Rumen monitoring:
How bolus data is changing our ideas
about SARA
Professor Toby Mottram
Douglas Bomford Trust Chair in Agricultural
Mechanisation
Royal Agricultural University
Cirencester
[email protected]
Overview
 An introduction to rumen boluses
 What we have learnt since the start of the bolus era
 How a bolus fits into herd management strategies
1.Diagnostic
2.Control
Rumen pH Bolus
Inserted by mouth
Retained in Reticulo-rumen
Data downloaded by radio
Uploaded to internet
Analysed and interpreted
What have we learnt from
boluses?
1.A bolus in the reticulum can monitor the rumen
2.Bolus life is determined by sensor poisoning
3.SARA can be detected and corrected
4.Mean Rumen pH is not correlated to milk yield
5.Systems factors dominate rumen pH profiles
Reticulum pH maps to
ventral sac pH
Limitations of boluses?
1. Bolus life is determined by sensor failure
2. Sensor Drift is non-linear but can be detected
3. Radio transmission is inhibited by fat deposition
4. The minimum size is determined by
1. Radio antenna and ground plane
2. Reference electrode
3. Battery
5.Do we need a long life bolus ?
Data from a bolus over 180 days
How boluses fail!
Ante
Partum
Gap no
download
Reference
Junction
Drift
Reference
Junction
Drift
Starts Gap no
download
SARA can be detected and treated
using rumen pH data by observing
systems patterns
Rumen pH is not what we
expected from research
On research farms rumen pH reveals repeatable
patterns
On real farms the daily patterns are different
– Less constraint on animals
–
Chaotic management routines
A dry cow at grass
Daily Profiles
Low pH but regular feed pattern with cows not eating at night
Same herd after a feed
change
After a feed change, pH is higher and cows eat more at night
Mean pH is not correlated to mean
milk yield
Rumen pH and % hours
below 5.8 v Milk Yield
This doesn't look well correlated ! R2 of 0.25 & 0.46
System effect on mean pH
& time below 5.8 pH
Daily patterns and values of pH
are dominated by systems,
routines and seasons
SYSTEMS PATTERNS
TMR
Specific daily pattern
Daily events for a TMR Herd – Feeding, Milking and Push Ups
Creatures Of Habit
Robot
Daily Routine Analysis
Grazing and Compound
Cows need order to be able to self
regulate their pH
Rumen pH determined by:
INTAKE
X
FERMENTABILITY
X
NDF
X
ROUTINE
How to use boluses
1. Mostly as a diagnostic tool
2. As a continuous monitor
Why is this cow still alive ?
This is the mean pH profile
of 3 cows in that herd
pH Bolus Plot
What happened?
New Seed Grazing
Summary
 Rumen telemetry can be used to diagnose problems
 Gives objective data about the cows routine
 We can use 5.8 pH as a threshold for SARA
 Time below threshold is still to be determined
 Known Unknowns:
• How damaging are short periods below threshold?
• What mean daily pH is too low ?
• What daily range of pH is ideal ?
•
Thank You
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