Bedding material comparison in a composting barn

Bedding material comparison in a composting barn

Summary

Composted bedded pack barns are an innovative solution to the problems of nutrient management, cow comfort, and manure storage faced by dairy producers in the Northeast. The largest obstacle to adoption of composted bedded pack barns is the dearth of cost-effective bedding material. Sawdust is the current best practice for bedding in composted bedded pack barns, but the cost of bedding with sawdust can exceed $0.50 per cow per day and not many cost-effective alternative bedding sources have been identified. Since composted bedded pack barns are still a relatively new housing system, there are still many gaps in the research.
Peanut hulls are a source of bedding that is well suited to composting and readily available, but initial results were highly unfavorable. Shredded paper may also provide another useable source of bedding, although moisture and pH requirements make sourcing just shredded paper more difficult. In this study, we planned to divide our pack in half to compare experimental bedding treatments — peanut hulls, peanuthulls and wood chips, and shredded paper — with a control sawdust treatment. We will collect data on the pack weekly and perform statistical analyses upon the completion of the study. We will continue to work with Cornell Cooperative Extensions in Madison County to identify bedding sources and implement our outreach plan including an open farm day and  a YouTube video with a companion fact sheet to disseminate our results

Objectives/Performance Targets

The objective of this project is to measure the efficacy and cost-effectiveness of alternate bedding materials in a composted bedded pack barn. The sources of bedding that we are evaluating are shredded paper by product, peanut hulls, and a mixture of  peanut hulls and woodchips. Peanut hulls have acceptable C:N ratios, are readily available, and have good attributes for composting. A mixture of peanut hulls and woodchips have adequate C:N ratios, are readily availble, have adequate attributes for composting, and aid in disease managment. Shredded paper byproduct has an acceptable C:N ratios, has good attributes for composting,and in theory should be easy to source — although pH and moisture have been a barrier.
At the beginning the experiment, we established a composted bedded pack by following the Minnesota Extension guidelines for establishing an effective pack. We divided the barn in half, with one half of the barn receiving a control treatment of sawdust and the other half receiving an experimental treatment (either peanut hulls, shredded paper, or a mixture of peanut hulls and woodcips). We planned to stick with each treatment for 4 months, but, due to animal health issues in 2014 had to abort the peanut hull only treatment early. We also completed our peanut hull and woodchip mixture experiment in 2015

The pack is tilled to 10” everyday following morning milkings using a c-tine cultivator pulled behind a Ford 9-N. Bedding material is added as needed while the pack is being tended. Every Saturday, we collected data to measure the effectiveness of the bedding material in the pack. We used temperature to assess biological activity in the pack and to determine whether the bedding is being fully composted. Temperature is critical to the breakdown of the pack into compost and indicates the level of biological activity.  We initially intended to measure cow activity on the pack to assess whether the animals show a preference. Tracking cow frequency and activity type in each half of the barn proved to be impractical; however, we are keeping an anecdotal account of noteworthy cow activity (i.e the cows love eating the peanut hulls off the pack). While we will not be able to do a statistical analysis of the cow activity, we do feel that we are capturing behaviors of note.

The cold weather and a few missed cultivations (due to the birth of our daughter) led to the pack dying in the winter of 2015. We held off on the running the paper byproduct experiment so that we could be sure that the pack was alive and our results were good. In May of 2015 we cleaned out the barn and prepared it for animal activity. The weather has been freakishly good since then and our cows are still out grazing pasture. We have identified an acceptable paper byproduct source (adequate pH and moisture content and reasonable price) and we will order the byproduct once we bring the cows into the barn and get the pack restarted. 

We have collected 3 nutrient samples on the pack and the samples are currently sitting in our freezer waiting to be taken to te Cornell Nutrient Analysis Lab for nutrient analysis. Composite samples were taken from 12” below the pack surface. We are collecting data for the financial analysis of the pack. We have tracked the unit cost of bedding and the quanity of bedding that we use. We have also tracked time, fuel, and vehicle maintenance required to maintain the pack. In addition, we have tracked morbidity and mortality in our cows. The financial analysis, temperature of the pack, and cow comfort/disease data all point towards sawdust remaining as the standard for bedding a composted pack barn. We are anxious to test the results of the paper byproduct.

Accomplishments/Milestones

Overall, a bedded pack has been great for cow comfort. We have 0% lameness in our herd. When given the choice between pasture and the barn, the cows show a distinct preference for the barn, even when the higher quality feed was located in the pasture. The cows have also showed a preference for cultivating and bedding the pack twice a day. We have actually found that we use less bedding when we cultivate twice per day, but the cost savings in bedding are off set by the increased fuel consumption of the tractor and time spent doing chores. 

We did have a mastitis problem when we first introduced our cows to the pack, however the problem was resolved once we switched to a non-iodine, barrier teat dip. Cow health has confirmed our beliefs about the superiority of a composted bedded pack.

The peanut hulls presented a number of challenges that indicated to us that they were not a good substitute for sawdust. The biggest issue with using peanut hulls was that the cows liked to eat them off both the pack and the bedding pile. We also had an outbreak of clostrdium that killed one cow and five calves. We believe this was related to the peanut hulls as the outbreak occurred immediately after we switched bedding types and our vet indicated that he believed them to be the cause; however correlation does not equal causation and it is possible that the clostridium was do to a different source (however, we don’t want to test that theory). Beyond the health issues, there were logistical issue with the peanut hulls. While they composted very well, they did not have the substance to support the skidsteer or the 9N, so we had difficulty maintaining the pack.

Peanut hulls mixed with woodchips solved the health and logistical problems mentioned above to some extent, but did not compost as well. We have not sent the nutrient samples for analysis yet, so we do not know how their nutrient profiles compare. The combinationo f the peanut hulls and woodchips proved to be a much lower cost solution than the sawdust; however, the cows prefered the side of the barn that was bedded with sawdust. It would be interesting to see how the cows reacted to the peanuthulls/woodchips if not given an choice of bedding types.

We have finally identified a paper byproduct source that has acceptable pH and moisture content, is relatively low cost, and does not contain staples. We are ready to restart the pack as soon as the cows come in from pasture and will be studying this bedding type through the winter. The cost of the paper byproduct is similar to sawdust, so it will be interesting to measure the speed at which we go through the byproduct and the impact — if any — it has on cow health. 

I also reestablished a connection with Cooperative Extenion. Karen Baase — our original advisor — retired at the end of 2014 and we were left without guidance. Katherine Brosnan has since become responsible for her duties and has assumed the role of advisor. Katherine and I met at the beginning of October and end of November and have established a plan for completing this project, including organizing an open farm day and working with the students at SUNY Morrisville to produce a video.

Impacts and Contributions/Outcomes

Peanut hulls resulted in significant cow mortality and acted as a breeding ground for bacteria. Peanut hulls also produced difficult conditions for the skidsteer, as they compacted under the weight of the machine.

Peanut hulls mixed with wood chips did not result in cow mortality, produced better conditions for the skidsteer, and were less expensive than sawdust; however the costs consistently showed a preference for the sawdust side of the barn. Our sawdust cost increased significantly during this test as we had to add bedding much more frequently and the cows were often cramped.

We have found a paper byproduct that looks promising and we will start that experiment as soon as the cows move into the barn for the winter.

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