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. Sanitary steps 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 References omitted but are available upon request at editor@progressivedairy.com —Excerpts from “Dairy Housing and Equipment Systems: Managing and Planning for Profitability” Proceedings

“Hey, Doc, my cows are eating dirt. Waddya got for that?” A few years ago, I posed this question at several dairy seminars in the Midwest: “Do your animals chew on wood or eat dirt if they have the chance?” A few said their cows would chew on wood. Almost all indicated their cows would eat dirt, if available.

Large dairies often make easy targets for protestors and activists. Similarly, organic dairies often come under fire. So what about a large dairy that’s also organic? While most people don’t normally think of “large” and “organic” in the same sentence, a few have combined the two.

Nutritionist Terry Dvorachek is in expansion mode. That’s because his clients are, too. Within a few weeks, Mountain View Dairy in Luxemburg, Wisconsin, will open a new freestall barn and expand its herd from 600 to 1,100 cows. To prepare for the expansion, Dvorachek has been stretching out the dairy’s forages. “What I’m trying to do is keep tabs on the inventory of their feeds and look for feeds that would fit their feeding program,” Dvorachek says. That includes finding good nutrient profile matches for the dairy’s forages, such as soybean meal/canola meal to feed with its haylage and corn gluten feed for its silage. Pairing forage nutrient profiles with off-farm commodities amounts to what Dvorachek calls, “forage stretchers,” which help the dairy make the most of its available forages. “Don’t be afraid of buying products,” Dvorachek says. “Don’t be afraid to look at different products to buy to help address forage and energy needs.” Dvorachek currently feeds a ration that includes 38 percent corn silage and 18 percent haylage. To help make the dairy’s forages last longer and feed more cows this year, the ration has included ensiled peas and oats and Western baled hay. Both commodities have helped to “fill the gap” in meeting the growing dairy’s forage needs. After the expansion is complete, Dvorachek plans to transition the dairy to a ration that includes 55 or 60 percent silage. He says this will be possible because this fall more of the 400 acres owned by the dairy, where most of the dairy’s forages are grown, will be harvested in corn silage, which has a higher yield per acre than alfalfa or other crops. “In our area, we are becoming corn silage-driven,” Dvorachek says. “Our farms are getting larger, and producers just simply can’t produce enough haylage alone to feed their animals anymore.” As the percentage of corn silage in his rations have increased, Dvorachek says he’s also monitored fungus toxins. Within the last year, Dvorachek has found mycotoxins and aflatoxins creeping into silages. In turn, he has added a mycotoxin binder in Mountain View’s ration and in other dairy rations he consults in the area. “A lot of dairies are adding in a mycotoxin binder as a status quo ingredient,” Dvorachek says. “It’s an extra 12 cents per cow per day, but when you do the math, if you eliminate some abortions, how do you put a value on that?” To prepare for expansion, dairy owners, Mark and Al Seidl, had to overcrowd a few of their pens. It’s an added stress that Dvorachek says both he and the dairy’s owners have been “limping through.” To help minimize stress and competition at the feedbunk, Dvorachek says he’s focused on keeping the ration digestible, and he’s added extra minerals. Heat in late August and early September compounded stress and limited milk production in overcrowded pens, but Dvorachek says that minus the heat the ration and its added minerals have performed well and the cows have transitioned through the expansion process well. PD

Feed cost is the biggest concern for today’s dairy producers. The price of commodities such as cottonseed and soybeans, continues to drive up the cost of dairy rations.

