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Scientifically Evaluating the Impact of Nutritional Management on Animal Welfare
A search of the empirical literature yields numerous citations on the impact of nutritional management on the welfare of production animals. While much advancement in this area has been made, a closer look at this literature often reveals that the full impact on animal welfare has not been completely addressed. Animal welfare science must focus on assessing three overlapping ethical concerns related to the quality of life of animals: 1) ability to live natural lives through the development and use of their natural behaviors, 2) freedom from prolonged and intense fear, pain, and other negative states, and 3) ability to function well. This review will, thus, provide several examples, primarily of dairy cattle, on the need for appropriate scientific assessment of the impact of nutritional management on animal welfare. For example, bucket-fed dairy calves may be provided adequate quantities of milk to grow well and remain healthy. However, they may experience decreased welfare as result of a deprived and frustrated natural desire to suck. Similarly, replacement dairy heifers provided a nutrient dense diet in a limited quantity may consume sufficient nutrients to grow at a specific rate and remain healthy, while experiencing hunger and frustration due to inability to express natural foraging activity. In many cases, nutritional practices may be perceived as acceptable if no immediate impacts on biological functioning are observed. However, long-term effects of alterations in feeding behavior or motivation may, in time, impact normal functioning. For example, increasing competition for feed access for dairy cows has often been associated with no immediate change in feed intake or production level. Unfortunately, such situations may also lead to less desirable patterns and timing of feed consumption, which, when sustained, may be linked to negative production and health outcomes. Thus, it is apparent that proper identification and integration of findings in all three areas of animal welfare science are needed to interpret the true welfare impact of nutritional management.
Keywords: nutrition, welfare, behavior