Sheets - 1998 Herd Production Medicine
Last Updated 08/22/99 JM Gay 3/98
Objectives: For you think about the herd
aspects of the problem that you select in all of its dimensions and complexity, organize a
logical approach to that complexity and, in the process, learn a lot about that problem.
Goal: A concise, logically organized several page guide for the
practitioner and fellow students. Assume that the audience for these is reasonably
familiar with the topic from an individual animal perspective but is almost completely
unfamiliar with the topic from a herd perspective and has limited time to spend learning
Focus: The veterinarian's role in detecting, solving, managing
and preventing problems, including a hierarchical approach to monitoring procedures, in
groups of livestock beyond that in the individual animal. Target northwest herds in terms
of nature of the problem, management, housing and diet.
Outline of Topic Sheet:
Remember that the following outline suffers from my attempt to
generalize it to all herd situations, which range from endemic to epidemic outbreaks of
infectious disease problems, production diseases such as displaced abomasums or
hypocalcemia, prevention as well as detection and control, and suboptimal production
problems such as low conception frequency or low production. Thus, not all of the
following questions or points may be relevant to a particular problem and other important
questions may be missing.
For uniformity of appearance, please use the following headings
in your topic sheets.
(See examples below)
- Problem Name:
Economic Impact and Intervention Cost-Benefits:
A brief, concise description of the different manifestations of the
problem in herds, its between herd (what proportion of herds are affected?) and within
herd prevalence (what proportion of animals at risk within a herd are affected?) including
typical clinical to subclinical ratios, major risk factors, biological pathways and
mechanisms. Focus on those items related to controllable risk factors, critical control
points and interventions.
How is the problem typically manifested? What are the management
target values (what should we aim for?) and what are the alarm values (at what levels
should we initiate a special investigation?)? What are the major risk factors for the
problem, especially those directly under management control?
You may wish to create a diagram showing the causal relationships
Herd Problem Workup Strategy:
The forms of economic impact are usually 1) lost production, 2)
reduced herd longevity, 3) reduced salvage value, 4) treatment costs, 5) prevention costs,
and 5) death loss. What is the economic justification for the producer to control or
prevent this problem in their herd? This is crucial information. Industry-wide loss
estimates are useful for policy makers but not for decisions at the herd level. How much
does the problem typically cost per affected animal? Because prices vary, this is best
stated in the units of production (e.g. lbs. of milk, lbs. of gain, no. of calves weaned).
What are the costs and benefits of potential interventions? How much does it typically
cost per affected animal in the subclinical and in the clinical forms? How sound is this
Herd Problem Prevention:
If a herd is in a crisis, what is the logical hierarchy of steps
steps to diagnosing and solving the problem? What are the potential risk factors? How are
the potential risk factors that are causing the problem in that particular herd
discriminated from those that are not? What previous performance data is useful? How can
information from this data be generated, particularly in the absence of a good production
accounting system with complete records? Which animals and how many should be examined (if
any)? What parts of the livestock premises, management or diet? What tests if any should
be done? What are the costs of these? If specialized tests are required, who performs them
and how can they be contacted? How do these tests perform in an outbreak situation in
terms proportions of true positives, false positives, true negatives and false negatives?
How do they perform in an endemic situation with a high proportion of subclinically
affected compare to clinically affected animals?
You may wish to diagram the logical approach to the workup as a
tree, the branches dependent on what you find at each decision point.
Herd Monitoring Procedures:
What are the management procedures necessary to prevent the
problem? How strong is the evidence for these (e.g., based on valid scientific studies,
subjective observation, or conjecture)? What is the optimal prevention strategy or
strategies? What is the cost-benefit of these? If procedures such as vaccination are
available, what is the efficacy of these? Are these based on randomized controlled field
What should be monitored to determine if control or prevention
procedures are functioning sufficiently to minimize economic losses from the problem? How
strong is the evidence for the efficacy of these? What is the logical hierarchy of the
best monitoring strategy? What is the cost of the monitoring procedures versus the value
of the information gained? If special software or equipment is required, what does it cost
and where can it be obtained?
You may wish to diagram the logical monitoring hierarchy as a tree, the
critical control points with the broadest coverage being nearest to the trunk and the
underlying critical control points being more distant branches.
