|Posted by Kim on March 23, 2017 at 2:15 PM||comments (0)|
Basics of Nutrition by Dr. Nancy A. Irlbeck
Nutrition is one of the major keys to animal health. Without a sound nutrition program, an animal will be unable to produce fiber or a cria to its maximum genetic potential. Limitations in the supply of nutrients can and do compromise an animal’s immune system. Therefore, having a working knowledge of the nutrients needed by the animal, and what feeds will supply those nutrients, is one of the most important steps in managing an animal. I strongly suggest that if you do not have a livestock background and are not familiar with herbivorous hoofstock, research the alpaca and what it needs BEFORE you bring it home. There are a lot of questions to be asked before you actually feed an alpaca, and I will attempt to address those in this text. There is not enough time or space to cover all the aspects of nutrition and the feeds that are used to feed these animals, but I will do my best to address some of the “basics.”
An animal can live for long periods of time with limited nutrients. The animal body has a unique way of “borrowing” nutrients from other parts of the body to enable life to continue. But there is a price for this “borrowing” and sooner or later those borrowed nutrients need to be replaced or the animal will become ill and may even die. Until the animal “crashes,” it is not obvious that there is a problem, and often the only symptoms that something is wrong may be subtle changes in production, a lower yield of fiber, or a cria of low birth weight and vigor. Records are a vital part of a production system and an alpaca owner needs to record body weights on a regular basis.
In addition to proper feeding management I encourage you to get to know your animals – really know them. Individuals that have worked with livestock previously – cattle, sheep, goats – are aware of subtleties to watch for. These subtleties are factors that can never be learned from a book, little things that can only be learned from actually working with animals. You might hear one of these individuals say,” That animal does not feel well,” and you think the person is “bonkers.” The animal is eating and moving around, adequately in your mind. But beware, it may be the way the animal is holding its head, or perhaps they are standing by themselves. Either way, an individual working/raising alpacas has to become familiar with their animals from the beginning. Get in with your animals. Walk among them, watch them and know what is normal. All animals are creatures of habit and if you are familiar enough to know “normal” and are watching closely, you will be aware when something is wrong. Do not be a “fenceline” manager. Combining these concepts and proper feeding management, you will be well on your way to a successful venture into (the) alpaca husbandry.
Nutrition is not always easy – it is a puzzle. And there are many pieces to that puzzle including management, behavior of the animal, potential disease, physiological status (i.e., pregnant, lactating, growing), economics involved with forage and grains and of course what feedstuffs are available to feed the animal. Becoming aware of these puzzle pieces and how they fit together is a good start when feeding the alpaca. Be aware that the nutrient requirements for the alpaca are not known. Data from small ruminants like the sheep and the goat have been extrapolated for alpaca to obtain an estimated requirement. I have incorporated those estimates in Table 1. All values shown in the table are presented on a dry matter basis (DM). What that means is that alpacas consume grass, hay and grains of differing moisture contents and it is difficult to directly compare nutrient contents with feeds have varying amounts of water. Thus if one uses dry matter nutrient values (all water removed), this allows nutritionists and producers to directly compare the values. This is done for all other species too.
Table 1. Estimated Nutrient Requirements of Llamas and Alpacas1– Dry Matter Basis (DM).
Nutrient Level Source
Crude Protein, % 8-14 Johnson, 1989
DE2, Kcal/kg BW 33 Carmean, 1992
Calcium, % 0.3-0.85 Van Saun, 1999
Phosphorus, % 0.16-0.40 Van Saun, 1999
Potassium,% 0.5-1.0 Van Saun, 1999
Magnesium,% 0.12-0.20 Van Saun, 1999
Copper, ppm 13-15 Van Saun, 1999
Iron, ppm 60-130 Van Saun, 1999
Manganese, ppm 45-55 Van Saun, 1999
Selenium, ppm 0.4-0.6 Van Saun, 1999
Zinc, ppm 40-50 Van Saun, 1999
Vitamin A, IU/kg 3000-3500 Van Saun, 1999
Vitamin D, IU/kg 3000 Extrapolated
Vitamin E, IU/kg 17-20 Van Saun, 1999
1 Irlbeck, 2000
2 DE = Kcal of Digestible Energy (DE) per kg of body weight (BW) of an animal at maintenance (DE is another more definitive energy expression than the traditional method of TDN (Total Digestible Nutrients). Animals that are growing, lactating or in the third trimester of gestation will have a higher energy requirement.
Understanding what kind of gastrointestinal tract (GIT) an animal has is an integral piece from the nutrition puzzle, and helps us to understand how an animal is fed. Types of GIT vary among the animal kingdom based on animal diets. The GIT is defined as the part of an animal’s body from the mouth, esophagus, stomach, small and large intestine and down to the anus. For example, a carnivore has a very short GIT because it’s meat-based diet is very digestible and a larger tract would not be needed. An animal that consumes forages like grass and hay (herbivore) must have a much larger tract as it needs to house the symbiotic microbe population. The microbe population is needed to break down or ferment cellulose, cellulose being a major component of plants. Mammals cannot digest cellulose. Yes, cattle, horses, sheep and even alpacas consume forages and seem to do quite well, but it is because of a resident microbe population. The microbes produce an enzyme called cellulase to ferment cellulose found in plants. Without this enzyme forages could not be fed to the above animals. Also, because of the sensitive nature of those symbiotic microbes and how they are affected by what we feed them, great care needs to be taken. If the microbes were to be hampered in any way by what we feed the alpaca, then the animal can be compromised. Symbiotic means that the microbes and the alpaca both are dependent on each other. The alpaca provides a “home” and food supply for the microbes, and the microbes ferment that food and produce volatile fatty acids. Volatile fatty acids provide a source of energy for the alpaca.
