Buckeye Dairy News: Volume 6 Issue 1

  1. Milking Machines and Milk Quality

    Dr. Kent Hoblet, Chair and Dairy Extension Veterinarian, Ohio State University

    Machine milking involves a complex physical interaction between mechanical equipment and living tissue. Moreover, this activity occurs two or three times daily for 300 or more consecutive days. As such, the milking machine may be a causative factor in the occurrence of mastitis in three ways:

    (1) The machine may physically facilitate the transfer of bacteria from an infected gland to a noninfected gland either on the same cow or to another cow,

    (2) The machine may cause damage to tissue, thus enhancing the ability of bacteria to gain entrance to the gland, and

    (3) Abrupt vacuum instability within the machine may result in the reverse flow of milk droplets causing teat-end impacts. If bacteria are present, these impacts may permit their entrance into the gland.

    The machine consists of five components. Typically, these include: (1) vacuum pump, (2) vacuum controller in most systems, (3) pulsation system, (4) milk transport system (pipeline or buckets), and (5) milker unit or cluster (bowl and teat cup assembly). To function properly, each of the above components must be of proper design and maintained in good working order. No one component is more important than another. Furthermore, it must be noted that an excellently designed machine kept in proper working order can be improperly operated. In fact, over 18 years of observation and troubleshooting herd mastitis problems, leads me to the conclusion that, all things being equal, excellence in operator performance is often more important than a perfectly functioning machine.

    Pump - The pump removes air from the system to create a partial vacuum. A principle of cow milking is that milk should be removed under vacuum and then transported by gravity. Therefore, everything else being equal, a low pipeline system is preferred to a highline system. A general guideline is that any pipeline system's pump capacity should be a minimum of 35 cubic feet per minute (CFM), with an additional 3 CFM per milker unit.

    Vacuum levels and vacuum controller - The National Mastitis Council (NMC) recommends an average vacuum in the claw during milking of 10.5 to 12.5" Hg. This normally indicates that the set or nominal vacuum on the system should be 12.5 to 13.5" Hg for low lines and bucket milkers and 14 to 15" Hg for high lines.

    Measurement: Measurement of effective reserve and manual reserve on a regular basis are necessary to ensure that air extraction and vacuum controller operation are optimal. A guideline for good cow milking is that vacuum stability should vary by no more than 0.6" Hg when measured in the milk pipeline. Effective Reserve (ER) is essentially the amount of air that can be admitted into the system without changing vacuum more than 0.6" Hg. This measurement is made with the regulator functional. Manual Reserve (MR) is the same measurement made with the regulator inactivated. The fraction (ER / MR) x 100 = efficiency of the vacuum controller which should be > 90%. When variable speed pumps are used, only the ER can be determined.

    An approximation of the effectiveness of pump capacity, vacuum controller, and piping system can be made by simulating a unit drop-off. In a properly sized and functioning system, the simulated drop-off of one unit (in a system with up to 16 units) should not result in > 0.6" Hg decrease in vacuum. There should be no observable override of vacuum levels.

    Pulsation - Pulsators should be monitored regularly for function. The optimal pulsation ratio (the ratio of time spent in vacuum creation:air admission) is 60:40 (range 50:50 to 70:30), with an optimal rate of 60 pulsations per minute (range of 50 to 60). A frequent source of teat damage is failure to have adequate pulsation. This failure can be a result of holes in short and long pulsation air hoses, as well as malfunctions of the pulsator itself. Recording vacuum in the milker unit while cows are actually being milked is an excellent method of determining the adequacy of vacuum stability. In low line systems, we expect that there should be less than 1" Hg (2" in high line) vacuum difference between the pulsated and milk sides of the system and less than 2" Hg fluctuation recorded in the claw.

    Cluster - There should be a provision for release of vacuum in the claw prior to removal of the milker unit from the cow. Synthetic rubber molded liners should be replaced every 1200 cow-milkings. Another guideline is to use liners no more than 90 wash cycles, even if the 1200 cow-milkings have not been exceeded. A frequent observation in herds with an elevated prevalence of Staphylococcus aureus infections is prolonged use of liners beyond these recommendations.

