DAIRY GOATS: FEEDING FOR PERFORMANCE
Most dairy goat farmers focus on getting energy, protein, and fibre right, and fair enough – feed drives milk. But even the best ration won’t
Most dairy goat farmers focus on getting energy, protein, and fibre right, and fair enough – feed drives milk. But even the best ration won’t
Managing trace mineral levels in dairy goats As high-performance ruminants, dairy goats need specialised nutrition to have them functioning at their best. When it comes
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.
Ketosis in any of its forms can lead to sudden and catastrophic loss levels around kidding time.
A number of goat farms this year experienced significant losses around kidding time and during early lactation. Farmers were puzzled as to the cause and unfortunately these losses happened rapidly, before any remedial action could be taken.
Such acute losses at this time typically come down to one thing, a catastrophic energy deficit experienced during a critical stress period, namely kidding and early lactation. This disease goes under a number of names and confusingly can take a number of different forms. The most acute form is often called pregnancy toxemia in goats, or sleepy sickness. In dairy cattle it is more commonly called ketosis, or fatty liver disease.
These different forms can be made up of a range of symptoms but all emanate from the same root cause – a lack of glucose production. When the body fails to produce enough glucose for energy it kicks into survival mode and begins to break down fat tissue for energy, releasing ketones.
To fully understand this disease and its differing manifestations we need to have a good understanding of the stresses involved during the lead up to kidding and early lactation. At this time there is a rapidly increasing requirement for energy and the body needs to have the capacity to meet these needs within a very small period of time.
UNDERSTANDING KETOSIS IN DAIRY GOATS
Ketosis is a metabolic disease common to all living creatures, but particularly problematic in high production ruminants. It will usually only appear at critical stress times, namely kidding/calving and early lactation.
Ketosis is related to the body’s inability to synthesize sufficient glucose from fatty acids produced in the rumen to supply its energy demands. The body then starts to mobilize body fat (some humans would say that’s a good thing). The mobilized fat is broken down into what are called non-esterified fatty acids (NEFA’s). When these non-esterified fatty acids reach the liver, they are either oxidized into energy forming substances (ketones) or removed out again as very low-density lipoproteins (VLDL’s). This process is complex and is largely regulated by hormones such as insulin, ghrelin and leptin (the satiety hormone). The problem is, when the production of ketone bodies is upregulated in favour of the more efficient glucose energy cycle, it can lead to a significant energy deficit. A serious side effect of the over utilization of fat for energy is fatty liver disease; when fat goes into the liver in greater volumes than the livers capacity to process it, and this causes a fat buildup that can quickly lead to liver failure. Once established this condition is very hard to reverse, particularly in small ruminants with more limited liver capacity.
It is tempting, given the limited research around goat nutrition to assume a goat’s nutritional requirements fit somewhere between that of sheep and cattle. This assumption would be a mistake. When it comes to mineral nutrition goats have very different requirements.
Based on a goat’s production level when related to body weight and feed intake, these small ruminants are probably better compared to the ruminant equivalent of an F1 racing car. Just as you wouldn’t run a high performance car on low octane fuel, you shouldn’t feed your goat the same way as you would cattle and sheep. Goats have different and very specific nutritional requirements. If these requirements are not met, the animal will not perform to its full potential, and worse still will be subject to a higher level of disease.
The interesting thing about goats is that their requirement is both higher and lower depending on the element in question. While their milk is in many ways more nutritious than that of a dairy cow, nature has at the same time designed the animal to survive under very different conditions, and on a very different diet from that of a cow.
SO WHAT ARE THE MINERAL REQUIREMENTS OF DAIRY GOATS?
Lets start with one of the key macro elements, phosphorous. Goats typically have a lower requirement for phosphorous to that of dairy cattle. They seem to be better at recycling it and while they have higher levels in their saliva, losses during rumination are lower than that of a cow.
In contrast calcium requirements are quite high and should be set at least twice that of phosphorous in the diet.