North Dakota State University
NDSU Extension Service
Vol. 10, No. 2, June 2000
Editorial
Coming Events
Forage
Management
Reproduction
Environment
Nutrition
The annual "June is Dairy Month" promotions are among just a few of the events slated for June 2000. Among them, a Dairy Summit has been planned for June 22 in Jamestown to coincide with the Midwest ADA meeting, North Dakota Milk Producer's board of director's meeting and of course, the Dairy Princess contest. As you prepare for the coming summer season, be sure to mark the dates below on your calendar. Note that the State Dairy Show is a week later than usual.
Regards,
J.W. Schroeder
Extension Livestock Specialist
June 21 Midwest Dairy Association Annual Meeting, Gladstone Inn, Jamestown
June 21 N.D. Milk Producers Association, Gladstone Inn, Jamestown
June 22 North Dakota Dairy Princess Coronation, Gladstone Inn, Jamestown
June 22 North Dakota Dairy Summit, Gladstone Inn, Jamestown
June 29-July 2 State Dairy Show (note date change) Stutsman County Fairgrounds
The latest research on alfalfa quality at North Dakota State University is showing that in wetter years, making harvest decisions based on plant height and plant maturity rather than on plant maturity alone may result in a consistently higher relative feed value (RFV) in the field — which translates into higher-quality alfalfa in the bale.
"In order to be considered prime hay, alfalfa in the bale must have an RFV of 151 or greater," explains Dwain Meyer, NDSU plant sciences professor. "The reason we shoot for an RFV of 175 to 180 in the field is because wilting, harvesting and storage can lower RFV by 25 to 30 points."
In trials during the past few years, Meyer has taken first cuttings on dryland plots at
the late-bud stage and discovered that the alfalfa had an average RFV of 125 in the field,
a value about 50 points lower than the in-field RFV goal. He attributes the lower quality
to above average rainfall, which has resulted
in more robust early growth of alfalfa plants, in the form of taller plants.
"The taller the plant gets, the earlier you need to harvest," Meyer says. "A first harvest at the late-bud stage in wetter years, or under irrigation, will be too late."
Based on his data, Meyer says that alfalfa producers managing a three-cut system should consider taking the first harvest no later than the late-vegetative or early bud stage if the stem height of the tallest alfalfa plants is nearing 30 inches. But if the first alfalfa growth is much shorter, then producers should postpone their first harvest, probably until the late-bud stage.
"Generally, dryland alfalfa may reach only 15 to 20 inches and it is not uncommon for the third crop of irrigated alfalfa to reach only 20 inches in height," Meyer says. "So in these situations, harvest can occur at a later growth stage, probably near the mid-flower stage, or about 20- to 50-percent bloom. At this stage, producers could still expect to harvest prime hay."
To determine plant height and maturity stage (pre-harvest alfalfa quality), producers should take samples from five representative 2-square-foot areas in fields of 30 acres or smaller and add one or two samples for every additional 10 acres in larger fields. Measure the height of the tallest stem, not the highest leaf. Meyer says the tallest stem may not be the most mature stem.
Meyer offers the following visual indicators for determining alfalfa maturity:
Late vegetative: stem is taller than 12 inches, but there are no visible buds or flowers.
Early bud: one or two nodes have visible buds, but there are no flowers or seed pods present.
Late Bud: more than two nodes have visible buds, but there are no open flowers or seed pods.
Early flower: one node is present with at least one open flower.
Late flower: two or more nodes have open flowers.
In summary, Meyer says, "Many producers take the first harvest too late to obtain quality hay in years with good moisture. Harvest should begin in the late-vegetative to very early bud stage. Conversely, several producers take the third harvest too early. Harvesting at the mid- to late-bloom growth stage can produce prime hay when the growth of the plant is less than 15 to 16 inches in height. In short, adjust the maturity stage at which harvest begins based on the height of the plant."
Dairy producers can't do much about the weather, and mechanical breakdowns may come at a bad time, but there are three factors they control to make good silage. It has been suggested the three most important things to do a good job of preserving silage are (1) rapid removal of air, (2) rapid production of lactic acid that results in a rapid lowering of pH and (3) continued exclusion of air from the silage mass. In other words, (1) fast and adequate packing, (2) addition of bacterial inoculants and (3) rapidly covering the silage.
As speed of filling silos increases, more attention needs to be made to adequate packing. Researchers have observed that packing time usually ranges from one to four minutes per ton of chopped forage for delivery rates less than 30 tons (as fed) per hour. Packing time was consistently less than one minute per ton (as fed) at delivery rates above 60 tons per hour. They suggested using a shallow packing layer (less than 6 in.) and heavier tractors to maintain good packing with fast filling. The shallow packing layer is particularly important to reduce the dry matter (DM) loss of the top 3-5 feet of the bunker or pile silo.
