pH Testing - Manure Matters Part 2

by Carl Doogan August 21, 2022 3 min read

pH Testing - Manure Matters Part 2

Written by Briony Witherow MSc RNutr. FHEA

Manure Matters: Part 2

In part 1 (link to P1 blog) we discussed the five Cs of monitoring manure and how a quick daily check (for count, control, colour, consistency and change in smell) can provide useful insight into digestive health. In this month’s blog we investigate pH, what this can tell us and how to use this alongside a visual check to promote gut health. 


pH Testing

While research suggests considerable variation between individual horses and the pH of their poo, getting an idea of what is normal for your horse and then checking in periodically, can provide a more objective marker to back-up visual checks mentioned in the previous blog. 


Before we discuss what pH we would expect to see in horse manure, a quick reminder of the pH scale and what this indicates. The scale runs from 1, very acidic, to 14, very alkaline with 7 (in the middle) being considered neutral. 


As you might expect, following on from the hindgut (where fibre is fermented for the horse by a microbial population which requires a near neutral pH to thrive), we would expect faecal pH to be within the region of 6.5-7. Any significant deviation from this, for a sustained period, may create an inhospitable environment for the microbial population and therefore indicate a challenged gut. 


Conducting a pH test is easy and doesn’t require a lab! All you need is a sample of your horse’s poo and a simple soil pH test kit (follow the instructions using manure instead of soil). Where possible, initially conduct this measure when your horse’s manure looks normal for them, this way, it can be employed in the future as an extra check when any of the five Cs are out of kilter. 

Interpreting the results:

 Manure Matters

Interpret the pH reading alongside the five Cs mentioned in part 1. This will help to provide a fuller picture, may help indicate potential cause and therefore solution.

Manure Scenario

Dietary Suggestions

Acidic pH

Reduce starch in the ration where possible and check that fibre intake is at least 1.5% bodyweight in dry matter. Promote a natural lifestyle and reduce stress. Spread concentrate meals out over the day and consider the use of a slow feeder.

Alkaline pH

Promote a natural lifestyle and reduce stress. Consider feeding a course of probiotic and prebiotic supplement. Assess forage quality and suitability and monitor intake.


Consult with your vet. Accumulation of sand/dirt can be a factor so conduct a sedimentation test and consider psyllium treatment (such as Sand Shifter). Consider management- fast changes can cause digestive upset. Transvite Excel can be used to help repopulate the gut with healthy microbes which can be flushed out during prolonged bouts of diarrhoea.

Soft manure with no clear faecal balls

Recent change in the moisture content of the diet can be to blame (i.e., turnout on spring pasture). Ensure all dietary changes are gradual. Provide additional fibre to the ration such as hay to improve water-holding capacity in the hindgut. Ensure minimum fibre requirement (1.5% bodyweight dry matter per day). Reduce starch intake and/or concentrate meal size. Consider a digestive enhance such as Transvite to provide digestive support.

Very firm faecal balls that do not break upon impact with the ground

May indicate dehydration/low water intake or indigestible fibre intake is too high (e.g., straw or old dry grass as primary fibre source). Promote water intake, ensure salt and electrolyte requirement is met. Adjust fibre source to include more digestible forage.

Manure that takes >15 seconds to pass and is coated with mucous

All recommendations as above. Also try and promote movement where possible to promote gut movement.

Very dark coloured (almost black) faecal balls

Consult with your vet. There may be bleeding in the digestive tract.

Free Faecal Water (free water accompanies, pre/post producing normal faeces).

Check the ration is balanced. Keep concentrate meal sizes small and provide ad lib forage where possible. Reduce starch intake (maximum of 1g/kg bodyweight per meal). Promote forage that has good water holding capacity such as hay.

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