SPRING SUMMER BONUS MAGAZINE 2026

Water trough space Adequate access to drinking water is crucial. As a minimum standard, dairy cows should be provided with approximately 6 cm of trough space per cow, although 8–10 cm per cow is recommended in high-producing herds or during periods of heat stress. Because cows tend to drink simultaneously, particularly after milking, the trough design should allow approximately 10% of the herd to drink at the same time. As a practical guideline, provide around 70 cm of drinking space per cow drinking simultaneously. For example, a 100-cow herd should have enough trough space for 10 cows (approximately 7 m of total accessible through perimeter). At least two water troughs or watering locations should be provided per group. Providing multiple, well-positioned water points is particularly important in larger herds and during periods of heat stress demand. Access to water troughs Even when sufficient water is available on the farm, poor trough placement can limit intake. Water points that are located far from feeding areas, resting areas, or cow traffic routes may discourage cows from drinking frequently enough. Cows typically spend only around 10 minutes per day actively drinking, but approximately 30 minutes per day around water points, making these areas prone to congestion. Water should therefore be easily accessible, particularly immediately after milking and during peak feeding periods. At pasture, cows should ideally not walk more than 250 metres to a water trough. Additional water points in collecting yards and along routes to grazing areas can further encourage intake. Troughs should also be located on dry, well- drained surfaces to maintain unrestricted access. Water supply and flow rate to drinking devices A common cause of reduced water intake is an interruption in water supply to troughs or drinking devices. Corroded valves, blocked pipes, faulty float mechanisms, inadequate pipe sizing, or poor maintenance can prevent troughs from filling properly. A minimum flow rate of approximately 0,15 L/min per cow in the herd is recommended (e.g. 15 L/ min for a 100-cow herd). However, because cows can drink up to 14 L/min per cow, watering systems should be designed to accommodate peak demand, as ten cows drinking simultaneously may consume up to 140 L/min. Chemical water quality High concentrations of dissolved salts, minerals, or other chemical constituents may reduce water palatability and discourage voluntary intake. In some cases, animals may tolerate poor-quality water for a period, but production losses can still occur due to reduced consumption and altered mineral balance. Contamination from manure, algae, fertilisers, agricultural runoff, or microbial organisms can negatively affect both water quality and palatability. Dirty troughs may develop unpleasant tastes or odours that reduce water intake, while bacterial contamination may pose health risks. Regular cleaning of troughs and routine water testing form an essential part of good water management. Case study The farm originally had small sheep water troughs (illustration 1). It was replaced with larger troughs (illustration 2). At a smaller trough, cow dominance plays a bigger role, as the dominant cows will occupy drinking spaces, preventing others from drinking. The bigger trough immediately allows more cows to drink at once, decreasing the cow dominance factor. Illustration 1: Orange lines and dashes are what need to be measured, and black lines must be excluded. Figure 1: The effect of water restriction on milk yield. Spring/Summer 2026 BONUS www.agribonus.co.za 94