Recognize important disease prevention practices and understand approaches to dairy herd health programs.. Recognize the importance of good nutrition in maintaining cow health and perfor
Trang 1When you complete this module, you will be able to:
1. Recognize important disease prevention practices and understand approaches to dairy herd health programs
2. Understand principles of recognizing calving problems and appropriately apply proper methods of correcting calving issues and associated diseases
3. Apply management practices to ensure calf survival upon calving and employ systematic methods for early recognition of calf diseases
4. Recognize challenges of disease in the cow herd and be able to implement a systematic method to readily identify sick or at risk cows
5. Understand the rationale for and organization of protocols for treating sick cows
6. Verbalize important issues related to antibiotic usage and implications on food productionpractices
7. Appreciate the importance of preventive disease practices and their application to a dairy farm
8. Recognize the importance of good nutrition in maintaining cow health and performance and integrate application of various disease prevention practices discussed to provide an environment to minimize health issues on the dairy herd
9. Glossary and Conversion Matrix in English
10.
11. Glossary
12. Antibiotic- Therapeutic compound used to kill or inhibit bacterial growth in treating a
disease condition
13. Antibiotic residue - Residual amount of an antibiotic compound or its derivative left in
milk or meat of a treated animal This is not related to resistance
14. Antibiotic resistance - Spontaneous, induced or acquired mutation in bacterial genes
resulting in one or more antibiotic agents no longer being effective in killing or inhibitingbacterial growth This process limits the use of antibiotics in treating disease in humans and animals
15. Biocontainment- Series of management practices used to minimize the transfer of
disease agents among animal groups or areas of the farm
16. Biosecurity - Series of management practices used to prevent introduction of infectious
agents or other disease agents entry to a farm
17. Blemish - A localized lesion (scar tissue) within muscle tissue resulting from an injected
compound inducing an inflammatory reaction An undesired occurrence in meat products for consumption often resulting from inappropriate administration of therapeutic agents
Trang 218. Brucellosis - Infectious disease caused by Brucella abortus that infects cattle and causes
reproductive losses A zoonotic disease that can be transmitted to humans through milk oranimal contact
19. Colostrum - Unique secretion from the mammary when first initiating lactation
Typically contains higher concentrations of energy, protein, minerals and
immunoglobulins
20. Clinical disease - Abnormal health condition where clinical signs shown by affected
animal will be specific to a given insult or cause
21. Dehydration - Disease process resulting from a loss of water from the body, typically
associated with diarrhea conditions
22. Dystocia - Difficult calving (birthing) process
23. Homeostasis - Metabolic regulatory process typically having two counter regulatory
hormones to control stability of a given nutrient (e.g., calcium, glucose)
24. Immunoglobulins - Antibodies formed by the immune system to protect against bacterial
or viral pathogens
25. Intramuscular - Pertaining to injections administered within muscle tissue
26. Intravenous -Pertaining to injections administered within a peripheral vein
27. Mastitis - Infectious disease of the mammary gland (udder)
28. Meconium - First fecal matter in the lower colon of the calf when it is born
29. Metabolic diseases - Unique disease conditions of cows resulting from some altered
process of controlling key nutrients such as glucose (i.e., ketosis), calcium (i.e., milk fever, hypocalcemia) or lipids (i.e., hepatic lipidosis or fatty liver)
30. Metaphylactic - Antibiotics administered to animals at risk for disease at therapeutic
levels
31. Metritis - Infectious disease of the uterus, typically occurs following calving
32. Pneumonia - Infectious disease process of the lungs (i.e., respiratory disease)
33. Postparturient or postcalving - Referring to events occurring after the time of calving,
typically the first few weeks following calving when cows are predisposed to disease events
34. Refractometer - Instrument used to evaluate total protein content of serum, measures
diffraction of light
35. Scours - Infectious disease process characterized by diarrhea
36. Subclinical disease - Abnormal health condition where non-specific clinical signs are
present, typically poor performance, increased disease susceptibility, decreased efficiency
37. Subcutaneous - Pertaining to injections administered under the skin
38. Subtherapeutic - Antibiotic being provided at a low level to promote growth or control
disease This practice is eliminating in an effort to reduce possibility of antibiotic
resistance
39. Transfaunation - Process by which rumen fluid from a healthy cow is transferred to a
sick cow to restimulate the bacterial population of the rumen
40. Transition period - Time frame typically defined as 4 weeks prior to calving through 4
weeks following calving Typically associated with greatest risk for disease of the cow
41. Tuberculosis - Infectious disease caused by the bacteria Mycobacterium bovis A
zoonotic disease that can be found in cattle and transmitted to humans through drinking
of milk
Trang 342. Withdrawl time - Defined period of time following the last administration of an
antibiotic or other therapeutic compound before milk or meat from the treated animal can enter the food chain
43. Zoonotic disease - An infectious disease that can be transmitted from animals to humans
44. Conversion Matrix
45. 1 kg = 2.2 lbs
46. 1 ppm = 1 mg/kg
47. 1 ppm = 1000 ppb
48. Hello, my name is Dr Robert Van Saun and I am a professor of Veterinary Science and
49. an extension veterinarian at Pennsylvania State University
50. I will be your instructor for
51. the metabolic diseases and herd health section of this course
52. Today's topic will introduce this section and
53. describe approaches by which we can keep cows healthy
54. Our goal for this video is to address the concept of biosecurity as it applies to
55. farms and to understand how herd health programs have changed
56. in addressing changes in the dairy industry
57. As you might imagine, my goal as a veterinarian is to keep cows healthy and
58. as free of disease as possible
59. However, infectious pathogens are invariably present in any environment,
60. whether it be a day care facility, a school, or office
61. So how do we keep groups of cows healthy?
62. Let's first understand the concepts of biosecurity and
63. biocontainment as it relates to disease risks
64. The role of biosecurity became very prominent during the outbreak of foot and
65. mouth disease in the United Kingdom in 2001, as seen in these pictures
66. Biosecurity is defined as a series of management practices designed to
67. minimize or prevent importation of infectious agents
68. Similarly, biocontainment uses the same methods shown here
69. to prevent disease spread within the farm
70. Unfortunately we cannot achieve a perfect state of biosecurity
71. by strict isolation of our farms from all their inputs
72. We need to address specific risks to biosecurity for a given farm
73. This means there is no one size fits all to farm biosecurity
74. Programs to address biosecurity and biocontainment need to focus on assessing
75. risk potential from various sources for a given farm
76. In this diagram, we can see how susceptible animals on
77. the farm could be exposed to new infectious agents,
78. via various farm inputs or visitors to the farm
79. Direct animal contact as well as indirect transmission through water,
80. feed, pasture or equipment can result in new infections
81. Biosecurity practices should be tailored to certain risks on a given farm
82. based on their potential inputs, farm interactions, and products sold
83. Biosecurity practices are often overlooked once the headlines from some disease
84. outbreak have passed, but it's practices are essential
85. as we move through the 21st century in caring for our dairy herds
Trang 486. Let's see how this relates to the application to the dairy
87. herd health programs
88. Let's first take a look at the history of dairy herd health programs
89. If we think back to the first half of the 20th century, all societies
90. were more agriculturally based, with many rural families having the backyard cow,
91. pig and chickens to help produce food for the family
92. During this time, productive efficiency was low, and
93. there were no vaccines or antibiotics to treat sick cows
94. Veterinary medicine was in its infancy, in treating and understanding disease
95. In the US the initial focus of cow health programs was initiated
96. by the federal government in wanting to eliminate these two diseases,
97. brucellosis and tuberculosis, that could be passed in milk
98. These diseases can be transmitted to humans, meaning they are zoonotic
99. Many countries are still struggling to eliminate these diseases
100. This table provides the different biosecurity practices that were
101. used to help eliminate these two diseases in the US
102. Starting in the late 1940s, the post war human population needed to be fed,
103. and financial rewards were being realized from selling animal based food
products
104. Emphasis on herd health programs was on the veterinary practitioner diagnosing and
105. treating individual cows
106. Antibiotics became available as well as improved diagnostic capabilities
107. In the mid to late 1960s,
108. the human population continued to increase and become more distanced from
109. direct agricultural production in most industrialized countries
110. Farms continued to become larger and needed to be more efficient,
111. thus a critical need for a systematic approach in maintaining cow health
112. An initial approach to organized herd health programs was focused on disease
113. diagnosis and treatment
114. The primary objective was to address individual
115. cow issues that ultimately would result in improved overall herd health
116. This herd health approach as shown here,
117. did not specifically address productivity or economic health of the farm
118. Since the late 1980s, there has been a progressive shift or
119. evolution in our herd health program focus
120. To not only address specific animal health issues, but evaluating
121. the efficiency of production and more on preventative health approaches
122. In this herd health approach, there is a critical need to constantly evaluate
123. the current state of the herd, compare to industry standards or
124. her goals, then make informed decisions about management changes for
improvement
