Clean, deep-bedded sand is associated with better outcomes in clinical and subclinical mastitis, hock lesions, cow cleanliness, cow lying times and cow preference. Similarly, recycled sand also appears to provide increased cow comfort and hygiene compared to straw and mattress systems, as does composted manure, which, if kept clean and frequently renewed, maintains a lower bacterial load.
Those conclusions are important considerations for veterinarians tasked with advising dairy clients on their best options for bedding, taking into account other criteria such as financial considerations, suitable housing design and logistics like restrictions on recycled manure solids.
The findings are from a critical appraisal of 59 studies, trials, case series and systematic reviews from 14 different countries, published as an extensive Knowledge Summary entitled “Are sand or composted bedding cubicles suitable alternatives to rubber matting for housing dairy cows?” in Veterinary Evidence in October 2018.
Key take-away messages from the evidence
- Clinical mastitis incidence was lower in herds bedded on deep sand cubicle systems
- Cows have been reported to have lower cleanliness scores (cleaner cows) on sand systems than on straw
- Lower bacterial counts have been reported from inorganic (sand/crushed limestone) bedding material versus organic (straw/manure)
- Higher bacterial counts have been found on teats on mattress systems versus sand and lower counts found on clean, new sand versus manure
- Heat treating or composting sand or manure has been found to reduce contamination
- The dry matter content and amount of organic material in the bedding has been found to affect bacterial growth within bedding of all types, so summer conditions appear to favour growth
- Associations have been found between increased Streptococcus spp. in manure and sand systems versus more coliforms and Klebsiella found in straw, manure and sawdust systems
- Bacterial coliform levels on bedding equalled faecal output within two days and treatment with inorganic compounds in an attempt to delay this did not reduce further bacterial growth in bedding
- In preference tests, cows appear to choose bedding types in the following order: sand>mattresses>waterbeds>concrete/straw
- Sand-bedded systems appear to have fewer lame cows
- Time spent lying in stalls is increased in sand-bedded systems versus others, with increased length of time of the first lying bout
- Cows may be seen spending more time in mattress stalls but they are standing rather than lying
- Compost manure and sand systems can both be shown to have reduced hock lesions versus mattress bedding
- When kept clean, there may be no differences in mastitis, somatic cell count, locomotion score and hock lesions between compost pack systems and deep sand cubicle systems
- When using straw for bedding material, it appears that chopping the straw can be associated with less hock hair loss than whole straw
- Lying time decreased by 11 minutes in a 24-hour period per 1cm depth of sand bedding
Full Knowledge Summary
Author: Mike Steele