The alpaca is an herbivore and is classified as a pseudoruminant. Being a pseudoruminant means that the alpaca (like the llama) is similar to a ruminant animal (cattle, sheep, goats and deer), but is not exactly the same. Ruminants cannot all be fed the same, so care needs to be taken which ruminant model is used for comparison with an alpaca. Cattle are able to do quite well on large quantities of low quality forage, the alpaca cannot. The feeding principles for the sheep and goat are closer to what alpacas need than those for cattle. Because of its size and metabolism, the alpaca needs high quality forages. I will discuss how you can determine what a high quality forage is shortly in this text.
When evaluating GIT differences, the most important GIT difference is the stomach. The stomach of the alpaca is not the same as what we think about for people, for dogs or even the horse. The alpaca stomach has three parts – Compartment I, II and III. Compartment I is the largest and analogous to the rumen in cattle, sheep and goats. It is here in Compartment I that microbial fermentation of the fibrous portion of plants occur. Compartment II is much smaller than the first and it is here that buffering agents and more digestive enzymes are added to the digesta (partially digested food). When the digesta leaves Compartment II, it enters Compartment III where nitrogen (urea) is recycled, and more buffers and digestive enzymes are added. The lower portion of Compartment III is analogous to the stomach of the human, horse or dog – it is here that protein digesting enzymes and hydrochloric acid are added. It is also here that microbes attached to food particles coming from Compartment I are also digested, becoming what we call microbial protein – an important source of amino acids for the alpaca as they are for ruminants like cattle, sheep and goats.
SO HOW DO WE FEED THE ALPACA
Many scientists, myself included, indicate that when feeding animals we need to consider what the animal was fed in its native habitat. For example, alpacas are South American camelids, and we need to closely evaluate what the animals are being fed in South America. Yes that is true. But we also have to consider that individuals raising alpacas in South America most often do not have the available resources that we in the United States have to feed animals. Animals in South America are quite often fed a subsistence ration and when consuming that kind of diet, they do not produce fiber and young at the same level as they do in the United States. They also do not live as long. If there is a consistent problem feeding in the United States, it is usually in our zeal to take care of these animals in the best possible way, we over-feed them. Rarely do alpacas get underfed in the United States, unless it is in ignorance.
So where do we start? In Table 1, we see that llamas and alpacas require 9 -14% CP (crude protein) on a DM basis. Alpacas require a higher plane of protein than the llama, thus we would use a value of 12-14% CP for the alpaca. But what does this mean and how do you supply 12-14% CP to your animals? The best way to provide an explanation is to talk about the nutrients in conjunction with the feeds that provide them. The best place to start would be the most important nutrient – water.
Water is the first nutrient of importance. Good quality water is becoming more difficult to acquire with the increase in human population. Regardless of the challenges of finding a good water source, we must keep in mind that an animal can only survive a brief time without water – the amount depending on environmental conditions. To determine if you are providing good quality water, have it tested. Test your water, even if it is city water, and definitely if it is well water. Many owners, many veterinarians and even nutritionists forget water when problems occur with an animal. But what do you test water for? In Table 2 I have listed a few “good” water standards. There are many other measures (i.e., individual minerals) of “good” water, but this is a start. If your water source meets these requirements and is low in bacteria, herbicides, and other chemicals at least you know that it is probably safe for the animals to drink. But, you also need to be aware of the mineral content of your water. For example, if it is high in iron, that iron may tie up other nutrients like zinc and copper. If zinc or copper is tied up and are no longer available to the animal, the immune system is compromised, as is fleece quality.
Table 2. Good Water Standards for Livestock Use
Total Solids Less than 1000 ppm1
Hardness Less than 1000 ppm
Sulphates 500 ppm or less
Nitrates Less than 45 ppm
Iron Less than 5 ppm2
Sodium 500 ppm or less_______
1 ppm = parts per million = mg/liter
2 Bauder, 1998
FORAGES AND GRAINS – THE CARBOHYDRATES
As indicated earlier the alpaca is an herbivore – it eats plants. Plants are carbohydrates. Carbohydrates are divided into two categories: 1) complex carbohydrates like cellulose and hemicellulose; and 2) readily available carbohydrates like sugars and starches. So what does that mean and how do I apply it to feeding the alpaca? Complex carbohydrates are forages such as grass and alfalfa hay (Table 3), grass that is grazed by the animals and any shrubs and tree material that the animals may consume. Readily available carbohydrates are grains – barley, corn, oats, and wheat (Table 4).
Lets talk about the complex carbohydrates – forages first! So what kind of hay should you feed to your alpaca? I can tell you idealistically, however, actual economics often plays a major role in determining exactly what an animal is being fed. I will provide you with the basic principles of what to use when evaluating forages like grass and alfalfa hays, but what you actually feed depends on where you live. Hays are not all the same as a multitude of factors affect the potential nutrient variability. Factors include the maturity of the forage when it is cut for hay, what was the weather when the hay was harvested, as well as losses due to harvesting and storage techniques. All producers know that if you want it to rain, cut down the hay!
