Relationship between Rectal Temperature and Vaginal Temperature in Grazing Bos taurus Heifers

摘要

This study evaluated the relationship between rectal temperature (T REC , °C) and vaginal temperature (T VAG , °C) in grazing Bos taurus heifers, to develop an understanding of the reliability of these measures as estimates of core body temperature. Nineteen Angus heifers (BW = 232.2 ± 6.91 kg) were implanted with intra-rectal and intra-vaginal data loggers. Rectal temperature and T VAG were simultaneously recorded at 20 s intervals over 18.5 h. Heifers were housed as a singular cohort on grazing pastures for the duration of the study. A strong linear relationship (R 2 = 0.72, p 0.0001) between the measurement sites was identified. The mean difference between T REC and T VAG was small, in which T VAG was on average 0.22 ± 0.01 °C lower than T REC . Individual twenty second T REC and T VAG data were used to determine the pooled mean T REC and T VAG and then to highlight the within measure variation over time. The coefficient of variation was, on average, lower ( p 0.001) for T VAG (0.38%) than T REC (0.44%), indicating that T VAG exhibited less variation. Overall, the results from the current study suggest that a strong relationship exists between T REC and T VAG, and that T VAG may be a more reliable estimate of core body temperature than T REC in grazing Bos taurus heifers.