Physiological Relationship between Stress and Reproductive Efficiency

摘要

The effects of both environmental and management related stressors on reproduction were examined. Reproduction is the ultimate measure of an animals ability to adapt to an ever changing external milieu as well as forming the basis of life-time production. Thus, one of the main goals in animal production is to achieve the highest possible reproductive success. Reproductive efficiency is the major factor affecting profitability in many livestock production systems. Reproductive success in livestock is essential for the economic livelihood of producers and ultimately affects the consumer cost of meat and other animal products. In many livestock production systems, poor fertility is a major factor that limits productivity. Unpleasant stress impairs reproduction. Reduced reproductive efficiency can occur as a result of environmental and management factors or stressors associated with animal housing, human-animal relationship/animal handling and management, modern production methods, temperature extremes or changes in photoperiod (day and night cycles). These stressors cause deviation in hormonal pattern and clinical manifestations. Reduction of stressful situations allows for greater well-being, growth and reproductive efficiency of the animal. To maximize reproductive efficiency during the summer/hot seasons, measures must be taken which reduce heat gain and facilitate heat loss to the environment. Animals should be exposed to positive handling and management practices. Further research aimed at obtaining greater clarity of the hormonal interactions involved should be carried out as well as further studies to provide input into management procedures that should be used in intensive production units for optimal fertility and productivity.