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Title Summary Date ID Author(s)
Dairy Management is a Continual Progression Dec 22, 2016
Dairy Pipeline: Activities Dec 22, 2016
Your Dairy History: Tracking Dairy Management Decisions Dec 22, 2016
Making the Tough Call Nov 1, 2016
Dairy Pipeline: Activities Nov 1, 2016
Be careful when cutting corners Oct 31, 2016
Biosecurity: Part II Sep 29, 2016
Dairy Pipeline: Activities Sep 29, 2016
Comparative Nutritional Quality of Winter Crops for Silage Sep 29, 2016
Equipment function affects milk quality Sep 9, 2016
A Fine Line — Biosecurity: Part I Sep 9, 2016
Dairy Pipeline: Activities Sep 9, 2016
Dairy Pipeline: Activities Jul 1, 2016
Alternative Housing: Raising Calves In Pairs Jul 1, 2016
Opportunity For Improving Calf & Heifer Management: More Complete Records Jul 1, 2016
A Current Update On Baleage Technology May 31, 2016
It Has Been A Great Ride! May 31, 2016
Dairy Pipeline: Activities May 31, 2016
A Fresh Look at the Margin Protection Program (MPP) for Dairy May 2, 2016
Dairy Pipeline: Activities May 2, 2016
Yeast and Molds: A Practical Summary for Controlling Mastitis

Mastitis cases caused by yeast and mold are typically sporadic and are usually not a significant issue in a herd. Yeast form white or creamcolored colonies that can easily be confused with coagulase-negative staphylococci. Gram staining will differentiate yeast from CNS; yeast are two to three times larger than CNS and typically exhibit budding. Mold colonies can have a fluffy texture and exhibit several different colors.

Apr 15, 2016 DASC-72P
Trueperella pyogenes: A Practical Summary for Controlling Mastitis

Trueperella pyogenes are environmental pathogens that typically cause an acute, purulent form of mastitis that is sometimes referred to as “summer mastitis.” Trueperella pyogenes are Gram-positive bacteria that can appear like coccobacilli — an intermediate between cocci and bacilli. When plated on blood agar, scant to no growth is visible at 24 hours. However, at 48 hours, tiny, pinpoint, smooth, whitish colonies develop and are surrounded by a narrow zone of hemolysis.

Apr 15, 2016 DASC-71P
Proteus spp.: A Practical Summary for Controlling Mastitis

Proteus spp. are uncommon environmental mastitis
pathogens that have been known to cause outbreaks.
Proteus spp. are Gram-negative and similar in
structure to other coliform mastitis pathogens. Little
is known about how Proteus spp. infect the mammary
gland, however procedures effective in controlling
coliform mastitis pathogens should apply to Proteus
spp. as well. When grown on blood agar, Proteus spp.
have been found to swarm on the plate and spread
across it.

Apr 13, 2016 DASC-68P
Pasteurella spp.: A Practical Summary for Controlling Mastitis

Pasteurella spp. are contagious pathogens that are
seldom reported as a cause of bovine mastitis. Mastitis
caused by Pasteurella spp. usually appears as a
thick, creamy-yellow, viscous secretion, sometimes
with a foul odor. Pasteurella spp. are Gram-negative
and similar in structure to other coliform mastitis
pathogens. Additionally, when grown on blood agar,
Pasteurella spp. have been found to have irregular,
rough colonies that produce a musty odor.

Apr 12, 2016 DASC-67P
Mycoplasma spp.: A Practical Summary for Controlling Mastitis

Mycoplasma spp. are contagious, mastitis-causing
pathogens that do not grow well on blood agar
under aerobic conditions and therefore must
be grown on a selective agar under anaerobic
conditions. Infected cows typically have mastitis in
multiple quarters and exhibit a dramatic decrease
in milk production. A Mycoplasma spp. mastitis
outbreak can be preceded by a respiratory disease
event in bovines of different ages on the farm.

Apr 12, 2016 DASC-66P
Enterobacter spp.: A practical summary for controlling mastitis

Corynebacterium bovis is a contagious, Gram-positive
mastitis-causing pathogen. C. bovis will typically
produce little to no growth on blood agar after 24
hours of culture, but it will show creamy, gray, or
white nonhemolytic colonies at 48 hours. C. bovis is
mildly pathogenic and will usually cause only a mild
increase in somatic cell count and a slight reduction
in milk production. Information in this publication
was summarized from the National Mastitis Council’s
Laboratory Handbook on Bovine Mastitis (Hogan et
al. 1999).