    Automatic detacher - There has generally been a tendency to have the end of milking and the time delay for removal of the unit set such that udders are milked too dry. Such overmilking can result in trauma and hyperkeratosis (callous formation) at the teat end. Producers and others frequently (and mistakenly) refer to hyperkeratosis as prolapsed teat ends. Good guidelines to consider are that after the milker units are removed:

    (1) Teat ends should not be reddened or edematous,
    (2) There should be an easily obtainable stream of milk remaining in each quarter, and
    (3) Cows should not flinch or kick when teats are touched after the milker unit is removed.

    In summary, maintaining a properly functioning machine is an important component in achieving excellence in mammary health. Cold weather often seems to accentuate the role of the machine in udder health. Most Ohio farms could probably benefit from a greater investment in preventive machine care.

  2. Fast Changing Feed Markets Bring Opportunities

    Dr. Normand St-Pierre, Dairy Management Specialist, Ohio State University

    The abrupt swing in the protein market, compounded with the bovine spongiform encephalopathy (BSE) case in Washington, has brought substantial changes in commodity prices. In these instances, some producers prefer to keep purchasing the same feed components, arguing that consistency in a feeding program is conducive to higher milk production. Although there is little doubt that ration variability affects performance, one should not confound variability (changes in nutrient density) with ingredient substitution (changing the source of nutrients). Using good nutrition practices, substantial savings in feed cost can be achieved by exploring the feed market for sources of nutrients. As usual in this column, we used the software SESAME to compare 28 feed commodities available in Ohio and partition them into three sub-groups: bargain feedstuffs, break-even feedstuffs, and overpriced feedstuffs. To do so, we priced the five most important nutrients from an economic standpoint in dairy diets: net energy lactation (NEL), rumen degradable protein (RDP), digestible rumen-undegradable protein (D-RUP), effective neutral detergent fiber (e-NDF), and non-effective neutral detergent fiber (ne-NDF).

    Compared to November 2003, prices of nutrients show (Table 1):

    1) No change in the price of energy, which remains at a level modestly high from a historical basis,

    2) A 50% drop in the cost of RDP, now being moderately high,

    3) A significant increase of approximately $0.06/lb for D-RUP (representing an approximate increase of $0.12 to $0.15/cow/day in nutrient costs),

    4) No change in the cost for ne-NDF, which is about priced at its historical average, and

    5) A modest increase of $0.01/lb for e-NDF, which is priced a bit above its historical average.

    In Tables 2 and 3, we report the results for all 26 feed commodities. The lower and upper limits mark the 75% confidence range for the predicted (break-even) prices. In short, feed ingredients can be grouped as follows in January 2004:

    At Breakeven
    Bakery byproducts
    Brewers grains, wet
    Corn, ground, shelled
    Corn silage
    Distillers dried grains
    Gluten feed
    Brewers dried grains
    Alfalfa hay (20% CP, 40% NDF)
    Whole cottonseed
    Gluten meal
    Expeller soybean meal
    48% soybean meal
    Wheat bran
    Wheat middlings
    Beet pulp
    Canola meal
    Citrus pulp
    Meat meal
    Soybean hulls
    44% soybean meal
    Roasted soybeans
    Blood meal
    Fish meal

    These results do not mean that you can formulate a balanced diet using only feeds in the bargains column. Feeds in that column offer savings opportunity, and their use should be maximized while respecting nutritional constraints, as well as other restrictions such as storage space, inventory turnover, etc.

    Table 1. Estimates of nutrient unit costs.

    Nutrient name
    NEL - 3X (2001 NRC)
    Digestible RUP
    Non-effective NDF (ne-NDF)

    - A blank means that the nutrient unit cost is likely equal to zero.
    - ~ means that the nutrient cost may be close to zero.
    - * means that the nutrient cost is unlikely to be equal to zero.
    - **means that the nutrient cost is most likely not equal to zero.

    Table 2. Calibration set.

