Final Flashcards
What drives the genetics at the beginning of cattle industry?
Seedstock producers
- they sell bulls and bred heifers
- control all the genetics of cattle industry
What controls the market price of bulls?
Market price of beef products
Who do the seedstock operators sell to?
Cow/calf operations
- sell weaned calves
Wear do the weaned calves go after being sold by the cow/calf operations?
Stocker/backgrounder
- take weaned calves and get them ready for the feedlot (where they will gain 3-4 lb/day)
T/F: mortality is increasing on feedlots across the country
True
-cost of antibiotics have increased dramatically as well (antibiotic usage is increasing, not just prices)
What is slide with cattle selling?
When the price per pound of meat is reduced due to the weight of the calf being more than the agreed calf weight at sale, or increased if the calf doesnt weigh as much
- usually expressed as sell price with (0.0$) slide which means 0.0 cents per 100 lb body weight
- weight at sell vs weight at delivery is how slide comes into play
T/F: value of gain of steers equals the sale price
F
- usually value of gain is between 2/3-3/4 of original sale price
T/F: The higher the value of gain, the more money a producer can make
T
What are the only 2 factors that can be controlled regarding cattle purchasing?
- type of calves purchased
- management of calves at receiving
What are the 4 categories of calves that can be purchased from a cow/calf operation?
Category 1: preconditioned calves
- ideal
Category 2: bought straight off of one farm
-no sale barn
Category 3: fresh market calves
-sold at livestock market- havent been there long
Category 4: stale calves
- have been at market for a while
What does preconditioning mean?
- calves have had their shots
- calves are home raised
- they come from a defined program with vaccination and other requirements
AKA they are vaccinated before shipping, weaned, and trained to eat and drink out of a trough
What vaccines should preconditioned calves have recieved?
- IBR-BVD type I and II, PI3-BRSV (5 way- at least 1 dose should be modified live)
- mannheimia hemolytica
- blackleg (7 way clostridial)
*should receive at least 2 weeks prior to shipping
What does “double vaccinated” mean?
-calves have received 2 sets of shots
When should cows be weaned?
Weaning: should be at least 45 days of age
- need to be eating something besides mammas milk and grass
How can you rate preconditioned cattle?
-Weaned calves, vaccinated and from one source or calves comingled prior to purchase
-Weaned calves, vaccinated, from multiple sources
- Unweaned calves, vaccinated from a single source
-Unweaned vaccinated calves from multiple sources
What should be done with category 1 calves after purchase?
Don’t need to vaccinate, can deworm+ delouse, add coccidiostat, +/- implant
What is the only reason why you would not implant calves?
If they are being marketted as “all natural”
What should you do with category 2 cattle?
Should be vaccinated within 24 hours after arrival (5 way, 7 way), dont need to use meta phylaxis, parasite control, +/- implant
What should you do with category 3 calves?
-group that is the most difficult to develop a receiving plan for
- always recommend parasite control
-plan depends on if you have more time or more money
*should remove cattle from market as soon as possible, provide fresh clean water and good quality hay immediately
What commercial cattle product contains selenium, copper zinc and manganese?
Multi-min
What should you do with category 4- aka stale calves on arrival?
-most will benefit from metaphylaxis, parasite control
What are the main bacterial pathogens involved in BRD?
-histophilus somnus
-mannheimia hemolytica
-mycoplasma bovis (much less common in beef than dairy)
-pasteurella mulocida
-bibserteinia (a lot of people like to blame this for a lot of acute deaths)
In most cases of BRDC, what bacteria are involved?
-single agent infections are the most common
-primary one is lungs is mannheimia, followed by histophilus, then pastuerella
-bibersteinia is rarely isolated as a sole agent
What is the main bacterial agent isolated from the upper respiratory tract in BRD cases?
Pasteurella followed by mannheimia
Describe the resistance overtime to ceftiofur, baytril (enro)
Ceftiofur: going up over time
Baytril: going up overtime
Nuflour: all over the place
Penicillin: increasing over time
Draxxin: all over the place
- price has gone down recently, low dose required (can use in dart gun)
Which antibiotic should you never use to treat BRD?
