Veterinary Handbook Disease Finder

Veterinary Handbook Contents

6.5 Detection Of Watering Problems

Water consumption is calculable for the whole ship but this may include water discarded when water troughs are cleaned. Sometimes, especially on modern ships, there are flow meters allowing calculation by deck and even by line of pens. The amount consumed per head per day as a percentage of body weight should be calculated daily. 

Investigations should be triggered if consumption stays less than 10% of bodyweight daily. Water consumption rates may start quite low early in the voyage but should steadily increase as the animals adapt to shipboard conditions. 

Investigation should also be instigated if there are unexpected declines in whole-of- ship water consumption, because consumption normally increases steadily during a voyage, and increases dramatically as the vessel enters the tropics. Note that water consumption on ships with troughs is usually 20% greater than on ships with drinker bowls due to greater wastage from spillage and cleaning. 

Water in every trough in every pen should be examined if contamination is suspected. When animals are dehydrated they may have reduced appetite and discoloured urine. 

A well hydrated animal has clear urine. Colour changes from yellow to orange to brown occur as dehydration progresses from mild to moderate to severe. Seriously dehydrated animals may be depressed or agitated and have a sunken-eyed appearance. Note that consistency of faeces is an unreliable indicator of hydration status. For example, severely dehydrated animals with enteritis may have diarrhoea; well hydrated animals on low digestibility feed may have constipation. 

Skin pinch test. A wrinkle of skin, produced by pinching the skin of the side of the neck, can be used as an indicator of dehydration. The time lapse from release of the pinch to disappearance of the wrinkle is usually a few seconds in normally hydrated animals. This should be performed in conjunction with observing urine colour and the presence of eyeball recession into the orbit, also indicating dehydration levels. 

The results of the pinch test vary depending on breed, body condition and the pressure and duration of the pinch. It has not been formally evaluated or validated in adult ruminants. Therefore it is best if stockmen calibrate themselves on a range of different types of normal animals before using the test to diagnose dehydration. Signs such as abnormal demeanour, dryness of hair coat and sunken eyes should be used in conjunction. Performance of a pinch test at regular intervals may be used to monitor changes in the hydration status of an individual animal along with the colour and specific gravity of urine. It may also be used to compare levels of hydration between pens of similar animals.