There are two things that can affect the stress level, and therefore the cortisol level, in the sheep. For these reasons, I choose to examine specific behaviors that can be considered aggressive in sheep, in addition to tracking zoo attendance for each day the observation was conducted. Analyzing faecal cortisol levels was the best option for my project because it is non-invasive and can be collected in a way that will not cause additional stress to the animal.
Faecal cortisol levels also provide a broader picture of the sheep's cortisol levels from the previous 24 hours, compared to when the sample was collected. This study suggests that zoos can be an important resource in successfully educating the public. All these aspects are essential to the success of the zoo and maintaining the health of each animal.
The animals' ability to keep a critical distance can be affected by visitor density and enclosure design. 15. This problem can also be improved with an enclosure design that allows the animals to retreat to a room where they can be alone if they feel frightened. 15. This gives the animal control over their environment and can therefore reduce unwanted behaviour. 15. 2002) concluded that large numbers of visitors may stress pet animals, but stressful environments can be minimized by allowing the animals.
Various methods can be used to evaluate how these factors influence animal welfare. Despite these factors, research is currently underway to determine how this can be improved. All of these factors can be modified in an attempt to eliminate or reduce the effect of the stressor.
A sign of ongoing stress can be identified by high levels of cortisol, a type of glucocorticoid steroid.15. The methods used to analyze cortisol levels, and therefore stress, can be one of the causative factors of stress in an animal due to the invasive techniques required to collect the sample. The visitor effect makes sense in theory, but statistically it can be very difficult.
All the sheep are eight years old and were born in the same spring. A graph was made of the percent binding of the standards to the anti-cortisol antibodies present in the sample. A value above 100% of this may be due to cross-reaction with other hormones in the matrix.
Differences across the wells of a plate can be due to plate reader or plate washing errors.
Results
It should be noted that on December 23, a sheep experienced unusually high levels of cortisol. However, a data point is not more than two standard deviations away from the mean, so it does not appear statistically as an outlier. If this data point is omitted from the data set for the winter time frame, the mean observed cortisol level becomes ng/g.
In summer, Toby's cortisol levels are generally higher day to day compared to other sheep with an average of 29.44 ng/g. Dolly's faecal cortisol levels were the lowest among sheep with an average of 22.76 ng/g. However, faecal cortisol levels in all sheep are more variable in winter and one is not consistently higher or lower than the others from day to day.
Overall during the winter, Dolly had the highest mean cortisol levels (44.75 ng/g) and Charlie had the lowest mean cortisol levels (41.34 ng/g). The sheep's cortisol levels were compared with visitor attendance data to see if increased visitors caused stress. The average number of guests during the summer was 2280 people per day, while during the winter period it was 362.7 people per day.
It should be noted that aggregate attendance data was used for this analysis and not necessarily all zoo visitors will go to the sheep petting zoo area. The sheep's cortisol levels are then compared to the temperature recorded at the time of observation or sample collection to see if there is a relationship between temperature and stress (Figure 7). The average temperature during the summer time period was 83.4°F while the average temperature during the winter time period was 32.8°F.
It should be noted that during the winter period the sheep were normally inside the shed, which is heated. Therefore, they were not always exposed to the cold temperatures for the entire duration of the day.
Discussion
However, these medications did not appear to have drastic effects on their cortisol levels, as levels still varied from day to day. The unusual amount of footprints can be attributed to the sheep's attempts to remove insects that had landed on the feet or legs. It was expected that higher fecal cortisol levels would have been observed during the summer months, when there are higher temperatures and a greater number of visitors to the zoo.
However, this trend was not seen, as the sheep had higher cortisol levels in winter, when there are lower temperatures and lower numbers of visitors to the zoo. Similar results were found in the Pyrenean wild goat, a mountain ruminant, that higher mean faecal cortisol levels were observed in winter (3000 ng/g) compared to summer (500 ng/g) due to endogenous seasonal adaptation .39 Cortisol levels observed from sheep were not nearly as high in both seasons, but a similar trend was observed. In terms of the relationship between cortisol levels and visitor attendance data, it was expected that there would be a positive relationship between the two, but this was not true.
In the summer, sheep are exposed to drastically more people each day, but their cortisol levels remain the same, if not lower. When this changes suddenly without an adjustment period, there can be a sudden increase in cortisol levels due to stress. The first is the sudden influx of visitors due to the holiday seasons and the time of the annual veterinary examination of the sheep.
The higher cortisol levels observed during the winter period may also be attributed to physiological adjustments; but the present results showed that the sheep are not. significantly more stressed due to lower temperatures. 1982) conducted a similar study with the aim of determining the effect of temperature and humidity on sheep plasma cortisol levels.40 The highest cortisol levels in sheep were recorded under cold-humid conditions nmol/l) and the lowest under warm-humid conditions nmol/l ) .40. Through an analysis of behavior and faecal cortisol levels, it was determined that any instances of aggressive behavior exhibited by the sheep were not due to high stress levels.
Temperature was not a significant factor in influencing faecal cortisol levels, whereas visitor attendance did significantly, positivity influence faecal cortisol levels. Further analysis would benefit from a year-long longitudinal study to observe continuous trends between visitor attendance and cortisol levels. This would help confirm whether acclimation to visitor participation is indeed the cause of the observed trends in cortisol levels.
Acknowledgments
Make sure you have enough 80% ethanol and assay buffer available for the number of extractions you need to perform (5 ml ethanol per sample; 1 ml assay buffer per sample) 2. Use the plate layout sheet on the back to assist with correct sample and standard identification. If using the 1 x 8 well strip plate version of the kit, K003-H1 or -H5, determine the number of wells to be used and return unused wells to the desiccant foil bag.
Pipette standards or samples along the plate strip columns (A to H) to ensure maximum use of the strip wells. The use of any wells in the whole plate versions of the kit, K003-H1W and K003-H5W will not allow the use of unused portions of that plate in a later test. Use the plate reader's built-in 4PLC software capabilities to calculate cortisol concentration for each sample.
NOTE: If using only part of a strip well plate, at the end of the assay, discard the used wells and keep the plate frame for use with the remaining unused wells. Create a standard curve by reducing the data using the 4PLC fitting routine on the plate reader after subtracting the mean ODs for NSB. Sensitivity was calculated by comparing the ODs of twenty wells run for each of B0 and standard #7.
The detection limit was determined at two (2) standard deviations from the B0 along the standard curve. The limit of detection for the assay was determined in a similar manner by comparing the ODs for twenty runs for each of the blank standard and a low concentration human sample. Linearity was determined by taking two human urine samples diluted 1:140, one with a low diluted cortisol level of 163.9 pg/mL and one with a higher diluted level of 2,974.9 pg/mL and mixing them in the ratios given below .
Three human samples were diluted with Assay Buffer and assayed in replicates of 20. Three human samples were diluted with Assay Buffer and run in duplicate in ten tests performed over several days by four operators. The following cross-reagents were tested in the assay and calculated at the 50% binding point.
Literature Cited
Evaluating the factors influencing the emotional responses of zoo visitors and the impact of emotions on nature conservation attitudes. The influence of visitors on the behavior of captive western lowland gorillas: the importance of individual differences in the study of well-being.
