Improved method for vaginal plug detection in rats

Time mating of rodents is essential in many experimental procedures. The presence of the vaginal plug is frequently used as an indicator to confirm that mating has occurred. In rats, vaginal plugs are often deep and therefore difficult to detect byvulvar inspection. This study was carried out to assess the applicability of a human otoscope for detection of deep plugs, and the predictive value of plugs for pregnancy. A total of 132 Wistar female rats in proestrous were mated and examinedfor vaginal plugs on the next morning with an otoscope. All the plugs were located deep inside the vagina and could not be seen without the scope. The pregnancy rate of all females in proestrous was 69.7 %. Of all females, 72.7% had a vaginal plug and the positive predictive value of plug detection was 91.7 %. The sensitivity of the vaginal plug method was 95.7 % and specificity 80.0%. In conclusion, this study shows that detection of plugs has value for predicting pregnancies in rats. The method devised is quick, straightforward and painless to the animals and it is easily taught to technicians

The use of aspen blocks and tubes to enrich the cage environment of laboratory rats

Female and male outbred Wistar rats (n=48) were allocated into three groups at weaning; control, tube and block groups (n = 8 males and 8 females in each) Animals were conventionally housed for five weeks in groups of four per cage with either an aspen tube (20x12x12 cm) or an aspen block (6x6x6 cm) in addition to the aspen bedding. The control animals had no enrichment items in their cages. The use of tube and block was assessed by measuring both the volume gnawed and via video recordings, which were done by the instantaneous sampling method at 1 min intervals. The growth of the animals was followed by weighing the animals three times during the study. Rats with the tubes in their cage spent over, 80 % of their time during light period inside the tube and over 20 % during dark period. Furthermore, when the lights were turned off, rats increased other contacts (on and beside) with the tube from 5 % to about 40 %. Animals with blocks spent about 3 % of their time during the light period on top of the block or in its vicinity and about 11 % during the dark period. The amount gnawed was essentially the same with both items and increased slightly with time. The enrichment items did not have any effects on the growth of the animals. In conclusion, the enrichment items have the advantage of not introducing any extra or new compounds into the cage environment, since they are made from the same raw material as the bedding. The rats used the items not only for gnawing but also for other activities. The inside of the tube was mainly used as shelter from the light The aspen tube seemed to have more enrichment value for rats than the aspen block‘ since it allowed a wider range of behaviour patterns to be expressed. These items were reusable, economical and species-appropriate for en riching the cage environment of laboratory rats. Keywords: environmental enrichment, gnawing, rat

Pain Alleviation in Laboratory Animals Methods commonly used for perioperative pain-relief

No abstract availabl

Serum antibody response to canine distemper Virus vaccines in beagle dogs

The three commercial triple CDV vaccines used for vaccination differ by the Virus strain and the method of production. The immunogenicity of these vaccines was studied in beagle dogs under experimental conditions using neutralizing antibodytiters as the measure.Differences in antibody responses were detected between the three distemper vaccines. Rockborn strain produced in canine cells (vaccine 1) induced on average the highest titers and smallest variance of serum neutra1i7ing antibodies betweenvaccine groups. There was also a significant difference between the 2 Onderstepoort strains (vaccine 2 and 3) inducing CDV antibodies in dogs one month after first vaccination indicating difference in antigenicity between the vaccines

Environmental enrichment may alter the number of rats needed to achieve statistical significance

Currently, environmental enrichment studies have focused on detection of differences in group means resulting from varied enrichments. The effects of enrichment procedures on variation and hence on study results have received far less attention. Within group variation in studies is directly related to adequate sample size and thus determines ethically correct number of animals to be used. The aim of this study was to evaluate the effects of enrichment items on clinical chemistryand physiological parameters of Wistar rats with the emphasis on the extent of variation. Fortyeight weaned female and male outbred Wistar rats from eight different litters were housed for five weeks in groups of four rats per cage with anaspen tube (20x12x12 em), an aspen block (6x6x6 cm) or without enrichment items (control animals). At the end of the study, adrenals and brown adipose tissues were weighed, growth calculated from initial and final body weights and thefollowing assays were performed from serum samples: AFOS, ALAT, ASAT, LDH, GGT, Pi, Ca, cholesterol, triglycerides, ereatinine, total bilirubin, protein and corticosterone. Based on the variation detected, SOLO Power Analysis was used to calculate the smallest number of animals required (n) to detect an arbitrarily chosen 20 % difference in all means, when significance was set at p=0.05 and statistical power at 0.90. Based on the n-values, additional N-ratio (nenrichment / ncontrol) was calculated to indicate, how many times more or less animals were needed in the enrichment group in comparison to the control group. The enrichment items did not have effects on group means. However. they seemed to influence the variation and hence on the number of animals needed, with enzyme parameters being the most sensitive in this respect. This relationship between enrichment, variation and number of animals needed should be kept in mind while designing experiments with ethically correct sample size

Comparison of and Habituation to Four Common Methods of Handling and Lifting of Rats with Cardiovascular Telemetry