In general there are two types of forages – legumes and grass. The most common legume fed in the United States is alfalfa, called lucerne in most other parts of the world. Clover, another legume is occasionally fed in the US, but predominantly in other countries. Nutritionally legumes are higher in protein and calcium than are grasses. There are in general three types of grasses: 1) cool season grass; 2) warm season grass; and 3) southern grasses. Examples of common cool season grasses include brome, timothy, and orchard grass. Cool season grasses do better in a temperate climate when it is cooler and there is ample moisture. Examples of warm season grasses are big and little bluestem, Indian grass and switchgrass. Warm season grasses do better when the temperature is higher and under drought-like conditions. Rotations of cool and warm season grasses are common to allow for seasonal changes. Southern grasses such as Bermuda grass are much lower quality than cool or warm seasons grasses – partially because they are grown in a much hotter climate. It is important for you to become familiar with the type of forages (and their idiosyncrasies) commonly fed/grown in your part of the country – before you feed alpacas!
Now let me discuss the simplistic components that make up a plant (Figure 1). A plant can be divided into cell solubles and cell walls. Cell solubles are starches, sugars – readily available carbohydrates that are digestible by all animals. Cell walls are the important part that we will use to determine forage quality. They are made up of lignin, cellulose and hemicellulose. For this discussion, lets say that lignin is not digestible by animal or microbial enzymes. Thus the more lignin in a forage, the more indigestible that it is, as the lignin ties up the rest of the plant components. The more mature forages are, the greater the lignin content. In general, the hotter the environment when a forage is grown, the higher the lignin content of that forage. Thus management (and luck) of the forage crop is critical when producing high quality forages.
In Compartment I of the alpaca GIT, the cellulose from forages is fermented by microbes. When the forage is more mature, there is more lignin and the cellulose fermenting capability of the microbes is diminished. The hemicellulose found in forages is very digestible by animals and microbes enzymes, but again if there are high amounts of lignin, the capability to digest hemicellulose will too be decreased.
Often alpaca producers do not produce their own forages, but purchase it from various sources. Thus, when purchased, a producer needs to sample that forage and have it analyzed. But what does that mean? What do you ask for when having forages analyzed and then how do you interpret the information that you get back from the laboratory? My recommendation is to ask for proximate analyses (includes CP and others), fiber analyses (to be defined shortly) and if possible the calcium and phosphorus levels. There are other measures that can be done, but at least this will provide enough information to determine forage quality.
Fiber analyses will be the focus of the next few paragraphs as these will help in determining the quality of your forage. Fibers are based on the principles of a scientist, Dr. Peter Van Soest, who developed the detergent fiber technique in the 1960’s. Thus the techniques are also called the Van Soest fiber analyses. There are two of Dr. Van Soest’s measures that we are going to use in this discussion and what you will need to ask for in the analyses request. They include: 1) acid detergent fiber (ADF); and 2) neutral detergent fiber (NDF). The ADF content of a plant includes lignin and cellulose concentration, while the content of NDF content of the plant includes the lignin, cellulose and hemicellulose concentrations. So what does an ADF or NDF level mean and how can you apply it to feeding the alpaca and determining quality of the forage being fed to your alpacas?
First lets look at the ADF concentration of the plant. The level of ADF can be used to determine how digestible forages are – digestible dry matter (DDM). If a feed is more digestible, then an animal can eat more and get greater energy and nutrient content from it, thus it is of higher quality. In Table 3, I have listed feeds of varying maturities with corresponding ADF and NDF values. In general, the more immature a forage when harvested, the higher the quality and the lower the ADF value. Likewise, the more mature the forage, the lower the quality, and the higher the ADF value. The %NDF can be used to determine the dry matter intake (DMI) of forages (remember we have to remove all the water to calculate intake). Like the %ADF, %NDF can be used to determine forage quality. The higher the forage quality, the lower the %NDF and the higher the DMI. Conversely, the lower the forage quality is, the higher the %NDF and the lower the resulting DMI for the feed. An alpaca consumes less than a ruminant. On average a ruminant consumes 2 to 2.2% of its body weight in DM, while an alpaca at maintenance consumes on average 1.8 to 2.0% of body weight DM. Animals of differing physiological stages (growing, lactating, gestating) will eat more than an animal at maintenance. Animals at maintenance may consume more than 1.8 to 2.0% of their body weight, but then they are often prone to obesity. Listed below are the equations that can be used to calculate DDM and DMI, and thus assist in making a decision on forage quality.
Digestible Dry Matter (DDM) – for ruminants
% DDM = 88.9 – (0.779 X %ADF).
For example – if the %ADF = 31, then
%DDM = 88.9 – (0.779 X 31) = 64.75%
This means that the forage is 64.75% digestible. Compare this to the values given in Table 3. Note: In the equation, 88.9 and 0.779 are constants and cannot be changed.
Dry Matter Intake (DMI) – for ruminants
%DMI = 120/%NDF
For example – if the %NDF = 40, then
%DMI = 3% of the animal’s body weight
A %DMI value of 3.0% means that the forage is high enough in energy that an animal could eat 3% of its body weight! That is very high, energy forage when you are looking for 1.8 to 2.0% for animal maintenance. This quality of forage would be excellent for females in late gestation and early lactation, assuming that the protein level is also adequate – and in the majority of cases, if the digestibility and resulting energy is higher, then so is the protein content. Note: In the equation, 120 is a constant and cannot be changed.
