LIVER FUNCTION – KEY TO PRODUCTION AND HEALTH OF MILKING GOATS
Prior to the 1600’s the liver was considered to be the most important organ in the body, much more so than the heart and the brain. Throughout the ages this organ has been steeped in myth, in the case of the Romans, the liver held a key place in their religious rituals. Roman priests closely studied sacrificed animal livers, these signs could indicate such things as, prosperity, famine, wars, or curses.
Today, the heart and the brain seem to have more emphasis placed on their importance. However, the ancients may have known more than we give them credit for, we should not be too quick to dismiss the liver. Regardless of the heart and brain, without a functional liver most living creatures would not survive very well, or for very long.
The liver is fascinating, and in many ways, I find it to be the most complex of all the bodies organs. It is a single organ with a massive number of functions, below are just a few of the key functions.
Key functions of the liver
• The production of bile – bile clears waste products.
• Produces many blood proteins, e.g. albumin, ferritin, cholesterol etc.
• Produces lipoproteins that carry different fats throughout the body.
• Controls energy – rapidly converts glucose to glycogen (storage) and then rapidly converts glycogen back to glucose as the body calls for more energy.
• Regulates amino acids, the building blocks of protein within the blood.
• Regulating (storing and releasing) hemoglobin levels of minerals such as iron, copper, etc
• Conversion of excess ammonia to urea (a major issue in ruminant digestion)
• Clears toxins from the blood (think feed toxins, aflatoxins, mycotoxins, ergot toxins)
• Important in the immune response in that the liver detects and clears bacteria and viruses arriving from the gut.
• Regulates blood clotting
• Clears bilirubin (broken down red blood cells) from the blood.
These are just a few of the key processes involving the liver. You can see from the list that these are all very essential processes. They are all reliant on a healthy liver, with enough capacity to consistently carry out every single function.
The Liver could be considered as the chief gatekeeper between the body and the environment. Even with the best diet, this organ will need to work constantly to ensure the body has sufficient energy. At the same time, it ensures toxins are excluded as much as possible from other key organs and tissues. The liver constantly suffers the stress connected to its job of detoxifying and eliminating toxins, free radicals produced as a byproduct of energy production, feed-based toxins, as well as man-made chemical toxins.
LIVER FUNCTION AND HEALTH
As this organ plays such a key role in energy production, it is no surprise that metabolic diseases such as ketosis in ruminants can be so affected by poor liver function. Commonly the issue with goats is over-conditioning during the previous lactation, and during the period leading up to kidding. Over conditioning in dairy cattle is easy to identify, but goats are more difficult to condition score accurately. Issues leading to fatty liver disease can often go unnoticed in goats until it is too late.
Over conditioning of goats has become such an issue that some goat farmers abroad have even resorted to milking their goats right through to the next kidding. This is simply to keep condition levels in check, and of course can lead to other issues.
A HEALTHY LIVER IS ALL ABOUT BALANCE
The liver is no different to any other organ in the body; it requires a correct balance of nutrients to function at an optimal level and remain healthy. The liver however is unique among body organs in that has a tremendous capacity to regenerate cells particularly when it is most under load. Invariably some liver cell damage will take place, however the liver has the ability to increase its rate of regeneration of new cells (provided the liver is being supplied with the key minerals, vitamins, and amino acids in order to allow regeneration).
KEY MINERALS THAT MAY BE REQUIRED BY THE MILKING GOAT TO SUPPORT LIVER FUNCTION AND HEALTH:
• Magnesium – helps with the release of toxins in the blood allowing the liver to do its job more effectively.
• Copper – involved in antioxidation, reducing byproducts of energy metabolism (free radicals), one of the most important functions of the liver.
• Zinc – plays a role in liver health through the regeneration of cells, as well as in antioxidation.
• Selenium – along with iodine, is involved in thyroid hormone production, as well as cell regeneration.
• Iodine – production of thyroid hormones, the liver is important in further synthesizing these hormones.
KEY VITAMINS TO SUPPORT LIVER FUNCTION
Vitamin B12 – important in methionine synthesis which is important for liver health. Of course, many other vitamins and minerals will be important, but most should be present in the diet in sufficient quantity.
KEY AMINO ACIDS IN LIVER FUNCTION
The amino acids (Methionine, Choline and Betaine), along with vitamins B12 and folate have been shown to have a positive effect on fatty liver disease in both humans and animals. Several studies have shown that feeding higher levels of methionine, choline, betaine, and B12 can increase energy levels, support reproduction, and help mediate the effects of fatty liver disease in ruminants. Because these amino acids and vitamins can affect DNA activity and can interchange and work in combination, they are commonly called methyl donors.
In the body these amino acids are normally supplied and absorbed from bypass protein. Basically, bacteria that have digested crude protein within the rumen, and then themselves destroyed by the abomasum and digested in the intestinal system. Simply supplying additional amino acids to the rumen won’t work. Rumen bacteria tend to convert them to ammonia; hence they seldom reach the intestine intact.
When supplementing a ruminant with amino acids, to ensure they reach the intestine intact they must be fed in a protected form. The best form of protection is to encapsulate the amino acids in fat, a coating that is sufficiently robust to withstand the harsh rumen environment to deliver the amino acids to the intestine intact. Once in the intestine, the fat coating is quickly broken down and the amino acid is absorbed to the blood and carried to the liver.
Much trial work has been carried out to perfect this process. The technology is at a point where these supplements are now becoming a very important tool in optimizing liver function in all classes of ruminants. Understanding liver function a little better hopefully emphasizes the importance of this essential organ to maintaining the health and productive capacity of these most productive of ruminants.