PD Poll Question
|Archives - Past Articles|
|Thursday, 27 September 2007 19:23|
The following is the first of a two-part series discussing design specifications for feed and water spaces in freestall barns.
Two basic ingredients in the production of milk are feed and water. Therefore, careful attention must be given to the design and management of these areas in freestall shelters. The feeding area should allow convenient delivery of the ration, provide enough space for the cows to consume an adequate amount of feed, be clean and free of debris and be easy to clean. It should also provide a productive and safe work environment for the caretaker and be cost-effective.
Water stations should provide plenty of good-quality, clean water offered from units conveniently located within the animal area that are easy for cows to drink from. This [article] will discuss design considerations for fenceline feeding and watering stations in freestall dairy shelters.
The feeding area should:
•encourage and allow each cow to consume an adequate amount of feed dry matter during each feeding episode during the day
•provide a comfortable feeding experience for the cow
•facilitate 24-hour availability of high-quality feed
•be easy to clean and use
The design, construction and management of a modern feeding system should contain the following key principles:
•Cows are fed at a fenceline, not a walk-around feedbunk.
•Facing fencelines are far enough apart to negate the feeling of confrontation.
•The cows eat in normal head-down (grazing) position.
•The eating surface is 2 to 6 inches above the cow alley.
•There is a flat feed table to encourage easy mechanical clean-out and feed push-up.
•The smooth, nonporous, easy-to-clean eating surface is 32 to 36 inches wide.
•There is a hard surface area at the same elevation as the eating surface where the food is “stored” after delivery or where cows may “push” feed back during eating.
•Feed should be pushed or scraped back to the eating surface, towards the cow, without becoming contaminated with gravel or mud from an unpaved driveway or vehicle track.
•The driveway is wide enough to allow the delivery vehicle to pass without driving where feed is to be delivered or on previously delivered feed.
•A separation device, or feed barrier, allows cows convenient access to the feed table without undue twisting, turning or repositioning of the head and neck.
•Expected contact points between cow and the separation device are shaped and located to prevent abrasion, penetration or bruising.
The dimensions of the feed delivery vehicle, both present and future, must be considered when determining the minimum height and width clearances of the driveway and shelter access opening.
Feeding space per cow
The feeding space refers to the amount of fenceline available to the cows. Feeding space per cow is calculated by dividing the total length of feeding space provided by the number of cows that have access to it. The amount of space required for cows to stand and eat comfortably is an important consideration.
One suggestion for determining the amount of feeding space required per cow is to multiply the chest width of a cow by 1.15 for non-pregnant cows and 1.25 for pregnant cows. Non-pregnant and pregnant 1,400-pound dairy cows with a chest width of 32 inches will require 25 inches and 27 inches of feeding space, respectively. Well-designed two-row and four-row freestall shelters can provide enough fenceline length for all cows in a group to eat at once, if the group is not overpopulated.
Three-row and six-row freestall shelters do not provide enough fenceline length for all the cows in a group to eat at once. Overpopulating a group further reduces the available feeding space per cow. Whether it is important for all cows to eat at the same time is a management decision, not an engineering decision. One study of two six-row freestall shelters indicated that even with limited feed space (15 to 16 inches per cow), the feeding area was fully occupied infrequently. No loss in production could be attributed to limited feeding space. However, they also recognized the limited nature of the study.
A more recent study of feedbunk length requirements for Holstein dairy heifers found that limited feedbunk length did not affect group growth rates, but it significantly affected individual growth rates. Perhaps the same is true with respect to individual dry matter intake (DMI) and milk production of lactating dairy cows.
Cow standing area
The width of the feeding alley should allow the cow to pass behind cows eating without disturbing them. A 12-foot alley width allows two-way cow traffic behind cows eating at the fenceline. If the feeding alley also provides access to a row of freestalls, 14 feet is recommended to allow cows to enter and exit the stalls more easily, without disturbing cows at the feeding area.
The surface on which cows stand should provide confident footing to reduce the chance of injury. Grooves in a parallel or diamond pattern formed into the concrete are common. The surface should be of good quality and construction to provide traction but not injure cows’ feet.