    Actual ($/ton)
    Predicted ($/ton)
    Lower limit ($/ton)
    Upper limit ($/ton)
    Alfalfa Hay, OH Buckeye D
    Bakery Byproduct Meal
    Beet Sugar Pulp, dried
    Brewers Grains, wet
    Canola Meal, mech. extracted
    Citrus Pulp, dried
    Corn Grain, ground dry
    Corn Silage, 32-38% DM
    Cottonseed, whole w lint
    Distillers Dried Grains, w sol
    Feathers Hydrolyzed Meal
    Gluten Feed, dry
    Gluten Meal, dry
    Meat Meal, rendered
    Molasses, sugarcane
    Soybean Hulls
    Soybean Meal, expellers
    Soybean Meal, solvent 44% CP
    Soybean Meal, solvent 48% CP
    Soybean Seeds, whole roasted
    Wheat Bran
    Wheat Middlings

    Table 3. Appraisal set.

    Actual [$/ton]
    Predicted [$/ton]
    Blood Meal, ring dried
    Brewers Grains, dried
    Feed urea
    Fish Menhaden Meal, mech.

    These estimates were derived using the software SESAME Version 2.05 written at The Ohio State University. For additional information, please refer to Buckeye Dairy News Volume 5, Issue 2, March 2003.

  3. Using Nutrient Cost to Benchmark Your Nutrition Costs

    Dr. Normand St-Pierre, Dairy Management Specialist, The Ohio State University

    In my regular column, I have explained how we can extract the implicit cost of nutrients from market prices of feedstuffs. In our software, SESAME, we apply this method to compare feedstuffs and determine which ones are bargains and which ones are rip-offs. The method of valuing nutrients yields an additional approach for feed evaluation: one can establish reasonable benchmarks for nutrition costs. Traditionally, this has been measured using feed costs. Although it is reasonably easy to calculate an estimate of feed cost for a group of animals, it is not so easy to establish a benchmark - to estimate a reasonable figure for what feed costs should be. Using the output from SESAME and the publication on Nutrient Requirements of Dairy Cattle from the National Research Council (2001), this can be easily done with reasonable accuracy.

    In Table 1, I prepared a set of estimates for three sets of cows. Cow A represents a Holstein cow typical of a herd with very good production (roughly 25,000 lb of milk/cow/year); cow B is for a Holstein cow in a sub-average herd (18,000 lb of milk/cow/year); and cow C is representative of a Jersey cow in a very good herd (18,000 lb of milk/cow/year). Daily requirements for net energy lactation (NEL), rumen degradable protein (RDP), digestible rumen-undegradable protein (d-RUP), effective neutral detergent fiber (e-NDF), and non-effective neutral detergent fiber (ne-NDF) are basically from NRC (2001), assuming a diet with 21% e-NDF, 9% ne-NDF, and 68% total digestible nutrients (TDN). Unit costs of nutrients and milk component prices are provided in Table 2. The rest is just simple arithmetic. For example, a 1500 lb cow producing 77 lb/day of milk with 3.5% fat and 3.0% true protein requires 34.8 Mcal/day of NEL. A unit of NEL (Mcal) cost on an average 6.63 cents. Thus, the cost of supplying the required energy is 34.8 x $0.0663 = $2.31. The calculations are done in a similar fashion for all nutrients of economic importance. We must also account for the cost of mineral and vitamin supplementation, which is typically around $0.20/cow/day. Hence, the cost of supplying the animal with all required nutrients equals $4.10/day in January 2004. The same calculations done on an animal of lower productivity results in a benchmark estimate of $3.35/day. At a same level of milk production (55 lb/day), the Jersey cow has a higher estimate ($3.81/day) due to additional nutrients needed to support the higher fat and protein concentration in the milk. Thus, the nutritional costs of the lower producing Holstein cow are substantially less than those of the high-producing Holstein cow or the high-producing Jersey cow. So, if one's objective was to minimize nutrient costs (feed costs), lower milk production would be desirable. This illustrates the fallacy of the absolute cost minimizer, i.e., those who try to reduce costs at the expense of production. This becomes clear when we calculate the value of the milk produced (milk gross income) and, finally, the income over nutrient costs (a figure analogous to income over feed costs). The high-productivity Holstein cow yields an income over nutrient costs that is $1.90/cow/day higher than that of the low-productivity Holstein cow. It is not my intent to do a profitability comparison across breeds. Additional factors would have to be considered to make a fair comparison of Holstein versus Jersey cows. Nevertheless, it should be apparent that the high-producing Jersey cow can be very profitable. Relative productivity within breed is probably a much more important factor to overall competitiveness than breed.