Apr 12, 2016 DASC-65P
Corynebacterium bovis: A Practical Summary for Controlling Mastitis

Corynebacterium bovis is a contagious, Gram-positive
mastitis-causing pathogen. C. bovis will typically
produce little to no growth on blood agar after 24
hours of culture, but it will show creamy, gray, or
white nonhemolytic colonies at 48 hours. C. bovis is
mildly pathogenic and will usually cause only a mild
increase in somatic cell count and a slight reduction
in milk production. Information in this publication
was summarized from the National Mastitis Council’s
Laboratory Handbook on Bovine Mastitis (Hogan et
al. 1999).

Apr 11, 2016 DASC-64P
Coagulase-Negative Staphylococci and Staphylococcus hyicus: A Practical Summary for Controlling Mastitis

Coagulase-negative staphylococci (CNS) and
Staphylococcus hyicus are mastitis-causing pathogens
that originate from skin flora and are generally
considered to be the most commonly isolated
pathogens in well-managed herds. A prevalence of 10
to 15 percent infected quarters is common (Hogan et
al. 1999), but an intramammary infection rate as high
as 43 percent of infected quarters is reported in some
studies (Dufour et al. 2012).

Apr 11, 2016 DASC-63P
Bacillus spp.: A Practical Summary for Controlling Mastitis

Bacillus spp. are environmental, Gram-positive,
endospore-forming pathogens that can cause mastitis.
Bacillus spp. will grow large, slightly gray colonies
with irregular edges that are often surrounded by a
clear zone of hemolysis when grown on blood agar.
Some Bacillus spp. can cause acute and potentially
fatal gangrenous mastitis. Spores from Bacillus are
heat- and chemical-resistant.

Apr 11, 2016 DASC-62P
Aseptic Technique for Milk Sampling and Teat Infusions

Mastitis, or inflammation of the mammary gland, is a production-limiting infection that remains one of the most common and costly diseases in dairy herds. More than 200 different pathogens have been found to cause mastitis in dairy cattle (Blowey and Edmondson 2010). Due to the high treatment costs associated with mastitis, farmers may find value in identifying these mastitis-causing pathogens and then determining the appropriate management decision such as treatment, culling, segregation, and prevention. Milk culturing can be an effective tool for isolating and identifying organisms as well as for providing a snapshot of a herd’s mastitis pathogen status.

Apr 8, 2016 DASC-61P
Pseudomonas spp.: A Practical Summary for Controlling Mastitis

Pseudomonas spp. are environmental mastitiscausing
pathogens that are Gram-negative and similar
in structure to other coliform mastitis pathogens.
Pseudomonas spp. have been isolated from milking
parlor drop hoses and are known to cause mastitis
through the use of water during milking. When grown
on blood agar, Pseudomonas spp. have been found to
smell like grapes.

Apr 5, 2016 DASC-70P
Prototheca spp.: A Practical Summary for Controlling Mastitis

Prototheca spp. are mastitis-causing pathogens that
are classified as colorless algae. Prototheca spp. will
appear on blood agar as creamy-white or grayish-white
pasty colonies after 24 to 36 hours of incubation.
Colonies could be confused with coagulase-negative
staphylococci or yeast but can be differentiated when
Gram staining because Prototheca spp. will exhibit
spherical or oval sporangia with or without endospores.