125. The continuation of the process, as shown in this diagram,
126. requires further evaluation following specific actions and
127. reassessment to determine if improvement has been made
128. This is the cycle of monitoring and evaluation
Trang 5129. As we have improved our understanding of animal health and disease risk,
130. coupled with farms becoming larger, more sophisticated and highly productive, our
131. herd health programs required attention to issues beyond just cow disease
132. We can see in this listing areas of disease monitoring and
133. milking machine function are being used to better address early disease diagnosis
134. Understanding the role of nutrition and
135. the environment has become a critical factor in addressing disease prevention
136. A veterinary colleague captured the essence of this approach to herd health
137. in asking this question
138. We know cows that become sick can recover, but
139. they may have residual issues such as greater risk for lower milk production
140. Poor reproductive performance resulting in greater risk for
141. being culled in the lactation in which they were sick
142. Thus our focus should be on preventing cows from ever becoming sick or broken
143. As we progress through this section of the course, we will address these
highlighted
144. components of a preventative medicine approached to herd health programs
145. Program components such as milking system management, reproduction,
146. heifer development and nutrition will be addressed in other course sections
147. To finish our discussion today, I have provided some reading materials found at
148. these websites and will provide an additional handout
149. I'm looking forward to our next discussion
150. Our next discussion will address health management of the calving cow,
151. which is the single most stressful event in a cow's life
]
Hello, my name is Dr Robert Van Saun and I am a professor of Veterinary Science and
an extension veterinarian at Pennsylvania State University
I will be your instructor for
the metabolic diseases and herd health section of this course
Today's topic will introduce this section and
describe approaches by which we can keep cows healthy
Our goal for this video is to address the concept of biosecurity as it applies to
farms and to understand how herd health programs have changed
in addressing changes in the dairy industry
As you might imagine, my goal as a veterinarian is to keep cows healthy and
as free of disease as possible
However, infectious pathogens are invariably present in any environment,
whether it be a day care facility, a school, or office
So how do we keep groups of cows healthy?
Let's first understand the concepts of biosecurity and
biocontainment as it relates to disease risks
The role of biosecurity became very prominent during the outbreak of foot and
mouth disease in the United Kingdom in 2001, as seen in these pictures
Trang 6Biosecurity is defined as a series of management practices designed to
minimize or prevent importation of infectious agents
Similarly, biocontainment uses the same methods shown here
to prevent disease spread within the farm
Unfortunately we cannot achieve a perfect state of biosecurity
by strict isolation of our farms from all their inputs
We need to address specific risks to biosecurity for a given farm
This means there is no one size fits all to farm biosecurity
Programs to address biosecurity and biocontainment need to focus on assessing risk potential from various sources for a given farm
In this diagram, we can see how susceptible animals on
the farm could be exposed to new infectious agents,
via various farm inputs or visitors to the farm
Direct animal contact as well as indirect transmission through water,
feed, pasture or equipment can result in new infections
Biosecurity practices should be tailored to certain risks on a given farm
based on their potential inputs, farm interactions, and products sold
Biosecurity practices are often overlooked once the headlines from some disease outbreak have passed, but it's practices are essential
as we move through the 21st century in caring for our dairy herds
Let's see how this relates to the application to the dairy
herd health programs
Let's first take a look at the history of dairy herd health programs
If we think back to the first half of the 20th century, all societies
were more agriculturally based, with many rural families having the backyard cow, pig and chickens to help produce food for the family
During this time, productive efficiency was low, and
there were no vaccines or antibiotics to treat sick cows
Veterinary medicine was in its infancy, in treating and understanding disease
In the US the initial focus of cow health programs was initiated
by the federal government in wanting to eliminate these two diseases,
brucellosis and tuberculosis, that could be passed in milk
These diseases can be transmitted to humans, meaning they are zoonotic
Many countries are still struggling to eliminate these diseases
This table provides the different biosecurity practices that were
used to help eliminate these two diseases in the US
Starting in the late 1940s, the post war human population needed to be fed,
and financial rewards were being realized from selling animal based food products Emphasis on herd health programs was on the veterinary practitioner diagnosing and treating individual cows
Antibiotics became available as well as improved diagnostic capabilities
In the mid to late 1960s,
the human population continued to increase and become more distanced from
direct agricultural production in most industrialized countries
Farms continued to become larger and needed to be more efficient,
thus a critical need for a systematic approach in maintaining cow health
Trang 7An initial approach to organized herd health programs was focused on disease
diagnosis and treatment
The primary objective was to address individual
cow issues that ultimately would result in improved overall herd health
This herd health approach as shown here,
did not specifically address productivity or economic health of the farm
Since the late 1980s, there has been a progressive shift or
evolution in our herd health program focus
To not only address specific animal health issues, but evaluating
the efficiency of production and more on preventative health approaches
In this herd health approach, there is a critical need to constantly evaluate
the current state of the herd, compare to industry standards or
her goals, then make informed decisions about management changes for improvement The continuation of the process, as shown in this diagram,
requires further evaluation following specific actions and
reassessment to determine if improvement has been made
This is the cycle of monitoring and evaluation
As we have improved our understanding of animal health and disease risk,
coupled with farms becoming larger, more sophisticated and highly productive, our herd health programs required attention to issues beyond just cow disease
We can see in this listing areas of disease monitoring and
milking machine function are being used to better address early disease diagnosis Understanding the role of nutrition and
the environment has become a critical factor in addressing disease prevention
A veterinary colleague captured the essence of this approach to herd health
in asking this question
We know cows that become sick can recover, but
they may have residual issues such as greater risk for lower milk production
Poor reproductive performance resulting in greater risk for
being culled in the lactation in which they were sick
Thus our focus should be on preventing cows from ever becoming sick or broken
As we progress through this section of the course, we will address these highlighted components of a preventative medicine approached to herd health programs
Program components such as milking system management, reproduction,
heifer development and nutrition will be addressed in other course sections
To finish our discussion today, I have provided some reading materials found at
these websites and will provide an additional handout
I'm looking forward to our next discussion
Our next discussion will address health management of the calving cow,
which is the single most stressful event in a cow's life
Welcome back to our second discussion in the Herd health section
I'm Dr Robert Van Saun and today we'll be discussing the single most
significant time in a cows life cycle in its relationship to disease
Today's objectives are to learn the normal stages of calving,
followed by an understanding of how to properly intervene when necessary
Trang 8The time of calving is the final culmination in the nine month
reproductive process
Goals of any farm relative to working with a calving cow are shown here The calving process is the single, most challenging time for
the cow from a health and production perspective
As was discussed in the pre-part of nutritional management discussion with Dr Vargo, the late, pregnant cow must undergo significant metabolic
adjustments to initiate lactation leading to increased risk for
a variety of metabolic and infectious diseases
This is in addition to the physical challenge of delivering
a 90 to 95 pound calf for a Holstein cow
Calving occurs over a period of time ranging from 3
to more than 24 hours depending upon cow age
This listing shows the three stages of calving
The normal time frame for Stage 1 is between 2 to 6 hours
Stage 2, 1 to 2 hours, possibly 3 with heifers
And 1 to 8 hours for Stage 3
Stage 1 is essentially the process of preparing the birth canal
in positioning the calf for proper delivery
Ligaments around the pelvic area will loosen,
thus allowing more give to deliver the calf
Other physical signs include swelling of the vulva and
plumping of the teats as they fill with colostrum
Cows will usually become restless and isolate themselves from others
One should observe these cows about every four hours to monitor progress During this time, the first water sac will protrude out and regress,
as it uses hydraulic pressure to expand that cervix and birth canal
It is important not to open the sac too early preventing its dilation actions Stage 2 is the physical delivery of the calf through the birth canal
Ideally cows should be placed in individual maternity pens that are clean, dry and have good footing and
restraint methods available should she need some intervention
Abdominal contractions will be obvious in addition to frequent
uterine contractions to move that fetus through the canal
Cows will typically lie down to complete the birthing process
Calf delivery is completed when either the hips or
shoulders are passed through the birth canal depending upon the presentation Stage 3 of calving is the process where the placenta detaches from the uterine connections and is released
Now that we understand how a normal calving should proceed,
how do we determine when to intervene?