    In the next issue of Buckeye Dairy News, we will show you how you can calculate a nutrition cost benchmark for your own herd and diagnose the source of the problem if your costs exceed the benchmark.

    Table 1. Estimating nutrition costs (feed costs) using nutritional requirements and estimates of nutrient costs.1

    Cow A
    Cow B
    Cow C
    Body weight (lb)
    Milk yield (lb/day)
    Milk fat (%)
    Milk true protein (%)
    Expected DMI (lb/day)
    Required NEL (Mcal/day)
    Required RDP (lb/day)
    Required D-RUP (lb/day)
    Required e-NDF (lb/day)
    Expected ne-NDF (lb/day)
    Nutrient Cost ($/cow/day)









    Minerals and vitamins



    Nutrient Cost ($/cwt of milk)
    Milk Gross Income ($/cow/day)
    Income Over Nutrient Costs ($/cow/day)

    1DMI = dry matter intake, NEL = net energy for lactation, RDP = rumen degradable protein,
    D-RUP = digestible rumen undegradable protein, e-NDF = effective neutral detergent fiber,
    and ne-NDF = noneffective NDF.

    Table 2. Unit costs of nutrients and milk component prices, Ohio, January 2003.

    NEL ($/Mcal)
    RDP ($/lb)
    D-RUP ($/lb)
    e-NDF ($/lb)
    ne-NDF ($/lb)
    Milk fat ($/lb)
    Milk true protein ($/lb)
    Milk other solids ($/lb)


  4. Managing Feed Costs for Lactating Cows

    Dr. Maurice Eastridge, Dairy Nutrition Specialist, Ohio State University (top of page)

    Feed costs account for the single highest portion of the variable costs of producing milk. Feed costs usually range from $0.06 to 0.08/lb of dietary dry matter (DM). The cost per cow per day will then depend on DM intake. To relate the feed cost to milk yield, we calculate feed costs per hundredweight of milk, which generally should be < $4.00/cwt. However, the value of the milk will depend on its protein and fat composition (plus some quality indicators). Therefore, we stress the importance of monitoring the income over feed costs (IOFC). With the increased price for protein supplements and the marginal milk prices expected for this year, IOFC should be watched carefully. The goal for IOFC is > $6.00/cow/day. There has been more emphasis recently on monitoring feed efficiency on dairy farms. One of the common methods to calculate feed efficiency is: 3.5% fat-corrected milk (FCM, lb) / DM intake (lb) and 3.5% FCM (lb) = 0.432 x lb milk) + (16.23 x lb milk fat). The desired range for this feed efficiency is 1.4 to 1.6. Our goal is usually to increase DM intake, but if the intake increases without a response in milk yield, then some other positive response should be occurring or the increase in feed costs is not making an economic return. Also, factors other than DM intake may be limiting milk yield, resulting in a low efficiency. A short-term, high feed efficiency may be reflective of excessive body weight loss, which increases the risks for several metabolic diseases. A spreadsheet has been developed at OSU to help manage these aspects relating to feed costs, with a separate spreadsheet available for Holstein versus Jersey cows.


    Planning for Spring Forage Management, Dr. Mark Sulc, Forage Specialist, Ohio State University (top of page)

    The next couple of months provide a good opportunity to plan ahead and prepare our forage management program for this coming spring. The weather patterns the last couple of years have demonstrated the importance of being well prepared in order to have any hope of achieving forage production goals. Being prepared is a key component to timeliness of forage production practices, which is critical to achieving high yields of quality forage. Below are 10 items to consider as you begin preparing for the coming season.

    1) Plan your forage inventory for the coming year and calculate the budget for the forage enterprises. Investigate ideas on reducing costs or increasing income from forages in your operation.

