Objectives: Bolus devices allow reticuloruminal pH to be continuously monitored over an extended time period, which has the potential to inform precision livestock management. Our aim was to describe pH patterns in clinically healthy dairy cattle and to assess their potential for predicting reduced productivity. Materials and methods: Remotely sensed pH data were recorded at 600 second intervals over a period of 45 consecutive days from 24 apparently healthy, co-managed cattle on a single dairy herd. The data were analysed using a non-linear model with a modified sinusoidal function that allowed the rate of increase in pH to differ from the rate of decrease in pH for modified sine functions with a daily frequency and a frequency determined by the interval between milking times. Longer term changes in pH were accounted for by alternating the non-linear model fit with a generalised additive model. All animals were modelled separately. Residuals from the fitted model were then summarised at daily intervals and correlated to future deviations in observed milk yield and dry matter intake. Results: There were strong similarities but also important differences in the daily pH patterns observed between the co-managed animals. Depending on the animal, between 20-40% of the observed variation was predicted by the time of day, and an additional 10-25% was predicted by fluctuation between milking times. Days with less predictable pH observations (higher mean absolute residual) were found to be significantly correlated to both reduced milk yield (p<0.001) and dry matter intake (p<0.001) at a subsequent time point. Conclusions: Remotely sensed pH data has the potential to be used for monitoring productivity in dairy cows. Further work to provide real-time warnings of a predicted reduction in milk yield using dynamic linear models is ongoing.
|Publication status||Published - Nov 2018|
|Event||ISVEE15: The 15th International Symposium of Veterinary Epidemology and Economics - Chiang Mai, Thailand|
Duration: 12 Nov 2018 → 16 Nov 2018
|Period||12/11/18 → 16/11/18|
Denwood, M. J., Jensen, D. B., Kleen, J. L., & Jonsson, N. N. (2018). Association between temporal patterns in continuously monitored reticuloruminal pH data and production characteristics in dairy cows. Poster session presented at ISVEE15, Chiang Mai, Thailand.