In almost all biological systems, it is important that pH not deviate much from a fixed value. For example, for blood to carry oxygen from the lungs to tissue, pH must be maintained very close to 7.4. When rumen pH is either too high or too low, microbial fermentation and absorption of end products of that fermentation are less than optimal. Buffers, and other compounds, are added to rations for ruminant animals to aid in maintaining both blood and rumen pH in the desired ranges. What is pH? Maintenance of blood pH, in terms of animal survival, is extremely important. Supplying oxygen to tissues and temperature regulation are the only functions that take precedence over maintenance of proper acid-base balance. While it is extremely important to recognize this fact, the first part of this article will focus on the role of buffers in the digestive tract. The term pH is commonly used to describe the acidity or alkalinity of solutions. In regards to this discussion, the item of interest, however, is not pH, but what it represents, which is the concentration of hydrogen ions. Use of the term pH to describe acidity may be slightly confusing as it is not a numeric scale but a logarithmic scale. A change in rumen pH from 6.0 to 6.5 may appear to be slight, only 8 percent, but represents a 316 percent reduction in hydrogen ion (acid) concentration. What are buffers? Buffers are defined as compounds that resist change in the pH of a system. While rumen pH can vary dramatically, the normal range may be considered to be from 5.7 to 6.7. In this range, bicarbonate is the primary buffering system in the rumen, although there are other minor buffers as well. Bicarbonate, as a buffer, is most effective at a pH of 6.37 and is effective at a range of from 4.67 to 8.07. Commonly used compounds (such as sodium sesquicarbonate, potassium carbonate, sodium carbonate, magnesium oxide, calcium and magnesium carbonates) are more properly termed alkalizing agents based on their mode of action. Practically speaking however, this distinction only applies to magnesium oxide as all other compounds mentioned add to the rumen bicarbonate pool. A byproduct: Volatile fatty acids Volatile fatty acids formed during rumen fermentation are waste products produced by bacteria. Rumen fermentation is an anaerobic process and, as a result, conversion of carbohydrates in feed to microbial cells is greatly exceeded by the amount of these various waste products. When these waste products are absorbed and utilized by the host animal, the amount of energy to provide for cell maintenance and growth greatly exceeds that available to rumen bacteria. Most common among the volatile fatty acids produced during fermentation are acetic acid, propionic acid and butyric acid. It has been estimated that if the rumen were not buffered, the pH may drop to approximately 3.0. Dissociation constants vary for common volatile fatty acids. This means that not all acids produced during rumen fermentation produce the same level of acidity. If propionic acid has a relative rank of 1.0, then butyric acid and acetic acid are 1.09 and 1.30, respectively. Lactic acid, found in silage and produced in relatively large quantities when animals are not well adapted to high-grain rations, is much more acidic than the volatile fatty acids. Lactic acid is 10.3 times more acidic than propionic acid, which can lead to problems when animals consume large amounts of silage. None of these organic acids can compare to hydrochloric acid, which is more than 70,000 times as strong an acid as propionate. Neutralizing acid Buffers also vary in their ability to neutralize or completely consume acid. Based solely on chemistry, one can rank buffers on a scale of from one to 10, 10 being the best. Table 1 shows a comparison of theoretical acid-consuming capacity and measured acid-consuming capacity. It should be noted that while magnesium and calcium compounds rank higher than sodium and potassium compounds, there is much more variability in quality for the former. Some calcium and magnesium buffers and alkalizing agents are relatively poor acid consumers, while others are quite good. Generally speaking, these are unrefined products and can vary based on the particular deposit from which they are mined. Potassium and sodium buffers and alkalizing agents are usually refined products and, as such, are more consistent in performance. Unrefined trona ore, predominantly sodium sesquicarbonate, tends to be less variable in performance than mined calcium or magnesium products. In general, products should be chosen based on consistency of measured results. Quantities of buffers added to rations depends on a number of factors: rate and extent of rumen carbohydrate fermentation, quality and quantity of fermented feeds (such as corn silage) and passage rate are some of the most important. It is possible to calculate the amount of buffering required if ration composition and kinetics of rumen degradation are known. Plant cell walls and starch are carbohydrates varying dramatically in rate and extent of rumen degradation. If one assumes rumen losses of plant cell walls are 40 percent, then for a cow consuming 50 pounds of dry matter (DM) with 28 percent plant cell walls, theoretical production of acetic acid, propionic acid and butyric acid from cell wall fermentation are 2.0, .90 and .80 pounds, respectively. Bacterial waste, as volatile fatty acids, are 3.7 pounds and .65 pounds of microbial cells are produced from 14 pounds of cell walls. If the same ration contained 35 percent starch and that starch was 90 percent fermented in the rumen, theoretical production from that portion of the feed yields 10.5 pounds of volatile fatty acid and about 2.0 pounds of microbial cells. Rations higher in fiber require less acid neutralization partly because of higher salivary secretions and lower rates of acid production. Feed fiber, especially that found in legumes, can remove acid much in the same way a water softener removes calcium from water (ion exchange). Total ion exchange capacity of most rations