Lambing supervision is not common practice in Australian lambing systems, therefore other strategies to reduce dystocia rates are required. The use of temperature loggers to measure body surface temperature (BST) of ewes may assist in predicting the onset and duration of parturition in ewes, due to the decrease in body temperature that occurs prior to parturition (Nabenishi and Yamazaki 2017; Abecia et al. 2020). The aim of this study was to validate the use of temperature loggers to detect the fall in BST which precedes and follows parturition in twin-bearing Merino ewes.
On approximately day 146 of gestation, temperature loggers (Micro-T 16-bit; Star Oddi, Iceland) were taped onto the skin surface on the inside of the upper front right leg of 27 twin-bearing, Merino ewes. The loggers recorded temperature every 10 minutes. Temperature data was averaged to hourly intervals (24 hours pre- and post-partum), where time point 0 was considered as the birth of the first-born lamb. Data was analysed through a general linear mixed model with ewe identification number fitted as a random factor.
There was a significant drop in BST from 5 – 0 hours pre-partum (36.37°C ± 0.21) compared to 24 hours pre-partum (36.97°C ± 0.21) P < 0.05). There was no difference in BST between the birth of the first and second-born lamb regardless birth interval (P > 0.05). BST increased post- partum and was significantly higher (P < 0.05) 15 – 24 hours post-partum compared to the time of birth for the second-born lamb (37.22°C ± 0.22 versus 36.74°C ± 0.22).
As BST lowered preceding the birth of the first-born lamb but not between first and second-born lamb, further analysis is required to create prediction models and develop innovative technology which could provide producers with real time information regarding ewes lambing.