Sampling strategy and measurement device affect vaginal temperature outcomes in lactating dairy cattle

Area of Science:

• Veterinary Medicine
• Animal Science
• Animal Husbandry

Background:

• Body temperature (BT) is a key indicator of health and heat load in cattle.
• Current methods for measuring BT in cattle vary, impacting data accuracy and interpretation.
• Inconsistent BT measurement can affect animal welfare, potentially delaying necessary treatments.

Purpose of the Study:

• To compare the accuracy of low-cost iButton loggers against high-accuracy StarOddi loggers for vaginal temperature (VT) measurement in cattle.
• To evaluate the impact of different sampling frequencies and strategies on the accuracy of 24-hour VT estimation in lactating dairy cows.

Main Methods:

• Vaginal temperature data were collected from 54 cows using both StarOddi and iButton loggers over 12 days.
• VT data from 20 cows were recorded every minute for 9-11 days using StarOddi loggers to test 11 sampling strategies.
• Statistical analyses included mixed models, regression analyses, and kappa coefficient of concordance to compare logger accuracy and sampling strategy effectiveness.

Main Results:

• iButton loggers showed significant under- or overestimation of VT compared to StarOddi loggers.
• Low-accuracy loggers failed to correctly classify cows with elevated VT, with kappa coefficients ≤0.35.
• Sampling VT every 120 minutes provided more accurate estimates than strategies recording temperature once to thrice daily.

Conclusions:

• The choice of data logger and sampling strategy significantly influences body temperature outcomes in cattle.
• Accurate BT monitoring in cattle requires careful consideration of device precision and data collection frequency.
• Optimized logger selection and sampling protocols are essential for reliable health and heat load assessment in dairy cows.