Vetpack – detect SARA

Detecting SARA with Vetpack

When a herd of cows has a nutritional problem it is hard to see what it is.  SARA is a common diagnosis but where is the evidence.   Very often the diet formulation looks OK but as we know silage varies through the clamp, people don’t put the right ingredients in, or they have a disorderly routine.  The rumen bolus tells what is really happening.    A Vetpack gives you all you need  to monitor a herd for 3 months by which time you will have identified and fixed the problem.

A pack of farmBolus, phone and carry case

VetPack for monitoring acidosis in farm conditions

The vetpack contains:-

  • A dedicated Smartphone with download antenna
  • 3 or more boluses (it depends how many cows you want to sample)
  • a dedicated online dataviewer to allow comparisons between farms
  • a bolling gun
  • all software and hardware support


How to use Vetpack

When you suspect a nutritional management problem put a farmBolus in 3 % of the problem group (usually early lactation cows) .  Choose cows giving average yields in the group (avoid the “best” or sick cows that the herdsman worries about).  Record the cow IDs on the smartphone so to associate the bolus ID with the cow ID. The bolus goes down the throat using a standard bolling gun.  After a few minutes it migrates to the reticulum and stays there continuously monitoring pH and temperature. To get data stand near the cow with the handset, select the cowID and press download.


A woman in a boiler suit holds a phone near a white cow to download data from the rumen bolus

Pick cows representative of the group, select the cow ID on the phone walk up to them and press the button to download data. This can be done anywhere but ideally where you can get behind the cow where signals can be found 5-10 metres away or 1 to 2 metres from the front or side.

Once the phone connects, the data comes out of the cow onto the phone.  You can view it immediately and this gives an immediate indication of the current pH.  On the next visit you can download up to 28 days data to see what is going on.  Whenever the phone gets an internet connection the data flows to the dataviewer so you can look back over the weeks to see trends and changes.  The results can be a surprise to the farmer and show the efficiency of the feeding system to give cows a routine with small daily ranges of pH.

daily pH graph

By overlaying daily pH values you can see the real routine of the farm which may surprise some farm managers, what is happening at weekends.



Benefits of the farmBolus

  • Early warning of SARA

Clinical conditions of SARA often don’t present themselves until months after rumen pH drops, by which time milk yields may have decreased. By monitoring ruminal pH you can detect SARA before symptoms arise and prevent reduced milk yield, reduced milk fat content and unnecessary culling.

See link for more information on SARA.

  • Improved diet through pH optimisation

Providing cows with the correct balance of forage to grain to provide optimum milk yield and still maintain a healthy herd is not easy and varies from herd to herd. By using the eCow farmBolus you can provide your cows with a type of personalised medicine to tailor a diet to their specific needs, ensuring a long lasting healthy herd and consistent high milk yields.

  • Reduced Left Displaced Abomasum (LDA) through improved diet

LDA is common in cows post-calving and requires expensive surgery to correct. By monitoring the cows health throughout this period and adjusting diet to compensate, LDA can be reduced significantly in a herd.

See link for more information on LDA.

  • Aids management decisions on feeding and movement routines

Using pH and temperature monitoring you can see how much and how often cows feed and drink, allowing adjustments in management practices to be made to maximise the intake and therefore milk production.

  • Improved use of supplements

Supplements such as rumen buffer that are used to prevent the pH of the rumen dropping too low are often recommended by veterinarians in high yielding herds. By monitoring ruminal pH it has been shown in recent studies that these costly supplements are not always necessary, as pH remains unchanged following their removal.

  • Monitoring of drinking behaviour and heat stress

Temperature drops in the rumen can be linked to drinking events and used to detect inadequate drinking facilities or unhealthy cows. Similarly, temperature measurements can detect heat stress and allow farmers to adjust management practices accordingly.

  • Detection of mycotoxins

The symptoms of mycotoxin poisoning in cattle are identical to the symptoms of SARA, aside from the drop in ruminal pH. With the symptoms of SARA and in the absence of low ruminal pH it can be deduced that mycotoxins are the likely cause of the symptoms and appropriate measures can be taken to recover the herd.

See link for more information on mycotoxin poisoning.


pH Measurements

The main feature of the farmBolus is its ability to accurately and continuously monitor rumen pH. The pH of a solution is a measure of the acidity of a solution, and as the acidity increases the pH drops. More specifically it is a measure of the relative hydrogen ion concentration and, as the hydrogen ion is electrically charged, it is possible to measure pH electrically.

When in constant use (i.e. within a cows rumen) the sensor readings can remain stable for up to 150 days (5 months), far longer than similar products.

