Today, biotechnology has a number of applications in livestock production. It is being used to hasten animal growth, enhance reproductive capacity, improve animal health and develop new animal products. In 1999, FFTC carried out a regional survey to draw up an inventory of technologies and products which have been developed using biotechnology for livestock production. Some of these are now being applied on farms, others are still being developed in research stations.
The survey covered five countries: Japan, Korea, Philippines, Taiwan ROC and Thailand. The results of the survey will be published by FFTC in the year 2000. A summary of the findings is given below.
Biotechnology can increase the digestibility of low-quality roughage, and genetically modify plants to improve their feed value, such as the amino acid balance. It can also provide hormones and other substances that enhance animal size, productivity and growth rates.
Synthetic hormone bST (bovine somatotropin) was among the first innovations available commercially. It can increase milk yield by as much as 10 to 15 per cent in lactating cows. Current development efforts are looking at a whole spectrum of genes that affect growth and production within the animal. Ways to genetically engineer cattle to increase their own natural hormone production are being considered, thus eliminating the need for synthetic bST. Locally produced recombinant bovine somatotropin (BST) is being used in Korea as a growth stimulant and for increased milk production in cattle.
Other important technologies related to feed and digestion include the following:
High-protein yeast cell products are being used as a feed additive for cattle, pigs and poultry. Highly palatable and nutritious, these products also help create a healthy balance of bacteria in the digestive tract, and prevent bacterial diarrhea.
A bacterial phytase formula, TRANSPHOS, is being used to replace the costly mineral phosphate used as an additive in the feed of monogastric animals in Korea. In the Philippines, a bacteriocin is being produced which has antibacterial properties against Listeria monocytogenes, Staphylococcus aureus, and other pathogens found in livestock feed and human food.
L-lysine monohydrochloride, a safe and stable form of lysine, is being produced in Korea by the fermentation of a special strain of bacteria in raw molasses. Lysine is one of the most essential amino acids. Livestock requirements for it are hardly met by the amount present in natural feeds. Lysine supplementation improves the nutrient balance of feed, and feed conversion rates by livestock.
Tissue culture is being used for the genetic improvement of forage cultivars in Korea, including alfalfa and orchardgrass. A particle bombardment delivery system has been developed in Korea for transferring useful genes with heat tolerance, drought tolerance etc. into forage crops. A DNA product cloned from Brassica campestris confers heat tolerance to forage crops which generally do not perform well in temperatures above 30oC. This will improve the productivity of tropical forage crops, and also help avoid the depression in forage yield seen during the summer in Korea.
Another useful gene being transferred into forage crops gives resistance to paraquat. This is a non-selective herbicide which kills all green plants. If forage crops can be given a resistant gene, paraquat will become a simple and effective way of controlling weeds in grassland.
In the improvement of silage, strains of the bacteria Lactobillus planetarium are being selected which increase the lactate content and reduce the pH and ammonia-N content.
Copra meal (made from dried coconut after extraction of the oil) is being inoculated with a bacterial soil isolate in the Philippines. The treated meal is a more nutritious and digestible livestock feed, with a lower fiber content, than untreated meal.
A bacterium, Rhodopseudomonas capsulata, has the ability to grow rapidly in simple synthetic media. It is being used in advanced swine waste treatment plants in both Japan and Korea. Short chain fatty acids, one of the main sources of the bad odor of swine wastes, decreased dramatically after treatment. The residues after treatment can be used as a safe organic fertilizer.
Biotechnology can greatly accelerate the speed at which desirable characteristics (e.g. better growth rates, or increased milk production) can be introduced into animals. While classical breeding to enhance animal traits works well, it takes decades to produce major changes. Through biotechnology, an organism can be modified directly in a very short time if the appropriate gene has been identified.
A recent breakthrough in animal reproduction is the combined application of the existing in vitro fertilization, and the state-of-the-art ultrasound-guided transvaginal oocyte pick-up (OPU) technique in cattle. When heifers reach puberty at 11-12 months of age, their oocytes may be retrieved weekly or even twice a week for embryo production and embryo transfer. There is even the possibility of applying this technology to juveniles. In this way, high-value female calves can be used for breeding long before they reach their normal breeding age.
In Korea, Japan and Taiwan, a range of hormone implants and treatments are being used to increase the production of mammalian oocytes and embyros. Various chilling and freezing techniques have been developed for preservation of oocytes and/or embryos, including ultra-rapid freezing by electron microscope grid.
Embryo transfer is being used on valuable animals, so that oocytes and embryos from high-value animals are transferred into the uterus of surrogate mothers. In Korea and Taiwan, a PCR (polymerase chain reaction) test has been developed to establish the sex of cattle embryos. This is very important, particularly when combined with embryo transfer, since it gives control over the sex of the offspring. Similar tests are being developed for other types of livestock. The hypoosmotic swelling test has been developed to evaluate the quality of frozen and thawed bovine sperm.
In Taiwan, transgenic pigs have been bred with a porcine lactoferrin transgene. Lactoferrin is a milk protein which promotes gut growth and prevents diarrhea. Sows with this gene maintain a high lactoferrin level in their milk throughout lactation. Transgenic boars can transmit this gene to their offspring.