For maximum quality and quantity, alfalfa is harvested at what we call 1/10 bloom. That means that approximately 1/10 of all blossoms on a plant or plants in the field are in bloom and the rest have not yet blossomed out. This is called early bloom in reference texts. In general, the more blossoms open on a plant the greater the maturity. In Colorado, it is usually possible to have three harvests or cuttings of alfalfa. At higher altitudes this may be reduced to a single cutting (if alfalfa can be grown at all), while in other parts of the country, six or more cuttings can be harvested. Emphasizing Colorado management in this dialogue, the first cutting of alfalfa in the season is usually of lower quality than later cuttings as it has larger stems, fewer leaves and more weeds. Later cuttings (second, third and fourth) have smaller stems and more leaves. Since the majority of the nutrients are in the leaves, the more leaves, the higher the quality of the forage. Later cuttings are usually of highest value and if managed correctly may bring a premium to the producer. The first cutting is usually classified as beef cow hay. The second and third cuttings of a forage is targeted by horse people. The third and fourth are considered dairy quality (if cut at an immature stage), as the highest quality forage is essential for maximum milk production. Therefore the later cuttings of a season are of higher quality in a perfect scenario. A perfect scenario is not realistic in most situations, as rainfall and other “situations” will affect the potential quality, even if you have harvested it at the perfect time.
Table 3. Nutrient content1 of forages commonly fed to alpaca (Dry Matter).______
Forage %CP %ADF %NDF____
Alfalfa, pre-bud 23 28 38
Alfalfa, early bloom 20 30 40
Alfalfa, mid-bloom 17 35 46
Alfalfa, mature 15 41 53
Alfalfa-grass, midbloom 15 38 55
Alfalfa-grass, mature 12 42 52
Brome, late vegetative 14 35 63
Brome, late bloom 8 49 81
Orchardgrass, late vegetative 18 31 55
Orchardgrass, early bloom 15 34 61
Wheat straw 4 54 85_______
1 Pioneer, 1995
Grass is normally harvested only twice in Colorado – thus, there are only two cuttings. At higher altitudes there will only be one cutting. When harvesting grass for hay, the more immature the grass is when cut, the higher the quality of forage. As the plant matures, seedheads develop and as they begin to emerge, the quality of the hay goes down. If all of the plants have seed heads, the hay is now called mature hay, and is of lower quality. Generally the first grass hay cutting of the season is of higher quality. As the season advances and temperatures increase, the amount of lignin in the plant increases, lowering the digestibility. Therefore, the earlier, more immature cuttings are of higher quality than later cuttings. Therefore, it is possible to break open a bale of hay and look for the number of blossoms and seadheads. The more blossoms and seedheads found, the more mature the hay and the lower the quality.
Once the forage has been harvested or purchased it needs to be stored correctly to protect nutrients in the feed. The best form of storage is to put the hay in an enclosed barn or shed. If that is not possible, a tarp can be draped over the stack of hay and secured. Either way serves to protect the forage from losing nutrients to bleaching from the sun or leaching of nutrients by rain or snow. After one year’s storage there is a decline in the nutrient content, so it is best to appropriate that amount of forage that can be fed in one year’s time.
Readily available carbohydrates like grain are an energy source. They are not a protein or mineral source (Table 4), and are to be used only in moderation for alpaca if the animal needs more energy. Times of higher energy (and nutrient) requirements for the alpaca include late gestation (last one third), early lactation, growth, in extremely cold weather and at times for the geriatric animal. Grain is commonly used as a carrier for a mineral supplement, and daily small amounts (quarter of a 8 ounce cup) are not a problem. Now as I am discussing this, some of you will say that the instructions for commercial pellets will recommend up to 0.5 kg intake. Remember that commercial pellets are only a portion grain and most pellets are high in dehydrated alfalfa – a forage. When purchasing a pelleted supplement, one needs to evaluate exactly what the pellets are made of and follow the recommended levels. Thus, one needs to be careful when defining what a grain is. When I indicate a “quarter of a 8 ounce cup” of grain, I am talking about whole grains such as corn, oats, barley and other grains, not commercial pellets.
The problem with overfeeding grain to alpaca primarily deals with the microbe population. Remember that the microbes in Compartment I digest/ferment the cellulose from forages. They also ferment the starch in grains. Starch is much easier to ferment than cellulose, and if too much grain is fed, then the microbes ferment it very fast producing large proportion of lactic acid rather than the traditional fatty acids we talked about earlier. The pH of lactic acid is very low and can actually burn the inside of Compartment I. In ruminants this is called acidosis, in camelids it is called “grain-overload.” The problem with grain overload in the camelids is that by the time you see any symptoms, it is probably too late to save the animal even with drastic surgical measures. For example, just recently a local producer had 9 alpacas consume a large amount of grain from a 55-gallon barrel. The producer called a vet who did not have alpaca experience and who asked if the animals were showing any symptoms – in ruminants symptoms are apparent in only a few short hours. Animals become lethargic with their heads hanging down and have labored breathing. Symptoms of a grain overload are often not apparent in alpacas for 24-48 hours. In the above scenario, the animals had not exhibited symptoms and thus were not treated. The next day when the first alpaca began to exhibit the symptoms of grain overload it was rushed to the veterinary hospital where the grain was immediately surgically removed from the animal. The animal died even with surgery, as did 7 of the other 9 animals. Thus, if your alpaca consumes a large amount of grain, immediately contact a veterinarian who has had camelid experience and take the precautionary measures. Further information about the nutritive value of grains is characterized for camelids in another article written by Fowler in 1989.
