Credit: Biovision-Infonet
Efficiency of Production
Efficiency of production in farm animals is defined as product per unit of food eaten by the animal. Unfortunately, it is not easy to calculate this in a way that makes comparison between different conditions and breeds. The following formula gives some measure of efficiency:
Efficiency (E) = (Product (P) : Food (F)) x 100
Where E is the efficiency, expressed as a percentage, P is the produce and F is the food intake.
Efficiency of Meat Production
Within species, efficiency of weight gain falls gradually as an animal grows. However, if animals of the same species, but of different mature size are compared at the same stage of physiological development, they appear to have similar efficiencies of weight gain. Thus faster growing larger breeds may not be more efficient than slower smaller breeds. It is possible to make adjustments for differences in mature size, so that percentage growth rates can give and indirect assessment of the efficiency of meat production rather than absolute growth rates.
The efficiency of growth can be affected by seasonal fluctuations of feed supply. Usually if an animal eats more it is likely to grow faster. Fluctuations in feed supply may cause live weight loss followed by compensatory live weight gain such as is often found when goats are grazed. Compensatory growth in goats has not been adequately studied, but it is not necessarily inefficient and farmers can take advantage of it. Faster growing goats are more efficient in energy storage but may be no better in protein storage than slower growing goats.
The food eaten by the dairy doe will include allowances for maintenance, pregnancy and lactation. In East Africa large litters are only feasible if the food supply is adequate. Extensive systems of grazing or conditions where the nutrient requirements of twin or triple births cannot be met are, therefore, disadvantageous. Most intensive rearing systems can meet the extra feed requirements.
Efficiency of Milk Production
The efficiency of milk production relates to the question of the efficiency of goats as compared to other lactating ruminants such as the dairy cow. It is known that dairy cattle produce more food energy than beef cattle. A high yielding cow will generally appear to be more efficient than a low yielding goat. Alternatively, a high yielding goat will be more efficient than a low yielding cow. Efficiency of milk production in goats is affected by persistency, feed utilization and feed conversion efficiency. Goats have a flatter lactation curve and peak yields are reached between 8 – 12 weeks of lactation. Alternatively cows hae a maximum milk yield between 4 – 6 weeks. This suggests that goats are more persistent milkers.
Goats also produce a relatively higher milk yield per unit of live weight compared to a cow. The relatively higher milk yield in the goat is due to the relatively larger mammary gland and volume of secretory tissue comprising a greater proportion of the total body weight.
A high yielding animal converts feed to human food efficiently. Animals that yield more milk or grow more rapidly will be more efficient, largely because the maintenance overheads are spread over a great volume of production. This is true of any kind of feed but the farmer will wish to establish which feed gives the best performance.
With goats the large daily intake of feed and larger production of milk per unit of body weight are functions of a higher metabolic rate related to body size.
Yield of Proteins from Meat and Milk
The most important criteria for successful goat production are the efficiency and yield of protein produced from meat and milk. It is well known that in cattle the yield of milk protein is superior to that of meat protein. This is because the efficiency compares the relative yield of protein in various meat and milk animals. The yield of proteins from indigenous goats is approximately 7 times and for exotic goats about 39 times that from meat goats. On a per hectare basis the results are high and even more striking.
The yield of protein from goats compares with similar yields from indigenous dairy cattle. This implies that the dairy goat rather than the diary cow may become more useful for milk protein production.
Milk products from dairy goats is more advantageous by the availability of offspring (mainly males that are not required for breeding) for meat production. These considerations clearly indicate that milk protein production is an important contribution.
Products from Goats
Meat
Goat meat is the most important product from goats in East Africa. It is widely consumed. The colour of goat meat is usually dark and it is somewhat coarse in texture. The fat content is usually sparse and fat is yellow in colour. The sparse covering of fat on the meat and the tendency for the fat to be concentrated more on the viscera is one of the characteristics of the species. There is often a strong odour especially in the meat of uncastrated male goats. There is little or no processing of goat meat in East Africa. The meat is, generally, consumed where it is produced or sold in markets by butchers for immediate consumption.
