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. Shredded paper may also provide another useable source of bedding, although moisture and pH requirements make sourcing more difficult.

In this study, we planned to divide our pack in half to compare experimental bedding treatments — peanut hulls, peanut hulls 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. After our study, we will work with Cornell Cooperative Extensions in Madison County to host an open farm day and create 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, is readily available, and has good attributes for composting, although pH and moisture can make sourcing more difficult.

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 had to abort the peanut hull only treatment early. 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.

Due to the timing of the animal health issues we experienced on the peanut hulls, we were not able to restart the pack from scratch prior to testing the efficacy of the peanut hull and wood chip combination; we did,however, apply a uniform layer of sawdust bedding for several weeks prior to establishing the new treatment. We believe that this action reset the barn to an acceptable base level.

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 La 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.

Accomplishments/Milestones

While we have collected data, I have not analyzed it, which means I cannot comment on trends with any certainty; however, based on observation we have noticed a couple things.

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.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. 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. I will be curious to compare the nutrient profile of the woodchips and peanut hulls to just the peaut hulls.

Impacts and Contributions/Outcomes

The outcomes will not be known until I sit down and do statistical analysis; however there are some anecdotal conclusions that can be reached. 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 and produced better conditions for the skidsteer.

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