It is important to remember that cows can calve on their own very well and only occasionally will need help
We don't want to intervene too quickly as this will increase the risk for
birth canal damage, greater contamination of the uterus and injury to that calf Farm managers should work with their veterinarian to develop appropriate
Trang 9Standard Operating Procedures or SOP in defining steps any worker should
complete in deciding when to intervene and how to assess and correct the situation Here are three key indicators of when you should decide to examine or assist a cow Listed here are three more criteria for deciding if you should intervene
A distressed calf will often appear with a yellow-brown
stain due to premature release of meconium during birthing
Meconium is that first feces passed from the calf when born
A lack of oxygen during birthing results in contraction of that lower colon,
thus passing the meconium and staining the calf
Potential causes of dystocia are shown here,
the first two will have some limitations and options for
corrections in often require cesarean surgery to deliver the calf
Some disease is such a uterine torsion or twisting, or
hypocalcemia can be corrected and birthing allowed to continue
The one where some practice in understanding corrective measures is
fetal malposition
This is where the fetus is not in a correct presentation to allow delivery
This might mean a head is back or one or two legs are flexed or
any combinations of these
Cows attempting to deliver twins could be a real challenge
in determining which legs belong to which calf
Okay, so, let's say the cow or heifer is taking too long in delivering the calf
What steps should we take to intervene appropriately?
The first step in assessing a dystocia case is to properly restrain
the cow to prevent injury to her, or assistance providers
Next, you want to tie the tail out of the way, but not to a solid object,
such as the barn
Clean the perineum thoroughly and
use clean sleeves to protect yourself and the cow
The next step is to insert your arm to perform a pelvic exam and
reach the calf to determine position
The best way to determine a calf presentation, head or
tail first, is to identify the proper body part
If not present, then one can use the legs to determine presentation
Front and
hind limbs bend in different directions, moving from the hoof up the leg
Once you have determined the calf presentation,
you will extend the two front or hind legs
To extend the legs, one will need to use obstetrical chains
Chains need to be applied correctly to prevent injury to the calf's leg
during the pull
A single loop just above the hoof could traumatically remove the hoof or
break a leg bone
A double half hit should be applied to distribute the tension along the leg
Once the chains are properly placed,
gentle tension should be applied to move the calf into position
Trang 10Once the calf is engaged in the pelvis, some assessment of fetal size, and ability to deliver the calf through the birth canal is made
Tension on the chains to pull the calf should be
coordinated with the cow's uterine contraction
Once the legs are protruding, pull downward at
a 45 degree angle to facilitate the natural contour of the birthing canal
If the pull is hard, one can alternate pulling on individual legs
to help reduce the size of the shoulders as they pass through the pelvis
Similarly, one can twist the calf 45 degrees
to take advantage of oblong nature of the pelvic opening
There is much more detail in becoming proficient in correcting
fetal malposition
But, we cannot cover each situation here
I encourage you to work with your veterinarian, or
other appropriate person to gain further instruction
Once the calf has been delivered, you should examine the cow to assess if there
is a second calf or some injury or damage to the birth canal
One should also keep records on the calving process,
termed the Dystocia Score, for all cows to identify problem cows or heifers This is part of that record keeping process of preventative
Herd health programs, as previously discussed
Potential disease issues that could occur at the time of calving, or
immediately afterwards, are shown here
Uterine torsion is a twisting of the birth canal,
preventing the calf from being passed through
This could be corrected manually in some cases
Or by proper rolling of the cow
In severe cases, a cesarean surgery may be necessary
In manipulating the calf within the birth canal, the uterus or
vaginal vault might tear
And have excessive bleeding
One can fill a clean sleeve with ice and
insert it into the birth canal to reduce inflammation and
swelling until the veterinarian can assess the severity of trauma or bleeding Another critical event requiring veterinary intervention is
a uterine prolapse
This is where the uterus is pushed out of the birth canal and turns inside out The uterus will need to be thoroughly cleaned and carefully replaced
Depending upon the duration and the difficulty of a calving,
there may be secondary damage to nerves passing along the pelvis
This may result in muscle weakness, or inability to stand, or
control of the hind legs
Musculoskeletal injuries may result from the cow falling due to poor footing, nerve damage or Hypocalcemia
One of the most significant metabolic diseases of dairy cattle
is Hypocalcemia or what is commonly termed milk fever
Trang 11This disease results from the cow's inability to replace the calcium loss via
colostrum precipitating a critically low blood calcium concentration
Clinical milk fever cows will be down, cold and depressed
Older cows are more commonly affected typically just prior to calving through
72 hours postpartum
More recently, a condition term, sub-clinical Hypocalcemia has been defined
as blood calcium concentration blood normal less then two millimoles per liter
or less then eight milligrams per deciliter but
above a concentration that would induce clinical signs
These cows will be weak and prone to slipping or falling
Hypocalcemia is considered a gateway disease as it is often associated with
other diseases such as retained fetal membranes, uterine prolapse,
mastitis and other metabolic diseases
Dietary prevention of Hypocalcemia has been intensively studied for
more than 60 years
In spite of all of this research,
disturbed calcium homeostasis remains a significant problem for calving cows Two documented methods of altering the prepartum diet for
at least 14 days prior to calving have been used to prevent Hypocalcemia
Calcium supplementation at the time of calving or immediately afterwards via boluses or drench has been used on many farms to minimize calcium related issues
In this session,
we have covered much material addressing critical issues of the calving cow Our objectives were related to understanding the normal and
abnormal birthing process, and how to properly intervene
We further discussed potential disease consequences of the calving process and highlighted the importance of calcium homeostasis
To this point, we have ignored management of the newborn calf
This will be our next discussion session in this course section
Hello again I'm Dr Robert Van Saun
Extension Veterinary with Penn State University
Our previous discussion focused on
the calving process and associated diseases of the cow
Today's topic we'll address the newborn calf and focus
on identifying disease early
for more timely intervention
Our lesson objectives are to become familiar with
the essential calf care practices at the time of
birth and to find
a systematic health evaluation process
and recognizing calf disease
Once the calf is passed through the birth canal,
we immediately need to focus on ensuring the mouth
and nose are clear of
mucous allowing the calf to breathe
Trang 12Proper inflation of the lungs is essential for
calf's survival and to
minimize future respiratory problems
There are a number of methods shown here to
stimulate good deep breaths by the calf
In the past we would have placed
the calf in a hanging position such as over
a fence as shown here in an effort to clear
the mucus from the respiratory tract, nose and mouth However, this approach is no longer
recommended as in this inverted position
all the abdominal organs press against
the diaphragm and limit
the lungs ability to inflate fully
We now recommend keeping the calf in
a sternal position as shown
here and stimulate the breathing process
Once we have the calf breathing
adequately we need to assess
the calf's status especially if there were
any problems or delays during the birthing process
Remember, from our previous discussion about meconium staining being an indicator of
calf distressed or in calving
This chart compares various physical exam findings
of the normal and
the compromise calf at birth and suggested
interventions to ensure survival of the compromised calf For each of these measures the compromise calf will have
a lower value all indicating
a serious lack of oxygen during the birthing process Compromise calves will require
more tender loving care and should
be forced fed colostrum to
ensure adequate passive transfer
Following birth and initiating breathing,
the single most important event in
a calf's life especially in reference to
disease prevention is the consumption of
high-quality colostrum in sufficient amounts
Other lessons in this course will address
specifics of colostrum feeding practices
After colostrum feeding
another important disease practice is dipping
of the navel in seven percent iodine
or similar disinfecting agent
Trang 13This practices to minimize risk of
environmental pathogens moving up
the umbilicus into the calf's body
and establishing an infection
It is best to actually dip the navel in
the iodine solution to ensure
proper disinfection and drying
It is not recommended to just spray the umbilicus
as this does not provide
complete coverage as shown in this photo
Between two and seven days of life
one could collect a blood sample from the calf and either directly measure
immunoglobulin concentration or indirectly
assess colostrum absorption by
measuring total protein in serum
Total protein is easily measured
with a refractometer and a drop of serum
Interpreting the results are shown in this table
Large calf raising operations require
this test before they accept the calf as
they know disease risk is highly
associated with passive immunity status
This pie chart comes from
the national animal health monitoring survey
showing the most common diseases for
nursing or wet calf losses
As we see in this data,
diarrhea or what's termed scours is the primary problem Respiratory disease or pneumonia is next and together, they account for nearly 80 percent of young calf losses
So how serious of
a problem are nursing calf losses in dairy herds?
