Part 2 - 3

FEEDING DAIRY GOATS

The goat is a ruminant, having a four-part stomach like the cow and sheep. The first part, called the rumen, is the largest; it receives food that has been swallowed without much chewing and stores it until it is regurgitated and chewed again. The food eventually goes to the third and fourth stomachs, where it is more completely digested. The rumen contains bacteria that break down plant fibers to soluble sugar and manufacture certain essential nutrients that may be absent from the diet. Digestion is completed in the small intestine.

Although the goat has a great capacity for consuming fibrous feed (roughage), it needs to be given forage or good quality, such as legume hay. In India this often consists of berseem (Egyptian clover, Trifolium alexandrinum), alfalfa (lucerne), groundnut hay, acacia beans or leaves from legumes (pulses). It is economical to give goats all the good quality hay they will consume, because this is often the cheapest source of nutrients for ruminants. Dry hay should be stored for use when green fodder is unavailable. Goats also like vegetable leaves and peelings; for example, cabbage, cauliflower, carrot tops, and turnip tops (potato peelings can be toxic). These should be fed with the regular forage, not in place of it.

The forage diet of dairy goats is often supplemented with a mixture of seeds and other materials, called “concentrate.” Farm by-products are sometimes fed to goats. Among traditional by-products used in Africa are cassava waste, cottonseed meal, and rice bran. Nonconventional sources include bagasse, poultry litter, and sawdust.

The main nutritional requirements are as follows:

Energy sources, Most of the goat’s energy comes from the breakdown of the plant fiber. The rest comes from the oxidation within the body of starches and fats from concentrate. The energy content of the diet is studied in the laboratory by burning a sample and measuring the heat that is generated. The results need to be refined, because some of the energy in food is lost to the animal in the feces, urine, and gases. Moreover, the body uses some of the energy just to do the work of digestion itself. In recent years energy measurements have been refined to account for the special needs of body maintenance, weight gain, or milk production.

A continued shortage of dietary energy sources will lower milk production. Goats at the very early stages of lactation (milk production) need more energy.

Protein - Protein is the main source of dietary nitrogen, makes up the basic cell and tissue structures of the body, and is vital for growth, milk production, disease resistance, reproduction, and general maintenance. Protein quality, a term nutritionists use when referring to the amino-acid content of food, has no significance in ruminant nutrition except at exceptionally high levels of milk production. This is so because rumen microorganisms manufacture all the amino acids needed by the host animal. Excess protein, if any, is oxidized in the body for its chemical energy and the nitrogen is eliminated by the kidneys. Since protein is generally the most expensive part of the
ration, it is unwise to feed more than is needed. Protein requirements vary from 12 to 16 percent of the ration dry matter the larger figure represents the need during high milk production.

Urea and other nonprotein nitrogen products can be used by the microorganisms of the rumen for the production of protein. However, they are not generally recommended for goats because the animals adapt slowly to foods containing them.

Minerals - Most of the minerals needed by goats are obtained from forage and concentrate. The major minerals are calcium, phosphorus, and sodium (as salt). These may be added to the concentrate or made freely available. The ratio of calcium to phosphorus should be kept around 1.5 to 1. Equal parts of salt and dicalcium phosphate are recommended for free-choice feeding. Selenium is essential in very small amounts; in some areas of the world it must be added to the diet.

Vitamins - The only important vitamins in ruminant nutrition are A, D, and E. Generally, goats on green pastures with plenty of sunshine require no vitamin supplements. When goats are confined indoors, vitamin mix, which is not very expensive, should be added to the diet. Stored forages are poor vitamin sources.

Fats - Fats are of little importance in the ruminant diet. Practically all feeds contain small
amounts of fat, and added levels are not practical. Levels beyond 5 percent in the grain mixture are not recommended.

Water - This may be the least expensive feed ingredient, but a deficiency will affect milk production more quickly than the lack of any other nutrient. Water is not only the largest single constituent of nearly all living plant and animal tissue, but it also performs exceedingly important functions during digestion, assimilation of nutrients, excretion of waste products, control of body temperature, and production of milk. Ready access to fresh water is important. Goats with free access to water produce more milk than those watered twice daily.

Although goats can sustain themselves in dry climates better than cows and sheep, their milk production also is considerably less.

Feed Formulation in India

Researchers at Ludhiana in North India suggest a diet of high-quality roughage (fiber) and concentrate (grains). The concentrate provides sufficient protein, minerals, and vitamins. The relationship of concentrate to the quality of roughage is shown in Table 1.

Table 1

Quality of Roughage and Protein Level Needed in the Concentrate

Protein
Quality Description needed, %

Poor Dry wild grasses, maize fodder, millet, 24
wheat or rice straw.

Fair Late cuttings of legume hay (without leaves) 20
mixed hay, silage from grass or maize.
Good Alfalfa, berseem, groundnut hay, good pasture 16

Excellent Extra leafy fine-stemmed alfalfa hay, berseem, 14
or excellent fertilized pasture containing
some legumes.

