ANIMAL HEALTH AND OBSERVATION RATS This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S. Department of Labor’s Employment and Training Administration. The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership. This solution is copyrighted by the institution that created it. Internal use by an organization and/or personal use by an individual for non-commercial purposes is permissible. All other uses require the prior authorization of the copyright owner.

RATS  Scientific name – Rattus norvegicus Norwegian Fisher 344 (Inbred) Lewis (LW) Wistar (Outbred) Sprague-Dawley (SD) Long-Evans (LE)  Black and white coat  Most commonly used  Often called hooded rats

BREEDS  Wistar – Albino rat developed at Wistar Institute in Philedelphia.  Outbred stock Wide head and long ears. Tail usually shorter than body.

BREEDS  Sprague-Dawley – Originally produced by Sprague-Dawley farms in Madison, WI.  Outbred stock Albino rat which is faster growing than Wistar. Longer, narrower head Tail is about same length as body

BREEDS  Long-Evans – Smaller than either Wistar or Sprague-Dawley.  Outbred stock  White body fur usually intermingled with patches of black.  Head is usually black.  Referred to as the “hooded” rat.

BREEDS  Inbred stocks used also  Fisher 344  Lewis

 One of the most common used animals in research  Experimental work with the rat in the field of nutrition began in the early part of the 20 th century. Popular becasuse its response to various nutrients is similar to the response of humans.

 Rat is similar to other monogastric animals. Two chief differences:  Rat has no gallbladder  The pancreas in the rat is a diffuse organ rather than well-defined.

BEHAVIOR  Normally stand on all 4 limbs on cage floor.  Communal Several males and females may be housed in a single cage with little fighting.  Nocturnal Often sleep on top of each other  Burrowers

HANDLING AND RESTRAINT  Can be picked up by the base of the tail If tail is grasped near the distal end, the skin might pull off. Rat can also twist around to bite handler.

HANDLING AND RESTRAINT  Rats in wire bottom cage should not be grasped by tail as they can hold on and injure its feet.  Can also grasp rat by skin along back, starting at neck.  Rats often urinate and defecate when picked up.  Be firm but gentle. They can become rather tame.

HANDLING AND RESTRAINT Handler has control of the rat by maintaining the hold on the tail

HANDLING AND RESTRAINT In the above pictures, you can see the handler has control of the head by grasping around the head with their thumb and index finger. Do not apply pressure to the trachea. Handler also maintains control of the tail

SEX DETERMINATION  Ano-genital distance is about twice the distance in the male as the female.  Testicles evident in an early age

BREEDING  Sexual maturity – days of age  Gestation – days  Litter size – 7-11  Weaning – 21 days  Female rat usually does not cannibalize her young unless they are unhealthy

HOUSING  Metal, hanging cages with wire mesh floor  Plastic or metal cages with solid bottom and wire lid. Care should be taken to prevent escape through wire lid. If rat can get its’ head through, the rest of the body will follow.  Neonates can be easily lost through a wire mesh floor Shoe-box cage with solid floor and bedding is caging type of choice for nursing females.

HOUSING  Cages should be cleaned and changed once or twice a week.  Shelving and cage racks should be sanitized at least once every two weeks

BEDDING  Wood chips  Shavings  Paper  Ground corn cob  Sawdust Should be non- allergenic, dust free, absorptive, non-toxic and clean.

DIET  Commonly fed ad libitum  Commercially available diets are complete and usually do not require additional additives or supplements.  Available in hard pellets to promote gnawing. Incisors continuously grow.

 Tears and saliva of rats contain porphyrin.  Porphyrin appears red or reddish-brown Can sometimes be seen around the eyes and on the end of the nose  Excessive accumulation of porphyrin around eyes, nose or front legs can be a sign of illness and should be reported to your supervisor.

DISEASE  Rats may obtain a variety of bacterial infections.  Chronic Murine Pneumonia (CMP) Most significant and serious  Symptoms Sniffling, sneezing, red-brown tears, rough hair coat and labored breathing.  Treatment Antibiotics