Milk
Goat milk is widely consumed throughout East Africa. The daily yield of milk per doe varies between breeds and locations due to various environmental effects, but even a small supply is important in many regions where there is both continued under nutrition and malnutrition. The chemical composition of goat milk varies with the individual, breed, stage and order of lactaion, season and nutrition. Whilst the size of fat globules in goat’s milk is of the same order as in cow’s (1-10 iu m diameter) the content of small globules is greater.
Goat milk also has relatively higher contents of fatty acid. Goat milk is a valuable source of aminoacids, is rich in histidine, aspartic and acid and tyrosine compared with cow’s milk and has a larger amount of non protein nitrogen. The nitrogen content of colostrum is higher than that of whole milk.
The sodium, iron and copper contents of goat milk are relatively high. Goat milk has a higher content of Vitamin A, nicotinic acid, choline and inositol compared with cow’s milk but lower amounts of Vit B6 and ascorbic acid (Vit C). An important feature of goat milk is that, unlike cow’s milk, it contains no precursors of Vitamin A, the vitamin being present intact.
Table: Composition of goat milk compared to indigenous cow milk
| Constituent (%) | Goat milk | Cow milk |
| Total solids | 13.9 | 13.5 |
| Fat | 4.8 | 4.8 |
| Protein | 3.7 | 2.8 |
| Non fat solids | 9.1 | 8.1 |
| Ash | 0.85 | 0.74 |
| Lactose | 5.0 | 4.6 |
Table; Comparison of vitamin content of goat milk and indigenous cow milk
| Vitamin (mg per litre) | Goat milk | Cow milk |
| Vitamin A | 2 074 | 1 560 |
| Vitamin D | 23.7 | |
| Thiamin | 0.40 | 0.44 |
| Riboflavin | 1.84 | 1.75 |
| Nicotinic Acid | 1.87 | 0.94 |
| Vitamin B6 | 0.07 | 0.64 |
| Pantothenic Acid | 3.44 | 3.46 |
| Biotin | 0.039 | 0.031 |
| Folic Acid | 0.0024 | 0.0028 |
| Vitamin B1 | 0.006 | 0.004 3 |
| Ascorbic acid | 15 | 21.1 |
| Choline | 150 | 121 |
| Inositol | 210 | 110 |
There is limited processing of goat milk in East Africa. Individual goats or small groups of goats are milked by hand, usually by small farmers and the milk is used for domestic consumption or distributed for sale locally. Cheese making is conducted on a small scale. Occasionally butter and ghee (rendered butter) are produced from goat milk.
Skins
Goat skins are a valuable by product, and in countries with high goat populations, these can earn valuable foreign exchange. The commercial value of skins is, generally, approximately 5 – 10% of the total value of the animal. The skins must be removed with care to preserve their quality for further processing. In organized abattoirs, this is some times achieved but skinning is likely to be less efficient in rural areas. If the skns can be transferred to the tannery with 24 hours no special treatment is necessary. However, some for of curing is necessary at the abattoir to preserve the skins for storage and transport.
- Air drying. This is the simplest and cheapest method i.e., by stretching the hide on upright frames in open, well ventilated sheds where they are protected against sun and rain. The hides must be suspended so that they can dry on all sides. Occasionally arsenical solutions are used as a preservative and the hides and skins are soaked in the solution before air drying.
- Use of Salt. This procedure requires more labour and care and is also relatively more expensive. The salt is applied to the flesh side of the skins. The skins are then stacked closely to allow for impregnation of the tissue. The stack is allowed to stand for about 10 days and is then rearranged with the topmost hide placed at the bottom. A slatted foor is helpful because this allows the brine to run off. Stagnant brine tends to spoil hides.
