Veterinary Handbook Disease Finder

Veterinary Handbook Contents

5.6 Feed Supply Problems

5.6.1 What Are The Problems Of Feed Supply?

Problems with feed supply are those related to:
  • Insufficient feeding of some or all animals (in the presence of sufficient stored feed).
  • Shortage of available stored feed.
  • Having excess feed left over at the end of the voyage.
Insufficient feeding may result in animals not achieving desired weight gains and increase susceptibility to diseases such as starvation, ketosis and fatty liver. Increased competition at the feed trough will increase stress, disease and injury occurrence. Insufficient feeding of hay or chaff to supplement the main diet of pellets may increase susceptibility to diseases such as acidosis, bloat, heat stress and possibly premature lactation. 

Running out of feed has potentially dire consequences for the welfare of the animals and the commercial outcome of the venture. Excess feed remaining at the end of the voyage may be usable on subsequent voyages, although there may also be commercial implications if fodder is left on board. The longer fodder it is held in fodder storage tanks, the greater the risk of spoilage or contamination. 

Periods of feed deprivation do occur during the export process, e.g. due to transport, curfews and cleaning of pens. When feeding resumes following a period of deprivation, animals may over-eat resulting in an increased risk of diseases such as acidosis, frothy bloat, simple indigestion, and possibly enterotoxaemia. 

Many problems with feed supply may be predicted based on knowledge of the types and sources of animals and other factors that may contribute to supply problems. This also means that careful planning and preparation should be able to minimise risks of feed supply problems.

5.6.2 Situations Leading To Feed Supply Problems

Situations where animals may become deprived of feed include:

  • During curfews and transport (trucks or rail), generally from property to assembly depot.
  • If feed is not fed ad libitum[4] (as a result of deliberate rationing or in hand-feeding systems when pellets are fed by crew a limited number of times per day).
  • When troughs are inaccessible to animals.
  • When there are difficulties either accessing or moving feed from storage to the animals (breakdown of automated feeding systems, the inability of automated feeding systems to handle some feedstuffs such as hay or chaff and poor access to some feed stores).
  • When prolonged deck cleaning interferes with feeding. Animals may also get wet and cold, exacerbating the potential for adverse impacts of feed deprivation.
  • During very rough weather.
  • Young, growing animals with large appetites.
Deliberate rationing may occur when feed budgeting has predicted a shortfall. This may be when insufficient feed has been loaded because of miscalculation, over feeding has occurred early in the voyage, a proportion of feed has been spoiled or contaminated, or when adverse sailing conditions, marine casualty or problems with unloading at the destination port have extended the period that animals must be on board. 

In feeding systems where feed is not available ad libitum, there is always a risk of stock going hungry. Troughs may be inaccessible when pens are crowded, especially to shy, non-competitive or sick animals. Horned animals may be unable to put their heads between pen rails to reach troughs. Small animals may be unable to reach elevated troughs. Automated feeding systems use electrical components, augers, pumps, pipes and taps. Corrosion of these components can occur with constant washing with sea water causing them to malfunction, resulting in disruptions to the delivery of feed. Feeding outlets may become blocked with lumps of feed, particularly if there is contaminated feed in outlet pipes. 

The relatively low volumes of hay and chaff loaded and the relative difficulty in handling them compared to pellets may lead to storage in distant or poorly accessible locations. This may result in animals receiving insufficient supplementary roughage. Poor operation of manual feeding systems may result in troughs that are furthest from the fodder outlets being fed slightly less feed at each feeding.
4. ad libitum feeding means food is available at all times with the quantity and frequency of consumption being the free choice of the animal.

5.6.3 Detection Of Feed Supply Problems

At sea, an investigation should occur if average feed consumption is consistently less than 2.5 % body weight (on a dry matter basis). Averages for daily feed consumption for the whole ship can be calculated and sometimes for each deck and for areas of decks depending on the feed storage and distribution systems. Consumption can be calculated as a percentage of live weight based on the number and weight of animals at loading with potentially some capacity for adjustment resulting from losses during the voyage. Feed consumption estimates are usually based on amounts of food that are fed and not on actual consumption. These calculations will over-estimate consumption since they may include feed discarded when troughs are cleaned out, or feed spilled on the floor. 

