On average, young calves sleep 16 hours a day and will lay down an additional 2-5 hours, meaning that calves spend between 18 and 21 hours a day laying in their “beds”. Well this may sound like the life, it does come with some unique management challenges. Like fawns, calves are classified as a hider species. This means the dam will guide their calves to a hidden spot after birth where they will remain lying unless they are nursing. As they get older they will start to move around more, but will still spend much of their time either sleeping or eating. As time budget, for a young calf, sleep and food are very important. When calves are housed away from the dam on bedding, the surface they are lying on is also very important. Ideally, we want to house them on bedding that is clean, dry, and allows the calves to be comfortable and maintain their body temperature.
The cleanliness of calf bedding is very important for preventing navel infections, respiratory disease, and diarrhea- the top three calf killers and money drainers. All penning, hutch surfaces, and floor surfaces need to be well cleaned between each calf to prevent the build up of bacteria and virus in the environment. Bugs can spread up through bedding quickly, so making sure the surface being bedded is clean.
For hutches, this means moving the hutches between calves to allow the sun to reach the surface and help disinfect it. It may also include occasionally removing the soil and gravel from the area to remove accumulated manure and bugs. For indoor housing, using a good cleaner to reduce the bio-film on the cement and penning is essential. On our farm, we use Bio-Solve Plus® as our detergent to clean our floors and penning. However, regardless of what detergent you use to clean - remember soap scum! The scourge of showers everywhere, if a soap (detergent) dries to a surface it creates a film that is hard to remove. This is not only a problem in showers, in your barns it will protect the bacteria from the water – undoing everything you tried to do. So, remember, lather, rinse, and repeat…. between each calf!
Once you have a clean base for the bedding, it is important to keep the bedding dry. If you look at basic physics, what goes in must come out. As an industry we have started to feed more biologically appropriate volumes of milk. Moving from 10% of body weight, ( 4 L/ day) up to 20% of body weight and in some cases as much as calves are willing to drink, which could exceed 14 L /day. This has resulted in healthier, and better growing calves, but it also means more liquid passing through the calf. This means more bedding is needed to keep the pens dry. Drainage is important. In 2012, there was a neat research project conducted by Camiloti and colleagues that showed that calves could detect a difference between sawdust that was 90% versus 78% dry matter, and clearly preferred the dryer sawdust. Calves almost completely avoided sawdust that had 30% dry matter. Indicating a clear preference for dryer surfaces. Besides just preference for their own comfort, wet bedding will leach the energy from the calves in the winter, and on any cool summer nights. Remember a newborn calf’s thermoneutral zone is between 10C (50 F) and 25C (78F), while a one-month old calf’s thermoneutral zone is between 0 C (32F) and 25C (78F). So, what is the solution? One solution is to ensure good drainage. Many experts support the use of deep gravel base under calf hutches to aid in drainage. The downside to this is that as bedding and manure get mixed into the gravel, cleanliness becomes an issue and the gravel will need to be periodically replaced. Alternatively, there is sloped cement as an option. This makes cleaning easier but there are limits to drainage and additional bedding will be needed.
Whichever drainage system is used, what is important is to evaluate the bedding calves are lying on and then adjust bedding practices to ensure your calves are kept dry. Many of you have probably heard of the knee test which involves dropping to your knees and seeing if your knees get wet. Well, if you are like me, there are a few issues with that test. One, I don’t wear fabric outer-wear. When working with calves the ability to clean and disinfect pants is a great benefit so I wear rubber pants that I can wash as I have yet to meet a calf that won’t try and get poop on you. The second problem of the knee test is that even if I did wear cloth pants I don’t want to spend the day with wet knees – also a reason for the rubber pants! For this reason, the knee test just doesn’t get done. However, there is a simple solution. Paper-towel. Put the paper towel down between you and the ground and test multiple pens/multiple areas. This way you can get the benefit of seeing if your pens are dry without spending the day with manure stains. As a general rule, if the paper is wet after 20 seconds then you need to either add bedding or change it out. Remember calves with diarrhea put out a lot more liquid than normal so will need to be bedded more frequently.
The final thing to think about when considering how much calves sleep is how comfortable they are. If calves can nestle down into bedding they are better protected from wind, and cold. By nestling they can reduce their exposed surface area and better maintain their core body temperature (see previous blog). Remember lots of fresh, clean and dry bedding is essential, with deep bedded straw representing our current gold standard. By giving calves lots to drink, and lots of time and space to sleep, they are well on their way to being healthy and making you wealthy and very wise!
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If you are curious about the study of calf preferences for bedding referred to in the main text, check out "Short communication: Effects of bedding quality on the lying behavior of dairy calves" by V. Camiloti, J. A. Fregonesi , M. A. G. von Keyserlingk , and D. M. Weary in the Journal of Dairy Science. (95 :3380–3383 http://dx.doi.org/ 10.3168/jds.2011-5187)
When you spend 75 to 85%of your time laying down..
Sometimes you have to get creative