Investigations on the water intake of lactating dairy cows

ABSTRACTThe influence of the level of dry-matter intake and the dry-matter concentration in the diet on the water consumption of dairy cows in early lactation was investigated for a 2-month period from early August to early October. The importance of the various components of weather on voluntary water intake was also examined. The cows used in the experiment either grazed pasture alone, or were offered pasture and pasture hay supplements. Mean voluntary water intake increased by 2·30 kg per cow per day for every additional kg dry matter consumed and also increased by 0·053 kg per cow per day for each g/kg increase in dry matter concentration. Of the climatic factors, rainfall had the greatest single influence on the daily fluctuations in voluntary water intake and this was negative. Intake was also negatively related to minimum temperature, relative humidity and wind, and positively related to sunshine and evaporation. Although maximum temperature per se had no apparent influence on intake, it showed a positive relationship after the removal of the effects of rainfall. A model for the prediction of total water consumption is:Total water consumption (kg per cow per day) = 11·34 + 4·63 dry-matter intake (kg per cow per day) –0·036 dry-matter concentration (g/kg) + 0·84 mean temperature (°C).This can only be used to predict the water requirements of lactating dairy cows in different environments.

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Factors affecting water intakes of lactating dairy cows offered grass silages differing in fermentation and intake characteristics

Animal Science ◽

10.1017/s1357729800009115 ◽

1998 ◽

Vol 66 (3) ◽

pp. 543-550 ◽

Cited By ~ 7

Author(s):

R. J. Dewhurst ◽

N. W. Offer ◽

C. Thomas

Keyword(s):

Dairy Cows ◽

Milk Yield ◽

Water Intake ◽

High Performance ◽

Volatile Fatty Acids ◽

Free Water ◽

Metabolizable Energy ◽

Factors Affecting ◽

Lactating Dairy Cows ◽

D Value

AbstractThe objective of this study was to investigate the effects of silage characteristics on water intake of lactating dairy cows and to examine the prediction of water intake. Sixteen grass silages, differing in fermentation and intake characteristics, were offered ad libitum to dairy cows in early lactation supplemented with 7 kg/day of concentrate (13·3 MJ metabolizable energy per kg dry matter (DM) and 216 g crude protein per kg DM). Four silages were offered in each of four incomplete change-over design experiments, consisting of three 3-week periods. Water intakes were recorded through individual Kent water meters and press water bowls over the final week of each period. Tree (drinking) water intake ranged from 20·1 to 89·9 (mean = 45·2; s.d. = 12·96) I/day whilst total water intake (also including food water) ranged from 48·4 to 123·8 (mean = 87·3; s.d. = 14·12) I/day. Water intake increased with increasing silage DM concentration, however free water replaced silage water at a rate less than 1. Milk yield and silage D value (digestible organic matter, g/kg DM) were strongly positively correlated with free water intake (r = 0·751 and 0·595 respectively), though fermentation indices were not good single predictors of water intake. Further analysis revealed problems owing to collinearity within the predictors of water intake: DM intake, silage D value and milk yields being significantly correlated, as were pH and volatile fatty acids as a proportion of total fermentation acids. The ridge regression technique was used to reduce collinearity problems and produce stable equations. The best prediction equations for water intake involved a combination of both animal and analytical information: diet DM concentration, milk yield and silage pH. The use of fermentation information, whether from titration or high-performance liquid chromatography did not describe real variation in water intake beyond that described by silage pH. Free water intake was higher with higher diet DM concentrations, higher milk yields and higher silage pH.

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