is limited; the equivalent of a fraction of an ounce of sodium bicarbonate. Amounts of buffers added to the ration can be calculated based on ruminal acid production, salivary bicarbonate production and feed pH. Excessive acid neutralization can be as deleterious as insufficient buffering, as dissociated volatile fatty acids are not absorbed as well as undissociated volatile fatty acids. When rumen pH rises too high, absorption of volatile fatty acids across the rumen wall ceases, as will rumen fermentation. At a pH of 6.0, approximately 95 percent of acetic acid is dissociated, as are 93 percent of both propionic and butyric acids. It is interesting to note that volatile fatty acid absorption across the rumen wall is more rapid shortly after a meal, before salivary secretion increases. Since estimates regarding production of volatile fatty acids and microbial cells have been made, a brief (unrelated to buffers) yet important discussion follows. Plant cell walls are important in overall rumen function; however, the role of rumen fermentable starch cannot be overemphasized. As can be seen from the previous example, the contribution of starch fermentation to microbial cell growth is much greater than plant cell wall fermentation. At amounts that might be found in a typical dairy ration, starch has the potential to grow three times the amount of microbes and nearly five times the amount of propionic acid as plant cell walls. The implications of this, as regards milk production, are clear. Regulating blood pH While rumen pH can vary over a broad range, blood pH does not. Under conditions commonly found in the rumen, acid content, as measured by pH, can vary 10 fold. Blood acid content is highly regulated and varies by no more than 10 percent from the average. Normal blood pH is 7.4; animals are alkalotic when pH is greater than 7.45 and acidotic when pH is less than 7.35. Metabolism must be altered to correct either condition as blood pH outside the range of from 6.8 to 7.8 results in death. Regulation of blood pH is not as simple as the situation in the rumen. Hydrogen ions (acid) in blood are positively charged and in order to maintain a zero charge, one of two events must occur. Introduction of acid (positively charged) must be accompanied by the addition of a negatively charged ion (anion) such as chloride or bicarbonate, or the loss of positively charged ions (cations), such as sodium or potassium. Potassium, sodium and chloride are classified as dietary fixed ions; they are quantitatively absorbed from the gut, are not metabolized and excesses are excreted in urine. Combustion of feed indicates effects on acid-base balance; ash from cereal grains is acid, while that from forages is alkaline. Cattle are much more tolerant of alkalosis than acidosis and, as such, require a slight dietary excess of positively charged fixed ions. The magnitude of this excess is determined by a number of factors including metabolic state. Growth is a state when animals are in a negative acid balance; while catabolic states, such as starvation, represent a positive acid state. Acid-base imbalance affects multiple metabolic processes; among these are impaired glucose metabolism and transport of compounds across cell membranes. Ultimately, under prolonged conditions of acid-base imbalance, animal health and efficiency are reduced. Modern management practices increase energy density to improve production, primarily with increased intake of cereal grains. Until recently, no attention was paid to acid-base balance in cattle. It has been suggested that benefits resulting from the addition of buffers, such as sodium bicarbonate, relate as much to fixed ion addition (sodium) as to acid neutralization. Sodium, potassium, chloride, phosphorus, sulfur, calcium and magnesium are commonly included in equations describing dietary acid-base status. Phosphorus, sulfur, calcium and magnesium may warrant inclusion occasionally, but these are typically added to rations to satisfy requirements. Unlike sodium, potassium and chloride, absorption of phosphorus, sulfur, calcium and magnesium is variable and often low. Sulfur is a constituent of several amino acids, and as such, metabolic state influences the contribution of sulfur to acid-base balance. Equations describing dietary fixed ion differences must be predictive of acid-base balance across all metabolic states. In addition, the simplest equation describing a system is to be used in preference to a more complex one that does not increase accuracy of prediction. Summary Regulation of acid-base balance in ruminants is a more complex system than that in non-ruminants. To meet the demands of high production, feeds are included in rations that can disrupt ruminal and metabolic processes. Buffers are added to rations to mitigate negative effects of acids produced during fermentation on rumen health and function. Additionally, buffers allow blood pH to remain in a range that maximizes performance and animal health. PD References omitted but are available upon request at editor@progressivedairy.com

Since other feedstuffs are typically priced to reflect the corn and soybean market, the cost of almost all feed ingredients has increased. Since feed is the largest single cost in producing milk, most producers review their feeding program to see if there are ways to reduce these costs. Any changes made to rations should only occur after a thorough review of the feeding program and must take into account the impact a change could have on other aspects of the overall operation.

Once upon a time there was a Grasshopper. He loved to dance and sing. All day in the summer he danced and sang to his heart’s content. He watched the ants carrying bits of grain and corn into their tunnels. He laughed at their labors.

Well, it’s official; I’m an adult. I know this, not because I’m married and have two kids or because my hair is thinning.

Dairy producers from Idaho are invited to attend the 2007 United Dairymen of Idaho Annual Meeting to be held at the Boise Centre on the Grove October 24-26.