well, but catching a cow that was out in the fields, at exactly the time of ovulation, was a different matter altogether. In the days before mobile phones, you didn’t know precisely when the AI man would turn up, so the cow had to be brought in early and tied up somewhere quiet to await his arrival. With skittish young heifers this could sometimes be a bit of a rodeo. Often you had to get the whole herd into the yard, separate the ovulating animal from the others and then take the rest back to the field, which could be some distance away. If you had 30 heifers to inseminate (preferably so that they would all calve within the same month, nine months later), it is not hard to see why AI might not have been the best method, and why I find myself in Chapter 10 on the road to Hereford to buy a bull.

  Even back then, when I was part of that world, I thought being an AI man was a pretty odd job, which attracted a strange type of person. Rushing round the countryside, from farm to farm, to catch a cow in season and squirt deep-frozen bull semen into her vagina would not be most people’s first choice of career. Although there were a few women doing it, most of the AI operators in those days were men; often mild-mannered, even shy, their ready embarrassment juxtaposed with the earthiness of their job afforded great scope for amusement.

  One summer I had a 15-year-old lad, Carl, helping during the school holidays. He was from the town and wasn’t too bright. He’d been advised by his careers master that farm work might suit him when he left school, the implication being that as farmers are a bit stupid, he would fit in perfectly. The AI man was coming that morning to inseminate a cow that I’d spotted in season – ‘bulling’ – but he still hadn’t arrived by the time I had to leave to go to the auction mart. I asked Carl to keep a lookout for him. Carl had no idea what AI was and I had to explain.

  ‘There are three black cows tied up in the byre,’ I added. ‘The one nearest the door is the one to be inseminated. There’s a big wooden peg in the post beside her so you will know which one she is.’

  I took him into the byre, showed him the cow and pointed out the peg.

  ‘What’s the peg for?’ he asked.

  ‘For the AI man to hang his trousers on.’

  He nodded sagely and I left.

  The next time the AI man came, he said, ‘That’s a strange lad you had working for you last time I was here. I’ve heard the old joke till I’m sick of it. But he wasn’t joking. He loitered around and twice showed me where to hang my trousers. When I’d done the job he looked really surprised and asked if that was all there was to it. God alone knows what he expected me to do.’

  When I told the story to a farmer friend who knew Carl’s family, he almost fell off his bar stool laughing. Apparently, after the war, Carl’s uncle had served a prison sentence for having carnal knowledge of a sheep.

  ‘It must be genetic,’ spluttered my drinking companion.

  In the 1930s, artificial cow vaginas were invented to collect semen from bulls called ‘mount animals’. And in 1936, over 1,000 cows were inseminated in Denmark, with nearly 60 per cent of them conceiving – almost as good as with natural service. The Danish professor who did much of this work, Eduard Sørensen, got the idea of using straws for the storage of semen and its deposition deep into a cow’s uterus when he saw his daughter’s friends at her birthday party sipping punch through oat straws.

  This stimulated an avalanche of research and development in other countries, particularly in the US during the 1940s. It was crucial to success that sperm could be kept alive longer than the few minutes it remained viable outside the bull’s body; and that some process could be devised to make each ejaculate go further.

  Researchers found that a mixture of egg yolk and sodium citrate would ‘buffer’ the semen, causing it to resist changes in pH and allowing it to survive for up to three days at 5°C. Sodium citrate is used to preven
t UHT milk from coagulating; when added to any cheese, it gives it the texture of processed cheese but supposedly allows it to keep the flavour of the original. This is popular in the US, where it is called constructed cheese and is based on a chemical process developed by James L. Kraft, who in 1916 created the first emulsified ‘melty’ cheese slice and a vast fortune for himself.

  With the discovery of penicillin and streptomycin, it became possible to control certain bovine venereal diseases that tended to be passed on with AI. It was then found that adding milk to the semen ‘extended’ it – that is, made it go further – so that it could be used at lower concentrations and more inseminations could be obtained from one ejaculate. It was also found that caproic acid (the fatty acid that gives goat’s cheese its distinctive smell) and catalase (the enzyme that protects living organisms against decomposition) added to 5 per cent egg yolk (a drug called Caprogen) would preserve semen at ambient temperatures. It also extended semen so that effective conception could be achieved with between 266 and 1066 sperm per insemination.