Apr 5, 2016 DASC-69P
Should We Be Looking at More than IgG Concentration in Colostrum? May 2, 2016
The Skinny on Mud: Why mud and dairy cows don't mix Feb 26, 2016
Dairy Pipeline: Activities Mar 31, 2016
Corn for Silage: Planting density effects on dry matter yields and nutritional composition Mar 31, 2016
Winter Crops as a Feed Source for Dairy Cattle Jun 27, 2016 DASC-85NP
Management of compost-bedded pack barns Mar 11, 2016 DASC-78NP
No More Unnecessary Midnight Calving Pen Checks! Feb 26, 2016
How Much, How Soon? Feb 26, 2016
Dairy Pipeline: Activities Feb 26, 2016
Watch Out For Bad Fat When Battling Milk Fat Sep 30, 2015
Dairy Pipeline: Activities Jan 7, 2016
Are you Delivering A Homogeneous Ration To Your Cows? Nov 3, 2015
Plan Your Forage Utilization For The Coming Year Sep 30, 2015
Raw Milk: Risk Or Reward? Nov 3, 2015
Dairy Pipeline: Activities Nov 3, 2015
Cow Mortality Data Can Provide Useful Management Information Sep 30, 2015
Dairy Pipeline: Activities Sep 30, 2015
Got Dry Corn Silage? Sep 30, 2015
Income Over Feed Costs in the Dairy Enterprise Sep 10, 2015 DASC-51P
Global milk prices lower than in 2009 Aug 5, 2015 DASC-57NP
Manejo del becerro recién nacido - Newborn calf management May 5, 2015 DASC-49
Silo Management, Learning From The Experts Jul 9, 2014 DASC-39NP
A Decision-Making Tool to Determine the Feasibility of Purchasing Virginia Milk Commission Base Jan 10, 2014 DASC-30P
Catastrophic Livestock and Poultry Carcass Disposal Nov 19, 2013 ANR-76NP (ANR-90NP)
Streptococcus agalactiae: A Practical Summary for Controlling Mastitis Jul 19, 2012 DASC-6P
Streptococcus uberis: A Practical Summary for Controlling Mastitis Jul 12, 2012 DASC-8P
Environmental Streptococci and Enterococcus spp.: A Practical Summary for Controlling Mastitis Jul 12, 2012 DASC-7P
Streptococcus dysgalactiae: A Practical Summary for Controlling Mastitis Jul 12, 2012 DASC-5P
Escherichia coli: A Practical Summary for Controlling Mastitis Jul 29, 2011 404-224
Klebsiella spp.: A Practical Summary for Controlling Mastitis Jul 29, 2011 404-223
Serratia spp.: A Practical Summary for Controlling Mastitis Jul 29, 2011 404-225
Staphylococcus aureus: A Practical Summary for Controlling Mastitis Jul 29, 2011 404-226
Nutrient Management for Small Farms Oct 8, 2010 442-305
Staphylococcus aureus Mastitis: Cause, Detection, and Control

Staphylococcus aureus (S. aureus) mastitis is extremely difficult to control by treatment alone. To date, successful control is gained only through prevention of new infections and culling of infected animals. S. aureus organisms colonize teat ends and/or teat lesions. Spread of infection can occur through milkers’ hands, washcloths, teat cup liners, and flies. During milking, irregular vacuum fluctuations can force bacteria up into the teat canal, leading to the potential for new infection. If not culled, infected cows must be segregated from the milking herd and milked last, or milked with separate milking units. A backflush system may help reduce bacterial numbers within the liners, but rinsing units by hand is certainly not recommended.

Jun 11, 2010 404-229
Reference Guide for Mastitis-Causing Bacteria Jun 10, 2010 404-230
Genetic Improvement Using Young Sires With Genomic Evaluations Apr 21, 2010 404-090
Manure Management and Environmental Stewardship Apr 1, 2010 442-309
Poultry and Livestock Manure Storage: Management and Safety Nov 19, 2009 442-308
Selection and Location of Poultry and Livestock Manure Storage

If you raise dairy cows, broilers, layers, turkeys, horses, beef cattle, sheep, goats, alpacas, or swine for income or a hobby, you will have to deal with the manure they produce. The amount of manure produced by the birds or animals you keep depends on their type, age, size, and diet.

Nov 19, 2009 442-307
On Farm Mortality Disposal Options for Livestock Producers Jul 31, 2013 2909-1412 (ANR-77NP)
Selecting a Treatment Technology for Manure Management May 11, 2009 442-306
Addressing the Consequences of Predator Damage to Livestock and Poultry May 1, 2009 410-030
The Role of Milking Equipment in Mastitis

The goal for any dairy farm should be to deliver a high quality product that has consumer appeal. The objective of any heards milk management program should include: (1) maximise yield secreted by the mamary gland, (b) milk cows out in a short peroid of time, (c) prevent damage to teats, teat ends, and the udder, and (d) have no adverse effect on chemical composition of milk. It must be recognized that factors other than milking equipment, such as milking practices, can influence milking performance and quality.

May 1, 2009 404-742
Testing Bulk Tank Milk Samples

Samples of bulk tank milk are collected regularly and milk quality tests are performed by milk coops, plants, or Virginia Department of Agriculture and Consumer Services. Some milk coops offer bulk tank profiles which involve several tests related to milk quality. The various tests are briefly described below, as well as a list of goals for high quality milk and conditions which adversely affect test results. Hopefully, an explanation of the use of these tests will help Virginia dairy farmers produce high quality milk, which has been defined by the Extension Milk Quality Leadership Council as milk with:

May 1, 2009 404-405
Preventing Drug Residues In Milk and Cull Dairy Cows

Preventing drug contamination of milk and meat is the responsibility of every farm. Drug residues can be avoided by a well planned drug use program. There is no way that a milk plant can use contaminated milk. The sale of contaminated milk or meat will cause the responsible party to be subjected to severe penalties, including suspension of permits and monetary loss. Milk with drugs can adulterate a whole truckload or holding tank of milk.

