animal health consulting

Forage testing

why test your hay and pasture?

Christine King  BVSc, MANZCVS (equine), MVetClinStud

Why should you have your hay and/or pasture tested?  Because it’s not possible to know its nutrient content any other way.

You can generally spot a 'bad' hay or poor pasture just by its appearance, but you cannot know the protein, sugar, and mineral content of a 'good' hay or pasture based on appearance alone — and these components matter, sometimes a lot!  In some cases, they're the whole ball game.

Forages, or 'roughage' — whether as pasture, hay, haylage, chaff, hay cubes, or hay pellets — should form the foundation of every horse’s diet after weaning, no matter what the horse does for a living.

A vet I once knew who was also an equine nutritionist used to say "grain should be fed only as a supplement." I would add "and only to the horses who need it."  Not every horse needs grain, and not every horse needing grain needs all that much when the diet is based on good quality forages.

It's the best use of your budget to spend your money first and most on good quality forages, not on bags of processed feeds and buckets of supplements. Your horse will be the healthier for it, as will your bank account when you factor in the health, hoof, and performance problems you'll avoid by cutting down or cutting out the high-carb bagged feeds.

Knowing the nutrient profile of your principal forages can make all the difference when it comes to...

* fertility (mares and stallions)

* pregnancy (mare) and gestation (foal)

* foaling

* lactation and neonatal (newborn) health

* growth and prevention of developmental orthopaedic diseases

* performance

* aging

* ability to cope with stress (physical and psychological)

* recovery after strenuous exercise, travel, or competition

* recovery from illness, injury, or surgery

* treatment and prevention of colic, laminitis, asthma, and other feed-related diseases (of which there are many!)

Forage testing is something you can do yourself, although if you haven't done it before, it would pay to have a professional help you with interpretation of the results.

Forage testing labs

Feed Central (Toowoomba, QLD)

The lab with the best forage testing package for horses is Feed Central, in Toowomba, Queensland. Select Equi-Tech from the list of feed tests. The package currently [Oct 2023] costs $125.00, and results take an estimated 10 days.

But while the Equi-Tech package provides by far the best overall nutritional analysis of forages for horses, especially for overweight or otherwise carbohydrate-sensitive horses, it doesn't include tests for selenium or iodine, two essential trace minerals that are often lacking in Australian soils and thus our forages. At Feed Central, selenium is an expensive add-on ($133).

SCU-EAL (Lismore, NSW)

The lab I use when I am most interested in the trace mineral content of pasture or hay is the Southern Cross University Environmental Analysis Laboratory (SCU-EAL) in Lismore, New South Wales.

On their sample submission form, request the Plant Testing package PA-PACK-001 ($57.75). It includes all of the relevant minerals, except selenium and iodine...

To request selenium, either as a stand-alone test* or as an add-on, request SS-SING-132 Se (currently $11.55 [Oct 2023]).

* For example, you could use the Equi-Tech package from Feed Central for the majority of your forage analysis and send another sample to SCU-EAL for selenium.

Selenium isn't included in their agricultural price list, but it is in their full analytical services price list.

To request iodine, either as a stand-alone test or as an add-on, request SS-SING-022 (currently $115.50 [Oct 2023]). That's not a typo; iodine costs 10 times as much as selenium.

This is an expensive add-on, but for horses on pasture, you need test your pastures only once to get a good idea whether you need to be supplementing iodine, and if so, how intensively.

The expense of this test makes it less attractive to use with hay samples, unless you're buying a year's worth of hay at a time or you have very valuable horses, particularly broodmares, breeding stallions, and youngsters (foals to 2-year-olds).

For pasture samples, also request Dry Matter Content (%), test SS-SING-225 (currently  $11.55 [Oct 2023]).

The importance of this inexpensive add-on is that it tells you the moisture content of your pasture before it was dried for analysis. That's useful if you're wanting to work out how well your pasture is meeting your horse's trace mineral needs.

The results of forage analysis (pasture or hay) are reported on a 100% dry-matter basis — i.e., all of the water is removed before analysis. If you want to know how much of a particular mineral your horse is actually eating when he's grazing, you need to know the water content of the pasture at the time it was collected for analysis.

This add-on is not as important with hay samples, because a well-cured hay should have a dry matter content of over 90%, which is close enough to 100% for the purpose of working out how well your hay is meeting your horse's trace mineral needs from that forage.

Soil testing

When I mention the importance of forage testing for pasture, I often hear this: "Oh, we've already had our soil tested."  That's good, but...

Soil testing is more about plant health and the plant's nutritional needs than it is about the nutritional needs of the animals grazing on it.

Yes, the two are interconnected, but the results of soil testing don't translate well to the nutrient content of the pasture or hay as it relates to the nutritional needs of the animals grazing the pasture or eating the hay — because soil testing is mostly about the plant's needs.

If you own pastures or hay fields, it's important to have your soil tested and work with an agronomist to optimise your soil mineral and carbon (organic matter) profile the best you can under the circumstances.

Even so, forage testing is needed in order to know the nutrient profile of what the horses are actually eating.

Interpreting forage testing results

If you're interested in doing your own forage testing, I've written a page each on the most important components of the test:

Dry matter (DM)

Crude protein (CP)

Fibre (lignin, ADF, NDF)

Nonstructural carbohydrates (NSC)

Major minerals

Trace minerals

© Christine M. King, 2021, 2022. All rights reserved.

[Testing prices last updated 13 October 2023.]