  Hardly surprisingly, researchers found that different bulls were excited by different sexual stimuli. So by catering to whatever turned him on, each bull could be manipulated into giving as many as six ejaculations a week, providing between 309 and 409 sperm per week per bull. This is about 200,000 doses of semen per bull per year. They also confirmed the long-held belief amongst cattle breeders that the bigger the testicles, the more semen is produced.

  But this was all of limited application because they could not keep semen alive in storage. In 1949, an English researcher into cryo-preservation, Christopher Polge, had preserved chicken sperm at low temperature by adding fructose and had produced chicks from eggs fertilized with it. But he could not get this to work with bull semen. After leaving it for six months, Polge decided to try his sugar method again. He added what he thought was the same fructose solution from the bottle he had used earlier, but this time, to his surprise, he achieved more success. When he analysed the solution he had used, he found it contained no sugar, but glycerol and protein in the same proportions as make up Mayer’s albumin, an adhesive (like egg white) used for affixing specimens to glass slides. Somebody had labelled the bottle wrongly. Thus is scientific progress made.

  What Polge had in fact stumbled upon was the original egg yolk/citrate ‘extender’ that had first been used in 1941. Later, egg yolk buffered with the enzyme inhibitor tris and mixed with glycerol was found to be most effective at protecting sperm from harm at very low temperatures. It was discovered that bull sperm could be stored viably for a long time in solid carbon dioxide at a temperature of minus 79°C, and stored in liquid nitrogen at minus 196°C, it would survive almost indefinitely. The problem of the glass ampoules containing the sperm tending to shatter during freezing and thawing was solved by using sealed plastic straws that could be fitted into a gun with a long barrel and plunger for insemination. And when it was found that a dose of semen could be reduced to 0.25 ml per straw, so that twice the number of doses could be stored in the same space, modern AI was on the way to revolutionizing animal breeding. The final hurdle to widespread, affordable AI was surmounted when the American Cyanamid Company began to make insulated portable canisters for the long-term storage of liquid nitrogen.

  These developments that made possible the cryo-preservation of sperm underpin the modern human fertility programme. Without them, none of the in vitro fertilization, artificial conception, cloning or other techniques in human and animal fertility across the world would have been possible.

  Ordinary cattle breeders can buy semen from the best bulls, which would previously only have been available to the richest pedigree breeders. They can select a different bull for each cow in their herd. Such a thing could never have been possible with conventional breeding, and it has resulted in a huge improvement in quality and productivity, particularly of dairy cattle, in all the pastoral countries of the world. In a few decades, the average yield of all dairy cattle has increased beyond anything our ancestors could have imagined. And now, with sex-selected semen, it is possible to breed almost exclusively heifer calves, which suits the dairy farmer and obviates the wasteful killing of unwanted bull calves.

  I had no idea that behind my herd of cows lay a web of science stretching halfway round the globe. Watching them quietly cropping the grass in my fields seemed the most natural thing in the world, the closest you could get to there being a simple relationship between farmer, animal and land. It assaulted my romantic sensibilities to know that their existence depended on such complicated scientific processes. I didn’t want to know that their father’s sperm had probably been harvested inside an artificial vagina in a breeding station somewhere in New Zealand, then frozen in liquid nitrogen and flown thousands of miles until it was eventually carried in a van in an insulated steel canister to a little farm, where a dairy cow was impregnated by semen from a plastic straw, shot from a gun, by a man in a brown overall.

  Echoing John Maynard Keynes’s aperçu that ‘practical men who believe themselves to be quite exempt from any intellectual influence, are usually the slaves of some defunct economist’, it is salutary to observe the hold that the dicta of Louis Pasteur have on public health policy across the Western world.

  There is no doubt that in Victorian town dairies, hygiene was sometimes dreadful. Milk was sold by the ladleful from open pails. Punch joked that London would have to wait ‘for a February with five Sundays to be able to get a clean glass of milk’. Public health campaigners began to agitate for the heat treatment of milk based on Louis Pasteur’s findings that germs did not spontaneously generate, as had been thought, but grew from other germs and could be destroyed by heat. In 1893, New York was the first city to make pasteurized milk compulsory, when Nathan Strauss opened the first pasteurization plant after his daughter died from tuberculosis apparently contracted from infected milk. Pasteurization was introduced in London a few years later, as a temporary measure, mainly to stop the spread of TB, and is said to have reduced by half the deaths of babies from infantile diarrhoea.