May 1, 2009 404-403
On-farm Tests for Drug Residues in Milk

The presence of drug or antibiotic residues in milk and meat is illegal. Milk supplies containing detectable concentrations are not acceptable. Unless drug residues are avoided to protect milk's reputation as a healthy, safe food, the market becomes jeopardized. Consumers want to be confident that their food supply is free of contamination by herbicides, pesticides, drugs, or antibiotics. Approximately 5-10 percent of the population is hypersensitive to penicillin or other antibiotics and suffers allergic reactions (skin rashes, hives, asthma, anaphylactic shock) at concentrations as low as 1 ppb penicillin. There is concern that small amounts of certain antimicrobial agents may significantly shift the resistance patterns in the microbial population in the human intestinal tract.

May 1, 2009 404-401
Cleaning and Sanitizing Milking Equipment

All milking equipment, lines, and utensil surfaces that come into contact with milk or dirt or manure must be thoroughly cleaned and sanitized before the next milking. Bulk milk tanks also must be cleaned after each milk pickup. and sanitized before the next milking. The purpose of cleaning is to remove milk soils, organic and mineral solids that form on equipment surfaces after the milk is removed. The purpose of sanitizing is to kill residual microorganisms present on these surfaces immediately prior to milking. Inadequate or improper cleaning or sanitizing or both allows bacteria to remain on equipment surfaces and to grow and multiply. This results in elevated bacteria counts in milk

May 1, 2009 404-400
Feeding Protein to Meet Dairy Cow Nutrient Requirements Can Result in Cheaper, Environmentally Friendly Rations

Animal agriculture is facing the significant issue of managing excreted nutrients, and researchers are designing programs to address the issue. The intense management of animals in the poultry, swine, and dairy industries can contribute to environmental pollution. Although there are more beef than dairy cattle in Virginia, beef cattle are typically maintained on pasture and dispersed over a greater area. Feed management in dairy cows to reduce nutrient consumption has been identified as being very effective in reducing output of potentially polluting nutrients such as nitrogen and phosphorus.

May 1, 2009 404-354
The Basics of Forage Testing

In order to have an accurate forage test for ration formulation, it is important to have a representative sample. The method of sampling varies with forage type. Silages (corn or hay crop) can be sampled either at harvest or at feed out. There is a slight reduction in dry matter and increase in fi ber during storage, but it is possible to use the analysis of the fresh material to indicate the quality after ensiling. If sampling fresh material at harvest, it is best to take three to four handfuls from every third load or more and place them in a container with all samples from the same field. Keep it covered to prevent drying. After mixing the composite, a sub-sample can be taken for analysis (only a pint or 100 grams is needed).

May 1, 2009 404-300
Abortions in Dairy Cattle - II: Diagnosing and Preventing Abortion Problems

Abortions can represent a significant loss of (potential) income - an estimated $500 to $900 per case - and present a frustrating challenge to dairy producers and veterinarians. The procedures presented here should help producers and their veterinarians increase the likelihood of diagnosing the cause of any abortions that may occur. In some situations, the prompt diagnosis of an abortion may help reduce the severity of an impending outbreak.

May 1, 2009 404-289
Abortions in Dairy Cattle - I: Common Causes of Abortions

Abortion in dairy cattle is commonly defined as a loss of the fetus between the age of 42 days and approximately 260 days. Pregnancies lost before 42 days are usually referred to as early embryonic deaths, whereas a calf that is born dead between 260 days and full term is defined a stillbirth. A low rate of abortions is usually observed on farms and 3 to 5 abortions per 100 pregnancies per year is often considered "normal." However, the loss of any pregnancy can represent a significant loss of (potential) income to the producer and appropriate action should therefore be taken to prevent abortions and to investigate the cause of abortions that may occur. Each abortion is estimated to cost the producer $500 to $900 

May 1, 2009 404-288
Heifer Inventory and the Economics of Replacement Rearing

Profitability in the dairy business is NOT the herd with the larger milk check, or the greater volume in the bulk tank, but the producer who retains a larger sum of revenues at the end of the month (income minus expenses equals profits). One of the larger expenses incurred on the dairy is replacement heifer rearing. Replacement rearing is second only to feed cost for the lactating cows. In surveys of dairy expenditures, this item accounts for 9 to 20% of the total expenses on the farm. In the authors' experience, producers are seldom aware of what heifers cost to raise, and most producers think that these expenses are negligible. Heifers are a high cost item when expenses are divided among the various enterprises on the farm.