The use of bacterial inoculants for improved silage fermentation has increased in the last few years. Part of this is probably due to research and development by (or sponsored by) companies manufacturing the bacterial inoculants that have resulted in improved product at the farm. This includes improvements in packaging and storage to assure a viable culture at the time of use. It is assuring to make spot checks on products before use to determine viability.
Research has indicated that bacterial inoculants increase the rate and extent of the silage pH drop by improved lactic acid production. This quick reduction in silage pH helps limit the breakdown of protein in the silo by inactivating plant proteases. It also inhibits the growth of undesirable anaerobic microorganisms such as enterobacteria and clostridia.
A summary of more than 200 laboratory-scale silage trials at Kansas State University that involved nearly 1,000 silages and 25,000 silos indicated that bacterial inoculants were beneficial was about two times greater than for corn.
All bacterial inoculants are not the same, and methods of incorporating them differ considerably from trial to trial as well as from dairy to dairy. Viable inoculants must be purchased and should be stored in the shade in the coolest area possible. The most consistent method of application is at the chopper, if care is taken that spray nozzles aren't plugged. Liquid solutions should be used preferably within 24 hours.
Covering silage bunkers, piles and pits is commonly done now even though it is not a simple fete. Without covering, losses in the top 2-4 ft. of the silo can exceed 50%. The top 3 ft. of a silo that is covered may have a 20% loss. At $25 per ton for the silage, the increased 30% loss equals $7.50 per ton. Labor and cost of material will equal about $1.50 per ton of this top layer, leaving a net of about $5 per ton.
Surface spoilage should not be fed. Whitlock et al. (2000) compared 90% corn silage, 10% concentrate rations in which the silage portion contained 100% normal and 0% slime: 94.6% normal and 5.4% slime: 89.3% normal and 10.7% slime and 84% normal and 16% slime. Increased levels of the spoiled material reduced intake and digestibility of fiber and protein. They also reported that the spoiled silage destroyed the forage mat in the rumen.
Increased size of silage bunkers, piles and pits has led to an increased rate of filling. Larger, higher piles mean that the lower protein of the silage will have good density and excellent air exclusion. Particular attention needs to be paid to packing the top 3-5 ft. to eliminated spoilage in that portion.
As more data accumulate, and possibly as bacterial inoculants improve their use, for improving silage fermentation has increased. Bacterial inoculants should be purchased from companies that have done extensive research and development on their product. Bacterial inoculants must be viable to be effective and must be uniformly distributed throughout the silage for maximum benefit. Handled correctly, bacterial inoculants pay with $10 milk and pay better with $13 milk.
It pays to cover silage with 4-6 mm white plastic containing ultraviolet light protection. Spoiled silage should not be fed — especially to the transition cow if it destroys the forage mat in the rumen.
Source: Dr.Ray Hinders, Feedstuffs, Vol. 72, No. 19. May 6, 2000
reproduced with permission
When trying to improve a herd's performance, we tend to look at the cows, but what about inspecting the manure? No matter what they tell you, it doesn't just happen. Combined with performance information, manure gives an excellent snapshot of what the cows actually ate, and what they did with their ration. Manure inspection is pretty straightforward: 1) see what it looks like where the cows are, and 2) see what's in it.
Walking out among the cows, if you see:
The above signs typically come from cows eating too little effective, chewable fiber, and too much grain. It means that cows are sorting their feed, are choosing to eat more grain than roughage, or that there was not adequate fiber in the diet to start with. These symptoms are often seen during heat stress. Getting the cows to eat enough effective fiber can encourage rumination, hold feed in the rumen longer to be fermented, improve performance, reduce digestive upsets, and improve feed efficiency.
Next, get samples from different cow pies in a given group, and bring them back to where you have a hose and a fine mesh (~1/6" openings, 7-8" diameter) kitchen strainer. Place the manure sample in the strainer, and carefully rinse it until the water runs clear. If you see much fiber longer than ½", undigested corn stalks, much ground grain, whole cottonseed or hulls with the lint still intact, or undigested citrus pulp, the cows are having digestive problems. Often, it relates back to a lack of fiber. The "best" manure contains fine fiber particles and little grain. The fine fiber particles mean that the forage stayed in the rumen long enough to be ruminated and digested. With problem manure, the cows are challenging you to figure out how to get them to eat the balanced ration they need.