Remember, our first discussion related to
monitoring and assessing the farm situation
Here in the US,
average mortality rate for
heifer calves prior to weaning has not changed
much in nearly 20 years
averaging approximately eight percent
We also noticed that over
this time period less calves are born alive
However, this metric is highly variable by
season of the year as well as between herds
Better herds can maintain less
than a one percent calf loss,
Trang 14whereas problem herds may experience as
highest 30 percent losses are more
What are the challenges that lead to calf disease?
These series of graphs
simply demonstrate the relationship between
calf resistance and pathogen
challenge resulting in clinical disease
The calf's resistance is reduced with birthing trauma, inadequate or poor colostrum feeding,
poor nutrition and environmental cold or heat stress Disease challenge can be increased with
poor housing conditions and
high pathogen exposure from cows,
other calves or a contaminated environment
When both issues occur at once,
then we have a large disease outbreak
Other than the obvious calf death losses,
why should we be concerned with disease rates in calves? Research shows long-term effects
of respiratory disease in calves in contrast
to no documented long-lasting effects for scours
These data collectively suggests we
need to identify scours early to prevent
death loss and work to prevent
respiratory disease to minimize long-term issues
As we discussed in our calving management lesson,
a standardized operating procedure or SOP should be constructed to ensure consistent and efficient methods are used to evaluate calves for a disease
Dr Sheila McGuirk at
the University of Wisconsin Madison developed
a systematic scoring system to evaluate calves for
disease risk and determining
which calves should be treated
This approach is based on
a validated visual criteria that facilitates
a repeatable evaluation process of
calf health relative to respiratory disease and scours Assessment of respiratory disease is evaluated
by a scoring system addressing body temperature,
nasal discharge, cough status and eyes or ears scores Specific criteria are categorized into
a simplified zero to three scale as shown in this table One would add up the score for
each parameter for a total respiratory score
If the total score is three or less,
Trang 15nothing is done to the calf
If the score is four then the calf should
be more closely monitored for potential problems
If the score is five or greater,
then some defined treatment protocols
should be initiated
Diarrhoea or scours would be
evaluated by a fecal scoring system as shown here Scores of two or three should
receive some defined treatment
Intensity of treatment for scours will
depend upon the hydration status of the calf With diarrhoea the calf is losing
water faster than it is taking water in
This scale shows the range of body water loss
or dehydration and associated
clinical presentation of the calf
As you can see,
it does not take excessive water loss,
just about 12 percent
before severe disease and death may occur
Severity of dehydration will dictate
the amount of electrolytes in fluids to be
administered and whether they can
be given orally or intravenously
So how do we keep calves healthy?
We need to think back to the balance between resistance and challenge of disease
We can raise the calf's resistance through
good colostrum, nutrition and vaccination
Secondarily, we can reduce the pathogen challenge through good sanitation and biosecurity practices Here are some fundamental
bio-security practices we could use in
managing calves to reduce
pathogen exposure to prevent disease
Ultimately, to achieve
the lowest potential disease risk in our calves,
we would want to increase the resistance at
the same time reduce the challenge as shown here Ultimately, this combination will result in
the lowest calf disease risk for the farm
We have covered a wide range of topics in
addressing proper calf care to ensure survival following birth as well as
underlying causes of calfhood disease and
Trang 16methods to appropriately recognize
disease early for better response to intervention
Our next lesson will focus on
disease recognition and prevention in the cow herd
Welcome back
I'm Robert Van Saun, extension veterinarian with Penn State University
In a previous topic we addressed specific calving related diseases
Our topic today will focus on common postpartum diseases and
how to identify sick cows earlier
Thus allowing for more timely intervention with the intent for a speedy recovery The first three to five weeks following calving is
the second half of what is termed the transition period
The significance of this eight to ten week period surrounding calving is
the metabolic modifications necessary for
the cow to adapt from her condition of pregnancy to one of lactation
Unfortunately, this transition does not go well for more than 50% of cows, and thus the period immediately after calving is a focal point for addressing disease issues
As can be seen in this graphic, most of the common disease concerns of cows occur at the time of calving and within the first month of lactation
Which means there is a great potential for adversely affecting milk yield for
the lactation
Much research has occurred over the past decades in an effort to determine
underpinning issues of disease risk for transition cows
Post-parturition or after-calving diseases are often termed
metabolic diseases, due to the association with abnormal or
perturbed metabolic adaptations during transition
This graph compares required amounts of key metabolic nutrients,
namely glucose, amino acids, fatty acids, and calcium,
either in the last two weeks of pregnancy or during the first week of lactation
If the cow is unable to maintain metabolic stability or homeostasis with these key nutrients, then specific metabolic disorders such as ketosis,
immune dysfunction, hepatic lipidosis, or
fatty infiltration of the liver, and hypocalcemia can occur
It should be recognized that these diseases are not independent of
each other
And often, one disease condition predisposes to another leading
to cows experiencing multiple disease events
In addition to metabolic derangements that occur around the time of calving
It has been well documented that the cow's immune response,
both the specific and non-specific branches, is compromised some
weeks prior to calving through three to four weeks post-calving
This situation increases the cow's susceptibility to mastitis,
an infection of the utter, metritis, an infection of the uterus,
and any other infectious disease process during the transition period
A key concern for transition cows relative to disease risk is the feed
Trang 17intake decline occurring around the time of calving
During the transition period, as shown in these graphs, intake drops a week or two prior to calving, is at its lowest point the day of calving,
then slowly increases over the early lactation period
Research has focused on this prepartum decline in intake
as an important factor predisposing to metabolic diseases
The challenge here is that many other factors beyond nutrition
can influence intake, making a solution to this problem very challenging Another critical factor recognized to contribute to increased metabolic disease susceptibility is the cow's body condition score during the dry period and into early lactation
Cows having excess body condition, defined as a score of four or greater
on a five point scale, were at greater risk for postpartum metabolic disease Heavier body condition score cows have a greater decline in
intake prior to calving
Body condition scoring has been addressed in other lessons
I have provided a link at the end of this video for a presentation on how to learn
to body condition score cows if you are not familiar with the method
The potential impact of intake is shown in these data from two different feeding studies completed at Penn State
Of all cows in the study, we identified those cows have no problems
during transition and compared pre and postpartum intake with cows
that had been diagnosed with ketosis in the postpartum period
You can see, even before the cows became sick,
their prepartum intake declined rapidly in the weeks prior to calving
In the post-calving period, there was a significant difference in feed intake Cows with ketosis consumed 500 pounds of dry matter less over
a five week period compared to healthy cows
This loss of feed intake would be equivalent to the cow losing either
0.9 score of body condition or
1,030 pounds less milk yield over this period
So why are we concerned about the diseases associated with transition?
