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OCR for page 135
Epilogue
Part I of this report provided a foundation of information relating nutrition
and environment. Both direct and indirect influences of the environment are
shown to have a major impact on nutrient intake, requirement, and utiliza-
tion. Clearly, the role of environment in livestock and poultry nutritional
management is a valid consideration.
Discussions describing the impact of environment on different species and
suggested techniques for nutritional management to deal with different envi-
ronments are presented in Part II. Some species differences in the depth of
understanding of nutrition-environment interactions are evident. For exam-
ple, for poultry a more quantitative approach is possible, whereas a more es-
timated approach is described for dairy cattle. Differences are also apparent
when schemes for maximizing efficiency of growth are compared with effi-
ciency of expelled products, i.e., eggs and milk. Yet, many similarities
among species exist. All species are affected by the influence of environment
on rate of feed intake and maintenance energy requirement. And, all are con-
cerned with maximizing caloric efficiency to conserve energy resources. Ef-
fect of environment on rates of energy flow is important in all cases and is
the basis for most observed nutrition-environment interactions.
The authors have projected their best estimates of nutrient adjustments for
livestock exposed to adverse environments. In some cases these adjustments
are based on limited research data and plagued with uncertainty. That is es-
pecially evident for ruminants. Research data are more abundant for poultry,
but still much is unknown. It is hoped that the material presented will be of
immediate value, but perhaps more importantly that it will stimulate addi-
tional research.
135
OCR for page 136
136
Epilogue
Research areas that need immediate study are numerous. Initially, a more
accurate system for characterizing the total environment is needed. Further
development of effective ambient temperature (EAT) iS necessary to accu-
rately assess environmental impact. Basic research to establish accurate and
reliable patterns of voluntary feed intake for animals in different environ-
ments is needed so that nutrient adjustments can more readily be incorpo-
rated in management systems. Maintenance energy requirement needs to be
known for varying degrees of thermal stress. This need is particularly lacking
for heat stress. An understanding of mechanisms and ramifications of accli-
matization to environment would enhance the development of management
strategies to deal with changing environments. More research must be con-
ducted to predict responses to fluctuating temperatures similar to those en-
countered under natural conditions. The impact of nonclimatic variables such
as psychological stressors and management systems on nutrient requirement
should be investigated. And, unknown subtle effects of environment await
discovery.
An integrated systems approach to managing livestock must include the
effects of environment if maximum utilization of resources is to be realized.
It is hoped this report will aid in achieving that goal.
Representative terms from entire chapter:
feed intake