Table 4. Nutrient content of common grains fed to alpaca (Dry Matter)
Grain %TDN %CP %Ca %P ____
Barley 84 13.5 0.04 0.34
Corn 87 10.9 0.03 0.29
Oats 77 13.3 0.07 0.38
Wheat 88 16.0 0.04 0.42____
If grain is supplemented to crias, they must be vaccinated for enterotoxemia as are lambs – actually I prefer good quality alfalfa hay as a creep feed. Just be careful of the animal consuming too many leaves as this may create a bloat situation. Without the enterotoxemia vaccination, microbes in the cria’s gut digest the starch from grains, changing the gut pH. A change in gut pH favors the Clostridium microbe population normally inherent in the gut. This organism then releases an endotoxin that will be absorbed and ultimately result in death.
One more note about grains. Notice the nutrient composition of the 4 grains presented in Table 4. Again – grains are an energy source (%TDN) and not a protein or calcium source. There are other feedstuffs that can supply more protein and definitely more calcium than grains. Do not use grains as a calcium source, there is none there, and besides there is more phosphorus than calcium which you do not want! Remember too that alpacas are extremely efficient and if too much energy (grain) is supplied, they can become obese. Animals should be weighed on a regular basis, monitored and records kept.
When evaluating the protein requirement of animal, one needs to be aware that a protein requirement is in reality an amino acid requirement. The animal’s requirements are for amino acids, not protein. The use of CP is part of an older system, but is still adequate in the alpaca scenario as we are not even sure about the CP requirement, much less the amino acids. Camelids, like ruminants, have an advantage because of the microbial protein supply from Compartment I that we discussed earlier in the text. Microbial protein aids in balancing out the amino acid requirements – as long as the animal is fed appropriately. The alpaca’s estimated CP requirement is 12-14% CP (Table 1). If alfalfa is fed, the CP requirement will be more than met, as the CP is higher in a legume forage than grass. Alpaca producers have heard that alfalfa is bad and that it should not be fed, and that is not exactly true. Alfalfa is high in protein and calcium – higher than what the animal requires. Too much protein will be excreted as urea in the urine. You smell it as ammonia near the dung heaps. Too much calcium may tie up other nutrients and be deposited as monoliths in the gastric pits of Compartment I. Whether these monoliths are of concern is not known. However, some alfalfa is not bad and in fact, I use it to my advantage because of the higher nutrient value. I often blend a little alfalfa hay in with grass hay for animals having those physiological stages with higher nutrient requirements. The alfalfa is of benefit particularly in late gestation or early lactation when CP and calcium requirements of the animal are higher.
The economics of the feeding situation also needs to be considered. There are several areas of the country where it is impossible to acquire good quality grass hay. Thus, if a producer does not have access to grass hay, alfalfa may be the only choice. Or if the only available grass hay is of low quality grass hay, then blending alfalfa with it works well. If a good source of immature grass hay is found, it will usually meet the CP requirements, but you will not know till you test it. If low quality grass hay is fed and alfalfa is not available, then supplementation with a protein source like soybean meal (50% CP) or corn gluten meal (65% CP), both plant protein source will be advised. However, remember that forage must always make up the majority of the diet. A producer may come up with the ideal to feed dehydrated alfalfa if alfalfa or good quality grass is not available – be careful! My research at Colorado State University very clearly shows that camelids physiologically need long-stem hay for gastrointestinal health, and a diet too high in a pelleted form of diet can easily become impacted.
I also caution you not to feed an animal protein like meat and bone meal or tankage for several reasons. One of those reasons is palatability meaning the animals will probably not eat it, but the greatest concern is the potential transmission of Bovine Spongiform Encephalopathy (BSE) also known as Mad Cow Disease. There have been no cases of BSE in the United States, but this is a safety measure by the feed industry to see that it does not occur.
Most alpacas need some type of mineral supplementation. What type of mineral is dependent on the area of the country where the animals are grazed or where the forage was harvested. In general, the soil mineral content will be characterized in the feeds grown on the land. The local county extension agent can help you find out what type of soil you have. You still may have to have soil tests done in addition to your forage analyses to characterize what is needed. It is to your advantage to know the land and if a mineral is deficient or found in excess. A local feed dealer often supplies nutritional advice if you were to buy the mineral supplement from them. Never haphazardly add a mineral mix without doing your research about what should be fed. Addition of a mineral to a diet that is already high in that mineral – whether it is from the feed or water – can create secondary mineral deficiencies or toxicities. Selenium is one mineral that caution needs to be taken with as selenium is cumulative in the body. A secondary deficiency is a deficiency in an individual mineral created when another mineral is too high or low in comparison – remember a balanced diet is the key.
Anecdotally it is said that camelids do not utilize salt blocks, but even that is controversial depending on the person you talk to. The best advice if to provide loose salt in a dispenser that will facilitate protection from the environment, in addition to providing a mineral mix (that) with a low level of salt. If possible do not utilize the red salt trace mineral blocks. The blocks are red due to iron oxide and iron oxide could tie up other minerals. There is much more that could be discussed on minerals, but that is for a later discussion. Other references such as Pugh (1996) or Van Saun (1999) are also good sources of information.
There are references on camelid vitamin requirements (Van Saun 1999) so little time will be spent on them in this text. I would like to caution alpaca breeders though, to take care when supplementing vitamins, particularly vitamin A, as it too is cumulative in the body. Good quality forages that have been properly stored will supply all vitamins needed by healthy animals in most situations.
