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Archive: Sand Beds

Published 1 September 09

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Standfirst: Sand bedding for cow comfort and slurry separation and handling came under the spotlight at a farm visit organised by DairyCo at Woodfields Farm, Ledbury, Herefordshire.

Cow health and welfare are top priorities for the Hitchon family at Woodfields Farm, Ledbury and they are hoping that sand beds will provide comfort for their cows while keeping mastitis at bay. Tim McKendrick, Dairy Husbandry Specialist with The Dairy Group said it was important to maximise lying down time. Cows at grass will choose to lie down for up to 11 hours a day and the more time they lie down, the less the pressure on their feet.

"There is no right or wrong type of bedding but you must look at cow comfort and udder health at the same time. There's a lot of pressure on farmers from mattress manufacturers and cubicle manufacturers to use certain products but as far as mastitis is concerned there's no better bedding than sand as it's inert and the rate of bacterial growth is lower than on other beddings," he said. In a three-month UK trial, mastitis incidence on sand was less than half that for straw (14 clinical mastitis cases compared to 31 for straw and 23 for sawdust).

Sand also provides comfort too. Trials show that rubber crumb mattresses encourage the highest cubicle occupancy rate (89 per cent compared to 79 per cent for sand) but lame cows on deep sand beds lie down for longer than when on rubber crumb mattresses.

"Research indicates that the softer the bed, the better as there is less chance of physical injury and damage to hock and knees," he said. "Cows are happier getting up and down on sand and there is benefit to feet as cows slip less."

Sand is easier to manage in terms of keeping clean and it requires less frequent application.

"The downside is that sand can polish the concrete so you may eventually need to groove the concrete floor to prevent cows slipping. And sand can be problematic with slurry - you will either have to go for mechanical separation or opt for complete containment." If you are seriously thinking about using sand, quality is first and foremost, continues Tim. "Clean, washed sand is ideal. It should break up when you move a ball of it from hand to hand three or four times. If it doesn't there's too much clay.

"And it mustn't be too abrasive, finer sand is better, and without stones.If you have a supply of sand on the farm you should do the ball test to check clay levels. And don't be tempted to mix lime with sand or you can end up with concrete." It's best to keep sand beds full and to bed up cows once or twice a week. You will need 80 to 100 kg per cow per week. It can be stored in a concrete bunker and is best loaded into the dispenser from the top, to reduce the amount of water taken in it.

Cubicle dimensions are important too (TABLE)

 

Weight of cow (Kg)

Total length of bed (m)

(Open front)

Total length of bed (m)

(Closed front)

500

2.05

2.05

600

2.15

2.15

700

2.30

2.55

800

2.40

2.70

Cubicles should be 1.15m, any wider and cows will often lie too far sideways. When designing the building allow at least 10 feet for passageways between cubicles and 15 feet at the feed standing. The longer the building, the greater the bottleneck will be at the end of the passages when moving cows to milking, so wider cubicle passages (up to 15ft) are required in buildings with large cow groups. And a fall of two to 2.5 per cent is ideal for flood washing to work with sand.

He advised the 20-strong group of farmers present at Woodfields Farm not to get hung up on division design. Any cantilever system is fine. The use of 'freedom cubicles' (single pole design) may be appropriate for dry cows but probably leaves too much room for milking cows, resulting in dirty beds.

Brisket control is important to get cows lying correctly in the cubicle. "The Brisket board is designed to position the cow when she is lying down and should have a distance to kerb of 1.7 to 1.8 metres, not greater than 0.15 m in height and should be rounded to prevent injury."

The head rail is designed to position the cow when she is standing:

•Distance to kerb 1.6-1.7m

•Height 1.20-1.27m above cubicle base

•Diagonal dimension 2.1-2.2m

For the Hitchon family, moving from straw yards to cubicle housing there will be a transition period when cows will end up in the passageways and lying half in the cubicles but they will very quickly accept them once a few cows start to use them. "If you have time you can try and introduce the herd to the cubicles before the housing period," Tim advised. When installing deep sand beds, tyres can be used as a base to maintain sand level and to stop the sand bed hollowing out but they need tying together to prevent them popping up.

"Use a 14 inch kerbstone - seven inches below the bed and seven above. You must be generous with the sand - allow five tonnes per cow per year if all year round housing," he recommended. If adapting existing cubicles, sand can be layered four to five inches on top of the concrete base or two inches on top of an existing mattress. Sand can be used for dry cows too, in smaller yards but it can be difficult to clean out, although in terms of mastitis, dirty sand is often better than straw.

The cost of sand will vary between £10 to £12 per tonne for local sand and £16 to £18 if hauled which is favourable when compared to straw at £50 to £60. There are no negatives against sand as far as the cow is concerned and Jim Hitchon said his vet was 100 per cent behind it. Handling the slurry from sand beds needs careful consideration.  It can be removed from the yard by scraper (tractor or automatic) or flood washing. The latter being ideal if you want to introduce water into the slurry handling system, but beware the smell and the high installation and running costs.

The simplest system will be to scrape everything into a complete slurry store, likely to be a lagoon (unlined, as you will have to get in it to clean it out) or a tin tank. The liquid fraction is pumped off the top and, then once a year the more solid fraction is cleaned out using a loader and spreaders.  Some producers remove panels off their tin tanks and drop a bobcat in to load into a differ bucket. This is a specialist job and care must be taken as always when entering slurry stores. If sand is in slurry it stays in suspension but if you introduce water it will separate into three fractions: sand, slurry liquid and fibre at the top.

"It is easier to keep it in one fraction to tanker out but some contractors won't touch it, so you need to make sure you have a contractor that will handle sand," Tim advised. Weeping wall slurry stores usually don't separate the fractions well, however Mefin Richards reported that he had seen this work successfully, but the gap size in the wall is key.

The other option is to use mechanical separation and then re-use the sand. The equipment can cost as much as £150,000 and the sand has to be quite coarse, which is not ideal for cow comfort. "Separations and settlement systems are being use by innovative farmers in the UK who are willing to try out new systems. These involve the use of roller brush type separators from which the liquor is pumped into lagoons," he explained.

Tim McKendrick and his Dairy Groups colleague, Becky Floate, both recommended leaving sufficient space on the site to install a settlement and separation system, just in case it becomes necessary.