In an attempt to create a more comfortable surface for cows to stand on when eating, some producers install rubber belting in the feeding alley where the cows stand to eat. The cushioned surface is typically 5 to 6 feet wide and runs the length of the alley. It stands to reason this surface is more comfortable for cows to stand on compared to concrete. Some suppliers offer belting with a grooved surface, but still it can become slippery when wet and covered with manure. However, cows often prefer to walk on the cushioned surface when they are not hurried and the surface is available.
Sometimes a curb, or step, approximately 4 to 8 inches high and 12 to 16 inches wide, is placed next to the feeding area. The purpose is to prevent cows from defecating into the feed manger. A sanitary step is not recommended along a fenceline feeding area since it may hinder the cow’s ability to assume a natural grazing posture.
The separation device (feed barrier)
A successful feed barrier must allow the cow convenient, injury-free access for eating while preventing her from walking onto the feeding area. She should be allowed to access the feed in a natural way with a minimum of annoyance or obstruction from the feed barrier or separation device. The separation device should also protect the feed from contamination by manure and minimize feed spillage into the standing area. Two feed barriers commonly found in modern freestall shelters are the post-and-rail design and self-locking stanchions.
The lower portion of the separation device consists of a curb, or low wall, to prevent manure and feed from mixing, discourage the cow from stepping onto the feed table and allow feed to be delivered to the feed table without spilling into the cow alley. The height of the curb should not exceed the recommended throat height since it can interfere with the cows’ access to feed.
The upper portion of the separation device should also be considered when determining the curb height. If self-locking stanchions, or a similar feed barrier, are installed or might be added in the future, the top curb should be approximately 3 inches lower than the maximum throat height to allow for the bottom rail and a space between the bottom rail and curb to prevent feed build-up. This will reduce the capacity of the feed table and may increase feed spillage in the cow standing area. Placing a 3-inch-high wood filler strip above the concrete can help reduce this concern, and it can be removed in the future if necessary.
The post-and-rail feed barrier provides excellent access to the feed table for cows, and it is relatively inexpensive to construct. Proper placement of the upper rail allows the cow good access to feed with a minimum of interference. The neck of the cow should only nudge the rail slightly when she is reaching for feed.
Self-locking stanchions, or head locks, allow the manager to restrain a group of cows, or a single cow, for observation, treatment or other herd management activity. This feed barrier type is often mounted to a slant so the cows can reach further into the feeding area more comfortably.
It is important to select a design that allows each cow to insert her head and neck easily and comfortably through the access opening without excessive twisting and turning. Some manufacturers have overlooked this important design consideration, perhaps intending to provide more opening in a given space, simplifying assembly or saving material. Downed cows are also a concern with this feed barrier type. Fortunately, designs are available that allow the lower section to open wide to aid in cow release.
The eating surface
The eating surface must be smooth, clean and free of leftover feed and debris in order to encourage good feed intake and aid in the control of disease. The low pH of silage can etch the manger surface, exposing the cow’s tongue and mouth to rough edges.
The feed table should be located 2 to 6 inches above the cow alley to allow the cows to eat in a more natural grazing posture. Cows eating with their heads in a downward position produce 17 percent more saliva – which directly affects rumen function – than cows eating with heads held horizontally.
The feed table should be 32 to 36 inches wide and should slope away from the fenceline approximately 1/8-inch per foot to help drain away moisture. High-strength concrete and admixtures are used to improve the durability of feeding surfaces. Properly installing tile along the length of the feed table provides a durable, smooth surface. Epoxy coatings are also used, but must be applied properly to allow for good adhesion.
Feeding area management
Without proper care and management, any feeding system design can fail. Feed should be readily available to the cows. This is especially important in feeding areas with limited feeding space or overpopulated groups. Cows tend to work feed away from the feed table and out of reach when eating. Feed should be pushed up regularly so it is available to other cows in the group. The feed table should be scraped clean of feed and debris daily so fresh feed can be put in its place. In addition, the feeding area should be well-ventilated and the cow alley cleaned frequently so cows do not have to stand in an accumulation of manure. PD
—Excerpts from “Dairy Housing and Equipment Systems: Managing and Planning for Profitability” Proceedings