Guide for the Care and Use of Agricultural Animals in Research and ...

ies are generally advocated: 1) behavior patterns; 2)pathological and immunological traits; 3) physiologicaland biochemical characteristics; and 4) reproductiveand productive performance of the individual animal.A judgment as to the balance of evidence provided bythese indicators has been used, when available, as thebasis for the recommendations in this guide.D. C. Hardwick postulated (cited in Duncan, 1978)and Duncan (1978) developed the idea that an acceptablelevel of animal welfare exists over a range of conditionsprovided by a variety of agricultural productionsystems, not under just one ideal set of circumstances.Improvements in certain environments may increaseanimal well-being somewhat, but any point in the rangewould still be considered acceptable with respect to animalwelfare. Good management and a high standardof stockmanship are important in determining the acceptabilityof a particular production system (Hurnik,1988) and should be emphasized in agricultural animalresearch and teaching facilities.Macroenvironment and MicroenvironmentAnimal well-being is a function of many environmentalvariables, including physical surroundings, nutritionalintake, and social and biological interactions(Hafez, 1968; Curtis, 1983; Yousef, 1985a). Environmentalconditions should be such that stress, illness,mortality, injury, and behavioral problems are minimized.Particular components of the environment thatneed to be taken into account include temperature, humidity,light, air quality, space (including complexityof space), social interactions, microbe concentrations,noise, vermin and predators, nutritional factors, andwater. See Chapter 4: Environmental Enrichment forfurther informationPhysical conditions in the room, house, barn, or outsideenvironment constitute the macroenvironment; themicroenvironment includes the immediate physical andbiological surroundings. Different microenvironmentsmay exist within the same macroenvironment. Bothmicroenvironment and macroenvironment should beappropriate for the genetic background and age of theanimals and the purpose for which they are being used.Domestic animals readily adapt to a wide range of environments,but some genetic strains have specific needsof which the scientist should be aware and for whichaccommodation should be made.Even in relatively moderate climatic regions, weatherevents such as floods, winter storms, and summer heatwaves may require that animals have access to shelter.If trees or geographic features do not provide enoughprotection, artificial shelters and (or) windbreaks orsunshades should be provided (Mitlöhner et al., 2001,2002; Johnson et al., 2008; Marcillac-Embertson et al.,2009).HUSBANDRY, HOUSING, AND BIOSECURITYGenetic DifferencesSome strains of agricultural animals may have requirementsthat differ substantially from those of otherstocks of the same species (Gross et al., 1984). Somestrains of pigs, for example, are particularly susceptibleto stress because they carry a gene that causes malignanthyperthermia when they experience even mildstress (Bäckström and Kauffman, 1995). Transgenicanimals may also have special needs for husbandry andcare (Mench, 1998). Practices to ensure the well-beingof special strains should be established independently ofthose made for the species in general. Refer to Chapter4: Environmental Enrichment for more detailed informationon enhancement of animals’ physical or socialenvironments.Space RequirementsFloor area is only one of the components that determinethe space requirements of an animal. Enclosureshape, floor type, ceiling height, location and dimensionsof feeders and waterers, features inside the enclosure,and other physical and social elements affectthe amount of space sensed, perceived, and used bythe animals in intensive management systems (Stricklandet al., 1979; Strickland and Gonyou, 1995). Whenpossible, animals in stanchions, cages, crates, or stallsshould be allowed to view one another, animal carepersonnel, and other activities where this would notinterfere with research or teaching objectives.Determination of area requirements for domestic animalsshould be based on body size, head height, stageof life cycle, behavior, health, and weather conditions.All area recommendations in this guide refer to theanimal zone (i.e., the space that can be used by theanimal). Unless experimental or welfare considerationsdictate otherwise, space should be sufficient for normalpostural adjustments, including standing, lying, resting,self-grooming, eating, drinking, and eliminating fecesand urine. When animals are crowded, body weightgain and other performance traits may be depressed(Gehlbach et al., 1966; Adams and Craig, 1985), andthe animals may show altered levels of aggressive behavior(Bryant and Ewbank, 1974; Al-Rawi and Craig,1975).Temperature, Water Vapor Pressure, andVentilationAir temperature, water vapor pressure, and air velocityare some of the most important factors in thephysical environment of agricultural animals. In addition,factors related to animal health (i.e., infectiousstatus) and genetics (i.e., trangenic modification) affectthe thermal balance of animals and thus their behavior,metabolism, and performance.17