Mainly because these diseases are very costly to the producer
The early lactation cow is the most efficient milk producer and
any disease process will reduce milk yield per day and per the full lactation Additionally there are animal-specific losses, as indicated here
More recently, research has described another form of postpartum diseases The diseases we've been describing so far have specific
clinical signs shown by the affected cows and are termed clinical disease
In contrast, a lesser form of the same disease
is described as being subclinical manifestation of the disease process
Subclinical disease is more prevalent within the population and
even though it does not produce the observable clinical signs in the animal,
it is more significant to the farm
Subclinical disease occurs when the underlying derangement is not sufficient
to cause clinical disease manifestations, but
Trang 18is sufficient to induce performance inefficiencies
Subclinical disease is often associated with decreased feed efficiency, reduced
reproduction, and impaired immune function leading to greater disease susceptibility This chart provides a summary of estimated costs associated with clinical and
subclinical forms of common postpartum diseases
You can see that although subclinical diseases have lower perceived costs,
their financial impact on the farm is greater as a result of their
greater prevalence compared to clinical diseases
As we discussed in our first lesson of this course section, one needs to compare current herd performance to industry or goal benchmarks
Ideally, one would want no disease to occur at all, but
this is not feasible nor reasonable to achieve
This table provides benchmarks for postpartum disease prevalence and
the action level
Which is the prevalence of disease where intervention to reduce the disease
would be expected to have financial rewards
Underlying cause,
metabolic or postpartum disease goes beyond just nutrition and feed intake
We need to consider management and environmental factors and
their impact on the nutritional program
Another veterinary colleague, Dr Ken Nordlund from the University of Wisconsin
at Madison, has indicated that nutrition only accounts for
less than 20% of transition cow problems,
with the bulk of issues related to cow management and the environment
We will address some of these concerns in our last lesson on disease prevention Okay, so now we have some perspective on transition cow health concerns,
underlying causes, and impact on herd health and productivity
How do we identify a sick cow early enough
to stop the disease from causing serious production or cow losses?
Identifying and treating sick cows is a common practice on all farms
The process should be consistent in its approach and
sufficiently thorough to identify all cows at risk
The challenge is devising a method to make this process simple, repeatable,
and not overwhelming to cows or workers
Often farms lock up all fresh cows and complete some form of examination on all cows to find the sick cow or small number of cows
This is time consuming and disturbs the healthy cows' normal activities
We developed a two-stage method of finding sick cows
The first step is used at a distance in observing cows in
a pen to identify those who need to be more closely evaluated
We use this acronym, OBSERVED, to address
important cow features that may indicate some health problem as indicated here These cow observations could also be coupled with other indicators linked to
automatic measures of milk production, feed intake, or other parameters
Once cows within a pen have been evaluated at a distance, and
those requiring further evaluation have been segregated
Trang 19Another acronym, INSPECT HER CAREFULLY,
was developed to provide guidance on the necessary close up examination process This program was developed to teach farm workers not very familiar with cows to gain what is termed cow sense, in recognizing how a sick cow
differs from a healthy cow in physical appearance and in behavior
There are many good methods in which a thorough and
systematic physical exam of the cow can be performed
The bottom line is that dairy farms must have some disease recognition program in place to identify sick cows in the early disease stages, so
that they might recover more quickly when treated appropriately
Individuals performing this task should have some experience and
be trained by the herd veterinarian to improve their diagnostic skills
Basic tools in performing these evaluations might include a thermometer,
colored chalk, or marker to identify treated cows,
a stethoscope to listen to the cow's lungs, heart, rumen and abdomen
And urine or blood test strips to check for ketosis
Of course, all evaluations should be recorded in the cow's record
Once a sick cow has been identified, there should be a developed standard
operating procedure, or SOP, to direct the person completing
the examination as to how to treat and follow up with the cow
Treatment SOPs should be developed with the herd veterinarian, and
be easy to follow for the worker
This listing provides some disease examples for
which SOPs could be developed
Our next topic will pick up from this point of our discussion and
address therapeutic protocols, proper use of antibiotics and
prevention of drug residues
As we finish this lesson, here is a link for the training materials and
learning how to body condition score cows
Welcome back to the metabolic disease and herd health section of this dairy MOOC I'm Robert Van Saun, Extension Veterinarian with Penn State University
Today's discussion will address an extremely important aspect of animal
health, developing treatment protocols in the use
of antibiotic compounds in treating sick cows
My objectives for this lesson are to provide a foundation for
understanding treatment approaches to sick cows and calves
And to provide information to you to better understand therapeutic options,
and provide insight on the controversial issue of antibiotic usage in
food producing animals
Up to this point,
we have address a variety of disease conditions in cows and calves
These disease require some form of intervention
in an effort to correct the disease condition, and
alleviate any secondary problems or associated pain and discomfort
When it comes to the metabolic diseases we discussed,
Trang 20this intervention is fairly specific to the underlying disease problem
For example, we would administer calcium to correct hypocalcemia
Or in the case of ketosis, administer glucose or
glucose precursor's such as propylene glycol
We may also administer additional supportive therapies to minimize relapse,
and to stimulate food intake
In less specific disease circumstances such as a cow being off feed,
we may administer a solution of electrolytes, calcium, fermentable feeds,
B vitamins, and yeast as a drench to booster the animal,
stimulate appetite, and support the rumen
One of the best methods to stimulate a dysfunctional rumen and the cow's appetite
is to transfer rumen juice from one cow to the sick cow's rumen via an oral tube This is termed transfaunation
In providing rumen fluid containing healthy bacterial populations,
many large farms may have one or two cows with a permanent rumen fistula to use as rumen content donors for their sick cow therapy
Any of these approaches provide supportive care to the sick cow
However, a vital aspect of sick
cow treatment comes from developing a defined protocol
Which has procedures in place to avoid any residues in meat or
milk, as outlined here
A protocol should ensure all cows are adequately identified with a proper
diagnosis, a consistent therapeutic approach is applied,
and all therapies are recorded in the cow's record
Finally, all treated cows should be reevaluated to determine
if they have recovered, or require further evaluation and retreatment
This essentially describes what is termed the treatment protocol, or
what we have previously described as a standard operating procedures for
other routine farm activities
It is difficult to define specific treatment protocols for
all potential diseases processes
Thus, treatment protocols should be developed for
common diseases seen on the farm
The herd veterinarian should be consulted or brought in to provide a diagnosis in situations where the cow does not fit into any protocol, or
when the diagnosis based on the protocol is uncertain
Because we are dealing with food animals, treatment protocols should be written by the herd veterinarian in conjunction with the herdsman and
herd workers to ensure proper use of medications,
adherence to all appropriate drug withdrawals for food safety
And buy-in by all those persons to perform protocol
In many herds the veterinarian may be solely responsible for
sick cow diagnosis and treatment
But many herds may not have ready access to a veterinarian
Or may be large enough to have workers perform many disease treatments
In the latter case,
Trang 21it is essential that treatment protocols are developed to ensure consistent and
proper animal diagnosis, and appropriate therapy is applied
When it comes to infectious diseases such as mastitis, metritis,
which remember is uterine infection, or pneumonia, we typically need to
administer a therapeutic agent that would inhibit growth of the infectious agent For the most part, we only have therapeutic compounds to address bacterial
infections, and these compounds are termed antibiotics
Use of antibiotics in treating sick calves, or cows, would be no different
than what a medical doctor would do for you or me if we were sick
The challenge here is that the calf or cow we treat may become a food source for people, and we want to be confident that there are no remaining medicines in
the milk or tissues of the animal when it is consumed for food
The use of antibiotics is a controversial issue in food and
animal systems as a result of implications of pervasive overuse and
abuse by veterinarians and producers leading to drug resistance,
as is portrayed in this article from the Time Magazine
As well as unwanted drug residues in the food supply
This topic is very complicated and an important one to address but
an extensive discussion is beyond the scope of this course
Let's just touch on some important concepts relative to antibiotics,
resistance, and residues
We have already defined an antibiotic as a compound used to treat bacterial diseases However, antibiotics may be used for colds,
or other virus induced diseases where bacteria
are known to become secondary invaders once the virus has caused its damage There are two reasons for using antibiotics in treating sick animals
The primary reason is to kill disease causing bacteria and
make the animal healthy again
The second reason is to control or prevent disease in high risk animals
The sub therapeutic usage defined as providing the antibiotic at
lower than treatment concentrations has been criticized, as it was perceived to be used for growth promotion, and thought to promote resistance issues
Most European countries, and recently here in the United States,
feeding of antibiotics for growth promotion has been banned
Metaphylactic use occurs when we know animals are at high risk for disease and antibiotics are used short term to reduce this disease susceptibility risk
This approach has also come under more regulation
The recent veterinary feed directive in the United States places
the use the antibiotics in feed for disease prevention totally under
veterinary control and prohibits the use the drug beyond its label directions
This would be termed extra label use
Antibiotics are highly regulated by governmental agencies to ensure proper
usage, and preventing potential contamination of food termed to residue
from treated animals entering the food chain
Here in the US, and in most developed countries,
the animal based foods are very safe
Trang 22A recent survey by the Food and Drug Administration in the US showed less than 0.01 of bulk tank milk samples had detectable drug residue
Not all of these, however, were above violation concentration
No residues are found in retail milk, so when is a residue a residue?