A typical concentrate contains the following ingredients, in percent by weight: maize 40, molasses 8, wheat bran 20, rice polishings 13, groundnut cake 15, salt 2, and mineral mix 2. Another formula contains: maize whole kernels or sorghum or other cereal 60; soybeans raw or (better) roasted, other legume or whole cottonseed 36, dicalcium phosphate 2, salt and trace minerals 2.

Feed materials were classified according to their protein content as low, medium, high, or very high. Examples are listed below:

* Low protein: maize, maize and cob meal, wheat, oats, barley, millet.
* Medium protein: wheat bran, rice polishings.
* High protein: copra meal, brewers dry grains, legumes.
* Very high protein: cottonseed meal, linseed meal, groundnut oil cake, soybean oil meal, dried milk, meat meal, blood meal.

It was found that, in making up a diet, any item could be substituted for another in the same class.
A suitable mineral mix contained the following ingredients, in percent by weight: sterilized bone meal 35, finely ground high-grade limestone or oyster shell 45, iodized salt 20, and trace amounts of copper sulfate, cobalt sulfate, zinc sulfate, and iron chloride. This formula can be made commercially or mixed at home.

Free-Choice Feeding Experiment in Germany

German scientists studied the diets that were freely chosen by five Saanen goats over a 24-month period. Such long-term studies are important, but infrequently performed because of their high cost.

The feeds offered were mixed grass and legume hay, a concentrate mixture, fodder beets in season, or chopped grass, dried beet pulp, water, and–for three weeks–alfalfa leaf meal. The low protein content of the hay was supplemented by a concentrate made of ground oats, wheat bran, seed meals, leaf meals, and dry yeast.

Milk production in the first year was good and in the second year was well above average. The results showed clearly that free-choice feeding of dairy goats leads neither to their eating too much concentrate nor to unprofitable production costs. Furthermore, it was shown that goats require liberal amounts of water and lush feeds for high milk production. Free-choice feeding can result in good milk production, although yields may vary among animals. Moreover, high milk production is cheaper than lower milk production under free-choice feeding.

Common Feeding Systems

Feeding systems for goats are linked to local methods of growing feed crops and are classified as follows:

Village systems - It is traditional in tropical countries to maintain goats in small areas (1 to 2 ha) of land. They are tethered for limited grazing or are fed kitchen wastes, usually by women and children. Concentrates are rarely used.

Primitive extensive systems - These allow limited grazing or browsing on larger areas of land of low crop productivity. Herds of up to 15 animals are usually made up of smaller herds and are controlled and kept together by a goatherd. The goats eat what is immediately available. There are usually one to four animals per hectare. Often the goats migrate from area to area in a pattern that uses the sparse vegetation without continuous grazing. The seasonal movements, inadequate feed supplies, and infection by parasites seriously affect live weight and cause high mortality. Very extensive systems of this type are found in Africa and parts of West Asia.

Semi-intensive to intensive forage systems - The goats graze on cultivated grasses and sometimes on legumes. However, intensive grazing of pasture is not very common, mainly because the land is valuable for other purposes. Goats can efficiently use cultivated pastures for either meat or milk production. A hectare can support 16 to 60 goats depending on the type of pasture, the amount of fertilizer applied, and the presence of legumes. Available farm by-products are sometimes used to supplement the intake from pasture.

Very intensive system (stall feeding) - Requiring higher labor and capital investment, this system is not commonly practiced in the tropics, but has commercial potential. It assumes continuous management of goats and is justified by the presence of abundant supplies of farm by-product feeds. The system also enables greater control over the goats. It is common in many countries of Latin America and parts of West Asia.

Integration with cropping systems - The nature and the extent of integration depend on the types of crops (annuals or perennials) and on the relative importance of goats in the local economy. Usually the integration of goats is more common with such perennial or tree crops as coconuts, oil palm or rubber. It efficiently uses herbage undergrowth, including mainly grasses, weeds and legumes. The dry matter production of the undergrowth is variable (400 to 1,200 kg/ha). An advantage is that the land becomes more fertile due to return of feces and urine, reduced fertilizer used, control of waste herbage growth, and easier management of the main crop. Success of the system may depend on the amount of dry feed produced from herbage.

Feeding tree leaves - Tree leaves are fed to goats throughout the tropics. The amounts fed vary according to availability of material and the time needed to harvest it, as well as the duration of grazing. Leaves provide variety in the diet as well as meeting part of the requirements for energy, protein and minerals. Many tree leaves are important sources of dietary nitrogen. In Africa, these include acacia (Acacia spp.), leucaena (Leucaena leucocephala), and cassava (Manihot esculenta). These and other tree leaves are an important and underused resource.

The use of farm by-products - Farm by-products can be used effectively for feeding goats. These materials are often abundant and are not suited for human consumption. Some examples are listed above, in this section.