Signs of insufficient feeding of pellets include animals rushing forward when feed is dispensed and feed troughs being licked clean. Some or all of the animals in a pen may be restless or listless. The relative emptiness of rumen and intestines will make underfed animals look “tucked up” in the abdomen, “hollow in the flanks”, “slab sided”. Animals may lose body condition and coat shine. If only some animals in a pen look like this, they may be the shy feeders or less competitive ones. 

Signs of insufficient feeding of hay or chaff include inappetence, absence of cud chewing, weak and irregular rumen contractions and looser than normal faeces. The appearance of shy feeders, diarrhoea, acidosis, laminitis, premature lactation and bloat may also indicate inadequate feeding of fibre in the form of hay and chaff. 

Acidosis, enterotoxaemia, polioencephalomalacia and bloat may occur in ruminants fed ad libitum pellets after a period of food deprivation. Rumen impaction with fibre may occur if hungry ruminants are fed indigestible straw. Deaths and injuries from smothering are well known in hungry lambs rushing feed troughs at feeding time. Note that these signs or conditions have multifactorial origins and feed supply problems may not be the major factor involved. An investigation should occur if any of the above mentioned signs are detected.

5.6.4 Interventions And Prevention Of Feed Supply Problems

  • The minimum amount and type of feed to be loaded on livestock vessels is prescribed in ASEL. Consideration may be given to exceeding the standards, especially the amount of pellets for contingencies and the amount of hay and chaff (for rumen health), as a general risk reduction measure to prevent occurrence of feed associated problems.
  • At sea, daily calculation of the amount of feed consumed and remaining in storage tanks will allow early identification of possible feed shortages and implementation of management strategies before the ship runs out of feed. Monitoring for possible delays at destination ports is also important as an indicator of whether animals may need to be fed on board for slightly longer than anticipated. It is important to plan for possible delays when budgeting total voyage feed requirements and also to be prepared to change rates of feeding during a voyage to manage reduced availability of quality feed or voyage delays.
  • Automated feedings systems should be checked and areas of likely breakdown noted or targeted for maintenance. Pay special attention to the amount of pellets supplied to pens in areas at the far end of feed delivery systems. If there are problems, they may become apparent first in these pens. While repairs are being conducted, animals can be fed by hand.
  • Access to troughs in each pen should be checked before loading and regularly during the voyage. It is recommended this be done twice daily during routine inspections. It may be possible to adjust gaps between pen rails, trough heights and stocking densities to improve access to feed. Report problems with feed trough design, location or height to the exporter if they may be contributing to excessive faecal contamination and rejection of feed.
  • Ad libitum feeding may prevent animals becoming excessively hungry thereby avoiding the risks of rushing feed troughs, overeating diseases and indigestion simply from fluctuating intakes. It also gives shy feeders time to become accustomed to feedstuffs and less competitive animals time to access troughs.
  • The frequency of feeding is usually determined by the volume of troughs. Once a day feeding is satisfactory if there is sufficient trough volume, however two or three times a day may be required in crowded pens with limited trough space. Troughs should be nearly empty when the next feed is due. This avoids uneaten feed going stale, being refused and needing disposal. It also reduces the risk of hungry animals becoming injured if they rush troughs during feeding.
  • Troughs should also not be overfilled in case spillage causes hungry animals to eat from the pen floor with increased consequent risk of faecal contamination.
  • If animals are very hungry after being feed deprived, rationing of the first few feeds and providing hay and chaff may prevent diseases of overeating. Taking steps to shorten the period of feed deprivation should be considered. For example, animals transported long distances and subjected to a feed curfew should have feed waiting for them in their pens or they should receive priority feeding after loading. Be aware that feeding during loading may disrupt movement of animals with the noise of augers and the activity of the crew.