Minimising Slurry Pooling in Winter

Published 1 September 08

Minimising slurry pooling in winter

With bringing cows in only a matter of weeks away, preparing for winter's battle to keep dairy cow housing clean should not be far from the front of farmers' minds. Rachael Grigg, DairyCo extension officer for Cornwall and west Devon, looks at some of the things that can be done to minimise slurry pooling in dairy housing.

"Slurry depth in buildings is the major influence on digital dermatitis incidences in housed cattle," says Mrs Grigg. "This is especially true if the slurry depth is consistently above the coronary band of the cow's foot, generally around 25mm above floor level. In general cows standing, walking and lying in slurry will be more predisposed to diseases as they become dirtier and have softer hooves. Recent figures have valued a case of digital dermatitis at £125 so costs can soon mount up.

"The objective for cow housing during the winter period is to keep the floors as clean as practically possible at all times. Put bluntly, prolonged standing in pools or piles of slurry is harmful to cow health."

The biggest influences on the depth of slurry encountered in dairy units, regardless of their slurry disposal system, are standing space per cow and frequency of scraping. Wide feed stances (the cow standing area adjacent to the feed barrier) and wide cubicle access, as well as actual building layout, are tremendous assets when it comes to combating digital dermatitis.

Mrs Grigg continues: "A 700kg cow produces about 70 litres of slurry per day, most of which will be deposited at feed stances and cubicle access passes. A cow will normally defecate and urinate three to five times a day but more frequently when excited, stressed or with changes to the routine. So cow housing must be as stress free as possible to keep it as clean as possible.

"Adequate space for the cows is key when it comes to slurry management. Cows of all breeds continue to increase in size and housing designers in the past have thought too small for today's cow. In a cubicle set up provide a combined lying and scraped standing area of at least 7.5 sq m per cow, on a two-row arrangement. This can be reduced to about 6.5 sq m per cow on a three-row arrangement. But whatever the cubicle layout the cow must have a total standing area of at least 4 sq m per cow.

"A DairyCo-funded mastitis project recommends cows on loose housing have 1.25 sq m per thousand litres production of lying and standing space."

The DairyCo publication Minimising slurry pooling in dairy housing looks at all types of dairy housing with a slurry component (loose housed lying areas with tractor scrapped passes, and cubicles with either tractor scraped passes, flush floor passes, automatically scraped passes or slatted passes) and discusses the design and management factors which best contribute to clean healthy feet. The publication also compares the costs and benefits of each system.

"In general, for all non slatted floors, a slope of anywhere between 1.5% and 3% to convenient gullies, drains or slatted panels for the length of the building is needed. This will avoid slurry ponding on the feed stance," says Mrs Grigg .

"Frequent scraping or cleaning is key. For tractor-scraped passages scrape at least twice a day when cows are milking. Additional scrapes of the feed stance area can be made if the cows can be shut away from the feed stance. For flush systems wash passes at least three times a day with relatively clean water. When using an automatic scrape system make sure passes are scraped every two hours during active times of the day (4am to 10pm) but that little or no scraping takes place overnight in order not to disturb the cows."

Fully slatted passes are not subject to the same ponding risks as solid floors. Pooling occurs in slatted units where solid floor levels do not complement slatted floor levels. The solid area then dams up with slurry. To avoid this, solid floor sections should drain towards slats to minimise the ponding risk.

To request DairyCo's Minimising slurry pooling in dairy housing call 02476 478695 or email publications@dairyco.org.uk.  

Rachael Grigg can be contacted on 07976 980759 or by email rachael.grigg@dairyco.org.uk.

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