Never underestimate the importance of a clean and consistent water supply, sage advice and an obvious statement. However, some of the practicalities of providing and maintaining water supplies are often overlooked.
Water is one of the largest daily nutrient requirements for livestock. Intakes will depend on a combination of yield, air temperature and dry matter content of the diet. A dairy cow may consume between 70 and 120 litres of water per day, beef cattle and dairy heifers 20-40 litres/day, calves ~5 litres/day (AHDB figures).
Whenever herd level problems occur, water supply should always be ruled out early on. Apart from vital biological functions, there is also a very definite positive relationship between feed intake and water consumption. From a veterinary point of view, it can be very satisfying to watch a ‘sick cow’ move directly to the feed bunk and eat after being drenched with fluids.
The first of the ‘Five Freedoms’ (Farm Animal Welfare Council) and the Red Tractor Farm Assurance Scheme both dictate free access to ‘fresh, clean…’ drinking water. There is, however, no requirement that this must be mains-sourced. In-fact alternatives to mains supply offer significant cost benefits, though not at the expense of quality. For example, direct access to streams/watercourses has been increasingly discouraged due to risk of contamination and erosion (Water Framework Directive). Shared watercourses also represent a significant conduit between farms jeopardising biosecurity.
Water quality can be tested by chemical and microbiological analysis of a sample and must comply with statutory permissible levels. Broadly, water quality issues involve one or more of the following, with some examples:
- ‘Mineral’ content/pH (e.g. Lead, Copper, Sodium, Chloride…)
It is not uncommon for certain minerals to impart an unpleasant taste on water (e.g. Iron, Manganese, Magnesium). Also, bear in mind that potentially toxic elements such as Copper may already be supplemented in the diet to a high level. Knowing the mineral content may influence feed rationing.
- Microbiological contaminants (e.g. bacteria, protozoa, algae)
Bacteria such as E.coli in the water supply indicate serious contamination, and risk to health.
- Pollutants/sediments/run-off (e.g. pesticides, fertilisers…)
High levels of nitrates can present health problems such as poor fertility and growth rates. High levels of sediment are thought to decrease palatability. High levels of sulphates can result in increased gut motility and decreased feed efficiency.
Clearly, any combination of the above factors may result in water that ranges from the mildly unpalatable to the outright toxic. However, even subtle decreases in water consumption can have pronounced effects in a herd at peak production.
Various technologies are available to sanitise prospective water supplies once a problem is identified e.g. Filtration (UV/Gravity), adsorption, ion-exchange, chemical treatment… but are beyond the detail of this article. For test kits and protocols contact your vet or local authority.
There is also a behavioural aspect to water intake, which can be limiting. A dairy cow may spend 4-5 hours a day feeding but only 20-30 minutes drinking. 50% of her daily intake is likely to occur in the few minutes after milking, or around the hours of sunset. As herd animals it is common for groups of cows to drink simultaneously, bearing in mind that a cow can drink up to15 litres of water/min.
Those statistics have led to the following recommendations:
- Trough space: 10cm/cow or enough space to allow up to 10% of the herd to drink at the same time.
- Trough Flow Rate: ~10 litres/minute, minimum.
- Trough Position: Increased access at the parlour exit and not further than 15 metres from the feed bunk, cows will not spend long periods of time searching for water.
For more information phone Molecare Veterinary Services on 01392 872934 or visit www.molecarevetservices.com