and real wage rates increase. With increasing wage
rates, more SM research will be needed to help
organize reproduction, feeding, slaughtering,
marketing and distribution systems to economize on
labor. Such research must be coordinated with that on
land-conserving animal husbandry. It will involve
agricultural engineering, veterinary medicine,
agronomy and, especially, economics. Labor-efficient
confinement feeding, rotation grazing, green-chop
systems, materials handling systems, computerized
controls and a large number of other technologies
should be combined to use labor more economically.
Social issues involving environmental quality,
unionization, economic and social structure, and
animal rights and welfare must be addressed. Both
public and private sector research will be required.

 Environmental Control Each food animal nas a
narrow temperature range for optimal performance.
Modifications in housing, feedlots, pastures and feeds
have great potentials for helping animals adjust to
temperature limitations. Controlling the number of
hours of light to which animals are exposed daily offers
a way to regulate reproduction, stimulate body growth
and increase the output of meat, milk and eggs in
several domestic species (Tucker and Ringer, 1982).
 Animal Welfare Research relating to animal
welfare will focus on modern livestock production
systems and their effects on animal stress and comfort.
Subject-matter research will assess the influences of
stress and ways to prevent it.
 Both animal agriculture and animal scientists are
criticized by humanists, animal rightists, nutritionists
and activists. The issues include chemical food con-
taminants, preservatives, cholesterol and nitrites, the
feeding to animals of grains fit for human consumption
and mistreatment of both laboratory and food animals.
Critics emphasize the need for animal scientists to con-
sider the sociological, humanistic and economic dimen-
sions of their research. Future research on animal
welfare must be related to changes in land and labor
costs. Research on the humane treatment of animals is
an integral part of farming systems research on land-
and labor-conserving animal husbandry.
 Aquaculture This may become one of the growth
industries for food production in both fresh and salt
water. Larger food creatures eat more and take longer
to mature than fish. Fish approach a one-to-one feed
ratio-one pound of feed to one pound of fish. Aqua-
culture lags in the United States and will likely con-
tinue largely as a summertime activity in the North
with some concentration on catfish farming in the
Southern states. One possibility is to raise temperatures
in ponds by covering them with single or double layers
of plastic sheeting. Specialty luxury species-shrimp,


lobster, oysters and salmon-could dominate produc-
tion and demand in the United States. Meanwhile,
integrated farming systems will gain in prominence in
countries such as Taiwan, Japan and China, where fish
culture is combined with pigs and ducks. Currently
integrated systems of chickens, pigs, ducks and tropical
fish require 250 pigs or 2,500 ducks per hectare to pro-
vide sufficient waste for the production of six tons of
fish per hectare per year of such species as Chinese carp
and tilapia. Almost half of the world's cultivated
fish-more than 20 million tons annually-is produced
in the People's Republic of China. Aquaculture can
become a star in agriculture's future, even in the
United States, as indicated by the recent phenomenal
increase in catfish farming in the United States and the
11 percent annual growth rate of fish production in
Taiwan. Also, the natural "forests and grasslands" of
lakes and seas are not yet adequately exploited as food
sources for humans and food animals.

Disciplinary Research in the
Biological and Physical Sciences
Relevant for Livestock
 Biological and physical scientists pursue many
projects of value to SM and PS research for livestock.
Relevant research on reproductive efficiency, en-
vironmental stress, disease control, health and animal
welfare will be discussed below.
 Reproductive Efficiency Parallel to the advances
of geneticists and cell microbiologists in genetically
engineered crops and plants are the potentials for
genetic improvements in livestock.
 Improved fertility is now a reality because of estrus
synchronization and hormonal control of the reproduc-
tive cycle. Semen preservation, pregnancy detection,
multiple births, superovulation, and non-surgical
embryo transfer and implantation are outcomes of
earlier DISC research (Seidel, 1981). All can increase
the number of offspring of genetically superior parents.
Non-surgical embryo collection is now aided by
extremely sensitive microscopic techniques for embryo
sexing, freezing and implanting. Genetic improvement
and increased productivity are now occurring for all
farm animals. Pregnancy rates of 74 percent have
resulted from non-surgical transfer of non-frozen cattle
embryos (Elsden, et al., 1982). Identical twin bovine
fetuses have been produced from bisected bovine
embryos. This DISC research now makes it feasible to
produce identical twin calves of either sex and thus
double the number of viable embryos per superdonor.
These developments, along with "surrogate parenting
of cows," provide unique opportunities to do research
to restructure the entire field of animal breeding. DISC
research to improve these techniques further is of high
priority.