Veterinary Handbook Contents

Feed quality problems often involve physical integrity and nutritional composition of the feed. They include provision of improperly formulated pellets, provision of nutritionally unsuitable hay and chaff, and spoiling of feeds. Consequences may include feed refusal, indigestion, and creation of unpleasant pen conditions if ammonia or moisture levels increase.

Situations where feed quality problems may arise include:

• Pellets, hay and chaff that are wet, mouldy, dusty or decayed.
• Contamination of feedstuffs either in storage or in troughs with fuel, chemicals, sawdust, saliva, urine, faeces, or sea spray.
• Sawdust used for bedding may be spilt in feed troughs during spreading. It is indigestible and may cause obstruction and even toxicity depending on the type of wood or whether the sawdust is contaminated with chemicals.
• Hay and chaff made from straw may be indigestible. In some cases, legume chaff/hay may contain sufficient levels of nitrogen that increase the risk of dietary diarrhoea and contribute to elevated ammonia levels.
• Fodder fines or dusty feeds may be associated with increased risk of bloat, respiratory and eye problems. Fodder fines may occur due to the manufacture of pellets if the series of heating, pressurising and steam conditioning processes has not been optimal. Dust levels in pelleted feed may be exacerbated when bags of pellets are repeatedly relocated by hand or loose pellets are repeatedly augured between silos.

Many feed quality problems may be detected by inspection of the feed which should be done routinely. Observation of animals is also very useful in detecting feed problems and may raise suspicions about formulation as well as other attributes of quality. These observations may include:

• High ammonia concentrations in pens may be from excess protein or urea.
• Acidosis and laminitis may be from excess starch (cereal grains in pellets may vary greatly in quality, some having high starch levels).
• Rumen bloat and irritation of the respiratory tract and eyes may be from excessive dust/fodder fines.
• Heat stress may be exacerbated if animals are ingesting insufficient salt in feed.
• Wet pen conditions and high ammonia levels in pens may be from excessive salt causing increased urination.
• Inappetence may be from excess salt, urea, urinary acidifiers, rumen modifiers or mould in the feed.
• Low weight gains may be from insufficient protein.
• Abomasal ulceration and rumen bloat may be from insufficient long length fibre.
• Premature lactation in female cattle may be more likely in animals being fed mouldy pellets.

Untouched feed or diarrhoea may be the first sign of problems with feed quality and should trigger a close physical examination of the feed for abnormalities.