General Ration Balancing Considerations for Goats
In large herds, it is generally impractical to feed each goat individually. The milking process is slowed and the risk of indigestion is increased if all of the concentrate ration is fed in the parlor.
Inevitably, some goats fed in a group are overfed and others are underfed. A measure of control can be maintained by grouping goats according to age and production (Skjevdal 1981). Using locking stanchions or short chains that clip onto collars and manger dividers permits each goat to consume its allotted share of concentrates without gross interference by more dominant does. The goats are then released, because they normally consume more hay if they can move freely from hay to water or salt block and back to hay (Morand-Fehr 1981a).Another problem associated with large herds that have gone beyond the hobby stage is that grain is sometimes cheaper (on a kcal of energy basis) than high-quality forage, and grain is certainly easier to store and feed than is hay. Thus, owners may choose to overfeed concentrates without considering the adverse effects on health related to this practice.
Zero Grazing
Zero grazing is an important step toward intensification of goat raising. The grazing goat eats slowly, carefully choosing young stems and leaves. It wastes a lot of forage and does not achieve maximum DMI unless supplemented in the barn. Some of these problems can be avoided by careful grazing management, including high-density stocking, frequent rotation, and adequate rest periods for the pastures. Even under such a system, goats do not graze as closely as sheep (Jagusch et al. 1981). A much greater production of milk per acre often can be obtained by cutting the forage and bringing it to the goats. This forage can then be analyzed and it becomes possible to identify deficiencies and excesses in the total ration, although what the goat eats will not exactly match the analysis.
At the same time, there is no need to maintain fences, the energy requirements for maintenance of the goats are reduced, and there should be less trouble with predators and internal parasites other than coccidiosis. However, an exercise lot at least twice the area of the stable is still desirable (Toussaint 1974).Even in total confinement, goats often waste more than 40% of forage placed in the manger. The goal should be to limit the leftovers to no more than 20% of the feed offered. This means not distributing a plethora of forage and constructing mangers that impede the goat's tendency to remove its head and drop part of every mouthful on the ground. Slanted manger bars are preferable to keyhole feeders. On the other hand, goats do not achieve maximum intake if they are not allowed to exhibit their normal choos- iness in eating; a bare manger indicates submaximal consumption. If hay is of poor quality, a greater excess should be distributed to encourage intake. Ideally, another livestock species (such as a pony or sheep) should be available on the farm to make use of the daily manger hay sweepings. Goats spend more time eating each day than do sheep. They ruminate approximately eight hours a day, six of which occur at night.
Traditionally, dairy goats have been offered a basal ration of forage (such as hay) free choice, with concentrates fed individually, according to production. Hay should be fed before concentrates, to decrease the risk of low rumen pH resulting from rapid digestion of non-structural carbohydrates in the grain. A total mixed ration can be fed to avoid excessive wasting of the forage and indigestion associated with “slug” feeding of concentrates and to improve consumption of less palatable feeds (Rapetti and Bava 2008). Chopped hay, grain, minerals, and vitamins are mixed with ensiled products (haylage, beet pulp) to obtain a final dustfree mixture. The formulation of the mixture is readjusted frequently during lactation to ensure that each goat consumes adequate fiber (optimum 1 kg hay) even when production and intake have dropped in late lactation (Hervieu 1990).
Forage Quality
Grasses and legumes typically give the highest yield in NE and protein if they are harvested at the early budding stage (Fick and Mueller 1989). In more advanced stages of maturity, the proportion that is stem increases, as does indigestible fiber such as lignin, while the amount that can be consumed daily decreases. Mineral content also decreases in mature forages. Because of the increase in digestible energy and protein, a smaller quantity of concentrate with a lower protein level can be fed when forage is cut early.
Owners purchasing hay should use both subjective and objective evaluations. Hay should be bright green (not yellow or brown), leafy, sweet smelling, and free of mold or weeds. If possible, the cutting number, cutting date or weeks of regrowth, and year should be ascertained. First-cutting hay can be very early to very late cut, depending on local weather and farming practices. Moldy, weedy, badly weathered, or severely overripe hay should be rejected. Large, round hay bales that have been stored uncovered in rainy climates are suspect, because the outer moldy part is a large proportion (often 25-30%) of the bale and rainwater will have leached soluble nutrients out of the hay in the center of the bale. If the hay appears palatable but its nutritional value is questionable, crude protein, available protein, ADF, and NDF should be determined by a forage testing laboratory. This is especially important with grass hays, in which stage of maturity is more difficult to judge than with alfalfa hays.