May 1, 2009 404-287
Monitoring Dairy Heifer Growth

Monitoring dairy heifer growth and development will insure that calves are on target to reach a weight of 1350 pounds at calving, with a height of 54 inches at the shoulders, and a body condition score of 3.25 to a 3.5 (5 Point scale) at 24 months of age (Figure 1). Heifers should start lactation with a post-calving weight between 1225 and 1250 pounds; therefore, they will need to add 50 pounds of body weight per month from birth to first calving for an average daily gain of 1.8 pounds per day. Average daily gains of 1.3 pounds per day are too low because they add only 40 pounds per month, resulting in a post-calving weight of 950 pounds. By strategically feeding during specific growth phases, producers can set goals for different months of age, cut expenses, and increase profits for the dairy.

May 1, 2009 404-286
Milk Production Evaluation In First Lactation Heifers

A critical evaluation of production in first lactation heifers once they reach the milking herd is important to determine the effects of the heifer rearing program. This can easily be done by monitoring start-up milk (milk production 0 to 40 days in milk), start-up milk butterfat and protein, and peak milk, peak milk butterfat and protein (41 to 100 days in milk) because these are directly related to heifer development.

May 1, 2009 404-285
Dairy Heifer Health, Disease Control, and Vaccinations

The future of the dairy herd is dependent on the production of superior heifers to replace culled lactating animals. Therefore, it is imperative that the health status of the replacement animal is optimized to present a healthy first calf heifer to the lactating herd. Studies have consistently demonstrated the detrimental effects of pneumonia in calves on age at first calving and on milk production once these animals enter lactation. Calves with respiratory infections were twice as likely to leave the herd and age at first calving was delayed by 6 months when compared with calves that did not experience respiratory disease or pneumonia. In another study, calves treated for scours were three times more likely to calve at 30 months of age or greater.

May 1, 2009 404-284
Nutrition For The Early Developing Heifer

Several factors can dramatically reduce replacement-rearing cost and increase potential profits for the producer: (1) maximizing immunity from colostrum to minimize mortality and sickness, (2) formulating rations for specific weight gains during strategic periods of development and avoiding over-fattening prior to puberty because it impairs mammary development, (3) formulating rations for an average daily gain of 1.8 lb. for Holstein heifers, (4) using AI sires ranking in the top 20% for (PTA$) to optimize genetic improvement, (5) monitoring age, body weight, wither height, body condition score as well as peak milk and ME milk yield of first lactation heifers to evaluate management at first calving, and (5) controlling the size of the replacement herd by calving heifers at 24 months and raising no more than needed.

May 1, 2009 404-283
Early Heifer Development and Colostrum Management

Raising dairy replacement heifers is expensive. In fact, if the dairy is divided into different enterprises (eg. labor, feed cost for lactating cows, facilities, etc.), rearing replacements is the second largest cost, behind feed cost for lactating cows. The percentage will vary from farm to farm, but approximately 9% to 20% of the expenses incurred will involve rearing and developing heifers. Therefore, heifers should represent a sound investment, as their impact on future herd profitability is enormous.

May 1, 2009 404-282
Handling a Herd Mastitis Problem

A herd whose bulk tank somatic cell count exceeds 200,000 or DHI SCC score is above 2.5-3.0, or a herd where more than 3 cows per 100 cows show clinical mastitis over a month's time has a costly mastitis problem because of significant lost milk production and reduced economic returns. Herds with elevated SCC may not have many cows that are clinical, but subclinical mastitis infections may cause permanent destruction of milk secretory cells with permanently lower milk producing ability. In other herds, short duration environmental infections may not have great impact upon SCC, but these cows also have depressed milk yields, and considerable milk may be discarded because of antibiotic treatments. Consequently, dairy herds are losing money through greater culling, increased labor intensity, and greater risk of shipping milk that may be contaminated with antibiotic residues.

