Biotechnology for Livestock Production
Biotechnology offers new benefits to small-scale livestock producers in the region. One of the most important is improved, low-cost vaccines. Another use is the development of new products, including livestock feeds, or food and medicines made from animal products. A recent FFTC regional survey drew up an inventory of useful products and technologies.
Livestock Breeding
Classical livestock breeding has been very successful. However, it is a slow process. Several decades may be needed to breed a livestock population with improved genetic traits. Biotechnology makes it easier to produce animals with superior genetic traits, and to multiply these animals rapidly.
An important advance is embryo transfer, in which embryos produced by superior breeding females are removed for gestation by other animals. These superior females may produce more eggs than normal, as the result of hormone injections (superovulation).
Not only embryos, but also unfertilized eggs (oocytes) can be removed from superior dams. Artifical insemination is then used to produce multiple embryos which are transplanted into unrelated females for gestation. Other advances in the use of biotechnology in livestock production include the production of clones (genetically identical offspring); improved freezing techniques for semen, oocytes and embryos; and genetic evaluation of the sperm used for artificial insemination. In poultry production, it is now possible to fertilize chick embryos and culture them inside an artifical egg until they are ready to hatch. This allows genetic manipulation at an early stage, before egg formation.
Genetically superior animals are still the basis of livestock breeding, as they have always been. With biotechnology, however, the best female animals are being used as a source of genetic materials rather than as a direct source of offspring. This means that they have a much higher reproductive rate than would otherwise be possible.
Water buffalo, for example, produce only one calf every two years. Superovulation and embryo transfer mean that a single buffalo cow may be used to breed many calves each year.
Animal Health
Testing for Genetic Defects
Biotechnology, including the DNA testing of blood samples, can now identify some genetic weaknesses. Animals carrying defective genes can be identified before they are used for breeding.
Porcine Stress Syndrome (PSS)
Pigs with this gene are vulnerable to stress. They may develop symptoms when they are handled, or transported to market. Under stress, pigs with this syndrome show tremors of the muscle or tail. Their breathing is labored, their skin is red and blotched, and their body temperature rises. Eventually the animal may collapse and die. Another disadvantage of the syndrome is that the carcasses of slaughtered animals often have pale, sweaty meat which fetches a poor price. This is an even greater cause of economic losses from the syndrome than the death toll.
A linkage has been found between sensitivity to halothane and Porcine Stress Syndome. A test has been developed in which halothane gas is administered to piglets for three minutes, using a face mask. When pigs with porcine stress syndrome are given halothane, their limbs become rigid. This reaction is not seen in normal pigs.
A new DNA test has been developed which can identify the gene which produces Porcine Stress Syndrome. Pigs carrying this gene can now be identified, and excluded from breeding programs.
Genetic diseases of cattle
A number of DNA tests are now available to detect inherited weaknesses of cattle. These are being used for national breeding herds in Japan. They are being applied to young active bulls used in artificial insemination programs.
Conditions identified by these tests include Leukocyte Adhesion Deficiency, which causes repeated bacterial infections, stunted growth and death within the first year of life, and Factor 13 deficiency, which prevents blood from coagulating normally. Many affected calves die at birth, because of severe bleeding from the umbilical cord, and the rest soon die from internal bleeding.
New Vaccines for Livestock
One of the most exciting products from biotechnology is a range of new vaccines to protect animals from disease. Some of these are cheaper and more effective versions of existing vaccines. Others are new vaccines, which offer protection for the first time against some infectious illnesses.
Some examples of the new vaccines include a combined vaccine for pigs which protects against three kinds of lung infection: pleuropneumonia, pneumonic pasteurellosis and enzootic pneumonia. In Korea, there is now a new and more effective vaccine against swine fever, a highly infectious disease with a high death rate. In the Philippines, biotechnology has been used to develop an improved vaccine to protect cattle and water buffalo against hemorrhagic septicemia, a leading cause of death for both species.
Other scientists in the Philippines have used biotechnology to develop new vaccines against fowl cholera and Newcastle disease of poultry.
These new bioengineered vaccines are not only more effective than traditional vaccines, they are also safer. Conventional vaccines can sometimes cause a virulent case of the very disease they are meant to prevent. The new vaccines can be genetically manipulated to prevent this happening.
They are also stable at room temperature, and do not need refrigerated storage - an important advantage for smallholders in tropical countries.
New ways of using vaccines
New vaccines developed by biotechnology are also being used for completely new purposes. Traditional vaccines are used to protect against disease, by stimulating the immune system. Some of the functions of the new vaccines include improving the efficiency of feed conversion, or modifying hormone production to increase the growth rate. Others can stimulate milk production, or produce a better-quality carcass with leaner meat.
New Animal Products from Biotechnology
One of the most exciting prospects from bio-technology is a new range of valuable animal products, to supplement the traditional products from live animals (wool, milk) and dead ones (meat, leather). This development is still in its early stages. Some of these new products are listed below.
New Foods and Food Ingredients
Biologically active peptides are being extracted from animal blood at slaughterhouses. These can be used as a food additive to improve human health. Another new product being extracted from animal blood is food colorant, which can partly replace nitrate in meat products.
Biotechnology is also adding extra value to milk and milk products. Human lactoferrin, an important protein in the diet of children, can now be produced by transgenic cows. Genes which add caseins to milk are being used in cheese making. Such milk coagulates faster, and has a firmer curd. Scientists are also working to remove from milk the proteins which cause lactose intolerance. This would increase the demand for dairy products in Asia, since 90% of Asian people are lactose-intolerant.
Index of Images
Figure 1 Brahman Bull from Breeding Ranch in Philippines
Figure 2 Backyard Native Cow Kept by Smallholder
Figure 3 Pig with Stiff Legs Is Sensitive to Halothene Gas, and Probably Suffers from Porcine Stress Syndrome
Figure 4 Normal Pig
