water on the production premise, this may be more 

 readily accepted as a criterion of safety than if the 

 only visible measurement is an anaerobic, black, 

 stinking, open pool of sewage. The latter situation 

 is often the case and public demand is strong to 

 induce modifications whether or not economically 

 feasible. 



It is apparent that large livestock establishments 

 need help in designing practical waste disposal 

 systems. The system must be able to handle odors 

 and gases as well as solids and the net result must 

 not create an excessive Biological Oxygen Demand 

 (BOD) in the terminal water. Some operations 

 avoid excess contamination of flowing water by 

 spreading liquid manure onto fields. The BOD may 

 be partially satisfied by introducing air under pres- 

 sure into sewage, by anaerobic digestion with pro- 

 duction of methane and other flammable gases, or 

 by other procedures. The total nutrients available 

 in solution, however, create problems in the 

 aquatic environment which can readily be meas- 

 ured by fish livability in terminal ponds. The possi- 

 bility of a marketable product of fish is a reality, 

 but only under unusual circumstances should 

 public fishing be encouraged. 



Fish in association with livestock will not meas- 

 ure the presence of pathogenic, enteric, or other 

 microorganisms except as biologic accumulators. 

 Fish disease organisms are usually of different 

 genera from those causing livestock diseases, al- 

 though some diseases, like salmon poisoning in 

 dogs and numerous parasitisms including fish in 

 their life cycles, are exceptions. 



Relationship between animal and human 

 water quality criteria 



Water is a vehicle for transmission of many 

 infectious diseases (viral, parasitic, and fungal) 

 affecting both animals and man. Generally speak- 

 ing, however, it is less significant than food or other 

 contact situations as a route of infection. Mineral 

 and chemical contaminants of water are hazards 

 from a health and economic standpoint for both 

 animals and man. The quality criteria for mineral 

 and chemical contaminants established for human 

 water supplies have been based primarily on ani- 

 mal experimentation and not human tests. Simi- 

 larly, the 50-percent lethal dose (LD^o) for most 

 drugs for humans is derived from animal experi- 

 mentation using the chick, duck (eggs), dog, 

 swine, rat, and rabbit as test subjects. Desirable 

 quality criteria for livestock drinking water should 

 ultimately be no less than for man. At the same 



time, it must be appreciated that a large segment 

 of the grazing livestock population obtains its 

 water from surface sources. 



Livestock are maintained in an environment 

 where exposure to coliform and other organisms 

 can be an everyday experience. Remarkable ad- 

 vances in animal production have been accom- 

 plished through management practices which have 

 eliminated many pathogens. The more advanced 

 the management program, the more important 

 the need for water criteria which approximate 

 human standards. Enteric organisms and viruses 

 may cause serious losses where management prac- 

 tices allow livestock to become more susceptible 

 to infection through lack of immunity. Nutritional 

 factors may also change the resistance to disease. 

 Although antibiotics in poultry and swine feeds 

 increased weight gain and improved feed effi- 

 ciency, the resulting reduction and alteration of 

 intestinal bacteria created an environment for 

 those organisms resistant to the antibiotics. 



There is evidence also that water is a vehicle 

 for the transmission of such diseases as colibacil- 

 losis, swine erysipelas, leptospirosis, listeriosis, 

 salmonellosis, streptococcosis, staphylococcosis, 

 and tuberculosis. Moreover, many fungus diseases 

 are transmitted by water although less frequently 

 than by other methods. Practically all of the trema- 

 tode, cestode, and nematode (parasitic) infections 

 may be waterborne. It is also suspected that many 

 virus diseases are waterborne. Under otherwise 

 ideal conditions for livestock, specific organisms 

 or viruses spread by water can cause explosive 

 epidemics and sometimes serious losses, as in the 

 case of amoebic dysentery and waterborne diar- 

 rhea. 



Not infrequently, livestock are watered from 

 the same source which supplies the home. Here 

 the standards must obviously be human oriented. 

 Watering livestock may provide additional prob- 

 lems through float-controlled tanks which either 

 leak or concentrate toxic substances through evap- 

 oration. Automatic float-controlled devices for 

 swine and poultry are particularly likely to over- 

 flow and the muddy, damp environment may in- 

 crease the hazard of disease. If the water supply 

 is from deep wells and artesian aquifers, the water 

 itself may be safe although its mineral content 

 may differ materially from surface water of the 

 area. When spilled on the soil, this deep-well 

 water may create environments suitable for para- 

 sitisms, acid-fast infections, leptospirosis, and 

 other diseases not common to the neighborhood of 

 shallow wells and surface water supplies. 



Some diseases are very dependent on water. 



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