    2) Plan new forage seedings and have contingency plans to meet your forage inventory needs. For example, what will you do if forage stands suffer severe winter injury and need to be replaced? Forage stands sometimes suffer winter injury in Ohio, and advance thought will pay off if it happens this year.

    3) Order seed and supplies for spring plantings. Consider both yield potential and forage quality goals when making variety selections. Study variety performance data from several sources (Ohio Forage Performance Trial data are available, with links to results in other states).

    4) If you buy or sell forages, communicate with your suppliers or customers to update contracts and establish plans for the coming year.

    5) If you utilize contract planting or harvesting services, meet with your service supplier to coordinate plans for the coming forage season.

    6) Order supplies such as fertilizer, herbicide, pesticides, and fencing according to anticipated needs. Nitrogen fertilization is especially critical to good production of grasses and should be applied early in the spring when grasses begin to grow and soils are suitable for transport of equipment. Potassium and phosphorus topdressing should wait until after the first harvest, when soils are firmer. Soils release more potassium after winter, so topdressing potassium later after the first harvest reduces the potential for elevated levels of this nutrient in the spring harvested forage. Always base fertilizer applications on current soil test results.

    7) Begin routine maintenance and repairs on forage planting and harvesting equipment. Order parts for haybine or disc mowers, choppers, and rakes or tedders. Order supplies such as twine, balage wrap, inoculants, etc.

    8) Frost seed legumes into small grains or pastures in late February to early March.

    9) If you utilize grazing, carefully consider what adjustments you will make to your grazing management during the coming season. How will you manage that spring flush of forage growth so as to maintain high quality pastures throughout the season?

    10) Keep snowmobiles and other traffic off alfalfa stands during the winter.

    Although the disease has been recognized since at least 1895, Johne's disease is now considered a major disease problem for the cattle industry. Current estimates from the USDA place the prevalence of the disease at about 22% of dairy herds and 8% of beef herds. These are conservative estimates. As evidence of the concern expressed by the livestock industries about this disease, in 2003 the USDA made available about $20 million to the states for Johne's disease control efforts. It is likely that there will be similar funding for the next fiscal year.

    Why all this concern? Johne's disease doesn't cause high death losses like the bovine respiratory disease complex (shipping fever) or reproductive losses like another important disease, bovine virus diarrhea (BVD). Johne's disease is a chronic infection that usually enters the herd silently, but once it is established, it may affect a large proportion of the herd and cause production losses, premature culling, and loss of marketability of breeding stock. The infection is incurable, and eradicating it is very difficult, time consuming, and expensive.

    Johne's (pronounced Yo'n-ees) disease is a chronic bacterial infection of the intestines that affects all ruminants. It occurs worldwide and is caused by a bacterium called Mycobacterium avium subspecies paratuberculosis (MAP), a hardy germ related to those that cause tuberculosis and leprosy. The signs of the disease in cattle include a chronic watery diarrhea that does not respond well to treatment and progressive, severe weight loss. In infected sheep and goats, diarrhea usually does not occur, or only occurs sporadically, and severe weight loss is the predominant sign. Most cattle become infected with MAP in the first few weeks of life, but they do not develop signs of the disease until at least two years later. Animals as old as 10 or 12 years-of-age may show signs of the disease, but the usual age is 2 to 6 years old. In cows, the disease frequently shows up after the stress of freshening, and beef bulls often begin to show signs after the breeding season. Unfortunately, infected animals may shed MAP in their manure for months to years before the signs of the disease are obvious.

    Infected animals often shed billions of MAP in their manure daily, and it may only take a few thousand to infect a calf. The MAP can survive in the environment for about a year. The key to control of the disease is sanitation and preventing young animals from ingesting the bacteria. Recommended control practices include:

    • Reduce environmental contamination by identifying infected animals and culling them from the herd.
    • Provide clean, well-drained areas for calving. Dirty udders and cows are sources of MAP for the young calves at the time they are most susceptible.
    • Calves should be removed from the calving area a soon as possible and placed in clean rearing facilities.
    • When possible, raise heifers separate from adults. Adult cattle represent potential carriers of infective bacteria. Do not spread manure on heifer pastures.
    • Isolate unthrifty animals or animals with diarrhea until a diagnosis is made or until the animal is culled.

