The Dairyland Initiative

Shrink, Leachate, and Pests

Understand different ideas and or programs to manage shrink, leachate, and pests within the feeding system. 

Shrink

Every dairy has shrink, but to really understand how to control it, farms need to measure it, accurately and scrupulously. Shrink has many areas of impact, and the only way to know what it is and where it is coming from, is to physically collect the data.

This data includes:

  • Routine physical inventories (estimates are OK, but you really need actual weights or zero values)
  • Deliveries (which weight is the dairy using – broker weight or on-site weight)
  • Amount used (what is fed and whether it is recorded in feed program or not)
  • Inventory used for non-feed purposes (i.e. bedding)

Shrink should be repeatedly measured over time to get an accurate assessment of actual shrink. It is not a static value; it can flex and change over time and is relative to the overall total amount of that ingredient over a given period and circumstances. Measuring shrink must involve numbers. A visual assessment does not quantify the extent of the shrink. It must be related back to total volume of the ingredient over a period of time.

Here is a list of areas to consider when evaluating shrink:

  • Physical inventory
  • Delivery data – what is your starting value? Using broker weight or on-site scale weight, how often are truck and feeding scales calibrated?
  • Usage data
    • Feeding (recorded in feed program),
    • Feeding (outside of feed program), bedding, etc.
  • Type of storage – bay, bin, pile, bunker, bags, bales, etc.
  • Feeder precision, accuracy, and routines
  • Cleanliness of feed area – spilled feed and where is it pushed
  • Weather – wind, rain, snow, etc.
  • Inventory data management
  • Timing of data entry
  • Ingredient DM
  • Scale calibration – truck scales, feed scales, etc.
  • Pests – rodents, birds, etc.

Below is a summary of actual farm data. Routine physical inventories were taken, the feed area was well maintained, and feeder performance was closely monitored. Please note that there is variation month to month and that sometimes there are positive values. These positive values and variation could be from a variety of reasons such as inaccurate estimates of physical inventories, misuse of ingredients, pushing spilled feed into inventory pile, missing/inaccurate delivery/usage data, and more.

Suggestions for when or how to record physical inventories:

  • After feeding at the end of each month/routine monthly checks
  • Any time a bay/bin is low/empty
  • Weekly for ingredients with large adjustments in the previous month
  • Monitor daily inventory levels in feed program to identify low inventory levels or possible delivery entry errors
  • Do not forget hay and straw. Use rolling bale weight averages for estimating tons. Record usage not going through feed program (ex. straw for bedding).

You will calculate more accurate shrink values with more consistent and accurate physical inventory and usage values.

Shrink determination is based on multiple data points over time. Tracking shrink within inventory management is a mindset. Controlling it is systematic and routine. Finding someone in your operation to take ownership of inventory management will be very important to be able to calculate your shrink because only then can you work on improving your shrink by finding ways to lower these numbers.

Shrink Scorecard

Although we just discussed in the previous section ways to measure shrink accurately with numbers, sometimes this may not be a viable on-farm option. Below is an example of a shrink scorecard that was created by the GPS team to provide general feedback on areas where a dairy may have higher potential for shrink. Although this scorecard does not provide exact numbers on shrink levels, it will provide a general guideline for areas of the feeding operation that a farm should focus on to improve their shrink. This is a great starting point for farms to improve the profitability of their feeding center.

Leachate

Why such concern over silage leachate?

Leachate presents an environmental problem when it flows into surface waters. Silage leachate has an extremely high biochemical oxygen demand (BOD). This means that leachate has a very high potential for consuming oxygen, and when it’s discharged into surface water, it can remove so much oxygen that fish and other aquatic creatures are impacted. As little as 1 gallon (3.8 L) of silage leachate can lower the oxygen content of 10,000 gallons (37,854 L) of river water to a critical level for fish survival. (https://www.canr.msu.edu/resources/environmental_stewardship_controlling_silage_leachage)

Below are some areas that can help to limit and/or manage leachate on farms:

  1. Minimizing leachate
    • Proper management of forage moisture is one of the best ways to minimize leachate from silage crops. Below are recommended dry matter levels for each crop:
      • Corn Silage: 34-36% dry matter
      • Haylage: 38-45% dry matter
      • Grass Silage: 32-38% dry matter
      • Snaplage: 62-57% dry matter
      • High-Moisture Corn (HMC): 71-75% dry matter
    • Protect feed from water
      • Cover feed if raining during filling process
      • Cover/wrap side walls and edges
      • Divert clean water away from feed storage structures
      • Minimize exposure when feeding
    • Keep feed pad clean of feed and standing water
  2. Leachate collection

Most leachate collection systems consist of both a leachate collection system and a vegetative treatment area (VTA). These systems are designed with a “first flush” concept, which is believed to maximize the constituent load per volume collected. After the initial first flush collection, flow from feed storage facilities is sent to a secondary treatment, commonly a VTA.

NRCS Code 629.V.C.1.c.1 requires all leachate to be collected on applicable farms. NRCS Code 635.V.D.1 further establishes that VTAs need to be designed to treat a minimum flow rate produced by the runoff from 25% of the peak flow of the 25-year, 24-hour storm event. The remaining portion of the 25-year, 24-hour runoff can be diverted from entering the VTA as this remaining water is expected to have negligible levels of contaminants.

Resources:

3. Collection designs

Above is one example of a new construction project that is designed to collect leachate. The blue lines on the drawing all represent the slope of the pad towards the center while the white line through the middle indicates the slope of the pad as well as represents the tile line that collects leachate off the forages to be dumped into a collection pit. The above was designed to be a 5” (13 cm) thick asphalt pad.

Leachate/Water Separation

Leachate Collection

 

A deep, wide concrete ditch on the south side collects all leachate coming off the forage piles and directs it to a collection area. There is a bridge through the middle that allows traffic to flow through without having to travel all the way around the system. The concrete ditch is also wide enough to clean out mechanically as needed.

Pest Control – Birds

Before looking into a control program, farms should understand the laws protecting birds in their area and be able to identify specifically which birds are causing the problem. Common bird species that are found around farms include pigeons, starlings, finches, and sparrows. Below are control measures that have been used with varying degrees of success. It may take a combination of techniques to successfully control the bird population on your farm.

Keeping the silage pad and commodity area clean and free of excess feed will help to limit pests on the farm. It would also help to limit nesting opportunities within farm buildings.

Noise makers can be used to scare birds away from the feed center. A few examples include a Zon 4 noise maker, which creates a loud gunshot-like noise periodically to scare birds. Another option is a predatory bird noise maker, which creates loud predatory bird noises periodically. These tend to lose effectiveness over time, so moving the location of the device can be helpful.

Pest Control – Other Animals

Other animals, including deer, raccoons, rats, mice, and others can also cause issues around the feed center. Some ideas to help control wildlife include noise makers, inflatables, or even solar-powered electric fencers. Keeping the area clean around forage pads can be a great starting place. Keep weeds and grass to a minimum around silage piles to reduce damage from wild animals that may chew plastic.  Inspect plastic on a regular basis and immediately repair any holes or damage found to limit spoilage.

Wisconsin does have a program that assists farms when wildlife damages their crops. The Wildlife Damage Abatement and Claims Program (WDACP) provides damage prevention assistance and partial compensation to farmers when wild deer, elk, bear, geese, and turkeys damage their agricultural crops. More information can be found here.

Shrink, Leachate and Pests Handout

Information on this website was compiled by GPS Dairy Consulting as part of their FeedFIT program. Company links and mentions do not indicate endorsement by The Dairyland Initiative, the University of Wisconsin, or GPS Dairy Consulting. They have been included for informational purposes only.