25 August 1995

Make sure stocks thirst is slaked…

DO you supply enough water? In hot, dry weather consumption of a 30-litre a day 600kg dairy cow can hit 115 litres (26 gal) a cow a day.

That is total needs at temperatures of 16C-20C (61F-68F) when no water is taken from feed, says Scottish Agricultural College nutritionist Mitch Lewis. At the same temperature 20-litre a day cows would require 100 litres (22gal). Cows on 30kg a day of 25% dry matter silage would take in 7.5kg dry matter and 23 litres (5gal) water from that forage.

Two main peaks

There are two main peaks in the day, the greater being from the end of the afternoon milking until sunset, says the SAC. The other main period is between mid and late morning. There is little drinking after dark.

Supplies will be inadequate when cows are restless and stand close to water troughs for long periods, linger at the farm after milking or suffer a drop in milk yields. Check water supply is sufficient – for example, a 100-cow herd will need up to 900 litres/hour. Also provide enough trough space for at least 10% of the herd to drink at the same time, limit the distance cows have to travel to the water, and clean troughs regularly, for dung and waste in troughs will reduce intake. Stores or finishing cattle require 6 litres (1.3gal) a day a kg DM intake. So a 350kg animal eating 7.5kg DM a day would require a total of 45 litres (10gal) water, says Dr Lewis.

Ewes require 3.7 litres (0.8gal) of water a kg DM intake at 16C (61F). This rises to 4.5 litres (1gal) at 20C (68F) and doubles at higher temperatures when a 75kg ewe on mainly dry feed could require as much as 9 litres (2gal) a day.

Check hill sheep

The SACs Dr John Vipond advises checking that hill sheep have sufficient water. Where natural supplies have dried up it was essential to check ewes were taking water from troughs. Clean troughs regularly to encourage intakes.