Some people would prefer a zero tolerance for any drug or medication
The practicality of this is limited, and there are potential negative consequences
on animal welfare in not treating animals appropriately that are sick
The challenge here is our technology continues to advance and
it's ability to detect compounds in food and blur their line of defining a residue
We can now measure compounds at a level of one part per billion, or even trillion Some analogies of just how small a fraction this is are shown here
So what is significant when it comes to residues?
Some compounds have a zero tolerance,
meaning that if they are found at any level it is a violation
Safe levels are those concentrations at which there is no perceived or
documented health concern for people consuming the food products
Governmental oversight of antibiotic usage varies tremendously between countries and even within a country
Some countries require all antibiotic treatments to sick animals to
be administered by a veterinarian
Some countries like the US allow some antibiotics to be purchased over
the counter by lay persons
There even are differences in specialty production systems,
such as organic production
Here in the US, antibiotics are not allowed to be used in organic herds
Thus, sick cows need to be removed if treated or
they are treated with non antibiotic pharmaceuticals
In contrast, organic production systems in Europe
can use antibiotics to treat sick cows out of a concern over animal welfare
But the time period to hold any milk or
meat from a treated animal is at least three times the drug recommendation
A legally approved antibiotic has undergone extensive testing to not
only determine its ability to treat a disease process, but
the time period following the last treatment required for tissue levels
of the drug to be either zero or below a defined amount considered safe
This time period is what is termed the drug withdrawal time
This period is defined for milk and
meat depending upon the animal type, beef or dairy, and which the drug is approved The challenge here is that the stated withdrawal time for
a given antibiotic is only applicable for the defined dosage,
animal type, and administration route described on the product label
There are a number of issues as shown here that may alter the withdrawal time
With the limited amount of antibiotics or other drugs approved for
use in food animals, veterinarians may use their clinical discretion
In administering drugs in a manner other than what is listed on the product label This is termed extra label drug use, and
Trang 23in the US this use must be carefully documented, and
within the guidelines of the Animal Medicinal Drug Use Clarification Act,
or what's known as AMDUCA
Extra label use of drugs can only be applied when
under the supervision of the veterinarian familiar with the farm
Length and withdrawal times need to be applied to this practice, and information
can be obtained from FARAD, which is the Food Animal Residue Avoidance Databank
As much as the usage of antibiotic and
other therapeutic drugs is highly regulated, there
are potential issues on the farm that result in an inappropriate drug residue
Most often this occurs when producers use over-the-counter
drugs without appropriate supervision
Some other causes leading to residues are shown here and
underscore the need to establish treatment protocols
As we have just described,
the improper use of antibiotics can result in unwanted drug residues in our food
Similarly, improper use of antibiotics, whether it is in humans or
animals, can also lead to bacterial resistance to the affect of antibiotics
Tissue drugs residues are not the same as drug resistance
Antibiotic resistance is an important health concern in both medical doctors and
in veterinarians,
as this means their tools to fight disease become less effective
Often antibiotic use in animals is implicated in causing bacterial resistance
for disease in humans
However, most of the antibiotics used in veterinary medicine are either not used or minimally used in human medicine
The excessive use of antibiotic use in our human medicine
is also to be scrutinized in this issue
The development of antibiotic resistance is a very complicated multi-faceted in
both human and veterinary medicine having a role
Again, this issue further underscores our need to use antibiotics judiciously and
properly to prevent resistance in residue issues
An additional consequence of treating sick cows also needs to be addressed
This is the issue of blemishes in meat
A blemish is different than a residue in that it is a physical change to
the muscle tissue as a result of an irritation
A blemish may indicate the potential for
a drug residue, but residues can be found in tissues without a blemish
The irritation inducing a blemish in a meat cut is most often the result of
an injected compound that causes localized inflammation
Many drugs, not just antibiotics or
even vaccines could induce localized irritation resulting in a blemish
Similar to many of the methods used to minimize risk for tissue residues,
here are some recommendations to prevent tissue blemishes
Blemishes are not only a risk for tissue residues, but
also a significant financial loss in meat cuts for retail sale
Trang 24High quality cuts, such as muscles around the pelvis and upper leg,
can have high blemish damage to prevent more desired meat cuts being produced, due to the trimming necessary to remove the blemishes
Although we focus on milk production as the primary food product generated
on the dairy farm, we must realize that our bull calves are used for veal or
raised for beef
And our cows being removed from milk production will enter the food chain
as a beef source
Here in the US, market or what's termed cold dairy cows, account for
7.7% of the slaughtered animals, but are responsible for
more than 66% of all residues found in commercial meat
Similarly, young veal calves account for
another 25% of all commercial meat residue violations
Thus, the dairy industry must address issues related to appropriate drug use and after care in treated cows and calves
All of these issues relative to proper antibiotic use, tissue residue avoidance, and blemished meat are addressed in dairy quality assurance programs,
like this program developed at Penn State
These programs provide educational materials for
dairy producers to enact best management practices, to ensure proper animal care, and a safe food supply, whether it be milk or meat
It is the responsibility of dairy producers, their workers, and
veterinarians to insure a safe food supply with appropriate use of therapeutic agents in treating cows with disease
One way to reduce antibiotic usage is to improve overall cow health and
Trang 25Help Us Translate
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[MUSIC]
Welcome to our 6th and final segment of the metabolic diseases and
herd health section of the course
I'm Robert Van Saun at Penn State University
Previously, we have discussed the many disease risks for dairy cows and
calves, and how we can initiate early diagnosis of disease
Our most recent discussion addressed treatment protocols for
the sick cow or calf, and potential consequences of antibiotic usage
In this final segment we will discuss potential preventative practices we can
use to possibly control or prevent disease from happening
Objectives for this lesson are to understand potential roles of vaccination,
parasite control and nutrition and disease prevention
As well as the role of the environment in disease risk, or control
In our first lesson, we ask the question,
should we be treating broken cows, or preventing cows from becoming broken?
Economics, production efficiency, and concerns for
animal welfare all direct us to disease prevention
So how do we prevent cows from becoming broken?
