How to Build an Automatic Milk Feeding Device for Orphan Foals

1. Introduction

Veterinarians often face the dilemma of having a newborn foal in their care that may require round the clock feedings of a supplemental milk source. Foals whose dams are deceased, have rejected them, or are simply not producing enough milk normally require either a nurse mare or an alternative supply of milk or milk replacer. Once a foal’s antibody requirements have been met with the ingestion of colostrum or the delivery of an IV hyperimmune plasma, a decision will need to be made regarding the source and delivery method of its nutrition.
A foal will require some form of milk for the first 2 to 5 months of life.¹  A commercially available nurse mare or an open mare who has been hormonally induced to lactate are two options that offer both a long-term source of naturally balanced nutrition and social upbringing. Unfortunately, both of these alternatives take valuable time to arrange, can be very costly, and still run the risk of foal rejection. In the meantime, it is necessary to provide feedings at 1–2 hour intervals for at least the first few days of the foal’s life.²  Owners may quickly become exhausted by feeding foals this frequently and paying staff can rapidly become cost prohibitive. Some caretakers are tempted to leave out large volumes of milk in the stall overnight for the foal to consume at will. This practice can lead to spoilage of the milk or overconsumption by the foal, which can cause colic, diarrhea, gastric ulceration, and lack of weight gain.³  Constructing a relatively inexpensive automated device to store, refrigerate, and distribute a programmed volume of milk into a small receptacle for consumption at timed intervals can save the practitioner or owner time, money, and provide a more natural digestive process for the foal. 

2. Materials and Methods

An area with a 110 V electrical outlet and protection from rain is required to run and maintain the feeding device. Always use caution to avoid flammable materials around any electrical device, and be sure the device does not sit in wet conditions. The materials required are readily available online, and overnight shipping can be used to expedite delivery. A busy breeding farm or veterinary hospital can construct the device before the beginning of foaling season to ensure it will be ready when needed. The unit as described here costs less than $400 in supplies to build, and our hospital was quickly able to reimburse costs by charging a deposit and monthly rental fee for at home use. Equipment to be purchased includes the following:

1.  A compact (dormitory) refrigerator. We use a Kenmore Chill 3.3 cu. ft. model no. 93382^a, which averages $143.99 at www.sears.com, $129.99 at www.amazon.com, or is available at Sears appliance stores. This fridge allows a larger milk receptacle to be used inside, as some compact refrigerators do not provide a large enough ventral footprint on which to place a container large enough to store milk for 12 hours of use.
2. A rectangular milk storage container that fits inside the chosen compact refrigerator. We use a 2.5 gallon Sterilite^b plastic trash can found at Dollar General or Walmart for around $2.00.
3. A peristaltic dosing pump with a timer. These can be purchased separately as a pump and programmable electric timer or as one unit. We have tried several methods with different pumps and timer combinations, and the listed all in one programmable peristaltic pump seems to be the most affordable for what it provides. We use a 115 VAC Beta DR-2000 Clock Based Chemical Feed System^c. This unit can be purchased at www.cannon- water.com for $224.50 at the time of publication although they can occasionally be found new or used on www.ebay.com for less. This pump uses a standard 110 V outlet and pumps an average of 150 mL/min of fluid. It can be programmed to cycle once an hour for up to 20 minutes, which would provide a 3 L maximum output per cycle. It may be programmed to cycle more frequently than once an hour but only stores 24 programmed cycles to memory, so the internal clock would need to be reset every 12 hours for more frequent feeds. The pump is very easy to program once you read the enclosed instructions. Using a peristaltic type pump keeps the milk out of the moving pump parts to avoid contamination. Peristaltic pumps usually require very little maintenance or part replacement. The pump tube inside the roller assembly may need replacement every few years depending on how well it is cleaned and the conditions of storage. All the major components can be purchased from Cannon Water. The internal battery of this particular pump will only store programming for 6 months when unplugged, so if it is stored unplugged for more than 6 months in the offseason, then it will have to be reprogrammed at the beginning of each season and a new replacement battery may be purchased from the distributer. When purchased from the distributer, the pump is supplied with the remainder of the fittings including 1⁄4 inch tubing, a mounting bracket, screws, drywall anchors, cable ties, squeeze tube fittings, and standpipe to stiffen the suction tubing and help keep it near the bottom of the milk receptacle.
4. An optional clear storage container to protect the pump from water and dust in a barn type environment. We used a 4 L plastic food storage container found at the Dollar Store or Walmart for $2.00 to $6.00.
    

An electric drill, a box blade, a 3/16 inch drill bit, a 1⁄4 inch drill bit, a marker, a hammer, and a Phillips head screwdriver are tools used to assemble the device.

Unpack the compact refrigerator and ensure the chosen milk receptacle fits within the closed refrigerator. Choose whether to mount the peristaltic pump (Fig. 1) to the top or the side of the refrigerator. The pump may be mounted with a sliding bracket or with 3 screws (Fig. 2). In this example, we have mounted the pump to the top of the refrigerator with 3 screws. If the pump is mounted within a protective container, ensure the pump fits within the closed container and use the box blade to cut exit holes for the power cord and intake and output tubing (Fig. 3). Place the container and pump in the selected mounting position on the top or side of the refrigerator, and use the marker to mark the mounting screw placement (Figs. 4 and 5). Use the 3/16 inch drill bit to drill the mounting holes, and use the hammer to place the drywall anchors provided with the pump. Mount the peristaltic pump within the protective container to the top or side of the refrigerator using the mounting screws or bracket provided with the pump and a Phillips head screwdriver (Fig. 6). [...]