I was asked recently about the use of rye straw as a bedding material for dairy cows.  The gist of the question was whether or not rye straw could be responsible for higher somatic cell counts or mastitis as compared to other small grain straws.  I found nothing in any research or literature that I looked at that suggested rye straw was in any way significantly different from any other cereal grain straw as a bedding material.  While sand is recognized as the gold standard for bedding, it is also clear that when well managed, all kinds of bedding materials can work and conversely when not managed properly all bedding materials can fail.  I came across a good presentation entitled “Bedding Options for Dairy Cattle” from Penn State Extension that I will use here to summarize some important aspects of bedding management. 

          Bedding materials can be categorized as either inorganic (sand, mattresses) or organic (straw, sawdust, paper).  Whatever the material, it needs to encourage cows to rest on it, it must minimize injuries such as hock and knee abrasions, swelling and lameness, and it must maintain cow cleanliness and udder health.  With regard to udder health the bedding material must remain dry and inhibit microbial growth.  If cows are not resting in stalls 12 or more hours per day the first thing to check is stall structure.  If the structure is suitable then next look to the bedding material and make sure is offers a comfortable resting surface.  Increase bedding volume and frequency of bedding, perform more frequent stall grooming and make sure the barn is not overcrowded.

          One of the biggest challenges with straw as a bedding material is keeping it dry and clean in the stall.  Moisture is the friend of bacterial growth.  Studies have shown that high populations of environmental mastitis pathogens can develop in 24 hours in organic bedding materials like straw when mixed with manure, urine and milk.  Recommended bedding management for any organic bedding material like straw is to remove the material from the rear half of the stall daily and replace it with fresh bedding.   Set a goal to groom stalls 3 times/day.   Grooming should consist of removing manure and soiled bedding and then covering wet and bare areas with clean, dry bedding.  Studies have shown that in herds using organic materials as bedding low somatic cell count (SCC) herds cleaned stalls an average of 2.2 times/day while high SCC herds cleaned stalls an average of 1.6 times/day.