May 1, 2009 404-238
Environmental Streptococcal and Coliform Mastitis

Well managed dairy herds with low somatic cell counts (SCC below 200-300,000) often may experience problems with onsets of clinical mastitis. Approximately 40-45% of the mastitis cases in low SCC herds are caused by environmental pathogens which can be difficult to detect because of their short duration. Cows in low SCC herds are most susceptible to environmental streptococci and coliform infections after drying off and just prior to calving but which appear in early lactation.

May 1, 2009 404-234
Understanding the Basics of Mastitis
Mastitis occurs when the udder becomes inflammed because leukocytes are released into the mammary gland in response to invasion of the teat canal, usually by bacteria. These bacteria multiply and produce toxins that cause injury to milk secreting tissue and various ducts throughout the mammary gland. Elevated leukocytes, or somatic cells, cause a reduction in milk production and alter milk composition. These changes in turn adversely affect quality and quantity of dairy products.
May 1, 2009 404-233
DHI Somatic Cell Count Program Guidelines
Somatic cell counts (SCC) from a day's milk is the best indicator of the extent to which the gland is involved in fighting a mastitis infection. The DHI program provides a monthly SCC which identifies those cows with subclinical mastitis. The DHI SCC is highly correlated to losses in milk yield. The DHI SCC program assists dairy farmers in monitoring herd subclinical mastitis status, progress in mastitis control programs such as milking practices or equipment, cow environment and dry cow therapy, and can be used in making decisions regarding cow segregation and culling.
May 1, 2009 404-228
Proper Dry Cow Management Critical for Mastitis Control

According to the National Mastitis Council, using FDA-approved intramammary antibiotics at drying off can decrease the number of existing mastitis infections and prevent new infections during the early weeks of the dry period. Dry cow therapy has the following advantages over lactation therapy: a) The cure rate is higher than that achieved by treatment during lactation, b) A much higher dose of antibiotic can be used safely, c) Retention time of the antibiotic in the udder is longer, d) The incidence of new infections during the dry period is reduced, 

May 1, 2009 404-212
Guidelines to Culling Cows with Mastitis

With the price of milk and the cost of milk production where they have been the past few years, tight control over dairy management decisions will make a significant impact upon farm returns. One decision which will improve profitability is to cull problem cows. A dairy farm's goals should include: (1) Maintaining profitable levels of milk production based upon sound feeding, breeding, and management programs; and (2) An effective herd health program to reduce losses from mastitis and other cow disorders. On most dairy farms, annual culling rates exceed 30-35% of the herd. According to December 1998 DHI summary for Virginia, 36% of all cows enrolled in Virginia's DHI program were culled. 

May 1, 2009 404-204
Distiller's Grains for Dairy Cattle and Potential Environmental Impact

Ethanol is produced when starch in corn grain is fermented. Most other constituents in the grain remain unchanged. The end product of the corn is distiller’s grains or DDGS (distiller’s grains with solubles). The DDGS retain the original fatty acids, protein, and phosphorus. In addition, variability in the grain nutrient content used in the fermentation process and the actual process itself results in a feed with variable nutrient content. Distiller’s grains can be fed either in the wet (less than 25 percent dry matter) or dry (greater than 85 percent dry matter) form. Wet DDGS are difficult to store and must be fed within a few days of production. The wet DDGS can be the most cost-effective, however, if used close to where they are produced.

May 1, 2009 404-135
Paying Attention to Dietary Cation-Anion Balance Can Mean More Milk and Fewer Metabolic Problems

Nitrogen (N) and phosphorus (P) are the two nutrients that cause the most concern with respect to environmental pollution from animal manure. Generally, higher concentrations of N and P in the ration result in their greater excretion in urine (N) and feces (N and P). Overfeeding these nutrients can be a significant problem, particularly if nutrient levels accumulate in the soil and contaminate water sources through leaching or surface runoff. Nitrogen can also volatilize as ammonia and pose a potential environmental problem with air emission standards, which are currently under review. 

May 1, 2009 404-131
Strategies to Reduce Amounts of Nitrogen and Phosphorus in Dairy Rations

Nitrogen (N) and phosphorus (P) are the two nutrients that cause the most concern with respect to environmental pollution from animal manure. Generally, higher concentrations of N and P in the ration result in their greater excretion in urine (N) and feces (N and P). Overfeeding these nutrients can be a significant problem, particularly if nutrient levels accumulate in the soil and contaminate water sources through leaching or surface runoff. Nitrogen can also volatilize as ammonia and pose a potential environmental problem with air emission standards, which are currently under review. 

