Estimation of Liveweight from Body Measurements through Best Fitted Regression Model in Dezhou Donkey Breed.

This research study focused on estimating the body weight of Dezhou donkey using body measurements and statistical analysis, also providing a more efficient model for use in the local breeding of this animal.

Objective of the Study

• The main goal of this research was to establish a precise and reliable method for estimating the body weight of Dezhou donkeys using their body measurements, in order to improve and expedite breeding, reproduction, and conversation practices in Shandong Province, China.

Methodology and Sample

• 162 Dezhou donkeys, both male and female, aged between 2 and 10 years, were used for this study. These donkeys were reared under intensive farms.
• These donkeys were measured for various body dimensional traits such as height of withers, body length, thoracic depth, thoracic girth, thoracic width, circumference of cannon bone, height of rump, rump length, and rump width. These measures were taken in centimeters.
• The team used SAS 9.4 software (Statistical Analysis for Windows) to conduct a correlation and multiple regression analysis between body weight and these measurements.

Results and Analysis

• The research found significant positive correlations between body weight and the measurements taken, with R values ranging from 0.58 to 0.88 (P is less than 0.01), indicating a strong linkage. Among all measurements, thoracic girth exhibited the highest correlation with body weight (R value 0.72, P is less than 0.01).
• Using stepwise regression equations, the researchers discovered that including more body measurement variables improved the prediction accuracy for body weight.
• The most fitting prediction equation found was “BW (kg) = 1.88 × Thoracic Girth + 1.27 × Body Length + 2.55 × Thoracic Width + 4.61 × Circumference of Cannon Bone + 2.18 × Rump Width + 1.78 × Rump Length – 422.8”. This equation had a superb R value of 0.906 and was statistically significant (P is less than 0.01).
• The research found that predicted body weight from their equations was very close to real body weight, indicating the efficacy of these equations.

Comparative Analysis

• The equations used for predicting the body weight of donkeys in Britain and Morocco were found to be unsuitable for Dezhou donkeys, since they either overestimated or underestimated the body weights, emphasizing the unique characteristics of different donkey breeds.

Conclusion

• The study provides a significantly reliable method to estimate the body weight of the Dezhou donkey breed using body measurements, which can be of great help in speeding up breeding and reproduction activities in the region.