Owners of small herds probably do not buy at auctions, where hay has been analyzed and graded to reflect nutritional value. Some are fortunate and find a local, wellmanaged farm where 20 representative hay core samples have been taken and analyzed from each batch of hay (Putnam n.d.). Alternatively, a cooperative extension office might lend the equipment and the hay seller might be willing to share the cost of the hay testing or pay for the testing, with the understanding that the price of the hay will be determined by its quality.
Sellers unwilling to cooperate often have poor hay.Stored forages have decreased vitamin content. Thus, supplementation with vitamins A, D, and E is usually imperative when hays or silages are fed many months after harvest.
Silage
Because of weather constraints, it is often easier to make young herbage into ensilage than into good-quality hay. For best results, including highest intakes, a preservative such as formic acid (0.2-0.5% added to the direct-cut crop) is used (Nedkvitne and Robstad 1981). When silage is fed, it is still important to offer an excess of feed, allowing at least 10-15% refusals, to obtain maximum DMI. Bunks should be cleaned daily to prevent spoilage. Though good milk production can be obtained when goats are fed silage in place of hay, the danger of listeriosis associated with silage feeding must be kept in mind. The herbage must be free of dirt that might carry Listeria organisms, and the silage must be properly made and stored so that it maintains an acid pH (less than 5) unfavorable for additional multiplication of the bacteria. In small herds, ensiling is often impractical unless plastic bags are used. A few animals do not eat enough to prevent spoilage at the leading edge of a pile or conventional silo.
Corn silage (stalks, leaves, and ears chopped together) is commonly fed to livestock in the United States. When kernels are well developed at the time of harvest and moisture content of the plant is appropriate, there is adequate carbohydrate to permit good fermentation and attainment of a low pH. Contamination with soil (during harvest or packing) and surface spoilage can still permit dangerous growth of Listeria. Manger sweepings of corn silage from cattle farms should not be fed to goats. Additionally, goats pick the corn kernels out of the silage by choice and eat proportionately less roughage or else eat the roughage portion of their diet after the grain has been consumed.
Palatability
Goats show great individual differences in what they prefer to eat.
Texture and taste are both important. Thus, goats generally dislike dusty feeds. Molasses makes a grain mixture more appetizing (Morand-Fehr 1981a). However, feeds with more than 5-6% molasses should be avoided (Adams 1986) because of possible adverse effects on rumen function. Coarse-textured grains (i.e., rolled, cracked, crimped, flaked) and pellets are more acceptable than finely ground meals.Past dietary experience is also important in determining what an individual goat will eat. This is important in range situations, when more palatable forages may be scarce or potentially toxic secondary metabolites are present in many plant species. Goats appear to adjust their intake of available plant species to maximize nutritive value while avoiding toxicity (Papachristou et al. 2005). Young goats may learn which species to consume in part by observing their dams (Glasser et al. 2009) or other more experienced members of the herd, and feed preferences developed in the second to fourth months may persist for life (Biquand and Biquand-Guyot 1992; Provenza et al. 2003). For this reason, converting a herd to a new feed resource base (different plant species, new region of the country, hay to silage, silage to cubes, etc.) may require a full year or even a full generation before previous productivity is restored.
Body Condition Scoring
In the adult goat, proper bw is a function of breed, frame size, and stage of gestation or lactation. Accurate scales on which to weigh goats are often not available. The frame size of an individual adult is constant, but deposition of fat and muscle (body condition) varies with nutritional and physiologic status. Body condition is a measure of the animal's lipid and protein reserves. These reserves are used in late gestation, early lactation, and times of environmental adversity.
Although sophisticated methods to determine body composition based on slaughter or biopsy techniques have been developed for goats (Morand-Fehr et al.
1992), a practical method must rely on palpation and visual assessment of the animals. A lumbar score has been applied to meat goats in Australia, using scores of 1 (very lean), 2 (lean), 3 (medium), or 4 (fat) (Mitchell 1986; McGregor and Butler 2008). A similar scheme using one-fourth or one- half point increments from 1 to 4 has been developed for indigenous goats of the Small East African type (Honhold et al. 1989). In score 1 goats, there is almost no muscle covering the intervertebral articulations; a score of 4 corresponds to muscle completely covering the vertical and horizontal processes of the lumbar vertebrae. In these animals, a change of 1 in the condition score represents an average of a 12% change in bw.Lumbar systems originally designed for sheep and cattle are not directly applicable to dairy goats, because most of the dairy goat's body fat is stored in the omentum and perirenal tissues (Chilliard et al. 1981). Even obese animals have little subcutaneous fat. A system has been developed specifically for dairy goats, but is appropriate for all breeds. This body condition score is an average of lumbar and sternal scores, each of which is divided into 0.25 point divisions. Integer scores from 0 to 5 used in this method are described in Table 19.6 (Morand-Fehr et al. 1989; Santucci et al. 1991; Hervieu and Morand-Fehr 1999).