    If you do not already have Johne's disease, DON'T BUY IT. Ask about the status of a seller's herd before purchasing if possible. Purchasing animals from herds participating in a testing program, such as Ohio's Johne's Disease Test-Negative Status Program, and finding out how long they have been testing is far, far less risky than buying from herds with unknown status.

    A series of meetings are being held around Ohio this winter in an effort to inform producers about this disease and the programs available in our state for testing and control. Topics to be covered include symptoms and description of Johne's disease, methods of prevention and control, testing procedures, and regulatory issues regarding the disease. The speakers will be from the ODA, the USDA, Extension, and producer members of the Cattle Health Advisory Committee to the ODA. These meetings will be held both in the afternoon and evening at some sites.

    Date and Location

    March 9, 2004
    12:30 - 3:00 pm
    Salem First United Methodist Church
    244 S. Broadway
    Salem, OH


    7:00 - 9:30 pm
    Millcreek Metroparks Mahoning County Farm
    McMahon Hall, 7574 S R 46
    Canfield, OH

    Ernie Oelker, (330) 424-7291, oelker@ag.osu.edu
    Dianne Shoemaker, (330) 263-3831, shoemaker.3@osu.edu


    March 10, 2004
    1:00 - 3:30 pm
    Fisher Auditorium
    Ohio Agricultural Research and Development Center
    Wooster, OH
    Tom Noyes, (330) 264-8722, noyes.1@osu.edu
    Terry Beck, (330) 264-8722, beck8@postoffice.ag.ohio-state.edu
    Roger Amos, (419) 281-8242, amos.1@osu.edu
    Dean Slates, (330) 674-3015, slates.1@osu.edu
    March 15, 2004
    12:00 - 3:30 pm
    Knights of St. John Hall
    Maria Stein, Ohio
    Food will be served and a registration fee will apply

    Joe Beiler, (419) 586-2179, beiler.1@osu.edu
    Roger Bender, (937) 498-7239, bender.5@osu.edu
    Woody Joslin, (937) 498-7239, joslin.3@osu.edu
    John Smith, (419) 738-2219, smith.132@osu.edu
    Steve Foster, (937) 548-5215, foster.99@osu.edu


    March 15, 2004
    7:00 - 9:30 pm
    Shelby County Extension office
    810 Fair Rd.
    Sidney, Ohio 45365-2949

    Joe Beiler, (419) 586-2179, beiler.1@osu.edu
    Roger Bender, (937) 498-7239, bender.5@osu.edu
    Woody Joslin, (937) 498-7239, joslin.3@osu.edu
    John Smith, (419) 738-2219, smith.132@osu.edu
    Steve Foster, (937) 548-5215, foster.99@osu.edu

    March 24, 2004
    7:00 - 9:30 pm
    Highland County (Location to be announced)
    John Grimes, (937) 393-1918, grimes.1@osu.edu
    Jeff Fisher, (740) 947-2121, fisher7@postoffice.ag.ohio-state.edu
    Ray Wells, (740) 702-3200, wells.1@osu.edu


  5. New Environmental Resources

    Dr. Maurice Eastridge, Dairy Specialist, Ohio State University (top of page)

    The Ohio Livestock Coalition and associated partners have recently released two publications that can be very helpful to dairy producers and they can be printed from the web:

    1) Guidelines for Livestock Operations (http://www.ohiolivestock.org/images/1_livestock_guidelines03.pdf) - The purpose of the 23-page booklet is to help individuals better understand the types of regulations, rules, permits, and plans that may be required of certain farming operations. The roles and contact information for various agencies are provided.

    2) It takes Two to be a good Neighbor (http://www.ohiolivestock.org/images/It%20takes%20two1.pdf) - This 2-page document was designed to help livestock farmers and rural residents/country dwellers to realize that each have a responsibility to be neighborly in the community. Tips for each party are outlined, and some typical farming practices are described.