Here is where we come full circle in our discussion
Trang 26In that same first lesson, we discuss the fundamentals of bio security
We indicated that bio security, or
bio containment was a series of management practices that limit the importation of disease onto the farm, and spread of disease throughout the farm
Application of biosecurity practice should be a starting point for
disease prevention on the farm
A second preventive practice is to employ a herd based vaccination program to address diseases of concern to the farm
More details on the vaccination programs will come later in the lesson
Another disease preventive practice, is parasite control programs,
which are becoming more important,
as more dairy farms are utilizing grazing, as part of their feeding practices
Finally, another important disease prevention practice is employing
a nutrition program that is properly formulated to support
specific requirements for each animal group
Other lessons in this course have addressed specifics of feeding practices
for various cow groups on the dairy farm
However, most requirements are focused on supporting some productive function and not necessarily addressing specific nutritional needs to support
immune function
Our data is limited in this respect, but is growing with new research
We need to appreciate that no preventive practice is 100% effective
Effectiveness of bio security is only as good,
as the inactive protocols and their compliance by all parties
Both vaccination programs and parasite control are critically
Trang 27dependent upon the role of nutrition on immune system function
In order for an animal to respond to a vaccine appropriately,
the immune system must by sufficiently responsive to the injected vaccine More research is suggesting animals in a better state of nutrition are better able
to handle moderate parasite loads without compromising productivity or health The cows or calves nutritional status is an integral factor in
maintaining the balance between a state of health or disease
The critical fulcrum between health and disease is the immune response
Good, well balanced nutrition can support the state of healthiness
Where as inadequate or improper nutrition can promote disease
The overriding confounder here is the level of stress as
it will promote disease conditions
In our transition cow lesson,
we indicated the cow's immune response is impaired around the time of calving Thus potentially increasing the risk for disease,
especially important production diseases, such as mastitis and [INAUDIBLE] Ohio State University research has shown increasing Vitamin E to 1000,
up to 4000 international units per day in the close up dry cal diet
can decrease mastitis in fresh cows and reduce severity of disease
Other research has suggested that Vitamin A status could also improve
mastitis resistance
Vitamin E also has been shown to reduce retained fetal membranes in fresh cows, which is often a precursor to metritis
This are just some examples but other nutrients such as energy,
protein and minerals also can effect the the cow's immune response in one or
Trang 28more ways tilting that balance, toward health or disease
Similarly, the calf's immune response
is first dependent on colostrum feeding practices,
followed by the calf's ability to generate its own active immune response
In this graph, we see there is a period of declining passive immunity from colostrum, before the calf's immune response is fully active
It is during this period of low immune functionality
that we see a greater prevalence of scours and
calves as we previously discussed in our calf health lesson
Inadequate milk or milk replacer feeding or
poor quality milk replacer could impair the calf's active immune response
A functional immune response is an absolute necessity we are to have
any functional use of a vaccination strategy for disease prevention
Vaccine programs for dairy herd need to be designed and
tailored for the specific issues or diseases recognized on the farm
And not blanket approach to using any and all available vaccines
Disease risks and available vaccines will vary tremendously across countries and
no one program will meet the needs of herd
Specifically objectives for a vaccination strategy for
a given herd should be defined by the herd veterinarian
In conjunction with stated heard goals and economics
Here are some key concepts to be addressed in developing in appropriate and
functional vaccination strategy for dairy heard
First Vaccinate against identified disease concerns for
the herd, where protective vaccine is available
Trang 29A second issue, is to ensure all at risk animals on the farm, for the identified diseases, are properly vaccinated to be protected from the disease
A third vaccination program consideration is whether the vaccine is applied in
a proper way to stimulate a protective immune response
This means we need to vaccinate prior to disease exposure and
should follow all recommendations from the vaccine manufacturer in handling and administering the vaccine
Finally, one should evaluate the economics of the vaccine program
This requires consideration of vaccine cost, labor, and
facilities to administer the vaccine, and effectiveness for disease prevention
versus the potential risk for loss from animal disease, or death
In some cases the potential disease risk is not sufficient to warrant investment in
a vaccine strategy even though the vaccine is available and efficacious
Considerations for a parasite control program
also requires a plan strategy based o herd goals and risk potential
Often we consider a parasite control program to follow the five steps of
integrated pest management or IPM plan as outlined here
This approach mimics what we had discussed earlier in evaluating herd productive performance status
We started by evaluating current herd status, instituted an intervention,
and continued with further monitoring and assessment
What then should be our goals for an appropriate parasite control program?
We want to be able to prevent the animals from becoming sick and
showing clinical signs
Yet minimize the rate of parasite resistance
Trang 30due to overuse of drug treatments
Ultimately, we want to minimize or prevent harboring parasites in animals over
the winter and promoting the rise prior to calving due to lowered immune response Our approach to achieving these goals will need to be tailored to the herd management and facilities
A key concept to address in understanding parasite control is that not
all animals are equally affected
We term this the 20-80 rule, where a smaller fraction of the herd,
say 15 to 20% account for
the greater majority 80 to 85% of the parasite problems
This would mean control program should focus on that specific population
with targeted treatment or
calling as these animals are more none resistance to parasites
This perspective is predicated
our recognition of parasite resistance therapeutic drugs
This is not as great a concern in dairy cattle
as it is currently recognized in sheep and goat operations
However, parasite control programs should focus more on management changes to minimize the potential interaction between parasite and host, rather
than solely relying on drug treatments to control animal parasite loads
As we discussed relative to vaccination programs, parasite control programs will differ from herd to herd for many of the reasons shown here
Again, the herd veterinarian should be consulted to help provide insight
as to parasite control and
integrate a program with specifics of herd management and facilities
Trang 31The environment plays an important role in parasite control programs,
as it is the conduit between host animal and parasite,
facilitating their interaction, promoting the continuing life cycle
The environment can play a similar role
as a disease interface between susceptible animal and pathogen
Consider this heavily contaminated calving pen and the potential for
pathogens in manure to gain contact to teat ends to initiate mastitis or
to be inadvertently consumed by a newborn calf to induce scours
Another possibility is to have the umbilicus of the newborn calf become
contaminated and the pathogens gain access to the calf's bloodstream,
causing a systemic infection
Manure contamination of bedding and
cow stalls also can contribute to greater risk for mastitis
Here are two bedding cultures showing very different bacterial loads
The environment can also play a role in inducing some level of stress
which can predispose the cow or calf to disease
Environmental temperature extremes of cold or hot or poor ventilation are examples of stress inducing situations that predispose the animal to greater disease risk
Cows are not very tolerant of heat stress and will reduce feed intake leading to
higher disease risk, especially if this occurs during the transition period
Calves are sensitive to both cold and heat stress
Heat stress induces changes similar to that of cows
Cold weather increases the calf's energy requirement
And if feeding rates are not adjusted, the calf will be energy starved,
become immune suppressed, and, more susceptible to disease pathogens
Trang 32We previously discussed pneumonia as a significant calf disease
This interesting research from the University of Wisconsin, at Madison,
showed differences in pneumonia risk,
in calves due to high bacterial counts in the air from poor ventilation
This study showed the amount of bedding for warmth, as indicated as nesting score and presence of solid or mess partitions between calves,
were significant factors leading to calf pneumonia risk
We can see from this research that, lower nesting scores in mesh
partitions resulted in increasing risk for pneumonia in calves
So, how do we keep cows from becoming broken?
Let's put this disease prevention practices and perspective
Keeping cows healthy comes from maintaining disease resistance
Above the risk of disease challenge
One way this is achieved is by increasing the cow or
calf's resistance to disease through good nutrition and vaccination
Another approach is to reduce the disease challenge and maintain resistance This can be achieved through good biosecurity practices to limit pathogen
burdens in good sanitation of the environment
Ideally if we really wanted to keep a greater proportion of our herd healthy
we need to imply both approaches
Use good nutrition and
vaccination to increase herd resistance in conjunction with good bio security and sanitation practice to reduce disease challenge as shown in this graphic
This completes the dairy mook section on metabolic diseases and herd health
I hope the information provided over these past six lessons will be
Trang 33useful to you in improving cow and calf health on your farm
If you are not directly involved in dairy farming, I hope this information is giving you some perspective on the challenges in maintaining cow health and
welfare on the dairy farm and how that near ends and farm workers
are invested in maintaining a healthy herd And high quality food products
I thank you for your attention, and
hope you continue through the remaining sections of the course
Hello, I'm Bhushan Jayarao
I'm the resident director of the Penn State Animal Diagnostic Laboratory, and
a professor of Veterinary and
Biomedical Sciences at the Pennsylvania State University
In this module on bovine mastitis and
milk quality, we'll look into the process of producing quality milk
The sole purpose of dairy producers all over the world is to produce quality milk
As we all know that milk is one of the safest foods if produced and
stored properly
It's also a very interesting to know that milk is perhaps the only food that when it leaves the cow's udder is untouched by a human hand all the way from the farm, the milk processing plant, the grocery store, till it reaches the consumers
And also, milk in many developed and
developing countries is the most tested food for its safety and quality
Now let us begin our journey on understanding as to how to produce safe
and quality milk
It begins with healthy cows free of disease, and with a clean and
healthy udder free of infection
She should be fed with a balanced and nutritious diet, with access to plenty
of safe water and housed in a clean and dry environment
Now when the cow is ready to be milked her, udders should be prepared for milking using sanitary practices
Following which she is to be milked
using a milking machine that is well maintained and clean and disinfected
This is what we call as milking practices of proper milking procedures
The milk from the cow that leaves the udder through the milk machine enters
a series of milk pipelines, then goes into the plate cooler, and
finally is collected in a bulk tank on the farm
In order to ensure clean and quality milk, the milking machine, the milk pipelines, the balance tank, the plate cooler, and the ball tank need to be well designed, cleaned and sanitized before and after each milking of the cows on the farm
Trang 34At this point in time, the milk that is produced on the farm,
its quality is typical determined by the number of somatic cells
It should be free of antibiotics and bacteria that cause mastitis,
bacteria that cause spoilage and foodborne illnesses
We will discuss these indicators in detail in our milk quality part of the module
In summary, it all begins with cows free of disease
That are provided with proper nutrition and well managed
Housed in a clean environment and milked using clean and
well functioning milking equipment
The milk is then cooled rapidly and
kept cold until it's picked up by the milk truck
Now let us talk about the advantages of producing quality milk
When you allow good practices on the farm,
the milk gets a better price in the market
And the milk and the milk products such as cheese, yogurt, and cottage cheese,
when produced using quality milk tastes better, and
stays for a longer time in the refrigerator, and
most importantly, it assures the consumers, that the milk and
milk products that they're consuming are safe and of the highest quality
Bovine Mastitis, Part 2
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Trang 35arrow keys for shortcuts, you can replace them with the H J K L keys Some screen readers may require using CTRL in conjunction with the alt key
[MUSIC]
Now let's talk about Bovine mastitis
As mentioned earlier, it all begins with a disease with a clean and healthy utter
A healthy utter is defined as an utter free of mastitis
So what's mastitis?
