When the trainer of I’ll Have Another,  Doug O’Neill was given a 45-day suspension for “milkshaking” a horse it brought the controversial practice out into the open. There’s nothing new, here — trainers have been looking for ways to enhance a horse’s performance since the day that they started racing —  but milkshaking and its variations have become a pervasive problem on racetracks across the country.

So what’s a Milkshake?

A “milkshake” is a mixture of water, baking soda, sugar, and electrolytes. It is given to horses by tubing them. Bicarbonate loading neutralizes the build up of lactic acid, which causes muscle fatigue. It is generally administered five or six hours before a race and has the greatest effect in races longer than 90 seconds (which translates to distances of at least a mile).

Bicarbonate loading first gained notoriety in Standardbred racing in the 1980s and then migrated to Thoroughbred racing. By the late 1990s race-day milkshaking was illegal but testing for it wasn’t conducted nationwide until 2004.

To determine whether a horse has been given bicarbonates, horses are tested for TC02 — Total Carbon Dioxide — levels. A reading higher than 37.o millimoles per liter is considered to be unnaturally elevated.

How common is it?

According to an article in the Paulick Report, “When is a ‘Milkshake’ not a Milkshake,”

In California, TCO2 testing did not begin until 2004, when survey tests were conducted to gauge how widespread milkshaking had become. The results were quite shocking: of 82 horses tested during eight races at Del Mar, 19 of them, or nearly 25%, tested above the 37.0 threshold. (In Australia, TCO2 tests are considered positive if they are above 35.0.) Most horses normally test around 32.0-33.0.

Now that TC02 testing is common, it is rumored that some trainers are trying to game the system by boosting performance without exceeding the tested limits by dosing based on the horse’s weight, fitness level and the length of the race. It would still be illegal since it would constitute milkshaking on race day. In the same article, the Paulick Report states:

A racetrack practitioner who spoke to the Paulick Report on the condition of anonymity said some trainers and veterinarians “push the envelope,” not by administering traditional bicarbonate loading through a gastro-nasal tube but by giving “bullets,” a paste-like mix of bicarbonates and electrolytes delivered via a dose gun in the back of a horse’s mouth four to five hours before a race. The concoction can contain an “energy mix” of amino acids, sugar or complex sugar.

What else can raise TC02 Levels?

In addition to bicarbonate loading, there are several other factors that can influence TC02 levels. After all, Carbon Dioxide (CO2) occurs naturally in all living things, including horses. According to a document published by the Michigan Office of Racing Commissioner, Understanding TC02 Testing,  there are many factors that can affect the acid/alkaline “pH” balance in a horse.

• Lasix: Administration of Lasix has been shown to influence TC02 levels. The Lasix “bump” is a known phenomena. Keep in mind that almost all racehorses now are given Lasix on race day.
• Dehydration: Excessive sweating, decreased water consumption due to cold weather or the deliberate withholding of water for long periods of time can lead to metabolic alkalosis which could result in an elevated TC02 level.
• Supplements: Supplements that contain bicarbonate, citrate and acetate can alter the acid/alkaline balance of a horse.
• Medications: Buffers, antacids and anti-ulcer medications can raise TC02 levels.
• Feed: Diets that have a high cation-anion balance — for example, those which include high amounts of alfalfa or soybean meal, can increase TC02 levels.
• Electrolytes and salt: Some electrolyte formulations contain bicarbonate or other alkalinizing agents. Some experts believe that high levels of salt and electrolites combined with limited water consumption can cause alkalosis and result in an elevated level of TC02.

Does bicarbonate loading have benefits?

Outside of the racing environment, there are legitimate uses for bicarbonate loading. For example, it can be very helpful to help horses that are tying up.