Website graph AgroParisT


The graph above shows the pH variation over a 3 month period, with the red line showing the threshold for acidosis. Towards the beginning of this period the cow shows signs of being at risk of acidosis. This is easily recognisable and afterwards the pH quickly rises to a safe level.

Temperature Measurements

As well as the pH functionality, the farmBolus continuously logs the temperature of its environment. This information can be used to monitor drinking activity, as cold water entering the rumen correlates with a sharp but brief drop in the temperature reading. It is important to note that these events are not changes in the overall body temperature of the cow and should not be treated as such. However, changes in the average (mean) daily temperature of the cow’s rumen can be linked to an overall change in the body temperature of the cow. As it is consistently 1°C above the rest of the body, the temperature of the rumen can be relied upon to give an accurate indication of overall body temperature. Peaks in temperature are often observed when a cow is suffering from an infection such as mastitis. Infections such as this may also be observed as a lack of drinks taken and a drop in ruminal pH.


Summary of recent farmBolus Trials  

Please follow this link if you would like to read the full report.

Between April and August 2013, a trial on eight commercial farms (Farm A-H) all located in the South West of England was run to determine how the eCow farmBolus could be used to improve farm economy and management. A benefit of this study was also getting feedback from the farmers and farm advisers about their experience using the farmBolus.

Farms were selected to include a range of feeding methods from fully housed herds with Total Mixed Ration (TMR) to grazing herds, and boluses were placed into different types of cows such as dry, fresh and early lactation. Farms had an average of 4 boluses each and farmers, vets and nutritionists were advised to put the boluses in average cows, no sickly ones, to get a better idea of the overall health of the herd.

A pH of 5.75 was defined as the acidosis threshold, as previous studies have defined it as 5.5 and the farmBolus sits in the reticulum which has been shown to have a pH about 0.25 above the main compartment of the rumen.

The initial data collected showed five of the eight farms potentially at risk of SARA, due to at least one cow per farm spent time with their ruminal pH below 5.75. In total, five farms have reported changing their feeding management by changing the total feed intake, the concentrate/forage ratio or the concentrate intake; one farm changed the time of feeding, another did not change any feed management because no feed other than grass was available and one did not provide a report. The results of these changes were an increase in the mean daily pH for three farms, which was interpreted as a reduction in the risk of SARA.

Table 2

During the recording period, 7 cows with boluses calved. Data revealed a potential risk of acidosis after calving due to a big drop in pH. Infection has also been seen in the data, represented by an increase in temperature. One or two days after these increases in temperature, farmers reported treating the cows for mastitis.

One particular farm that stood out was Farm B which, over the final three months of the trial, saved a total of £14,647.50. This was due to two ration changes, the first of which was a change in the concentrate/forage ratio in terms of dry matter intake (DMI) from 1.27 to 1.19, with the same total intake. This change resulted in a decrease in feed cost of £0.15/cow/day with a reduced risk of acidosis. The second change was a further reduction in concentrate/forage ratio from 1.19 to 0.95 with an increase of +5kg to the total intake. This change saved the farm £0.60/cow/day and reduced the risk of acidosis in one cow, the rest remained in the safe pH region.

Records in milk for this period didn’t show any decline in milk production or milk composition compared to the records of the year before. In total they saved £14,647.50 in three months by changing the cost of the ration and looking at the pH level of the cows.

Farm E had a different approach. By changing the time when the farmer moved an electric fence from evening to morning, the time a cow spent grazing increased and so did her milk yield. A yield response of 5 more litres per day was recorded for this animal. Although a positive response was seen from the herd, the increased intake did push the cow’s pH down and therefore augmented the risk of SARA, as shown by the data collected by the farmBolus presented below.

Figure 9

A survey was sent to both farmers and advisers asking for their feedback on the farmBolus. 60% of the persons questioned have seen or think that it will be a monetary benefit for farmers to use boluses because they help appreciate the risk of SARA and consequently will increase production and/or reduce the cost of SARA in the long term. Furthermore 100% of advisers have seen a commercial benefit for them or their company using the boluses to have better discussions with farmers and between each other.

These trials have proven the quality of such technology and its positive impact on farms as well as the dairy sector.

The farmBolus is designed and built in Exeter

The eCow farmBolus is a wireless telemetric device swallowed by the cow that provides continuous and accurate measurements of pH and temperature inside the rumen (more specifically the reticulum). It records data at 1 minute intervals and saves averages every 15 minutes to provide 96 readings per day. This data is stored on the bolus and then can be retrieved every time the mobile phone handset is brought within range of the cow.

Bolus Picture
For more information see For farmers – the farmBolus or our FAQs.

Below is an example of daily pH fluctuations within the rumen of a cow, with the daily average shown in red.


For the latest updates and developments with our rumen monitoring system, visit our news page.