Oxytet- very high resistance
What ancillary treatments can be used for BRDC?
NSAIDs, antivirals, vitamin C injections
-adding in banamine is nice
What signs should you tell a producer to look out for for BRDC?
-increased respiratory effort (open mouth breathing, neck extended, head down)
-lethargy (droopy ears), not with herd
-coughing, nasal discharge
*temp will guide treatment
What are the ideal AI conception rates, bull conception rates and season long pregnancy rates in beef herds?
AI: 60-65%
Bull: 60-65%
Season long rate: 90+%
What are the 3 most important factors in having a successful reproductive program?
-successful reproductive program last year
-cow nutrition
-bull +/- AI
What are the number one things affecting return to cyclicity in beef cattle?
Days post-partum and body condition at calving
-age (after 10- consider culling based on overall physical), suckling, presence of bull and use of exogenous hormones also contribute
Why is a successful breeding program last year important to the breeding program this year?
The earlier cows calf last year the sooner they will return to cyclicity this year and get bred back
-cows calving later into calving season have a higher percentage of reproductive failure
What is a wet 2 year old?
A first lactation heifer
- has to both grow on top of lactation
- hardest group to get bred back
How long after calving ends are bulls turned out?
Around 2 months (cannot wait much longer)
- allows adequate time for uterus to involute before being bred back
- early embryonic death decreases as days post partum increases
Is it easier for spring cows or fall cows to have a good BCS at calving?
Fall cows
- harder to have them gaining weigh during breeding season
*spring cows are the opposite
T/F: For spring calving cows, mother nature takes care of the positive plane of nutrition at calving
False- this is true for fall calving cows
- for spring cows, mother nature takes care of this at breeding
Why do we care about reproductive profiling?
- important metric for determining herd repro performance (required for beef cow-calf herd economic sustainability)
-create focused herd repro health program
-assist in diagnostic strategy for suboptimal repro efficiency
-guide design of intervention strategies
What should be the focus of the repro profile?
- distributions of calvings within a calving season
- number of calves born per cow exposed
- length of calving season
What are the goals of a repro profile for a traditional bull bred herd vs a herd using timed AI with a clean up bull?
Bull bred: all cows cycling at the beginning of the season
-65% total preg in first 21 day cycle, 23% in second cycle, 8% in third cycle
- less than 4% open at end of breeding season
- front end loaded calving season
AI with clean up: 75-85% pregnant within first 30 days of breeding season
-55% pregnant in first 21 day cycle by AI (goal is to have them cycle twice in one month)
-allows maximization of front loading of calving season
What does front end loading of the calving season allow for?
- more opportunities for cows to get pregnant (reduces number of open cows at the end and increases calves to sell)
-calves born earlier will weigh more and result in increased value per calf at sale
-cows stay in the herd longer (decreases numbers of replacements needed and replacement costs)
-allows for shorter period of intensive watching/processing of calves
If 10 calves are bled for a BVD titer, and 2 had high titers, and all ear notch tests are negative, what does this mean?
At some point this group of calves were exposed to BVD
T/F: over 90% of US beef herds are now using AI in addition to a bull
False
- 90% still only using bulls
-bull is responsible for over 50% of the reproductive program in most beef herds (bull has to do his job, cow has to do hers)
What is the cost of owning a bull?
25-50$/pregnancy
What are the owners responsibilities to assess bull fertility? Veterinarians responsibility?
Owner: evaluate libido and watch for problems
Vet: Breeding soundness exam- only part of the bull evaluation
What is the ideal bull to cow ratio?
In mature bulls: 1:25-40
In yearlings: 1 cow per month of age until 30 months old
- turn out at 15-16 months
What percent less bulls do you need if you are adding in a timed AI program?
25% less bulls
-always want to have enough bull power in these herds
What is the bare minimum that cow/calf herds need to record to set up a repro profile?