The only other vitamin of discussion in this text will be vitamin D. In most cases, animals can acquire this vitamin from sun-cured hay (less than one year old and if stored correctly) or from direct sunlight. Ultraviolet light (290-320 nm) from direct sunlight converts a precursor found in the animal’s skin to active vitamin D. However, in some parts of the country like Colorado, the orientation of the sun, particularly from November to March does not allow for this to take place. In such a situation, a female that is in late pregnancy (last 3 to 4 months) will need an injectable vitamin D supplement or the developing cria could potentially develop rickets. The females should be supplemented with 150,000 IU vitamin D once during late gestation. The cria born during that time period should too be given a vitamin D injection (based on body weight), fed a mineral mix having a 2:1 (calcium: phosphorus) ratio and provided alfalfa hay as a creep feed.
Briefly the physiological status of an animal determines it nutrient requirements. The stages of highest nutrient requirements are: the third trimester of pregnancy, early lactation, growth, work (individual animal, altitude, humidity and temperature), extreme cold and geriatric animals. Geriatric animals will suffer from stiffness (arthritis), have compromised immune systems and less ability to heat or cool their body. One of the key management tips is to watch their mouths. With age, they will lose teeth or the teeth will become in poor condition making it difficult for them to chew without pain. If they are unable to chew, they will eat less and will lose body condition. Provide geriatric animals with warmed water (just above freezing) to allow adequate water consumption. If the animals stop drinking water they will not consume food. One other comment, gelded males have lower energy requirements than intact males.
Care needs to be taken in very cold or hot weather. In both extremes, animal health can be compromised particularly in geriatric animals. Geriatric animals are less able to cool or heat their bodies. In this situation, shelter from the wind in the winter and a supply of heated water (just above freezing) will aid the animal significantly. In hot weather, the animals will need some type of shade and other cooling measures to prevent them from overheating. In the AOBA proceedings (Irlbeck, 2000), environmental issues are discussed in greater depth.
I have tried to discuss several basic concepts in a brief amount of space. More research is needed to quantify alpaca nutrient requirements, and yet the requirements mean little if an alpaca owner is not familiar with the feeds to provide those nutrients. Determining the nutrient content of feed, water and soil is one management tool that cannot be ignored when feeding alpaca.
Bauder, J. 1998. When is Water Good Enough for Livestock? Montana State
University Extension Service. Bozeman MT
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Energy Requirement of the Mature Llama. American Journal of Veterinary Research 53:1696- 1698.
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Breeder’s Association Annual Conference Proceedings. June 4. Louisville, KY
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Annual Conference. Denver, CO.
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How to Feed a Horse: Understanding the Basic Principles of Horse Nutrition (B 1355)
Kylee J. Duberstein, Ph.D.,Department of Animal and Dairy Science, University of Georgia
Edward L. Johnson, Ph.D.,Department of Animal Sciences, University of Florida
How do you properly feed a horse? With so many feed, supplement and hay choices available, many people find themselves wondering exactly what their horse needs for good health and nutrition. Many horse-feeding opinions and myths make deciding what to feed even more difficult. The law requires commercial horse feed manufacturers to put information concerning their feed on a "feed tag," which is either attached to or printed directly on the bag. This tag provides essential information on what the horse will be eating. However, most horse owners either don’t understand or don’t take the time to read this information. This publication explains your horse’s nutritional needs, common guidelines to observe when feeding your horse and how to determine if your horse’s nutritional requirements are being met.
When feeding horses, it is important to recognize that there are six basic nutrient categories that must be met: carbohydrate, protein, fat, vitamins, minerals and water. Often, feed companies will balance the first five nutrients for us; however, it is critical not to forget about water. A normal, healthy horse will consume 5-15 (or more) gallons of water per day depending on temperature, humidity and activity level. Clean water should be provided daily, and ideally, should be available at all times for the horse to drink when it is thirsty. If this is not possible, horses should be watered a minimum of twice daily and allowed several minutes to drink each time. Horses that do not drink enough water are more susceptible to conditions such as dehydration, intestinal impactions and other forms of colic.
The rest of the horse’s diet should be formulated based on its requirement for each of the other five nutrients. These requirements differ from individual to individual and are influenced by the horse’s body mass, age, workload and metabolic efficiency. It is a very useful skill to be able to look at a feed tag and determine if that feed is going to meet your horse’s requirements. Let’s look at each category of nutrients you will encounter when evaluating your feeding program.
Carbohydrates will most likely be the largest part of the horse’s diet. They can be divided into two groups: structural (fiber) and non-structural (sugars and starches). Structural carbohydrates are found in the largest amounts in the roughage that the horse eats (e.g., hay, grass) and are able to be digested thanks to the design of the horse’s intestinal tract. Following digestion in the stomach and small intestine, the horse’s digestive material enters the large intestine (hindgut), which in the horse consists of the cecum and colon. The cecum and colon contain microorganisms that are capable of breaking structural carbohydrates down into an energy source that the horse can absorb. This is why horses get so much nutritional value from grass and hay.
It is important to feed good quality hay that is free of mold and dust and is cut at an appropriate length and stage of maturity. Hay that has too coarse a stem or hay that is too fine can cause digestive problems such as impactions. Hay that is overly mature when it is cut has little nutritional value to the horse due to an increase of a component called lignin, which is completely indigestible for the horse or the microbes in the gut flora.