  Heat treatment is now routine in Europe and the Anglophone countries and in many is enforced by law. Pasteurization involves heating the milk and cooling it immediately afterwards, either for a short burst of 16 seconds at 72°C or a longer exposure for 30 minutes at 63°C. The higher the temperature, the more microorganisms, enzymes and vitamins are killed. Milk can also be sterilized (it is not actually sterile) by heating it to about 115°C for 20 minutes. In the process, it loses most of its vitamins and enzymes. Ultra-heat-treated (UHT) milk is flash-heated to 135°C for a second; the process kills good and bad bacteria and destroys or damages the vitamin, enzyme and other nutritional content, and it loses much of its taste in the process. In fact UHT milk is so unnatural that bacteria won’t touch it. It will keep without refrigeration for up to 60 days in plastic bottles and up to five months in sterile glass ones.

  In Britain, with our history of drinking fresh liquid milk, only about 8 per cent of the milk market is UHT because we don’t like the tasteless stuff, but almost all of it is now pasteurized. By contrast, in hotter countries in Europe most of the milk is UHT. In 2008, in an effort to conform to European standardization, the UK government proposed that 90 per cent of our liquid milk sales should be UHT by 2020. The stated reason was to reduce the need for refrigeration and reduce greenhouse gas emissions. Mercifully, the big dairies and milk processors opposed it and the proposal was abandoned.

  The target organism that had to be killed if pasteurization was to be effective was the germ that causes TB, Mycobacterium paratuberculosis. But testing for this took between 24 and 48 hours and the milk could have gone off before success could be verified. So another test was developed based on an enzyme called alkaline phosphatase (ALP), which is present in the milk of all mammals. It requires slightly more heat to kill it than the target organism and its presence is easily tested by measuring whether the milk becomes fluorescent when exposed to active ALP. This is now
the standard method in the UK to show that milk has been pasteurized successfully. Unfortunately, destroying the phosphatase enzyme impairs the body’s capacity to absorb calcium. Pasteurization also alters or destroys many amino acids, and reduces the digestibility of protein by about 17 per cent. Beneficial bacteria that prevent milk from decomposing are also destroyed, so that pasteurized milk goes rancid rather than souring.

  Pasteur’s theory, which affects the diet of almost everyone in the West, is that illness is caused by ‘germs’, which must be destroyed to maintain human health. Pasteur did not go unchallenged, particularly by his great rival, another French scientist, Antoine Béchamp, whose counter-theory based on the principle of ‘wellness’ animates an alternative view of health and illness.

  Béchamp made the point that our bodies contain a colony of over 10,000 interdependent species and subspecies of bacteria, particularly in the gut, without which we would not survive for long. This vast and complicated range of ‘good’ and ‘bad’ bacteria (Pasteur’s ‘germs’) works like the ecosystem in a rainforest and maintains a balance in the human body; illness only strikes when something upsets the equilibrium. Béchamp called this ‘cellular theory’ or ‘vitalism’ or ‘microzymian’ theory. A healthy body is protected against illness unless something goes wrong to cause it. Treating illness therefore involves restoring the basic conditions that promote health and allowing the body to bring itself back into order.

  This contrasts with Pasteur’s view that disease defines life negatively, rather than as a positive force. Mainstream Western medicine largely accepts Pasteur’s model, and takes it for granted that pasteurization is necessary to maintain the health of the population. Antibacterial handwashes, kitchen and bathroom cleaning fluids and disinfectants that kill ‘germs’ and preserve us from disease find a ready and highly profitable market in the West.

  Béchamp and Pasteur had a long and often bitter professional rivalry. But in the end, Pasteur’s ideas found a readier reception than those of his more sophisticated, subtle and perhaps more challenging colleague. Pasteur’s theory informs all public health legislation across the Western world. Diseases are caused by particular microorganisms (germs) that invade the body and make it ill. They can attack anybody at any time, irrespective of whether or not the individual takes care of himself. This largely absolves the sufferer of responsibility for his own health.