May 1, 2009 404-130
Tests Available for Measuring Forage Quality

Forage quality has typically been determined by measuring the dry matter, crude protein, fiber, and estimated energy content. Forage testing labs are now able to estimate the actual digestibility of feeds by using newly available tests.

May 1, 2009 404-124
Limit These Feeds in Rations for Dairy Cattle

When feeding lactating dairy cows it is best to limit amounts of certain feeds. Reasons can be problems with palatability, high oil or fat content, and imbalances of certain nutrients. Knowing these restrictions can prevent problems from occurring. Also, combinations of some of these feeds can be a problem if the maximums are used with no regard to type and amount of nutrients that are provided. This is where your nutritionist can be an asset in identifying optimal relationships with consideration for cost of the ration. Here is a list of some feeds used in Virginia and suggested maximums. Remember that these are maximum amounts and not necessarily optimum amounts.

May 1, 2009 404-119
The Income Side of Seasonal vs. Year-Round Pasture-based Milk Production

One issue in the debate on dairy production is seasonal versus year-round milk production. The frame of reference in this debate is seasonal price trends. Farmers historically receive the lowest milk price for milk sold during the six months following spring pasture flush. Conversely, the season's highest price is received during the period of October to January. The driving force behind the current interest in grass-based dairy production is lowering total costs per hundredweight of milk sold by using pasture as the primary source of forage. 

May 1, 2009 404-113
Dairy Crossbreeding Research: Results from Current Projects

Many dairy producers practice some crossbreeding, and the numbers increase every year. Motivating factors include a desire to improve fertility, survival, milk components, and calving ease. Some producers want cows smaller than mature Holsteins. Several large, long-term dairy crossbreeding experiments have been conducted in the United States in the past. Cows involved in previous projects were not the result of intensive selection programs for type and production that produced today’s purebred populations.

May 1, 2009 404-094
Dairy Crossbreeding: Why and How

The Merit indexes are dairy sire selection tools published by USDA that combine genetic evaluations for production, health, fitness, and fertility traits. The indexes are designed to improve the lifetime economic performance of future dairy cows. Periodic revisions include new traits and adjusted economic weights. This document describes the indexes as revised for August 2006. Future changes are inevitable, thus the title “2006 Version.” 

May 1, 2009 404-093
The Merit Indexes - 2006

The Merit indexes are dairy sire selection tools published by USDA that combine genetic evaluations for production, health, fitness, and fertility traits. The indexes are designed to improve the lifetime economic performance of future dairy cows. Periodic revisions include new traits and adjusted economic weights. This document describes the indexes as revised for August 2006. Future changes are inevitable, thus the title “2006 Version.” 

May 1, 2009 404-088
Sire Evaluations for Health and Fitness Traits

Dairy producers have selected for higher milk production for many years. Genetic improvement causes an average Holstein cow born in 2003 to produce over 7,000 pounds more milk in one lactation than her ancestor born in 1960 produced. Type traits, particularly udders and feet and legs, have also improved because of intensive selection. However, the health and fertility of dairy cows cannot be included among these success stories. Genetic trend was responsible for half of a 9-point decline in pregnancy rate in Holsteins between 1960 and its low point in 1995. Dairy-cattle breeders responded by developing national genetic evaluation programs for a number of fitness traits in recent years. 

May 1, 2009 404-087
The All-Breed Animal Model
The all-breed animal model is the genetic-evaluation system used to evaluate dairy animals in the United States. Scientists and technicians at the Animal Improvement Programs Laboratory (AIPL) at Agriculture Research Service in Beltsville, Md., developed and support the system. There are two major differences between the all-breed animal model and the single-breed animal model it replaced:
  1. Accurate genetic evaluations of animals with relatives in more than one breed are now possible.
  2. Animals of different breeds within the same herd are now used together for contemporary comparisons.
May 1, 2009 404-086
Using Heritability for Genetic Improvement

Concepts surrounding the word "Heritability" (frequently represented by the symbol h2) are among the most important that a breeder of dairy cattle should understand. Heritability applies to a single trait measured on animals in a specific population at a given point in time. Estimates of heritability for a trait can differ between breeds of dairy cattle and may change slowly over time. Heritability is estimated from performance records on animals and pedigree information used to establish genetic relationships between those animals. Heritability helps explain the degree to which genes control expression of a trait. Heritability is used to calculate genetic evaluations, to predict response to selection, and to help producers decide if it is more efficient to improve traits through management or through selection. This guideline highlights definitions and uses of heritability and lists estimates of heritability for several important traits in dairy cattle breeding.