Daily routines in the animal house may influence the results and interpretation of experiments. Handling  is one such routine since it is necessary to immobilize animals for even minor procedures. This study  assesses the influence of four common handling and lifting methods on cardiovascular parameters (blood  pressure, heart rate) and locomotor activity of Sprague-Dawley and Wistar rats. Seven rats were implanted  with radio-telemetry transmitters. After a recovery period, they were housed in groups of three with two  intact rats. Each instrumented rat was subjected to the four methods of handling and lifting (scruff, encircling,  plastic cone, lifting and holding by the tail on the arm) and, the same method was repeated during  three consecutive weekdays. The method was changed every second week in a rotational order. Handling  increased cardiovascular parameters for about 30 min, these changes being statistically significant (p <  0.05) as compared to control conditions immediately before the procedure. With holding by the scruff, the  response duration decreased significantly from day one to days two and three, indicative of habituation to  this procedure. Rats did not habituate to the cone handling, nor to encircling or lifting and holding by the  tail; with the restraint cone being apparently the most disturbing. In conclusion, we have found that there  are measurable differences in the impact of various handling and lifting methods and the correct choice  permits refinement (one of the “Three Rs” of animal usage) of the procedure. Cardiovascular telemetry  appears to be a useful method when used for refining procedures on animals, such as handling and lifting.

Cage position preferences of rats

Polycarbonate and stainless steel are commonly used cage body materials for laboratory rodents. The aim of this study was to assess preference of rats for the cage material. Altogether 64 male rats were used, 32 in two different facilities. The study cages were made of either stainless steel with a polycarbonate false inner half (Kuopio) or polycarbonate with a steel false inner half (Oulu). There were four different options for alignment of false cage halves and food hopper, and likewisetwo options for which end of the cage faced the wall. A video camera with time lapse recording of one second each minute was used. Weekly recording started at 16.00 and ended at 01.30, and each cage was recorded when the rats were agedfour, five, six. seven and eight weeks, The results were processed separately for both facilities and for day and night. Statistical analysis was done with ANOVA using alignment of food hopper to false inner cage half and direction to the wall asthe main effects during the daytime the location of the rats in nontransparent steel body cages is largely governed by the light intensity created by cage walls and hopper, but stainless steel was clearly preferred in three of four possiblecombinations. During the night the element of tight direction became less important, but again hopper and steel combination was more attractive than the hopper and polycarbonate combination. In polyearbonate cages with false steel inner half cages: the light intensity difference had a less prominent role. However, during the day, placing the feed hopper with steel was preferred. During the night, the even distribution was indicative of a slight preference to the familiar wall material,polycarbonate. In conclusion, in both study sites stainless steel was favored in 3 out 4 possible combinations during the day, During the dark, when transparency of the material was less critical, animals accustomed to a stainless steel cagespreferred steel over polycarbonate, but for animals raised in polycarbonate cages neither steel nor polycarbonate was favored

Deciduous wood chips as bedding material: Estimation of dust yield, water absorption and microbiological comparison

Dust yield, water absorbing capacity and airborne microbes of laboratory animal beddings made of deciduous wood were compared. Three different bedding materials, aspen, alder and birch, two chip sizes and effects of a softening treatment were studied. Overall dust yield from Chips was relatively low. Aspen should, however, be preferred to alder, because it was less dusty. Small (1 X 2 X 1 mm) aspen Chips yielded less inhalable dust than the large chips (4 X 4 X 1 mm). Water absorbing capacity was better in small chips than in large chips and could also be increased with a softening procedure. In this study softening of small aspen chips resulted in unacceptable high dust yield. Though alder had a better water absorbing capacity, aspen seems to soak up urine well enough during a normal change cycle

Recommendations for health monitoring of pig, cat, dog and gerbil breeding colonies: Report of the Scandinavian Federation for Laboratory Animal Science (Scand-LAS) Working Group of Animal Health

No abstract availabl

Durability and Hygiene of Aspen Tubes Used for Providing Environmental Complexity for Laboratory Rats

In Europe the provision of environmental complexity for laboratory animals is mandatory unless there is  some welfare-related or scientific reason to prevent their inclusion. Any chemical compound present in the  added item to the cage represents a potential confounding factor in the study. The best remedy to this problem  is to use a material, such as the wooden bedding material which is already present in the cage. The  durability of wooden items means they can be used several times, but they are considered difficult to sanitise.  Furthermore, items that are made of several parts may be more easily destroyed than those made of a  single unit. This study was designed to explore the durability and possible practical problems associated  with sanitation and hygiene of a commercially available aspen tube intended for routine use with rats. The  wooden items used were rectangular tubes (20 x 11 x 11 cm) made of dried aspen board with the walls  being held together with aspen pins. Before the first use, all of the aspen tubes were autoclaved. At each  cage change, the tubes were rinsed either under a pressure washer without detergent or rinsed combined  with autoclaving. The tubes were observed for durability and sampled for microbes after use and after sanitation.  All of the tubes were discarded before the 14th use. Washing as the sole sanitation method  decreased total bacterial burden and coliforms during the first three cycles as compared counts prior to  wash. With respect to fungi there were no differences between the sanitation groups. In conclusion, when  aspen tubes are cleaned with plain water and pressure, they can be effectively cleaned for up to four cycles.  When autoclave treatment is added to the wash cycle, it is the macroscopic damage, which determines the  usable life of the item. It appears that aspen blocks can be used in rat cages more than once without any  danger of elevating the microbiological burden.