Horses can easily digest nonstructural carbohydrates, mostly in the small intestine. These sugars and starches are primarily found in grains (e.g., corn, oats, barley) and provide a more concentrated form of energy than structural carbohydrates (thus, the term "concentrates" is often used when referring to grains and grain mixtures). It is important to recognize that the horse’s digestive system evolved to process a roughage-based diet; therefore, concentrates should be used only to supplement the forage program and meet nutritional requirements that cannot be met by forage alone. The horse should always be fed a minimum of 1 percent of its body weight in forage (on a dry matter basis); the ideal is 1.5 to 2 percent of its body weight. Feeding less roughage than this can lead to health issues such as colic and ulcers.
There are currently a number of "safe" feeds marketed to the horse industry. These feeds are manufactured with ingredients that are high in digestible fiber and low in sugars and starches. For example, "safe" feeds often use ingredients such as beet pulp and soybean hulls, which have a high composition of digestible fiber, a low starch content and avoid use of ingredients such as corn, which is high in starch. Often feed tags will give an average starch percentage listed on their guaranteed analysis to allow owners of those horses with special needs (e.g., Cushings, metabolic syndrome, chronic laminitis, ulcers or recurring colic) to select a horse feed with a low starch content.
Protein, which is necessary for body growth and maintenance, is a nutrient that is poorly understood by many horse owners. Proteins are broken down in the small intestine into amino acids that are recombined to make proteins in the body that make up muscle, hair and hoof. It is important to realize that proteins are composed of amino acids, and the proteins that the body makes have very specific amino acid sequences. The amount of protein that the body can synthesize is limited by the amino acid that basically runs out of supply first. For horses, this is generally lysine. Therefore, on many bags of horse feed where the protein percentage is listed, it might also say "added lysine" and list an additional percentage for the lysine content. This, in essence, improves the protein quality without increasing the total amount of protein in the feed.
There are advantages to improving protein quality without increasing the total protein amount. It is a commonly held misconception in the horse industry that higher protein is associated with higher energy. In reality, proteins are the most difficult energy source for the horse to digest and convert to usable energy. Protein requirements for growth and maintenance vary depending on age and workload. In general, growing horses need a higher percentage of protein than mature horses. A growing horse generally needs between 12 and 18 percent crude protein in its diet for proper growth and development. Horses need more protein when tissue is being laid down for growth (i.e. young horses in rapid growth phases, gestating mares in their last trimester, and lactating mares that need to produce large quantities of milk). Mature horses will most likely do fine on a lower protein percentage (8 to 12 percent), depending on their workload. Horses that are in intense training need more protein than the maintenance horse because they are developing muscle tissue; however, most will still do well on a 12 percent protein feed. Feeding horses higher levels of protein than they need simply means that the horse breaks down the excess protein and excretes it as urea in its urine, which is rapidly converted to ammonia. This is not desirable since excess ammonia can lead to respiratory problems in stabled horses.
It is important to recognize that forage is also a source of protein. Select hay that will help meet the horse’s protein requirement. Hays can be categorized as either grass hays (e.g., bermudagrass, timothy) or legume hays (e.g., alfalfa, peanut, clover). In general, legume hays are higher in protein than grass hays. Good quality legume hay can have roughly 18 to 22 percent crude protein, while good quality grass hay can have 10 to 16 percent crude protein. Again, quality and growth stage at harvest determine how digestible the hay is and influence how much protein the horse receives from it.
Feeding high-fat diets is a relatively new trend in the horse industry. It has been demonstrated that horses can tolerate a fairly high level of fat in their diet. Fat is an excellent and easily digestible source of energy. Commercial feeds that are not supplemented with additional fats contain approximately 2 to 4 percent fat. Many commercial feeds are now supplemented with fat in the form of some type of stabilized oil. These feeds can contain anywhere from 6 to 12 percent fat. Since adding fat to a feed increases its energy density and the horse will require less feed, it is important to be sure that all other nutrients (i.e., protein, vitamins, and minerals) are also high enough to meet your horse’s requirements. While commercial feeds will be nutritionally balanced, if you are increasing the fat in your horse’s diet by simply pouring some type of oil or fat supplement on the feed, it is important to be sure that you are meeting his other nutrient requirements and not just his energy requirement.
Vitamins are critically important organic compounds. They must be present in the body to enable important reactions to take place that allow the animal to live. Vitamins are divided into two categories: the water-soluble group consists of the B-complex vitamins (e.g., B1, B2) and the fat-soluble group is comprised of vitamins A, E, D and K. Some vitamins also have associated names (for example, B1 is also known as thiamine). It is important to recognize that the horse synthesizes many of the vitamins it needs and therefore does not typically need dietary supplementation of all vitamins. This would include vitamin C, B-vitamins and vitamin K; therefore, you will often not see these vitamins included on commercial horse feed tags. It is important to check your feed and be sure that all of your horse’s vitamin requirements are being met since vitamin deficiencies can lead to various health problems. However, it is also important to realize that extreme excesses in these vitamins are not desirable either, particularly regarding fat-soluble vitamins. Excess water-soluble vitamins are generally excreted in the urine; however, fat-soluble vitamins are stored readily in the animal’s fat tissue and therefore can build up to high levels if fed in excessive amounts. Since excessively high levels of vitamins can lead to toxicity, it is important to use good judgment when feeding nutritional supplements that are high in particular vitamins. In most cases, a good forage program combined with a well-formulated concentrate will provide adequate vitamins to meet your horse’s requirements.
