Drinking regime evaluation with continuous ruminal monitoring boluses

© Slovak University of Agriculture in Nitra Faculty of Agrobiology and Food Resources


Introduction
Water supplies for both humans and livestock are becoming a subject of increasing importance.Indeed, climate change and drinking water deficits in certain areas have meant that supplies of clean water for livestock are becoming problematic, at least during certain periods of the year.Water is considered the most important nutrient for health and performance in dairy herds.Loss of water from the body occurs through milk production, urine and fecal excretion, sweat and vapour loss from lungs (NRC, 2001).A adequate water intake is essential to avoid negative effects on animal health, performance and welfare (Murphy,1992;Meyer et al., 2004), and 25 and 50% restriction of drinking water relative to ad libitum intake decreased feed intake and milk yield in dairy cows (Steiger Burgos et al., 2001).Results of several experiments showed that an average of 83% of the water demand is met by drinking (NRC, 2001).Many studies found the association between water intake and outside temperature and between water intake and the number of drinking events (Matarazzo et al., 2003;Brown-Brandl et al., 2006;Arias et al., 2008).Drinking activity can be monitored continuously and simultaneously for randomly enrolled cows using a data acquisition system based on an individual radio frequency identification collar (Cardot et al., 2008) or with observers (Jago et al., 2005).Huzzey et al. (2005) monitored drinking activity of dairy cows using video cameras connected to a video multiplexer and a time-lapse videocassette recorder.Bewley et al. (2008) monitored ruminal temperature using boluses permanently residing in the cow's reticulum and indentified temperatures influenced by drinking events.The aim of this study was to monitored drinking regime of dairy cows using boluses during lactation in relation to the outside temperature, daily drinking regime and the impact of drinking on rumen temperature.

Animals and housing
Measured data from 7 dairy cows of Holstein breed (average age 3.57) in cooperation with the University Experimental Farm in Oponice during 24 lactation weeks were collected.Selected cows had average milk production 10 175 kg per lactation with 3.94% of fats, 3.10% of crude proteins and 4.70% of lactose.Experimental cows were housed in the groups with another dairy cows together.The aim of this study was to continuously monitored drinking regime of 7 dairy cows of Holstein breed using boluses during 24 weeks of lactation in relation to the outside temperature and observed daily drinking regime with the impact of drinking on rumen temperature at University Experimental Farm in Oponice.Animals were fed once daily and milked 3 times per day.The bolus pH and temperature values implemented via esophagus were measured every 15 minutes (96 data points per day) with accuracy ±0.1 ph and °C.Outside temperature by FREEMETEO meteorological server (48 times per day) was measured.Outside temperature can affect the drinking regime of dairy cows.During lactation weeks with higher outside temperature higher average number of drinking events (ANDE) was determined.The biggest difference between weeks in ANDE 18.33% (p = 0.000) was found.Daily ANDE 9.25±1.85and average daily temperature (ADT) 19.03±5.19°C were observed.The most of the drinking events (NDE) concentrated to 4 main peaks (25.17%) during working hours (74.98%) was found.After the feed intake and milking the highest frequencies of NDE were observed.The highest average ruminal temperature after drinking (ARTAD) during night before first feeding due to lower NDE in this time were found.Overall ARTAD 36.86 °C was observed.The most measured ruminal temperatures after drinking (RTAD) (51.53%) in the interval 35-37 °C were found.This research proved that continuous ruminal monitoring with boluses is an appropriate tool for drinking regime evaluation and heat stress determination in herd of dairy cows.

Statistical evaluation
Statistical evaluation with IBM SPSS v. 20.0 was realised.Descriptive statistics with One-way ANOVA were recalculated.Statistically differences between average daily outside temperatures (ADT), average ruminal temperatures after drinking (ARTAD) and average numbers of drinking events (ANDE) with post hoc Tukey Test were determined.Effect of outside temperature on number of drinking events with Pearson correlation coefficient (r) was realised.As drinking event a decrease in ruminal temperature less than -0.70% and ruminal pH less than 0.00% with previous data point using data filter was selected.

Results and discussion
Drinking regime of dairy cows during lactation with average temperatures during drinking events in the Figure 1   previous week for 9 weeks was determined.The average increase in ANDE 4.68±4.24%and ADT +22.12±15.49%compared to previous week for 10 weeks was observed.
Temperatures measured after drinking and number of drinking events in Figure 2

Figure 2
Ruminal temperatures measured after drinking and number of drinking events during day abbreviations: RTAD -ruminal temperature after drinking; NDE -number of drinking events and -33.91% at 23:00 in NDE was observed.This decrease continued to 3:00 when NDE fall down by -1.32% (0:00), -30.00% (1:00), -26.67% (2:00) and -18.18% (3:00).The biggest difference in NDE 83.80% between 3:00 and 21:00 was determined.It can be state that dairy cows during night drink less.Only 12.78% of NDE between 22:00 and 3:00 was realised.On the other side during 4 peaks (5:00, 13:00, 19:00 and 21:00) 25.17% of NDE was found.This fact means that dairy cows drink water mainly after feeding and milking and during night is water intake low.During experiment 74.98% of NDE during working hours and 25.02% out of working hours were determined.Cardot et al. (2008) found 2 main and 3 smaller consumption peaks and 72.70% of NDE per day during working hours and 27.00% during night on the farm was achieved.Osborne et al. (2002) claims that 25.00 of NDE during night was realised.NDE occurred during the whole day but NDE peaks were in relationship with feeding and milking (Nocek and Braun, 1985;Osborne, 2002).

Conclusions
Outside temperature can affect the drinking regime of dairy cows.The weak linear relationship between ADT and NDE r = 0.132 was determined (p = 0.001) but in 19 cases the same change -both increase or decrease in the comparison with previous week between NDE and ADT was found.During lactation weeks with higher outside temperature higher NDE was determined.
The biggest difference between weeks in NDE 18.33% (p = 0.000) was found.Daily NDE 9.25±1.85and ADT 19.03±5.19°C were observed.The most of the NDE concentrated to 4 main peaks (25.17%) during working hours (74.98%) was found.After the feed intake and milking the highest frequencies of NDE were observed.The highest ARTAD during night before first feeding due to lower NDE in this time were found.Overall ARTAD 36.86 °C was found.The most measured RTAD (51.53%) in the interval 35-37 °C were found.This research proved that continuous ruminal monitoring with boluses is an appropriate tool for drinking regime evaluation and heat stress determination in herd of dairy cows.

Table 2
Average ruminal temperature after drinking event Different letters in the columns indicate significant differences.The mean difference is significant at the 0.05 level (Tukey Test); abbreviations: S.D.standard deviation, Cv -Coefficient of variation, Min.-minimal value, Max.-maximal value http://www.acta.fapz.uniag.sk© Slovak University of Agriculture in Nitra Faculty of Agrobiology and Food Resources 2 nd milking.Lower NDE by -34.12% in comparison with NDE at 14