May 1, 2009 404-084
Using DHI records to make culling decisions: Lactation Ratings, ERPA's, and Predicted Producing Abilities

Culling decisions affect the profitability of the dairy herd. Feed resources and management skills used to maintain unproductive cows would generate more income if applied to productive cows. DHI records contain important information to help guide culling decisions. This guideline describes three systems for rating cows for production traits. Producers recognize that information about production must be combined with reproductive and health status, age, and other factors to make profitable culling decisions. Suggestions for combining information to make good culling decisions are offered.

May 1, 2009 404-083

The mating of related individuals is called inbreeding. New dairy animals created by AI or natural service inherit a random sampling of the genetic makeup of each parent. If the parents are related, some of the genes transmitted to offspring by each parent will be copies of the same genes found in the common ancestor(s) which caused the parents to be related. As the genetic relationship between parents increases, the likelihood that pairs of genes in offspring are copies of a single gene in an ancestor generations back increases. Such genes are said to be "identical by descent."

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Mycoplasma in Dairy Cattle

Mycoplasma is a tiny bacterium that can cause mastitis, metritis, pneumonia, drooped ears, and lameness in dairy cattle. While this bacterium has existed for more than 100 years, the current disease was first recognized in the 1960s and 1970s, and has only recently become a problem in Virginia. There has been a steady rise in the frequency and severity of disease associated with Mycoplasma in the last ten years. Mycoplasma is a highly contagious disease that can have devastating economic effects on a dairy farm due to decreased milk production, additional veterinary costs, culling of cows, calf loss, and treatment cost. All dairy animals can be infected, including calves, heifers, dry cows and lactating cows.

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Your Herd's Reproductive Status
Maintaining a high level of reproductive efficiency is required if dairy herd profitability is to be maximized. Reproductive performance of a dairy herd is a function of certain management policies and how well these management policies are implemented in the day-to-day management of the herd.

The first step in evaluating the reproductive performance is to identify key measurements and use them as guides in developing or altering herd management policies and practices. The calving interval should be the starting point in evaluation of prior herd performance. For maximum production, a calving interval of 12.3 to 12.8 months must be achieved. When calving intervals vary beyond this range, milk production drops significantly, with a sharp drop when calving intervals exceed 13.6 months. 

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Fencing Materials For Livestock Systems

Good fencing protects and confines valuable livestock by presenting barriers to restrict animal movement. Barriers may be physical, psychological, or a combination of both. Physical barriers consist of enough materials of sufficient strength to prevent or discourage animals from going over, under, or through the fence. Psychological barriers depend upon inflicting pain to discourage animals from challenging a physical barrier of inferior strength.

Traditional livestock fencing materials have included barbed, woven, mesh, and electrified wire, and combinations of these materials. Board fences have also been popular. These conventional materials are still widely used and make excellent fences if properly constructed. However, new materials such as high tensile wire should also be considered when selecting fencing types.

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Bedded-pack Dairy Barns

Bedded-pack barns are an alternative type of dairy housing for producers wanting to upgrade or modernize their milking herd facilities while minimizing capital costs. These barns provide cows with a large bedded pen for resting rather than individual stalls (Figure 1). Bedded pack refers to the mixture of bedding, usually wood shavings or kiln-dried sawdust, and manure on the pen floor. A properly managed bedded pack provides a healthy, comfortable surface on which cows may lie.

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Ammonia Emissions and Animal Agriculture

Agricultural producers are under constant pressure to minimize the impact their management practices have on the environment. Although most environmental concerns related to animal agriculture have focused on water quality during the past two decades, air quality issues have become an increasing concern. Odors have been the main air quality concern related to agricultural animal production. However, ammonia emissions from livestock and poultry operations have recently received significant attention. New air quality standards that cover ammonia emissions in the United States were adopted in 1997. These regulations will have a significant impact on the future of animal production operations. The purpose of this publication is to provide an overview of ammonia production associated with animal agriculture and to explain why it is receiving greater attention from those concerned with environmental quality.

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Site Selection for Dairy Housing Systems

Good site selection is essential for a successful dairy operation. Site selection requires careful planning to ensure that your investments allow you to build towards the future rather than continuing the past. A few essential factors are important to ensure that you have a site suitable for the present and for 20 to 30 years in the future. This publication provides guidelines to make the site-selection process easier.

May 1, 2009 442-096