If individual testing is involved, how many individuals in an at-risk
group should be tested? How frequently? How do these tests perform in a monitoring
situation in terms proportions of true positives, false positives, true negatives and
false negatives? How strong is the evidence for the validity of the tests? What is the
cost of this testing versus the value of the information gained?
If the problem is infectious, what is the optimal method of certifying
that the herd is free from the infection?
Specialized Skills, Knowledge and Equipment:
What are the critical control points for the problem? How can they be
monitored efficiently and economically?
What special skills or techniques are needed by the veterinarian to
carry out either diagnostic work-up or ongoing monitoring procedures? Where and how can
the practitioner learn these skills? What are the key literature and internet references
What equipment is needed? What does this cost and where is it obtained
(include address and phone number of manufacturers if not readily available)?
Names of Resource People:
A carefully selected set of the best internet materials, papers and
book chapters on the problem that if read will enable the practitioner to answer in the
shortest time the above questions and to motivate their client. Include a short summary of
the essential information in each and a succinct evaluation of the strength of evidence of
each. Is it based on valid scientific evidence or less strong evidence? Internet materials
are especially valuable for practitioners because they are immediately available at no
cost. However, they can also vaporize in an instant. Journal papers are the next best
because they can be faxed from libraries within several days of request but at a cost.
Books must be purchased, are usually not current even at the time of publication (due to
the time lag between the writing and the publishing) and may have gone out of print.
A list of currently active practitioners, academicians, extension
personnel, private consultants and others with special expertise on the topic as evidenced
by their publications, public presentations or consulting activity.
Cite all other sources used to answer the above questions, using a
citation style similar to JAVMA's for the references. To avoid the necessity of
renumbering when references are changed or moved in your text, I recommend that you use
the (author, year) style in the text and order your reference list alphabetically by
author's last name. The purpose is to provide more background material for those who want
to dig deeper than the annotated bibliography and to enable them to check the sources of
your statements. Provide URL's for any relevant materials that are located on the
Procedure and Timelines:
I intend that this be a group project that everyone participants in and
that everyone benefits from. The primary group will be responsible for authoring the topic
sheet. Everyone else will provide feedback to the authoring group on the first and second
drafts. I will grade the final draft. My primary objective is to have you think about the
herd aspects of the problem that you select in all of its dimensions and complexity and
that you organize a logical approach to problem workup and knowledge.
Select a major problem affecting a type of operation that involves herd
monitoring and veterinary interventions to solve production and management problems in a
group of animals. The following is certainly only a partial list. Although you are free to
propose a variation on any of the following or one that isn't on the list, be sure to okay
it with me before getting too far into it.
With each problem are some focus questions or points intended to get
you started thinking about the problem. These are not exhaustive and do not necessarily
identify all the important dimensions of the problem that are important to consider.
BVD herd problem detection, management and prevention
"How do I get it out of a herd once it is there? What tests do I use on which
animals already in the herd how often? How do I keep it out? Which vaccines do I use, if
any, on what schedule given to which animals? What procedures do I use on incoming animals
to prevent re-introduction?"
Johne's disease detection, management and prevention
"How do I go about getting it out of a herd? Do I test and, if so, with which test
on what animals how often? What are the benefits and pitfalls of testing? How do I
resonably certify that a herd is disease-free? What management practices will enhance herd
biosecurity, with respect to both introduction into the herd and transmission within the
Declining or low (compared to industry targets) per cow per day milk production
Transition cow feeding and grouping management to minimize endemic problems of
hypocalcemia, lactic acidosis, ketosis and displaced abomasum.
NEFA's, rumenocentisis, MUN's, urine pH, balancing forage macrominerals, body condition
scoring and management, ration balancing and feed delivery management, forage particle
Stall design with dimensions, bedding material selection and
management, feeding timing and management, cow flow at milking time, maximum standing time
and maximum time away from feed and water for individuals, environmental factors
(ventilation rates, temperature and humidity levels), alley and pen surfaces,
recommendations on design specifications such space per cow, stalls per cow, lockups per
cow, bunk space per cow, air exchange per cow, waterers per cow.
