Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/15/2011
Publication Date: 6/20/2011
Citation: Petersen, M.K., Reil, M.S., Muscha, J.M., Mulliniks, J.T. 2011. Access to warm drinking water prevents rumen temperature drop without affecting in situ NDF disappearance in grazing winter range cows. Western Section of Animal Science Proceedings 62:335-336.
Interpretive Summary: Results from this study shows that cows grazing range and coping with climatic low winter temperatures are found to have daily rumen temperature above 37°C 98% of the time when heated water is provided to cows grazing winter range with no influence on extent of in situ NDF and OM disappearance.
Technical Abstract: Ingestion of large quantities of cold water or frozen forage may result in changes in temperature of ruminal contents. Rumen microorganisms may be sensitive to temperature changes in the ruminal environment. Therefore, this study was conducted to assess the variability in ruminal temperature and extent of in situ OM and NDF disappearance during winter in grazing range cows supplied with drinking water at either 8.2 ± 0.4°C (cold) or 31.1 ± 1.3°C (warm). Two adjacent paddocks (average 320 ha) were grazed from December through February in 2010-2011 by 24 pregnant range cows of which 4 were fitted with rumen cannulas at USDA-ARS Fort Keogh Livestock and Range Research Laboratory in Miles City, MT. Each paddock provided cold or warm stock water delivered in Ritchie waters. Warm water drinkers were heated by a Rheem outdoor tankless propane water heater. The four cannulated cows had Kahne rumen temperature continuous recording boluses (KB1000; recorded temperature at 5 min intervals) for 22 d in January. The recorded data were used to determine the frequency of timed events when rumen contents were below 37.9°C. Two separate in situ trials were conducted 1 wk apart for approximately 72 h. Three nylon bags containing approximately 5g of winter range forage extrusa collected in November were placed in each rumen at 1400 h and incubated for 72 h for OM and NDF disappearance analysis. Cows in warm water paddocks had less (P < 0.01) variability in ruminal temperature than cows in the cold water paddocks. During a 22-d period only 1.5% of the time did ruminal temperature drop below 38°C while the cows that had access to colder water were below 38°C 9.4% of the time. In situ NDF and OM disappearances were not influenced by the temperature of water the cow had access to drink (P > 0.64). Results from this study show that daily rumen temperature is less variable when heated water is provided to cows grazing winter range with no influence on extent of in situ NDF and OM disappearance.