Inflammation of one or more quarters of the udder is called as mastitis
An udder with mastitis may show signs of swelling,
painful to touch, warm, and may also at times show signs of redness
All the four signs that's including swelling, pain, warm, and redness alone
All in combination are signs of mastitis in a cow
Mastitis as a disease is one of the most costly disease affecting dairy cows
through all the world
In the Untied States alone it is estimated that mastitis causing at
loss of close to $200 per cow per year
And annually the total lose due to mastitis may be about $2 billion per year
The economic losses are due to low in milk production,
use of antibiotics to treat bacterial infections
Veterinary fees,
losses due to removing the cow from the herd, or death of the cow
So let us understand what causes mastitis
Nearly 70% of the mastitis in cows is caused by bacteria
While only 2% of the infection may be caused by yeast and molds
went for nearly 28% of the cases, we don't really know what causes mastitis
Trang 36There is some evidence to suggest that factors such as injury, or trauma, and
weather extremes could result in mastitis
One would ask where do these mastitis causing organisms come from?
These organisms, or bacteria, are likely to come from three sources
The first one being an infected udder
The second one is the environmental source such as bedding, soil, water, and manure The third source can be cows with mastitis that have been recently purchased
to replace other cows
Back to the cause can be broadly grouped into two categories
The first category of bacteria is called as contagious mastitis pathogens
These bacteria prefer to live and multiply in the udder, then the environment and these bacteria gain access to other uninfected udders at the time of milking
The second category of bacteria is called as environmental mastitis pathogens
As the name implies,
they originate from the environment such as bedding, manure and soil
If one were to ask how mastitis develops,
the following illustration will help us understand the process of infection
Briefly, the bacteria from the environment such as bedding, manure, and soil come on
to the teat skin and between milking they enter the udder through the teat canal They then migrate up through the teat canal and colonize the udder
Once they have colonized the udder,
they produce toxins that are harmful to the udder
The udder recognizes the bacteria and its immune system is then activated
When it activates its immune system, it then sends the white blood cells to
kill and stop the bacteria from causing further damage to the udder
Trang 37This fight between the bacteria and the udder could result in three outcomes The first being the udder is free of infection
The second outcome could be that infection could not be stopped
And results in clinical infection, all signs of mastitis
When the third outcome could be what is termed as subclinical mastitis,
in which the infection is present in the udder, and,
if not taken care of, could result in clinical mastitis
So the big question is, what happens to the white blood cells that are present in the udder to fight infections
We tend to call the white blood cells that are present in the udder as somatic cells The somatic cells leave the udder to the milk, so cows with infection that's
primarily clinical, subclinical mastitis generally have high somatic cells numbers, while cows free from infection have very low somatic cell numbers
So, where do these somatic cells in the milk end up on the farm?
The somatic cells in the milk end up in the bulk tank on the farm
So the first indicator of milk quality is the number of somatic cells
The U.S standard for somatic cells in bulk tank milk is that the bulk
tank milk should contain less than 750,000 cells per milliliter of milk
Let us further examine what are these somatic cells?
Somatic cells, as I earlier mentioned, are nothing else but
white blood cells that come into the udder through the blood stream
Their primary role is to fight infections and
repair the damage caused by the infection
So typically somatic cells are present in very low numbers at
any given time in the udder of a healthy cow
Trang 38Somatic cells are one of the best indicators for
determining the status of the udder health
Milk quality and lost of milk production due to mastitis
Milk for cows with low somatic cells also that is less than 200 thousand cells per milliliters such is that the cow is free of mastitis and the quality of milk is
excellent to very good with little or no loss in milk production
As the number of somatic cell count increases in milk,
the likelihood of cows having mastitis is also elevated
Along with lower milk production and increased loss of milk production
So what do high somatic cells do to milk quality?
Somatic cells produce enzymes which break down milk proteins and
fat which result in foul odor and taste to milk
And milk products made from milk with high somatic cells have poor quality and lower shelf life
Also, use of milk with high somatic cells for
making cheese could result in lower yield of the product
It is also been shown that enzymes released by so milk itself are resistant
to pasteurization temperatures, and could continue to breakdown proteins,
even when the milk is kept under refrigeration temperatures
And let's talk about Detection and Diagnosis of Mastitis
Mastitis can occur in three forms, clinical, sub clinical, and
chronic mastitis
Cows with clinical mastitis invariably exhibit pain on touch, and
swelling of the udder
Is also often frequently observed
Trang 39The milk from these cows can range from blood in milk to clots,
flakes, to straw colored milk
The ability to produce milk also significantly declines, and
if untreated, could result in systemic infection in the cow
Cows with subclinical mastitis do not show clinical signs
The only changes observed are that the milk may have clots,
flakes, or the milk may be thin
Subclinical mastitis is 5 to 40 times more common than clinical form,
and a dairy herd with many cows with sub clinical mastitis
could result in significant milk production on the farm
Chronic infection is a long standing infection
resulting from a previous clinical or sub clinical infection and
is quite often seen with the increasing age of the cow
Mastitis can be diagnosed by physical examination of the udder of the cow Examining the milk from the cow suspected for mastitis
By performing a California Mastitis test or a cow site somatic cell contest
And the last one can be is doing farm culture test or
sending the suspect milk sample
The laboratory could test for bacterial culture for mastitis pathogens
This slide provides an overview as to how to perform on a California mastitis test The next slide provides links to two videos on YouTube
The first one is on proper milk collection, and the second two videos
are on performing the California mastitis test, and inputting the results
The number of somatic cells in milk samples is one of the best indicators to determine
Trang 40If a cow has mastitis, an alternate to California Mastitis Test
There are now quite a few calcite kits that you can actually use,
to determine the number of somatic cells in the milk sample in real time
One such instrument is the DeLaval -DCC,
that provides the number of somatic cells in a few easy steps
A web link is provided on this line that shows how the DeLaval instrument can be used to determine the number of somatic cells right on the farm
The most reliable and accurate method of determining if a cull has mastitis
Is to culture the milk sample and identify the organism or
the bacteria that is causing the infection
The milk sample from the cow suspected from mastitis in a diagnostic
laboratory is examined for a variety of mastitis pathogens
The findings of the laboratory analysis is typically provided to the owner and
a veterinarian to come up with the most appropriate decision on treating the cow,
or preventing mastitis in the herd
Bovine Mastitis, Part 3
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