Individual drinking water intake of dairy cows in an AMS barn
Sammanfattning: Today’s dairy cows have high requirements of nutrients and water to give a large milk production. Factors that under normal circumstances affect drinking behaviour are cow’s eating pattern, the temperature of the water, whether the water is supplied in a water bowl or a trough, the cows’ dominance order and if the water bowl is shared with other cows. There are several factors that are positively related to water intake such as temperature, humidity, dry matter intake, milk production, ration dry matter content, lactation day, body weight and also sodium and potassium intakes. The aim of this study was to investigate which factors that could best explain different levels of water intake in dairy cows and how social rank was related to diurnal pattern of water intake. A further aim was to evaluate a system for automated recording of drinking water intake with the help of observations of the drinking behaviours and social rank order. The study was performed in a barn with automatic milking system (AMS), and took place at The Swedish Livestock Research Centre, Swedish University of Agriculture Sciences, Uppsala, with dairy cows kept in a loose housing system. The number of cows in the barn section where the study took place was 60-65 cows. The dairy cows in the study were of the breeds Swedish Red and Swedish Holstein. The feed ration contained grass/clover silage and concentrate. The seven water bowls that were used in the barn had equipment which could identify the cow and measure the water flow for recording water consumption. From the 92 cows that was in the observation period there were 37 cows that were left when the other cows were removed because of reasons such as wrong registration, had been in the VMS group too short time and cows that splashed or licked out water. Data were compiled in Microsoft Excel 2013 and the built-in functions were used for calculating arithmetic means and making graphs. Statistical evaluation was done with procedures of SAS 9.3 (SAS Institute Inc., Cary, N.C.). Thirty-seven cows (42%) were correctly identified during the observation period. Cow identification with the necklace transponders did not show optimal results with the original placement of the antenna. The individual drinking water intake had a range between 23.9 and 130.4 kg/day and the total water intake (including feed water) were between 55.9 and 203.5 kg/day for the 37 cows. Drinking water intake was positively correlated to most of the factors including milk yield, dry matter intake, total water intake, potassium intake, sodium intake and nitrogen intake in the feed. The 37 cows in this study drank 56.0 % of their total daily intake between 8:00 to 20:00. Heavy cows, Swedish Holstein cows, lower ranked cows and parity 3 cows were cow categories that drank numerically most water/hour during a day. There was a main difference among cows regarding both the number of registrations/day and the duration/registration.
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