PDF(Pubmed)
Abstract：
The primary aim of this study was to investigate the effect of the pelvic dimensions of Holstein cows on the traction forces during parturition. Additionally, the relationship between calf measurements and traction forces was explored. For this purpose, a modified in vitro biomechanical model simulating obstetric tractions was used. For the requirements of the experiment, six bone pelvises of deceased Holstein cows were collected based on their estimated pelvic inlet area (EPA) and prepared. Additionally, six stillborn calves were collected based on their body weight (BW). The parameters of the pelvic inlet and cavity were measured using computed tomography (CT). Using the simulator, every calf was pulled in a random order through all pelvises, realizing a total of 36 obstetrical tractions, and the required forces were documented with appropriate software. In each extraction, three peaks of forces were recorded, with the first peak occurring at the entrance of the elbows into the maternal pelvic cavity, the second peak at the entrance of the thorax, and the third at the entrance of the calf\'s pelvis. Logistic regression revealed an exponential relationship between pelvic parameters and traction forces for the entrance of the elbows and the pelvis, with the recorded forces being higher in the two smallest pelvises and stabilizing at a lower level thereafter, while for the entrance of the thorax, the correlations were either exponential or linear. The adjusted coefficients of determination (r2) were generally above the threshold of 0.5 for the entrance of the elbows and pelvis and lower (0.3-0.4) regarding the thorax and were statistically significant (p < 0.05) in all cases. Regarding the relationships between the calf dimensions and the required traction forces, the types of correlations were primarily linear and of lower magnitude. The combination of pelvic and calf parameters in a multivariate model resulted in an r2 of 0.72 for the entrance of the elbows using the pelvic diagonal and calf\'s body weight, an r2 of 0.62 using the pelvic area and calf\'s thoracic circumference, and an r2 of 0.75 using the pelvic diagonal and calf\'s fetlock joint width. In conclusion, under the conditions of the present experimentation, the applied traction forces were mainly influenced by the pelvic dimensions in an exponential manner, whereas the calf body measurements showed a weaker effect. Based on these findings, critical cut-off points exist, different for every pelvic parameter, below which a significant increase in the required traction forces is expected.
摘要：
这项研究的主要目的是研究荷斯坦奶牛的骨盆尺寸对分娩过程中牵引力的影响。此外,探索了小腿测量值与牵引力之间的关系。为此,使用了模拟产科牵引的改良体外生物力学模型。对于实验的要求，根据估计的骨盆入口面积（EPA）收集了6头死亡的荷斯坦奶牛的骨骨盆，并进行了准备。此外,根据体重（BW）收集六只死产小牛。使用计算机断层扫描（CT）测量骨盆入口和腔的参数。使用模拟器，每只小牛都被随机拉过所有的骨盆，共完成36次产科手术，并且用适当的软件记录所需的力量。在每次提取中，记录了三个力的峰值，第一个高峰出现在肘部进入母体盆腔的入口处，在胸腔入口处的第二个峰，第三个在小腿骨盆的入口处。Logistic回归显示，肘部和骨盆入口的骨盆参数与牵引力之间呈指数关系，记录的力在两个最小的骨盆中较高，此后稳定在较低水平，而胸腔的入口，相关性呈指数或线性。调整后的测定系数(r2)通常高于肘部和骨盆进入的阈值0.5,而对于胸部则更低(0.3-0.4),并且在所有情况下都具有统计学意义(p<0.05)。关于小腿尺寸与所需牵引力之间的关系，相关性的类型主要是线性的，幅度较低。多变量模型中骨盆和小腿参数的组合导致使用骨盆对角线和小腿体重的肘部入口的r2为0.72，使用骨盆区域和小腿的胸围，r2为0.62，使用骨盆对角线和小腿的fetlock关节宽度，r2为0.75。总之,在本实验的条件下，施加的牵引力主要受骨盆尺寸以指数方式影响，而小腿身体测量显示效果较弱。基于这些发现,存在临界截止点，每个骨盆参数都不同，在这之下，所需的牵引力预计将显著增加。
