05 16 2007

STUDY 1 - BODY CONDITION SCORING

OBJECTIVES

  • To evaluate overall animal health condition
  • To ensure positive effects and system efficiency

SCORING

5: Obese; bones cannot be felt at all
4: Well-fleshed; bones barely felt
3: Optimal; bones palpable but not prominent
2: Thinner; bones prominent
1: Advanced muscle wasting; fats gone; bones very prominent

APPLICATION TO ML 1

Used for submissions

Objective

To assess the benefits of ML system through regular exercise to the hamsters

Hypotheses

H1 = Hamsters playing ML (exercising) will not have a change in BCS
H2 = Hamsters playing ML (exercising) will have a BCS closer to 3 after the 6th week

Subjects

  • 20 Phodopus roborovskii hamsters aged 1-2 years
  • Viral antibody and parasite free

Procedures

  • 1st and 6th Week: Hamsters’ BCS were taken by 3 observers and the mean was taken
  • Assessment: Hamster is placed on a flat surface. Exception for roborovskis which need to be caught .
  • Scoring of flesh and fat at the sacroiliac area (back and pelvic area)
DSCF7400.jpg
Sacroiliac Area of roborovski Hamster
DSCF7399.jpg
BCS Assessment on Hamster

Controls

  • For 6 weeks, food amount are monitored. Food consumption: 10% of hamster weight = 10-15g (inclusive of food used during training)
  • Cages in room with controlled lighting and optimal temperature and humidity
  • Hamsters play ML for 1 hour each on every weekday. Usual training can lasts a maximum of 15 minutes per hamster.

Graph: Result of BCS Observation on the 20 Hamsters

BCS1a.jpg

Statistical Analysis and Conclusions

Using Wilcoxon signed-rank test for paired data (normal distribution: more than 15 samples)

For Hypotheses 1,
Test statistic: z = -3.8, p = 0.0006
Hypotheses was rejected.
ML was found to be able to change the BCS of the subject hamsters over the study period.

For Hypotheses 2,
Test statistic: z = -1.4, p = 0.16
Hypotheses is accepted.
After 6 weeks of playing ML, the hamsters' body condition tends to optimal score.

APPLICATION TO ML 2

Objective

Further experiments are carried out to determine whether BCS assessment on roborovski hamster has an impact on their training results and behavior.

Hypothesis

H1 = There is no difference between Meena's median change in BCS and that of Nora's

Subjects

Meena and Nora

Procedures

  • BCS was measured daily for 2 weeks (excluding Sunday).
  • Scoring: degree of flesh and fat covered
  • Experimental: Meena; She was allowed to play ML for 15 minutes each on every weekday in that period
  • Control: Nora; She was not allowed to play ML

Graph: Result of BCS Observation on Meena and Nora

BCS_MN.jpg

Statistical Analysis

Using Wilcoxon rank-sum test for independent samples (normal approximation version as n ≥10)
Test statistic: 4.503
Hypothesis rejected.

Conclusion

There is a difference in BCS between Meena and Nora.

Problems

Before we can conclude that ML actually has a positive effect on Meena's health and body condition, we need to consider a few points.

  • Roborovskis are frightened of being chased and grabbed → misleading results
  • Meena's BCS assessment was done inside the tank. She runs around in vain to escape from being caught. This stresses her and makes her exert energy as well. Hence a drop of BCS from 4 to 3 and a difference of BCS from Nora's (4 or 5 score).
  • Her training result was disrupted - she lost interest in chasing the attractor and instead tries to escape from the tank. To her, the tank = being chased, caught and examined.
  • Positive reinforcement (food) was not effective on her and negative reinforcement (knocking) had to be done to make her chase the attractor. This has a negative impact on her and would be against the Duncan method (hamsters are supposed to like choosing to play the game and enjoy it).
  • Her behavior also changes - runs a lot on the wheel, climbs throughout her cage

NEXT EXPERIMENT

1.) Assess Meena's and J's BCS in a separate location (i.e. a box) twice a week

  • To avoid confusion and stress on them in the tank
  • To avoid disrupting training results which are at satisfactory level now

2.) Get a different hamster breed (Winter Whites) which are friendly and can be touched/held

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-Share Alike 2.5 License.