"How do I determine if cows are or aren't comfortable and if they aren't, how do I
go about identifying what factors are causing the discomfort and then solving the
Contagious mastitis outbreak control and continual reduction of endemic infection
(mycoplasma, S. aureus)
Milking time hygiene, bulk tank monitoring, milk quality maintenance, milking machine
evaluation and monitoring
Environmental mastitis outbreak control and prevention
Milking practices, bedding type and management
Dairy calf BRD management and prevention
Colostrum management, housing, weaning and grouping strategies, selection and timing of
Declining or low (compared to industry targets) weaning weight per day of age
Perinatal calf mortality / weak calf syndrome
Weaning BRD management and prevention.
"What is the optimal weaning management program? What when?" Selection and
timing of vaccinations is always a major question that producers ask.
Preconditioning for retained ownership through feedlot
"What is the optimal vaccination and management program for beef calves going to a
How do you detect the problem, how do you eliminate it and how do you prevent it?
Select your problem and your groups. By Tuesday, March 3rd,
tell me what problem you are working on and who you are working on it with.
Begin by familiarizing yourself with the problem as described in
major textbooks such as Smith Large Animal Medicine, Radostits Herd Health,
Radostits Veterinary Medicine. Check for any relevant issues of Vet Clinic of
North America. Identify the current major clinical papers by using Cornell Consultant.
Using Medline, VetCD and the Guelph listing of table of contents, identify the relevant
applied clinical papers dealing with the problem. Read through your selected papers,
paying particular attention to answering the questions above. Identify the important
aspects of the problem, particularly those things related to management.
If you find one or more papers that summarize most of the above
information, verify the author's conclusions by checking the references in the paper as
well as other references that you locate. In your estimate, what is based on
objective scientific evidence and what is based on subjective observation, hypotheses, and
dogma? Sometimes the later is all we have but it is important to recognize when the
supporting evidence we are using is weak.
If you can't find information that you need, state what is needed and
why, and how you might go about determining it for individual operations (such as clinical
First draft due by 5 PM Friday, April 3rd in with
copies for the rest of the class in their mailboxes and to me either at my office (116S
South McCoy) or in my mailbox in the VCS Department Office in McCoy Hall. Using the
questions similar to the following, everyone in the class will review and provide comments
back to the authoring group.
Overall, does this topic sheet provide me sufficient specific
information and references to begin developing confidence to tackle problems of this
nature in herds in the Northwest? Is the information specific enough? For example, is
sufficient detail present that the reader could go to an affected herd and set up a
successful monitoring program?
Is the causation evidence and the workup and monitoring approaches
organized in a concise logical, hierarchical fashion? What important aspects of the
problem are missing or don't receive sufficient emphasis? What statements may be in error?
Of the above items, what needs to be developed further and what could be reduced? Was the
search for relevant materials thorough? Are any important resources missing? Is the
synopsis consistent with these materials? Does it resolve areas of disagreement between
Another question for guidance is "Is this of sufficient quality
that it could be published in The Bovine Practitioner?" If not, why not? For a senior
Comments provided back to the authoring group by everyone in the class on Tuesday,
Second draft is due on 5 PM Friday, April 17th to
classmates and to me, along with a disk copy that includes one of the group's e-mail
address and is in a format that is in or will translate to Microsoft Word 7.0. I will
convert these to RTF (Rich Text Format) and will load them onto the class Internet website
using Microsoft Frontpage. At that time, I will invite comments from bovine practitioners
and academic clinicians. If you are concerned about this aspect, please discuss your
concerns with me.
Comments returned to groups by Tuesday, April 21st.
Final draft incorporating suggestions from the website is due in
class on Tuesday, April 28th, along with 1) final copies for evaluation
by the class, 2) a disk copy as above for final posting on the website and 3) copies for
me of the comments that you received via e-mail.
Final evaluation and grading of topic sheet. The evaluation will be
along the lines of the questions in the fourth step.
Your input, comments and questions are welcome at
anytime in person in my office (116S South McCoy), in class, via e-mail or by telephone.
If these dates conflict with other major events, such as exams, please let me know what
date will work better. If I can help you with any part of this assignment, don't hesitate