THE INTAKE OF DRINKING WATER BY GRAZING DAIRY COWS. THE EFFECT OF WATER AVAILABILITY |
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| Authors: | M E Castle J N Watson |
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| Institution: | The Hannah Research Institute, Ayr, Scotland |
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| Abstract: | In a 16-week grazing experiment with six spring-calved Ayrshire cows, drinking water was available to the animals in three different ways, and the effect on milk prodnction was studied. The water was available from a water howl in the cowshed for 2.8 h/day in Treatment A, from a trough in the field for 21.2h/day in Treatment B, and from hoth sources for a total of 24 h/day in Treatment C. The cows on all treatments were grazed in individual plots of intensively-managed perennial ryegrass, stocked at the rate of 1 cow/0.22 ha (0.54 ac). The mean daily intakes of drinking water were 10.1, 15.3 and 15.5 kg (2.23, 3.37 and 3.42 gal)/cow, and the mean daily milk yields were 17.0, 17.2 and 16.8 kg (37.5, 37.9 and 37.0 lb)/cow in Treatments A, B and C, respectively; milk yields were not significantly different The herbage had an average DM content of 17.3%, and contained 19.6% crude protein and 66.5% digestible organic matter in the DM. The weight of water drunk was significantly and positively related to the DM percentage of the herbage, the air temperature and the daily hours of sunshine, and negatively related to daily rainfall. It is concluded that when dairy cows are grazing leafy herbage of high digestibility as their sole feed, the time during which drinking water is available may safely be restricted. |
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