BCS at beginning and end of breeding season (record weights of heifers), calving date, preg checks (extend possible calving interval 21 days on either side), udder health, general health (feet, eyes), weaning weights
What are the principles behind a good biosecurity program?
Know the source of the infection, know who is susceptible, understand the mode of transmission
What are the 3 main principles of biosecurity?
- stringent bio-exclusion
- ruthless biocontainment
- early detection/vigilant surveillance
Describe the appetite vs tolerance concept regarding risk
Appetite is the owners willingness to go above and beyond to keep disease out of their herd
-tolerance is what they are willing to accept in terms of disease prevalence
*you want to try and create an environment that encourages clients to tell you when they are having problems keeping disease out- vs them becoming tolerant
What should you do before recommending a certain program to keep a disease out of a herd?
Make sure the client understands the risk and is willing to comply
- make sure they understand the outcomes that may come of the testing
What are some cattle diseases that can be controlled (minimized) but not eradicated?
Johnes, Tritrichomonas (can minimize through AI, can test bulls, maybe test cows), Moraxella bovis, mycoplasma bovis
What are some factors that ease the eradication of disease?
-easily identifiable, produces severe disease
-rarely subclinical
-no carrier state or recrudescence
-one immunotype
-no animal reservoir
-inexpensive vaccine
If a client wants to get rid of a disease in their herd, what are the next steps you should take?
-find out whats currently present in the herd
-discuss each pathogen and its relevance (are they getting paid more for disease free cattle, is the disease affecting production-ringworm doesnt affect anything, are they trying to avoid quarantine or depopulation in the case of TB or brucella)
-determine whether the client is willing to get rid of or isolate positive cattle (client must accept that no test is 100%)
-set up testing strategy for incoming cattle (ideally prior to entry, isolate facilities after entry)
What can diagnostic tests tell you?
Pathogen detection (culture, virus isolation, PCR, ag capture elisa, IHC, mcmasters) with clinical signs= infected and likely infectious
Pathogen detection and no clinical signs- infected or carrier, may be infectious
Serology: exposed or vaccinated, may be infected or infectious depending on the pathogen
- best used for organisms without a vaccine
How does baysean analysis play into pathogen testing?
What you know prior to the test influences your interpretation of the test
What does culture/viral isolation vs PCR vs immunochem/ag capture vs serology vs skin tests tell you?
Culture/viral isolation: live organism is present
PCR: organism is present, may be dead or alive
-good at detecting low amounts of organism- can complicate interpretation however
Immunohistochem: tells you organism is present and shows where it is causing infection
Serology: IgM raises before IgG
- with some diseases, presence of titers infers infection (BLV, anaplasma)
- increases or decreases in convalescent titers suggest exposure (BVDV, IBR, lepto)
-4 fold rise= 32 times original titer
Skin test: results in a type 4 hypersensitivity in positive cases
-poor individual animal test, but its all we have
What is the difference between a screening and a diagnostic test?
Screening test: tends to be cheaper and/or faster
-may identify a preclinical phase
-rules in or rules out
-determine if pathogen is in a herd
Diagnostic or confirmatory test: confirms a diagnosis
-identify the infected animals
T/F: the same test can be a screening and a confirmatory test
True
T/F: the physical exam is a screening test
True
- guides what diagnostic tests you will do next
What are the benefits to pooling samples for PCR?
Acts as a screening tool
- can save money and only run confirmatory test on the pool that tested positive
Why is it easier to find TB in a herd vs on an individual basis?
Live animal tests better on herd basis (caudal fold test)- not good for individuals
- gold standard for individuals is PCR after necropsy
When is testing commonly done for TB?
For sales and interstate transport of purebred animals
-individual herds can do CFT testing annually or biannually to be labeled as a TB accredited free herd
T/F: the US is currently considered free of tuberculosis
True
-main risks right now are deer in Michigan and cattle from Mexico
Describe the regulation of brucella in the US currently?