Wet salting should be done in rooms where the temperature does not exceed 15.6deg C. With higher temperatures deterioration sets in. The alternative to wet salting is dry salting which is a combination of air drying and wet salting. In this sytem, the hides are allowed to dry after wet salting for a few days to remove the moisture. If the hides are marketed after wet salting the moisture content is high and this increases the cost of handling and transport.
Hair
Common Goat Hair:
This type of hair varies with the breed. The fibres are usually multi coloured, very coarse and mostly medullated. They are sometimes straight, non elastic and of variable length. This type of hair is used in the manufacture of carpets, underfelts, ropes and coarse blankets and bags.
Abattoir by-products
A number of important abattoir by-products are produced during the organized slaughter of goats besides the skins. These are tallow (fat), meat, bone and blood meal. Tallow has a wide variety of industrial uses, perhaps the most important being the manufacture of soap. More recently it is used extensively as a valuable high energy animal feed – NOT encouraged for Organic Farming, as farm animals apart from dogs and cats are not supposed to eat animal products
Meat, bone and blood meal is a valuable protein feed and is used extensively for non ruminants such as pigs and poultry. Such protein feeds are in short supply and in intensive animal production these by products are very useful. Additionally, rumen contents can be used as an animal feed. This is particularly rich in the B vitamins.
Other by-products include glue from horn and hooves, various handicrafts from horns, gelatin from bones, hemoglobin from blood. In some parts of Africa the guts from goats are preserved in salt and exported for use as casings for sausage manufacture.
Many parts of the offal of goats are potentially useful by-products and these are the following: Bladder, Kidneys, Blood, Lips, Bones, Liver, Brain, Lungs, Bristles, Meat Scraps, Condemned carcass and parts, reproductive organs, endocrine glands, Skin, Fat *, Spinal cord, Feet, Spleen, Gall bladder, gall and gall stones, Stomach, Hair, Sweet Breads, Head and Head trimmings, Tail, Heart, Tongue, Hide, Trachea, Hooves, Trimmings, Horns, Udder, Intestines and Wool. (*Highly contaminated or partially rancid fat unfit for human consumption) A number of the by-products listed above are edible and their extent and range are determined by such factors as affluence, preference, taste and customs. This is reflected in geographical differences in total edible percentage and total saleable percentage of slaughtered goats. In Africa the estimated total edible and saleable proportions are approximately 50%. Usually livers, kidneys, hearts, tongues, brains and head are sought after in urban areas.
Cheese
Cheese made from goat milk is a much sought after product. However, it must be made properly from milk that is not tainted with the odour associated with goats. This odour comes through in the cheese very strongly and many people find it offensive. If you are planning on making cheese you will need a good recipe book and access to a supplier of starters and cultures, as most cheeses cannot be made without these. It is also essential to have a clean, dry room in which to make the cheese, where it will not be contaminated by dust and flies. A very simple but tasty and nutritious cheese is made in many cultures by leaving the milk to stand until it has ‘turned’. This process can be speeded up by warming the milk a little (to blood temperature) and adding a little lemon juice. When the curds have separated from the whey, the cheese should be hung in a muslin bag, over a basin, and allowed to drain overnight. The curds should then be flavoured with salt and pepper and, if you have them, chives. This makes a delicious ‘cottage or cream’ cheese. If not eaten the same day it will need refrigeration.
Manure
Goat manure is a useful product with commercial value and is used in many parts of East Africa. The manure has a higher content of nitrogen and phosphoric acid than that of cows. The urine is rich in nitrogen and potassium. The manure is an excellent fertilizer and has the potential to increase crop yields.
Compost
A very efficient method of making compost is to stack the manure in a neat square pile (manure from other livestock can be added to make an even more valuable by product, i.e., cow, sheep, donkey, chicken and camel dung). Where possible the pile should be kept moist by watering. After two weeks the whole pile should be turned over and left to mature. Whilst this pile is maturing a second pile can be started. In this way the farmer has a continuous supply of compost for his farm or for sale.