Hay Preservation Glossary — Forage Quality, Biological Inoculants, and Dry Matter Terms

ADIP (Acid Detergent Insoluble Protein)

Protein in stored hay that's become bound to carbohydrates via the Maillard reaction — the same browning chemistry that happens in cooking. ADIP is largely indigestible to livestock; it shows up on a lab forage analysis as protein that's there but not nutritionally available. High ADIP indicates the hay heated significantly in storage.

ADG (Average Daily Gain)

The average weight a cattle animal gains per day over a measurement period. Used to evaluate feed efficiency, ration quality, and forage performance.

What is aerobic stability?

Aerobic stability refers to how long a stored forage resists heating and spoiling when exposed to oxygen. It matters heavily at feed-out; forage with poor aerobic stability will rapidly heat up and grow mould as soon as the bale is opened or the silage face is exposed to air, destroying feed value and triggering bunk refusal. Biological hay preservatives actively improve aerobic stability by maintaining a dominant population of beneficial bacteria that suppress opportunistic moulds even after the bale is opened.

What is dry matter loss?

Dry matter loss is the physical shrinkage of your harvest—literally pounds of forage vanishing into the air as carbon dioxide and water vapor due to microbial heating and spoilage. In dollar-cost framing, a 15% dry matter loss on a 500-tonne stack of $180/tonne hay means $13,500 of feed value simply evaporated. Minimizing dry matter loss through proper preservation ensures that the tonnage you paid to grow, harvest, and bale is the exact same tonnage you actually get to feed.

Bacillus amyloliquefaciens

A species of beneficial soil bacterium widely used in agricultural biocontrol applications. It produces antifungal lipopeptides (surfactin, iturin, fengycin) that suppress moulds and yeasts. The DB38 strain in HayRite is a specific selection within this species.

CFU (Colony-Forming Unit)

The standard measurement of viable bacteria in a product. HayRite contains ≥10⁹ CFU per millilitre — i.e., at least one billion viable bacterial cells in every millilitre of product.

Competitive exclusion

The biological mechanism where a beneficial population establishes on a surface or in an ecosystem first, occupying the niche and consuming the resources that would otherwise feed harmful organisms. The basis for how HayRite works.

DB38

The specific Bacillus amyloliquefaciens strain in HayRite, selected from the same Queensland research lineage that produced the H57 sister strain. NCBI accession SUB15815306.

DMI (Dry Matter Intake)

The amount of feed (excluding water) an animal consumes per day. A primary metric for ration evaluation; reduced DMI on a forage usually indicates palatability problems.

Forage analysis

Lab testing of a hay sample to measure crude protein, fiber digestibility, ADIP, mineral content, and other nutritional parameters. Used by dairy and beef nutritionists to design rations.

GHS (Globally Harmonized System)

The international standard for classifying and labelling chemical and biological products by hazard. HayRite is not classified as hazardous under GHS.

GRAS (Generally Recognized As Safe)

A US FDA designation for substances that have been adequately shown to be safe for their intended use. Bacillus amyloliquefaciens as a species has GRAS status for many feed applications.

H57

The sister strain to DB38, also Bacillus amyloliquefaciens, characterized in published feeding studies (Ngo et al. 2021; Pan et al. 2022). Manufactured at the same QUT MRBPP Mackay facility as DB38.

Heaves

The common name for Recurrent Airway Obstruction (RAO) in horses — a chronic respiratory condition strongly associated with dust and mould exposure from hay. The veterinary equivalent of asthma in humans.

Lipopeptides

A class of naturally produced antifungal compounds. Bacillus species produce three main types — surfactin, iturin, and fengycin — which together suppress mould and yeast growth on hay surfaces.

Maillard reaction

The chemical reaction between protein and carbohydrate that produces ADIP in heated hay. The same reaction that browns meat in a pan. In stored hay, the Maillard reaction kicks in above 120–130°F and accelerates rapidly with rising temperatures.

Mycotoxins

Toxic compounds produced by certain moulds. The relevant mycotoxins in hay include DON (deoxynivalenol), T-2 toxin, zearalenone, and ochratoxin A. Mycotoxin contamination is a major concern in dairy and equine forage.

What is propionic acid?

Propionic acid is a naturally occurring, corrosive organic acid widely used as the active ingredient in chemical hay preservatives. When sprayed onto hay at baling, it works by artificially lowering the pH of the forage surface below the threshold where moulds and yeasts can survive. While effective at stopping microbial respiration and heating, it requires heavy application rates, specialized acid-resistant equipment to prevent baler corrosion, and strict safety handling protocols for the operator.

QUT MRBPP

Queensland University of Technology's Mackay Renewable Biocommodities Pilot Plant. The 1000-litre commercial-scale fermentation facility where HayRite (and the H57 sister strain) are manufactured.

RAO (Recurrent Airway Obstruction)

The technical name for heaves in horses. A chronic respiratory disease driven primarily by dust and mould exposure from hay. The dominant controllable factor in RAO management is hay quality.

SCC (Somatic Cell Count)

The count of immune cells in milk — a marker of udder inflammation and milk quality. Elevated SCC can be associated with mastitis or feed-related stress, including mycotoxin exposure from contaminated hay.

What is a silage inoculant?

A silage inoculant is a biological additive—typically lactic acid bacteria—applied to wet, chopped forage (60–70% moisture) before it is packed into a bunker or silo. It works in an anaerobic (oxygen-free) environment to rapidly ferment sugars into lactic acid, dropping the pH to preserve the feed. This differs completely from a biological hay preservative like HayRite, which operates in an aerobic (oxygen-rich) environment on much drier forage (15–25% moisture) to outcompete moulds and prevent heating.

What is the difference between a silage preservative and a hay preservative?

While both aim to preserve forage quality, silage preservatives and hay preservatives operate in fundamentally opposite environments and use completely different mechanisms. Silage preservation relies on an anaerobic (oxygen-free) environment. When wet forage is packed tightly and sealed, silage preservatives (usually lactic acid bacteria inoculants) accelerate fermentation. They convert plant sugars into lactic acid, dropping the pH so low that spoilage organisms cannot survive. The goal is rapid, controlled fermentation in the absence of air.Hay preservatives, on the other hand, are applied to much drier forage (typically 15–25% moisture) that is stored aerobically (exposed to oxygen). Because hay is not sealed in an airtight bunker, fermentation is exactly what you want to avoid. A hay preservative—whether a chemical acid or a biological competitor like HayRite—works to suppress microbial respiration, yeast, and mould growth in the presence of air. If you use a silage inoculant on baled hay, the bacteria will die or fail to activate due to the lack of moisture and the presence of oxygen. Conversely, applying a hay preservative to a silage bunker wastes money on preventing a mould issue that the anaerobic environment already handles.

SDS (Safety Data Sheet)

The standardized regulatory document summarizing a product's hazards, handling, storage, and emergency response information. See the HayRite SDS information page →

Spore

A dormant, environmentally resistant form of a bacterium. Over 90% of the Bacillus in HayRite is in spore form, which is why the product has a 12–24 month shelf life. Spores germinate and become active when applied to the moist hay surface.

TMR (Total Mixed Ration)

A feeding system, common in dairy operations, where forage, grain, supplements, and other feed ingredients are combined into a single uniform mix. Forage quality consistency is critical for TMR rations.

Withholding period

The mandatory waiting period between treatment and feeding (or harvest, for crops). HayRite has no withholding period — treated hay can be fed immediately.