The goat is evaluated while relaxed and standing evenly on all four feet. The sternal score correlates better with the proportion of adipose tissue in the goat, while the lumbar score (determined over the second to fifth lumbar vertebrae) better reflects body protein (Morand-Fehr et al. 1992). Each 0.25 change in the final score corresponds to approximately 1.5% lipid content of the body (Morand-Fehr et al. 1992). Owners are advised to select and score 15 lactating goats one to two months before breeding will begin. Three of these animals should be high producers, nine average producers, and three low producers. The same 15 goats are scored again at the end of lactation and immediately after parturition. A sick or injured goat is replaced with an animal of equivalent milk production. The lumbar score for Alpines and Saanens in France averages 2.5-2.75 at dry-off, 2-2.25 at parturition, and 2.25-2.5 before the breeding season. The average sternal scores for the same time periods are 3-3.25, 2.5-2.75, and 2.75-3. The combined score should not drop by more than 0.5 points during the dry period (Hervieu and Morand-Fehr 1999). A group of 10 doelings can be followed in a similar fashion to monitor the nutrition and well-being of that age group.
A very similar scoring system for meat goats also takes into consideration the degree of fat deposition over the rib cage. This body condition scoring system has been illustrated with videos and photographs of individual goats with each whole integer score (Langston University 2000)
Table 19.6 Body condition scoring scheme for dairy goats.
Lumbar score
0 The animal is extremely emaciated. The intervertebral articulations are easily felt and the skin seems to be in direct contact with the bones.
1 Muscle extends at most two-thirds of the distance out along the transverse spinal processes. Intervertebral articulations are still palpable but barely visible.
2 Dorsal and transverse spinous processes are prominent, and the skin forms a concave line between them.
3 Spinous processes are still easily felt. The space in the vertebral angle is filled with muscle and the skin determines a straight line between dorsal and transverse processes.
4 Dorsal and transverse spinous processes are difficult to detect and the skin forms a convex line between them.
5 There is a prominent groove down the back line and the fat and muscles mound up on each side of this groove.
Sternal score
0 Costo-sternal articulations are very prominent. The bony surface of the sternum is easily felt. The skin callous over the sternum lacks mobility.
1 Costo-sternal articulations are more rounded but still easily felt. The depression over the sternum is not filled in but the callous is movable.
2 Costo-sternal articulations are difficult to feel. Internal fat pads develop under the muscle layers on each side of the sternum, and subcutaneous fat partially fills the central depression.
3 The central depression is completely filled with a thin and mobile mass of subcutaneous fat. Distinct depressions are palpable on each side between the mass of fat and muscle and the bones. The costochondral articulations are palpable.
4 Sternum and ribs are no longer palpable, but a depression is still palpable on each side of a thick mass of subcutaneous fat.
5 Subcutaneous fat is no longer mobile. No depressions are palpable laterally or caudally.
Source: Based on Morand-Fehr et al. 1989; Santucci et al. 1991; Hervieu and Morand-Fehr 1999.
and a scorecard is available for download (Villaquiran et al. 2015).
Body condition scoring is useful for monitoring the adequacy of the feeding program under intensive and extensive conditions. Critical times for scoring goats might include dry- off, the last two weeks of gestation, six weeks into lactation, at turnout onto pasture, at the beginning of the dry season, and at the beginning of the breeding season (Morand-Fehr et al. 1989). Dairy goats need body reserves at parturition to support maximum milk production in the subsequent lactation. Angoras kidding in good body condition also produce more milk, thereby limiting kid losses because of starvation. Under French intensive dairy goat conditions, the body condition score should be more than 2.25 and less than 3.5 alt dry-off, and more than 2.75 and at or less than 3.5 alt parturition. The score should not be less than 2 at; peak lactation (45 days), nor should it have decreased more than 1.25 points from parturition (Morand-Fehr et al. 1992).
Target scores need to be established for extensively managed goats to obtain satisfactory production and reproduction (Santucci et al. 1991). For instance, recently shorn Angora goats with a low body condition score have a greater risk of dying during inclement weather (McGregor and Butler 2008). Body condition also should be considered when implementing a selective deworming program (see Chapter 10).
Apparent Starvation in the Face of Plenty
When an individual in the herd appears to be malnourished despite free access (including protection from competition) to a palatable and nutritious ration, other reasons for reduced consumption or utilization of nutrients must be investigated. These include dental disease, lameness, blindness, and chronic infectious and parasitic diseases. The clinical approach to such an animal is described in Chapter 15.