Genetic markers for milk production traits have been established for dairy cattle. This would be a great benefit in identifying the best progenitors for a high-yielding dairy herd.
One important benefit from biotechnology is the diagnosis of livestock diseases, and genetically transmitted conditions which damage health and productivity. Biological techniques can also produce cheaper and more efficient drugs. In cases where a natural source material is prohibitively expensive, genetic engineering (in microbial or tissue culture systems) can be used to produce drugs of high value for humans or animals. Examples are insulin, human growth hormone and tissue plasminogen activator (used in treating heart disease).
Vaccines are used to stimulate an animal's immune system to produce the antibodies needed to prevent infection. Recombinant DNA technology has provided the means to produce large quantities of inexpensive vaccines, while a better understanding of the immune system has helped produce vaccines that do a better job of boosting the body's immune system. These engineered products are safer than traditional vaccines. Whereas conventional vaccines sometimes revert to virulent (disease causing) forms, the new vaccines can be engineered to eliminate this threat.
Biotechnology is also producing an entirely new use for vaccines. They are being used to modulate hormones to increase growth rates, improve the efficiency of feed conversion, stimulate milk production, contribute to improved carcass quality and leaner meat, and enhance or suppress reproductive functions.
Some recent developments include the following:
In Taiwan, a DNA vaccine with an encoded target gene is being used to produce new vaccines. Tests have shown that the DNA vaccines consistently induced antibody response, and were resistant to toxin challenge.
They also have other advantages. They offer protection against diseases for which no vaccine is currently available. Their production does not need dangerous infectious agents. With mass production, they will not cost much to produce. Since they are stable at room temperature, storage costs will also be low.
Korean scientists have developed a combined vaccine against pleuropneumonia, pneumonic pasteurellosis and enzootic pneumonia in swine. Molecular biology has been used to produce an improved vaccine to protect pigs from swine fever. In the Philippines, it has been used to develop an improved vaccine to protect cattle and water buffalo against hemorrhagic septicemia. This disease is the leading cause of death among these animals. The new vaccine gives improved protection at a very low cost. A field kit has also been developed, to diagnose this disease from nose swabs.
A number of improved vaccines for poultry have also been developed in the Philippines to protect birds from Newcastle disease, fowl cholera and infectious coryza.
In Japan and Taiwan, DNA testing is being used to diagnose hereditary weaknesses of livestock. One test identifies the gene which produces Porcine Stress Syndrome in pigs. Pigs with this gene tend to produce pale, poor-quality meat when they undergo the stress of transport or slaughter. Now that pigs with this gene can be identified, they can be excluded from breeding programs, so the gene will become less common.
DNA is also being used in Japan to diagnose a mutation of Holstein cattle that causes leucoyte adhesion deficiency. Cattle with this condition suffer diseases of the gum, tooth loss and stunted growth. They usually die before they are one year old. This test will identify carriers and eliminate them from breeding herds. Bulls used for breeding can be tested to make sure they are not carriers.
Another DNA test identifies a hereditary condition that produces anemia and retarded growth in Japanese black cattle.
Biotechnology can lead to new and improved animal products. For example, it can modify the composition of milk, or the fat content of meat. Genetically transformed cows can produce designer milks with superior properties for use in various milk products. Added caseins in milk, for instance, can enhance cheese making. Increasing the phosphate group in casein can enhance the level of calcium. Removal of the source of lactose intolerance in milk can have a significant impact on the market for dairy products, especially among the 90 % of people with an Asian or African background who are lactose-intolerant.
Some new products made possible by biotechnology in the Asian region include:
There is no doubt that biotechnology can bring about improvements in animal growth and production, nutrition, reproduction, health and animal products. It can do this while conserving natural resources and the environment.
Since biotechnology is so new, these techniques may not yet be of much benefit to Asian smallholders. The contribution to their future could be enormous, but only if scientists and institutions working in this field focus on farmers' needs. They must ensure that the technology is developed and extended in a way which will benefit ordinary farmers. Advances in biotechnology need highly trained personnel and state-of-the-art equipment and facilities. There is a danger that within countries, and between nations, the poor may remain on the periphery while the prosperous take most of the profits.
We must also ensure that in developing biological resources, we do not neglect the development of human ones. Especially in animal breeding, technical developments must keep pace with training and incentives for the technicians who are applying these methods in laboratories and in the field.
Countries surveyed : Japan, Korea, Philippines, Taiwan ROC, Thailand.
Members of the survey team were:
Dr. Takao Oishi, National Institute of Animal Industry, Japan
Dr. Il-Cheong Cheong, National Livestock Research Institute, Korea
Dr. Edwin C. Villar, Livestock Research Division, PCARRD, Philippines
Mr. Shan-Nan Lee, Taiwan Livestock Research Institute
Dr. Chanvit Vajrabukka, Department of Animal Science, Kasetsart University, Thailand
Figure 1 Biotechnology Is Producing New Vaccines That Are Cheaper and More Effective, Such As an Improved Vaccine Developed in the Philippines to Protect Water Buffalo against Hemorraghic Septicemia
Figure 2 Poultry with Newcastle Disease. Biotechnology Has Provided a New Vaccine against This Disease.