Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada; Livestock Research and Extension Branch, Alberta Agriculture and Forestry, Edmonton, AB, T6H 5T6, Canada.
J Dairy Sci. 2019 May;102(5):4427-4440. doi: 10.3168/jds.2018-15221. Epub 2019 Mar 15.
Most Canadian dairy herds operate in tiestall housing (61%), where average estrus detection rates may be lower than 54%. The objective of this study was to evaluate infrared thermography and behavioral biometrics as indicators of estrus in dairy cows. Eighteen cyclic multiparous cows (Synch) were subjected to an estrus synchronization protocol, and 18 pregnant cows (control) received a sham protocol on the same schedule and frequency as the cyclic cow treatment. A decline in plasma concentrations of progesterone and the appearance of a dominant follicle using transrectal ultrasonography were used as indirect indicators of estrus, and the disappearance of a dominant follicle was used to confirm ovulation. All cows were monitored via visual cameras to determine the frequency of treading, drinking, neighbor interaction, tail movement, lying, and shifting behaviors. Infrared thermograms were recorded at the eye, muzzle, cheek, neck, front right foot, front left foot, rump, flank, vulva area, tail head, and withers. To evaluate the accuracy of behavioral and thermal parameters, a predefined minimum acceptable value (i.e., threshold) for estrus alerts (>0.30 Youden J index and >0.60 area under the curve) was used. Ovulation was confirmed in 14 (77.7%) out of 18 Synch cows. Eye, cheek, neck, rump, flank, vulva area, and wither thermograms exhibited higher temperatures at 48 h [cycle threshold (Δt) = +0.30 to 1.20°C] and 24 h before ovulation compared with 4 d prior to ovulation (Δt = 0.06 to 0.11°C) and during ovulation day (Δt = 0.03 to 0.32°C) in the Synch group. In addition, control cows exhibited greater treading activity per day compared with Synch cows (20.84 ± 0.39 vs. 16.35 events/5 min ± 0.34), and tail movement frequency was greater in Synch cows compared with control cows (14.84 ± 2.7 vs. 10.11 ± 4.7 events/5 min). However, within Synch cows, tail movement was the only behavior that significantly increased in frequency 2 d before ovulation (11.81 ± 1.71 events/5 min) followed by a decrease in frequency 1 d before ovulation (4.67 ± 1.05 events/5 min) compared with ovulation day (0 d; 6.10 ± 1.25 events/5 min) and during luteolysis (3 d before ovulation; 6.01 ± 1.25 events/5 min). Upon evaluation of all variables (thermograms and behavior frequencies) as estrus indicators at 48 and 24 h before ovulation, treading and tail movements before milking and 9 thermal locations satisfied the predefined minimum acceptable value for estrus alerts. This study demonstrates that fluctuations in radiated temperature measured at specific anatomical locations and the frequency of tail movements and treading behaviors can be used as a noninvasive estrus alerts in multiparous cows housed in a tiestall system.
大多数加拿大奶牛场采用牛舍卧床饲养（61%），发情检测率可能低于 54%。本研究旨在评估红外热成像和行为生物计量学作为奶牛发情的指标。18 头周期性多胎奶牛（Synch）接受了发情同步方案，18 头妊娠奶牛（对照）在与循环奶牛治疗相同的时间和频率接受了假方案。血浆孕酮浓度下降和直肠超声检查中出现优势卵泡被用作发情的间接指标，优势卵泡的消失被用来确认排卵。所有奶牛都通过可视摄像机进行监测，以确定踩踏、饮水、邻接互动、尾巴运动、躺卧和移位行为的频率。红外热图像记录在眼睛、口鼻、脸颊、颈部、前右脚、前脚、臀部、侧腹、外阴区域、尾巴头和肩背部。为了评估行为和热参数的准确性，使用了发情警报的预定义最小可接受值（即阈值）（>0.30 Youden J 指数和>0.60 曲线下面积）。18 头 Synch 奶牛中有 14 头（77.7%）确认排卵。眼睛、脸颊、颈部、臀部、侧腹、外阴区域和肩背部的热图像在排卵前 48 小时（Δt = +0.30 至 1.20°C）和 24 小时（Δt = +0.30 至 1.20°C）的温度高于排卵前 4 天（Δt = 0.06 至 0.11°C）和排卵当天（Δt = 0.03 至 0.32°C）。此外，与 Synch 奶牛相比，对照奶牛每天的踩踏活动次数更多（20.84 ± 0.39 次/5 分钟±0.34），Synch 奶牛的尾巴运动频率也高于对照奶牛（14.84 ± 2.7 次/5 分钟±0.34）。然而，在 Synch 奶牛中，尾巴运动是唯一在排卵前 2 天频率显著增加的行为（11.81 ± 1.71 次/5 分钟），然后在排卵前 1 天频率降低（4.67 ± 1.05 次/5 分钟）与排卵日（0 天；6.10 ± 1.25 次/5 分钟）和黄体溶解期（排卵前 3 天；6.01 ± 1.25 次/5 分钟）相比。在评估发情前 48 小时和 24 小时的所有变量（热图像和行为频率）作为发情指标时，挤奶前的踩踏和尾巴运动以及 9 个热部位满足了发情警报的预定义最小可接受值。本研究表明，在牛舍卧床系统中饲养的多胎奶牛，特定解剖部位测量的辐射温度波动和尾巴运动及踩踏行为的频率可用作非侵入性发情警报。
