Administration approval. Still more ionophores will be
identified by SM research and their use will increase in
the future.
 For the 21st century, genetic selections to increase
protein synthesis will be a definite possibility. Also,
genetic engineering will play an important role beyond
the current possibilities in disease control.
 Swine production for the year 2000 and beyond will
emphasize breeding at an earlier age (six to seven
months), first farrowing at 10 to 11 months of age, in-
creased ova fertilization, implantation and placenta-
tion with greater embryo survival (10 to 12 large,
sturdy pigs farrowed per litter), reduced neonatal
losses and the weaning of nine to 10 pigs per litter after
a three-week lactation, and rebreeding on first estrus
(five to seven days after weaning) allowing for up to
2.5 litters per sow per year and up to 25 pigs marketed
per sow per year. With the recent findings of retinal
binding proteins in high levels of riboflavin in swine
uterine fluids during early pregnancy, it will be impor-
tant to study vitamin A and riboflavin nutrition at
discrete stages of reproduction. Most males will either
remain intact or receive controlled-released testos-
terone implants to improve protein accumulation and
energy utilization. Traditional nutrient requirement
studies will have to be redone continually to determine
how requirements change with such endocrine altera-
tions. Alterations from the pork growth hormone por-
cine, insulin and glucagen levels will be affected by
genetic cloning, rDNA production, and controlled
release in both males and females. Again, traditional
studies of changes in nutrient requirements will be
needed. Ideal endocrine levels for ova implantation
and embryonic survival and nutrient requirements will
need to be determined. Ways need to be researched to
increase placental and mammary transfer of iron from
the sow's diet to the fetus and milk to eliminate special
administration of iron to the nursing pig to prevent
baby pig anemia. Increasing availability of phosphorus
from grains and plant proteins will help eliminate
costly feeding of supplemental phosphorus.
 SM research is needed to improve dispensation of
 food and water to swine from programed feeders to
 reduce feed wastes and improve feed utilization. Com-
 puter programing of inputs will help. Grain (corn,
 sorghum, barley) and soybean meal diets will pre-
 dominate, but synthetic amino acids-lysine and
 tryptophane-will be used extensively to reduce the re-
 quirements for soybean meal. Flash-dried blood meal
 and other by-products of food manufacture will also
 find a place in feeds. Economical means will be
 developed for the biological digestion of cellulose.
 This, along with the production of improved bacterial
 protein from yeast, will allow greater use of low-grade
 feedstuffs for both swine and poultry. Other SM


research promises to increase gains in lean body
weight.
 Animal Health Improved animal health will re-
quire SM research on livestock management, vaccines
and other products of microbial synthesis, such as the
interferons and growth hormones. Results of DISC
research by geneticists and cell microbiologists will be
important in the production and use of these sub-
stances. Computers will make it economical to monitor
changes in the health of animals and provide early
warning of diseases. High payoffs are anticipated for
SM research on dairy cow diseases, reproductive prob-
lems, mastitis, calf mortality and exposure to toxic
substances. Health problems for beef cattle are pri-
marily respiratory diseases (shipping fever), reproduc-
tive disorders and calf mortality. For swine, reproduc-
tive disorders, interic or digestive diseases, respiratory
diseases and locomotion problems are subjects that
must be addressed. Again, disease control is linked
with genetic resistance, reproductive problems, nutri-
tional deficiencies and environmental constraints.
 Continued refinements in the uses and benefits of
computers to collect and store information on animal
health, nutrition, costs, selection and culling, and to
monitor and use other biological, environmental and
economic information, will be necessary.

 Land-Conserving Animal Husbandry Conserving
land used for livestock production will become increas-
ingly important as we continue to press our land
resources. Land now in improved pastures and hay
will be converted to grain production. Unimproved
pastures, brush and scrub forestland will be converted
to improved forages. Such forage land will require
land-conserving animal husbandry to avoid overgraz-
ing, ditching along pathways and fencing, and dust
wallowing on exposed slopes. New systems of rota-
tional grazing, confined feeding, central rather than
field farrowing, green chopping, and forage harvesting
and storage will be required. Such subject-matter
research will require inputs from agricultural
engineers, agronomists and economists. Economists
will be important because increasing land values and
wage rates will determine the need for and feasibility
of various land-conserving animal husbandry systems.
Environmental considerations will be increasingly im-
portant and will tend to place feeding operations away
from population centers in environmentally stable
areas or disperse them into smaller units near sources
of roughage. Public values will tend to be neglected by
implement, feed, chemical and biological companies
seeking private profits. This will create a need for
public sector research and regulations.
 Labor-Conserving Animal Husbandry This will
 become more important as U.S. per capital incomes