# Application of Ultrasonic Nondestructive Testing for Breeding of Meat Pigeons
## 4 Discussion  
Meat pigeons are mainly bred to provide BM. The percentage of BM of meat pigeons is about 18-30% [20]. Therefore, it is necessary to continuously select to improve BM in order to meet the requirements of the meat pigeon industry. Traditionally, the BMW of meat pigeons is measured after slaughter, and thus individual birds with excellent BM cannot be further used for breeding, resulting in a waste of resources and prolonging the breeding cycle. UNDT has the advantages of being non-invasive, real-time, and operationally simple, which makes it very applicable in examining fattening results or, in our research, determining the yield of the most valuable musculature in commercial breeding. However, while this study confirms the reliability and efficiency of UNDT, a critical analysis of its limitations is essential. For instance, operator dependency can significantly influence the consistency of measurements, emphasizing the need for rigorous training protocols. Additionally, environmental factors such as lighting and temperature may impact imaging quality, highlighting the importance of standardized measurement conditions. BMW is an important economic indicator that is affected by various traits, especially BMT at point A, BMT at point B, live BW, slaughter weight, breast width, and BD. Our results indicated that the correlation coefficients between BMT at Point A and BMW in Carneau pigeons and Silver King pigeons were 0.907 and 0.897, respectively. These values were significantly higher than those at Point B or for other body measurement traits. These higher correlation coefficients compared to earlier studies may be attributed to the larger sample size, refined measurement protocols, and precise selection of anatomical sites, such as point A. Further comparative studies with other poultry species and equipment types would provide deeper insights into these findings. This suggests that Point A, located 1 cm to the left side of the top of the keel of the meat pigeons, is a stable and representative measurement site. This finding aligns with previous studies, such as [PERSON] et al., who found a significant correlation between breast muscle thickness and weight in Yangzhou geese, underscoring the importance of precise anatomical site selection [8]. [PERSON] et al. were the first to use UNDT to measure the BMT of meat pigeons in China and created a univariate linear model of weight, BMT, BD and BMW of meat pigeons with a correlation coefficient between the BMT and BMW of meat pigeons of 0.658 [6], which was lower than in the present study due to the small sample number. More than 100 samples were selected for this study, thus demonstrating stronger credibility. This study further validated that this method is unaffected by sex and breed, enhancing its versatility. For instance, [PERSON] et al. used ultrasound to measure breast muscle thickness in Peking ducks and found a strong positive correlation with slaughter traits [7]. [PERSON] et al. used ultrasound to measure the muscle thickness of broilers and found that the correlation between BMW and carcass value was relatively high at 0.64-0.69 [21]. [PERSON] et al. developed a multiple linear regression model to estimate the carcass weight of broilers. The results showed that BMW and other carcass indicators could be estimated with high accuracy by ultrasound and that measurements of the right BM were consistently more accurate than the left [22]. Prior studies of UNDT for the measurement of BMT and correlation analysis with BMW reported notable differences in correlation coefficients [6; 8; 13; 21; 23]. Potential reasons for these disparities may be differences in poultry species, the number of samples used for correlation analysis, the accuracy of the B-ultrasound detector, and especially the measurement of BM at different sites. Therefore, it is particularly important to determine an accurate and easily identifiable site for UNDT. Inthe present study, BMT and BMW were significantly correlated at points A and B (\(p<0.01\)).