Minerals are critical inorganic materials that must be present in adequate amounts for the body to function properly. Minerals are another item that can be found in supplements on feed and tack store shelves. It is important to understand that mineral needs will change depending on your horse’s age and status (i.e., if the horse is working, gestating or lactating). Most commercial feed companies balance their feed to meet the mineral requirements of different classifications of horses. Forage will also provide minerals. In some cases, additional supplementation of some minerals may provide desirable results. For example, biotin, zinc and copper supplemented above requirements have been shown to improve hoof strength. However, care should be taken because excessive amounts of minerals may also cause toxicities, lead to serious health conditions or interfere with absorption of other minerals.
If your horse does not receive a commercial concentrate or eats very little of it, it may be important to supplement additional vitamins/minerals to his forage diet by feeding a product called a ration balancer. Ration balancers are manufactured by many feed companies and are designed to be fed at a low level (approximately 1 pound per day) that contains the needed vitamins, minerals and protein. It is also possible to meet vitamin and mineral requirements by providing a free-choice loose salt-vitamin-mineral mix. Horses are inefficient lickers, so loose mixtures tend to work better than salt blocks. Also, mineral blocks are generally less than 5 percent mineral and more than 95 percent salt, so they do little to provide for the horse’s vitamin/mineral requirements. A loose vitamin/mineral premix or a ration balancer is a good option for horses maintained on pasture and adapted to eating all-forage diets. If providing a loose mixture, a general rule of thumb is to expect horses to consume 1.5 to 3 oz. per day.
One common mineral ratio you will see when looking at a bag of feed is the calcium:phosphorus ratio. It is important to check that both commercial feeds and vitamin/mineral premixes have a calcium:phosphorus ratio between 1:1 and 2:1. If the phosphorus levels are high in relation to calcium, calcium will be pulled from the bone into the blood stream to balance the calcium:phosphorus ratio. This is not typically a problem for grazing animals since phosphorus is fairly low in grasses, but grains are very high in phosphorus and commercial feeds are generally supplemented with some form of calcium. Feeding single grains, such as oats, can cause an inverse calcium:phosphorus ratio if calcium is not supplemented in some form. Another important mineral consideration is your horse’s sweat loss. Horses that are in moderate to intense work and are sweating heavily lose electrolytes in their sweat. For these horses, it may be necessary to supplement both salt and additional electrolytes (such as potassium). A balanced electrolyte mix can be added to the horse’s grain mixture as needed.
Simple Calculations to Determine Nutrient Intake
Nutritional requirements vary from horse to horse and it is important to be able to examine a feed tag and assess whether or not that feed will meet your horse’s needs. Manufacturers typically put feeding instructions on the tag to help buyers determine if the feed is appropriate for their horses and how much of it should be fed to each individual. However, it is beneficial to be able to look at a particular feed and understand why it is or is not a good choice for your horse.
If you want to examine your feeding program more closely, the most in-depth listing of requirements can be found in the National Research Council (NRC) recommendations for horses (Nutrient Requirements for Horses 6th Edition, 2006). Approximate nutritional requirements based on a horse’s age, workload and status are listed along with the nutritional value of different grains and hays. This resource is based on scientific research and is updated periodically to stay current with recent findings. To access this database online, go to http://nrc88.nas.edu/nrh/. This Web site allows you to select the age, weight, status and workload of a particular horse (under "Animal Specifications") and determine its specific nutritional needs for macronutrients (given in the table at the bottom of the web page) as well as vitamin and mineral needs (under "Other Nutrients"). This program also allows you to select certain forages and other feedstuffs (under "Dietary Supply" — click on "New" to change feedstuff) to determine how much of your horse’s requirements are being met by a particular feed or combination of feeds (you must input the weight of each feedstuff being consumed).
Sample By-Hand Calculation
If a mature horse weighs 400 kg and is not exercising, maintaining his weight and body condition will require approximately 504 g of protein (according to recent NRC guidelines). If the horse is eating 1.5 percent of its body weight in coastal bermudagrass hay, it is eating approximately 6 kg of hay each day (400 X 0.015). The average coastal bermudagrass hay contains approximately 10.4 percent crude protein. If you multiply 6 kg by 0.104, you get 0.624 kg, or 624 g. Therefore, in this instance, the horse’s protein requirement is being met through the forage it is consuming.
As another example, if that same 400 kg horse is working at a very intense level, it will require approximately 804 g of crude protein. If the horse is eating the same 1.5 percent of its body weight in coastal bermudagrass hay, it will be short 180 g of protein (804-624) necessary to meet its needs. Therefore, a concentrate (grain) must be provided to make up the difference, and/or hay with higher protein content (e.g., alfalfa) can be fed instead of coastal bermudagrass. (Special note: When allowing the NRC computer program to calculate the dietary supply a certain foodstuff you are providing, it will often calculate slightly lower than when you calculate by hand. This accounts for losses that are difficult to determine by hand calculations; however, hand calculations will still give a fairly accurate estimate as to whether your feeding program is meeting your horse’s requirements).
Calculating whether a feeding system meets a horse’s nutrient requirements can be done on virtually every nutrient (including digestible energy that is provided primarily by carbohydrates and fats). Commercial feeds typically provide recommendations based on the horse’s weight, age and activity level. These recommendations are based on NRC recommendations as well as the composition of their feed. Because there are many myths surrounding the practice of feeding horses that really have very little or no truth, it is important to understand your horse’s nutritional requirements and be able to apply your knowledge in a practical manner.
Status and Revision History
Published on Aug 19, 2009
Re-published with minor revisions on Jun 15, 2012
Reviewed on Jul 5, 2015
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