Assessing the quality of stored forage for horses

Forage : main feed for horses

In order to live, grow, produce (milk, meat or work), a horse has certain daily requirements which need to be satisfied :

In energy : expressed as horse forage units (UFC in French)
In protein : expressed in grams of digestible nitrogen matter (MADC in French)
In minerals and vitamins : expressed in g, mg or IU = International Units

For the horse’s well-being and for the digestive system to function correctly, the horse requires time to eat, and a quantity and quality of feed that only forage can provide. In a « good quality » hay, both the nutritional value, and sanitary quality should be assessed :

Hay that is harvested at a late vegetation stage , characterised by a good sanitary quality but a low nutritional value (fibrous), is suited to horses on a maintenance diet.
Hay harvested early in good weather conditions, will potentially have a good sanitary quality and a high nutritional value. This type of hay is more suited to animals with higher needs (growing foals, horse in intensive work, lactacting bood mare...).

To remember:

Forage is essential to the horse for his digestive well-being and for its nutritional value.
Do not confuse sanitary quality (no mould, or bacteria) with nutritional value (more or less rich in protein or fiber).

In order to have an idea of the requirements covered by the hay, and therefore how much hard feed is necessary, it is essential to have a knowledge of the nutritional value of the forage. In addition, it is important to assess the sanitary quality of the hay provided, to avoid digestive and respiratory problems linked to poor harvest and/or storage conditions.n.

An observation with the senses of the forage purchased and then fed is therefore essential. Ideally, it should be completed with a chemical analysis, or even a laboratory preservation analysis for wet forage.

Factors leading to variation of the nutritional quality of forage

The quality of forage depends on :

The species composition (grasses, legumes, various species…), the value can be very variable in terms of nutrition and productivity ;
The development stage of the plant at harvest : generally speaking, the later the harvest, the lower the nutritional value – the proportion of leaves decreases, whereas the stems rich in cellulose (less digestible) increase, and the protein content is also lower ;
The development cycle : a second crop in the season (called regrowth) is generally composed of a higher proportion of leaves, and has a higher protein content ;
Management of the surfaces : fertilisation and enrichment, usage in terms of grazing/ mowing ;
Harvest conditions and conditioning : machinery used and operating mode, weather (amount of sunshine, temperature, relative humidity) ;
Storage conditions.

Swathing and baling as haylage : the choice of harvesting techniques have an influence on the quality of forage © Ifce

A fault in the airtightness of the bales causes a more or less local deterioration of the forage © Ifce — Un défaut d'étanchéité des bottes provoque une altération plus ou moins localisée du fourrage © Ifce

Note : Legumes (clover, alfalfa…) have a more constant nutritional value over time but are very sensitive to poor harvesting conditions (loss of leaves).

Assessing the forage with the senses

Elle permet une approche de la qualité alimentaire et sanitaire du fourrage.

Criteria	Observation	Explanation
Color	Green	Reflects good harvest conditions
	Yellow	Reflects late stage harvest Long drying time on the ground before pressing, maybe rain during harvest Stored at the edge of the barn (exposed to weather and sun). Only on the outside of some bales.
	Brown	Sometimes at the heart of the bale : forage pressed while still damp, which « heated up » incurring a loss in energy content but often better palatability (concentration in sugars).
	Grey, yellow patches, white areas (sometimes in slabs)	Rain during harvest, sometimes pressed damp, causing mould development This type of mould can also develop in haylage or silage when the airtightness of the wrapping is not perfect during storage
Smell	Dry grass	Ideal drying conditions, presence of particularly fragrant species (sweet vernal grass)
Smell	Acrid smell of mould or rot	Poor harvest conditions Disrespect of the humidity rate relative to the technique used Low density pressing (too much air in the silage or haylage preventing fermentation) or density too high (hay) Bad storage conditions : pierced wrapping (silage or haylage) or hay subject to humidity during storage (capillarity from the ground, condensation under tarpaulin, rain when badly sheltered… Often associated to visual signs (colour, rot, dripping moisture, more or less locally mouldy…) or smell (mould, dust for hay)
Composition	Plant diversity	Plant diversity ensures higher mineral content but often a lower energy content
	Proportion of leaves and inflorescence (ears)	High proportion of leaves : forage with a high nutritional value High proportion of stems and ears : decreased nutritional value Proportion of legumes in the hay : higher protein content Almost total absence of ears : sign that it is a hay from regrowth (2nd crop)
	Unwanted species, or poisonous	Some species (dock or thistles) are not consumed by horses. The seeds contained in the hay can be disseminated when the hay is fed. Some plants are poisonous even after dessication (ragwort, stinking willie). The ability of the horse to select may be lessened when the plant is dry.
Dust (only for hay)	Mould, myco toxins Pollen Soil Other	Signs of bad harvest or storage conditions Harvest at the flowering stage, always more or less present depending on the plant species Grass cut too low or presence of molehills Dust from the stems breaking up either linked to the mower, or to the hay being « handled » when it is too hot and dry during harvest
Foreign bodies	Earth, stones Droppings Wood Various detritus	Molehills or grass cut too low, irregular ground, grazing before cutting (and/or using a dung spreader) From hedgerows Often near roads

All these observations give an approach to assessing the quality of the forage considered.
This, will enable you to discard some, unfit for consumption, to fine tune your choice when purchasing, or even to negociate the price. Nevertheless, only carrying out a chemical analysis can give a precise idea of the nutritional value of the forage, which in turn will alow you to supplement according to the horse’s requirements (which is both an economical and nutritional advantage).

fourrage enrubanné moisi — In the case of haylage, it is important to respect the technical process : density at which it is pressed, thickness and tightness of the plastic wrapping… Airtightness should also be checked before feeding © L. Le Masne

round-baller de foin moisi — Even a well harvested forage can go mouldy if badly stored © L. Le Masne

Assessing the quality of stored forage for horses

Forage is the horses basic feed. It is therefore necessary to be capable of discerning between good and poor quality forage, and to understand the causes which could lead to its deterioration, so as to avoid them when possible.

Forage : main feed for horses

Factors leading to variation of the nutritional quality of forage

Assessing the forage with the senses

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