The reliable detection of estrus is an important scientific and practical challenge in dairy cattle farming. Female vocalization may indicate reproductive status, and preliminary evidence suggests that this information can be used to detect estrus in dairy cattle. The aim of this study was to associate the changes in the vocalization rate of dairy heifers with behavioral estrus indicators as well as test the influence of the type of estrus (natural estrus vs. superovulation-induced estrus). We analyzed 6 predefined estrus-related behavior patterns (standing to be mounted, head-side mounting, active mounting, chin resting, being mounted while not standing, and active sniffing in the anogenital region) and vocalization rates in the peri-estrus period (day of estrus ± 1 d) of 12 German Holstein heifers using audio-visual recordings. Each heifer was observed under natural estrus and a consecutive superovulation induced by FSH and cloprostenol. Estrus was determined by behavioral patterns and confirmed by clinical examination (vaginoscopy and ultrasound imaging of the ovaries) as well as by the concentration of peripheral progesterone. Estrus behavior and vocalization rates were analyzed in 3-h intervals (an average of 19 intervals for each heifer), and an estrus score was calculated based on the 6 behaviors. The interval with the highest estrus score (I0) was considered the estrus climax. We demonstrated similar time courses for the estrus score and vocalization rate independent of estrus type. However, in natural estrus, the maximum vocalization rate (±SE) occurred in the interval before estrus climax (I−1; 42.58 ± 21.89) and was significantly higher than that in any other interval except estrus climax (I0; 27.58 ± 9.76). During natural estrus, the vocalization rate was significantly higher within the interval before estrus climax (I−1; 42.58 ± 21.89 vs. 11.58 ± 5.51) than under superovulation. The results underscore the potential use of vocalization rate as a suitable indicator of estrus climax in automated estrus detection devices. Further studies and technical development are required to record and process individual vocalization rates.

可靠地检测发情是奶牛养殖中的一项重要科学和实践挑战。女性发声可能表示生殖状态，初步证据表明该信息可用于检测奶牛的发情期。这项研究的目的是将奶牛小母牛发声率的变化与行为发情指标相关联，并测试发情类型（自然发情与超排卵引起的发情）的影响。我们分析了6种预定义的与发情有关的行为模式（站立，头侧安装，主动式安装，下巴休息，不站立时安装以及在肛门生殖器区域内的主动吸气）和发情期的发声率（发情日±1 d）使用视听记录的12只德国荷斯坦小母牛。在自然发情期观察到每个小母牛，并由FSH和氯前列醇诱导连续的超排卵。发情是通过行为方式确定的，并通过临床检查（阴道镜检查和卵巢超声检查）以及外周孕酮的浓度进行确认。以3小时为间隔分析发情行为和发声率（每个小母牛平均19个间隔），并基于6种行为计算发情分数。发情评分最高（I0）的时间间隔被视为发情高潮。我们证明了与发情类型无关的发情分数和发声率相似的时间课程。但是，在自然发情期，最大发声率（±SE）出现在发情高潮之前的时间段（I-1; 42.58±21）。89），并且比发情高潮（I0; 27.58±9.76）以外的其他任何时间间隔都高。在自然发情期，发情高潮前的发声率明显高于超排卵期（I-1； 42.58±21.89 vs. 11.58±5.51）。结果强调了发声率作为自动发情检测设备中发情高潮的合适指标的潜在用途。需要进一步的研究和技术开发来记录和处理个人发声率。结果强调了发声率作为自动发情检测设备中发情高潮的合适指标的潜在用途。需要进一步的研究和技术开发来记录和处理个人发声率。结果强调了发声率作为自动发情检测设备中发情高潮的合适指标的潜在用途。需要进一步的研究和技术开发来记录和处理个人发声率。