Source: Mary Beth Hall, Florida Dairy Business, April 1999
For dairy herds that use bulls, either partly or exclusively, in their reproductive program, DHIA records may be useful for evaluating herd reproductive performance. However, this record system is not designed to express efficiency and performance information specifically for natural service programs. In an effort to aid producers and veterinarians, the reproduction committee of the American Association of Bovine Practitioners has published a set of formulas and recommended indices for use in evaluating herd reproductive performance among herds that routinely employ natural service.
Cow to bull ration Formula: Number of open cows exposed to a bull but not confirmed pregnant % (-divided by-)
Number of bulls with access to open cows
The recommended ration is between 20 and 30 open cows per bull. This calculation can be useful for ruling out insufficient bull power as a cause of herd infertility.
Percentage of pregnant cows resulting from natural serviceFormula: Natural service pregnancies X 100 % (-divided by-)
Total pregnancies
This calculation is useful for estimating the contribution of natural service breedings in herds using both natural service and artificial insemination (AI). This parameter requires that conception dates be estimated via palpation so that pregnancies resulting from natural service and AI can be differentiated. High values may signal a problem with some component of the AI program, i.e. semen handling, estrous detection, etc.
Average days open with a bullFormula: Sum of days between `date turned with bull' and `estimated conception date' % (-divided by-)
Total number of cows confirmed to a bull breeding
The recommended value is between 40 and 50 days. Elevated values signal an infertility problem within the natural service program but cannot differentiate between a bull or cow specific problem.
Bull services per pregnancyFormula: For all cows confirmed pregnant to a bull during a specified period... Average of: (conception date - [turned with bull date + 10])
% (-divided by-)
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An estimate of conception rates to the bull can be derived by computing the reciprocal of this figure. This number can then be used to compare conception rates between AI breedings and natural service within a given herd. The `specified period' is typically a per month or per year period.
For additional information on these and other reproductive indices described by the reproduction committee of the AABP, the following reference is recommended. Fetrow J, et al. 1990. Calculating selected reproductive indices: Recommendations of the American Association of Bovine Practitioners. J Dairy Sci. 73-78.
Source: Douglas W. Shaw, DVM, PhD, Extension Veterinarian, Food Animal Reproduction, The Ohio State University
Is there a chance that you are overfeeding phosphorus which could contribute to water pollution? Scientists compared data from the Cornell University dairy farm for 1994 and 1979 and found that increased concentrations of nitrogen (N) and phosphorus (P) in well water over this period was attributed to increased purchases of these nutrients in feed. When more phosphorus is imported in feed or fertilizer than is exported through milk or animals, the excess is lost form the farm as surface runoff or it accumulates in soils.
Cornell milked between 360 to 400 cows over the 15 years. Of five wells located in corn fields, nitrate nitrogen concentration doubled in four of them and increased in the fifth by 40 percent. The N concentration in water from the well located near the center of the heavily farmed area exceeded EPA's accepted standard of 10 ppm. The soil phosphorus level increased in corn and alfalfa fields because of P in manure. Milk yield per cow increased from 14,964 lb. to 22,559 lb. and feed purchased to support the higher milk yield was the major source of increased N and P. Although N and P imports through fertilizer purchases were reduced, feed imports increased the balance of nutrients beyond those needed for milk production.
Scientists at the University of Wisconsin estimate that US dairy producers are feeding about 25% more P than recommended by the National Research Council, who complies nutrient requirements for dairy cattle and other animal species. The published requirements in the US are higher than other countries such as Germany, England, and Netherlands. Many herds feed rations averaging 0.48% P or higher; however, research shows that levels of 0.37-0.40% are adequate for high producing cows without negative effect on milk production, animal health, or reproduction. Lower ration P will reduce P output to the environment which will consequently reduce the amount of land required to spread manure. If you are overfeeding nutrients, there's a very high chance that the excess is working into the water table.
Proper feeding of anionic salts can reduce milk fever and the severity of low blood calcium at calving, says Bill Weiss, dairy nutritionist at Ohio State University (formerly of NDSU). However, anionic salts are not recommended for everyone since they can reduce dry matter intake — and that could increase the incidence of ketosis. Consider using anionic salts if you meet the following criteria:
Dairy Connection, Vol. 10, No. 2, June 2000
NDSU Extension Service, North Dakota State University of Agriculture and Applied
Science, and U.S. Department of Agriculture cooperating. Sharon D. Anderson, Director,
Fargo, North Dakota. Distributed in furtherance of the Acts of Congress of May 8 and June
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North Dakota State University
NDSU Extension Service