Respiratory and enteric diseases. Respiratory 

 diseases are one of the most economically impor- 

 tant limitations to eHicient animal production. 

 Control of the diseases is very difficult due to 

 the complex etiology involving one or more path- 

 ogens and many environmental effects. Funda- 

 mental research is needed on: (I) The nature and 

 inheritance of innate defense mechanisms of live- 

 stock and poultry species, (2) methods of effec- 

 tively stimulating specific immunity, and (3) the 

 contribution of environmental and behavioral 

 stressors on the susceptibility of animals to dis- 

 ease. Enteric diseases, particularly in young ani- 

 mals, cause an estimated $1 billion annual losses 

 in the United States. Diseases such as calf scours, 

 transmissible gastroenteritis, swine dysentery, col- 

 ibacillosis of all species, and salmonella are exam- 

 ples of the broad range of enteric diseases that 

 threaten every animal producer. Basic research is 

 needed to develop simple but efficient methods to 

 diagnose the cause of the disease and to stimulate 

 the cellular immune mechanisms in the neonate. 



Hormonal control of growth and reproduction. 



Many aspects of the growth and reproduction of 

 animals, plants, insects, and other organisms are 

 regulated by hormonal growth substances. Under- 

 standing the nature of these controlling mecha- 

 nisms, the causal agents, and their mode of action 

 could provide keys to embryonic mortality, ovula- 

 tion synchronization, and growth efficiency in ani- 

 mals; uniformity in growth and ripening of plants; 

 and insect population control. 



Physiological control of cellular growth in ani- 

 mals. Progress in analytical methodology now will 

 permit greater in-depth study of cellular function 

 and the physiological mechanisms regulating the 

 cellular composition of tissue. The quantitative and 

 qualitative aspects of meat and animal products as 

 food relate primarily to the animal's ability to de- 

 posit the desired quantity and quality of protein, lip- 

 ids, and other compounds in tissue. 



Factors at the cellular level influencing rate and 

 efficiency of synthesis of protein, lipids, and other 

 compounds are poorly understood. Isolation and 

 identification of the cellular constituents that regu- 

 late tissue synthesis and degradation and the dis- 

 tribution and quantity of lipid deposition is neces- 

 sary to determine which mechanisms are amena- 

 ble to control. 



Human nutrition. Knowledge of the precise 

 kinds, quantities, and balance of nutrients re- 

 quired for human health and productivity is seri- 

 ously lacking — not only for persons living in an 

 ideal environment, but particularly for persons 

 subject to dietary, climatic, and other types of 

 stress. Support provided by this program empha- 

 sizes (I) determining nutrient requirements for 



26 AGRICULTURE 



healthy people with varying needs such as those 

 occurring at different ages, sex, and occupation, 

 with particular emphasis on needs of high risk 

 groups; and (2) identifying and evaluating factors 

 affecting the biological availability and utilization 

 of nutrients. 



Basic properties of food systems. Fundamental 

 knowledge is needed on model animal and plant 

 food systems (fluid, semisolid, and solid) to un- 

 derstand the role of various components in the 

 systems and the effects of component interaction 

 on the piiysical, chemical, organoleptic, micro- 

 biological, nutritional, functional, and structural 

 properties. Basic data are needed to establish 

 improved criteria for the safety and wholesome- 

 ness of foods and food ingredients. Research 

 should include development of new screening 

 methods to identify potential carcinogens, muta- 

 gens, and/or naturally occurring toxicants. Knowl- 

 edge regarding microbiological hazards is incom- 

 plete. Procedures for enumerating cells in pro- 

 cessed foods may fail to quantitate thermally 

 stressed cells or recovery cells. 



Terrestrial and aquatic ecology as related to 

 atmospheric transfer and precipitation systems. 



Historically, it was accepted that local ecology 

 was dependent primarily upon local geophysical 

 characteristics, water precipitation, humidity, 

 temperature, and local human activities. It is now 

 recognized that materials other than water are 

 transferred in the atmosphere over long distances 

 and that those materials can have an important 

 ecological effect in the locale in which they are 

 precipitated. Those atmospheric deposits may 

 play an important positive role as supplemental 

 plant nutrients, or they may be injurious to plants. 

 Those precipitants from the atmosphere may also 

 influence the health of man, domestic and wild 

 animals, and aquatic life. 



Atmospheric transfer and deposit of materials 

 are to a large extent subject to control by man. 

 improved understanding of atmospheric transfer 

 and precipitation systems and their effects upon 

 the ecology of affected locales is needed. Social 

 decisions about the composition and location of 

 activities must reflect these second order or spill- 

 over costs and benefits. Since many of those spill- 

 over costs and benefits are transmitted to society 

 through the land-based agricultural and forestry 

 industries, basic research on the relationships of 

 atmospheric transfer and precipitation systems to 

 agricultural and forest ecosystems will contribute 

 to the agricultural research mission. 



Crop growth models. Mathematical models can 

 be developed to describe crop response to envi- 

 ronmental conditions at different stages of pheno- 

 logical development. Major emphasis is placed on 



