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.
We consider it is always a good idea to supplement some vitamin D in the diet in order to ensure dietary uptake of calcium is maximized, particularly if your goats are housed in sheds. Where we as humans are relatively hairless and can therefore very efficiently synthesise vitamin D from sunlight, animals with fur coats such as goats are up to 80% less efficient at synthesising the active form of this element.
Recently we have implemented some anionic salt blends into goat feeds during late gestation in order to maximize calcium uptake at kidding and early lactation. This is based on research that proves this approach works equally well for goats as it does for dairy cattle. The use of anionic salts in the transition period also stimulates rumen recovery earlier and allows higher energy absorption in the early lactation.
DAIRY GOATS DO HAVE SIMILAR MACRO MINERAL AND VITAMIN REQUIREMENTS TO DAIRY CATTLE
For example, if a reasonable level of grass makes up a portion of the diet then potassium levels are normally well covered. Green pasture also supplies high levels of vitamin E, (180 – 350 mgs per kg/DM, silage 80 – 150 mgs) and this is usually more than enough to cover requirements. Likewise for vitamin A, ruminants are normally very efficient at synthesising good levels from the high natural carotene levels supplied in green
Goats are generally slightly more efficient at absorbing magnesium than dairy cattle, however we normally suggest similar levels are fed, 0.22 – 0.28% Mg on a per kg of dry matter basis, on the higher end during the transition and early lactation period. Sodium and chloride requirements are also similar, if a little lower than those required by cattle.
HOWEVER, DAIRY GOAT TRACE ELEMENT REQUIREMENTS ARE VERY DIFFERENT…
The trace element levels required by goats are very different to those required by other stock. Goats have much more specific requirements here.
Copper requirements for a goat are many times higher than that required by sheep, and are thought to be much higher than the requirement in cattle. Where a goat differs from cattle is in the liver storage department. It has been shown that a goat has less than 1/10th of the copper liver storage capacity to that of cattle on a live weight basis. While goats have this very poor ability to store copper they at the same time have a very high requirement for copper and suffer much worse when copper deficient. We have found the best way to deal with these relatively high demands is through the use of the highly efficient chelated forms of the mineral.
In this way we can better utilise the natural storage capacity within every cell of the body without the increased risk of toxicity. Chelated minerals that are bound to natural amino acids are much better absorbed, translocated, and more efficiently stored throughout the body.
The same principle applies to the mineral zinc, which is second only in importance to copper in goats. By utilising chelated forms of the mineral that work well with copper, we can ensure adequate levels of bioavailable zinc are efficiently translocated to every cell in the body. Good levels of bioavailable zinc raise the body’s level of immunity, improving reproductive performance and hoof integrity.
The other all-important mineral for goats is selenium, being a high-performance animal with a high metabolic rate, goats have a high requirement for this element. When it comes to our goat supplements we tend to favour the form of the element that is naturally synthesised by plants, that form being selenomethionine. This natural selenium protein is formed during plant growth when some of the sulphur is displaced from the amino acid “methionine” and replaced with selenium. This same product can also be synthesised by using a yeast culture bringing about the same process under very controlled conditions. This is the form of selenium we favour as a selenium source in all of our goat blends. Selenomethionine yeast is guaranteed to deliver high levels of very bioavailable selenium in a form that can be more efficiently utilised and stored by the body.
SELENOSOURCE SUPPORT DURING EARLY LACTATION
Provided the dam has received good selenium nutrition during gestation, both calves and goat kids are born with very high levels of selenium stored in the liver and kidneys. This is a reserve adequate to tide them over until they start replacing milk with an all plant diet. Typically, an all milk diet is very low in selenium and drinking milk quickly depletes these reserves. Feeding selenomethionine during early lactation doesn’t just ensure better health status in the early lactation animal it also covers the selenium requirements of the young through the milk they will consume containing a much higher amino acid bound selenium level.
ENSURE CAREFUL MANAGEMENT OF IODINE LEVELS
Iodine is not popular in the diet of dairy goats due to the unpredictable levels that can come through into the milk; hence it will normally be excluded from products we blend for the dairy goat industry. However, typically goats have a high requirement for this mineral and New Zealand grasses unfortunately provide very low levels of this essential element.
Iodine effectively drives energy and metabolism through its essential role in the formation of the various
thyroid hormones. The good news is that selenium, although it doesn’t take the place of iodine, selenium works in tandem with iodine in the efficient synthesis of these thyroid hormones. Provided there is a minimum of available iodine in the diet, good levels of selenium should ensure that adequate levels of these hormones are available.
And lastly there is cobalt. Goats, unlike cattle, seem to be quite efficient at extracting cobalt from feed. Cobalt of course is an essential pre-curser element for the formation of vitamin B12, a vitamin that is vital in feeding the bugs within the rumen and efficiently allowing the breakdown of cellulose to fatty acids. Due to its importance and the fact that ruminants are very tolerant to higher levels we always put good levels in our blends.
Most other elements such as iron, manganese, and chromium are normally not so critical, however ruminants being very tolerant to higher levels of these minerals means that it is good practice to underpin the levels in our blends.
Agvance Nutrition specialises in the formulation of late gestation, as well as lactation premixes for goat nutrition. Mineral premixes are fully formulated blends containing both macro as well as trace element salts, and can be built specifically to balance your feed requirements. We also produce both soluble and insoluble trace element blends.
We take the work out of having to formulate and weigh out these minerals yourself. We blend them for you and put them all into one bag, saving you time and giving you accuracy of dose.
If you would like further mineral advice or guidance for your dairy goats, you are welcome to get in contact with the team here at Agvance.