We have been lucky enough to experience a handful of hot dry days this Summer. On these hot days in particular our thoughts turn to the availability and uptake of water in our calf pens. The average producer waits 17 days before offering fresh drinking water to calves (Wickramasinghe, 2020). When this practise is compared to offering fresh drinking water from birth the following differences have been recorded:
- In the first 16 days of life calves consumed an average of 0.75kg of water per day.
- Calves with access to water from birth consumed more milk and had greater hearth girths and bodyweights during the pre-weaning period.
- When re-assessed at 5 months these calves still had greater body weights than the calves offered water from 17 days.
The increased bodyweight was not as a result of greater starter feed intake; although you may expect it in this study no difference was seen between the starter consumption in the two groups. The difference is the result of greater feed efficiency. Rumen microbes must live in a water environment, without sufficient water bacteria cannot grow and rumen development is slowed. Drinking water goes directly into the rumen creating the ideal environment for fermentation. The fermentation of cereals release the VFAs; acetic, propionic and butyric acid.
Unlike acetic and propionic, butyric acid is not absorbed through the rumen wall but instead is converted into an energy source used by cells in the rumen wall for rumen development. It is important to remember this water cannot come from the water in whole milk or milk replacer as that bypasses the rumen and is directed into the abomasum. Only drinking water or ‘free water’ can act as an aid to early rumen development.