-federally regulated control based on vaccination and testing
- screening tests are based on serology
- most states are free (yellowstone bison are infected and mexico still affected)
- herds can test annually and become brucella certified
Should we continue to vaccinate for brucella?
- there is a human health risk with vaccine (can be found in milk)
- people may stop vaccinating for this reason
Describe the control measures of Johnes in the US
-voluntary program which combines risk assessment and herd testing
- screen with ELISA and follow with fecal culture or PCR
- no herds are designated as free, get a herd status score (high to low risk)
Describe the clinical features of bovine leukosis
-widely prevalent in dairies, less in beef
-blood transfusion thought to be primary route of transfer
-screening and confirmatory tests by serology (AGID or ELISA)
-young cattle (<6 mo) may be positive due to antibody interference
-seropositive cattle may be less productive, cows that get leukemia and lymphosarcoma die
How is anaplasmosis transmitted?
-endemic in southern states, moving north with ticks
-can transfer via tick bites or like BLV on needles, tattoo guns, etc
-calves and yearlings are fairly resistant (can make RBCs fast enough to replace loss)
-kills native adult cattle
-serologic testing or PCR for carriers, may see marginal bodies on blood smear of acutely infected cattle
How is BVD persistent infections controlled?
-primarily through vaccination
-PI cattle can be identified through ear notch
-data is conflicting as to benefit of keeping PIs out of feedlot, good idea to keep out of breeding herd
-same test used for screening and confirmation 3 weeks apart (a small percentage of ear notch cattle may be acute infection and can clear in 3 weeks)
What cattle should be tested for tritrichomonas?
All bulls over 18 months or all non-virgin bulls
What is recommended to keep mycoplasma and staph mastitis out of a herd?
Culture cows prior to putting into herd
What is recommended to keep neospora, lepto and theleria out of herds?
Test prior to entry into herd
What is the main challenge for getting rid of IBR?
They can form a latent state in neurons
What is the national veterinary accreditation program?
A program through the USDA: federal and state veterinarians authorize veterinarians to perform certain regulatory functions
- any vet can be nationally accredited
- this is voluntary, must be authorized by each state
- goal is to increase effectiveness, credibility, and global recognition to ensure continued health and well-being of US animals (animal health and disease prevention and preparedness for future)
What do you do as a US accredited veterinarian?
-testing, vaccination and certificates (health certificates)
-conduct surveillance and monitoring for diseases of concern
What is the difference between category 1 and category 2 accreditation?
Category 1 includes all small animals
- 3 training modules per 3 year renewal period
Category 2 includes all of the category 1 animals plus farmed food/fiber animals
- 6 training modules per 3 year renewal period
What is the most important job of a USDA accredited veterinarian?
-must immediately report to the area veterinarian in charge and state animal health officials all diagnosed or suspected communicable animal diseases for which USDA control or eradication program exists or all diagnosed/suspected cases of foreign animal disease
What is the eradication program for brucella?
This is zoonotic- no treatment in cattle
- in humans, can be difficult to treat
- humans acquire from drinking from raw milk
Moving from census based to statistical sampling for slaughter to reduce the number and cost of testing
- involves slaughter sampling of blood and lab based surveillance of abortions in cattle
All states are status free
What are the rules for the brucella vaccine?
Only use in females 4-12 months of age
-have to put in tattoo on ear - RB 51
How is tuberculosis transmitted?
Through respiratory and mammary secretions
-has variable intubation period, weeks to years
-highly contagious
ZOONOTIC
What type of surveillance is most common for TB?
Slaughter surveillance followed by epi investigations of affected herds (caudal fold tuberculin testing with supplemental comparative cervical Tb test)
- retest with comparative cervical must be within 10 days of original caudal tail test (or else you have to wait 60 days and no animal can go off of that farm during that time)
T/F: BSE is contagious
False
- but the variant Creutzfeldt-Jakobs disease in humans is linked to meat consumption from positive cows
-US is currently classified as negligible risk
What are the current control efforts for BSE?
-prohibition of the slaughter of down cows
-inhibiting the feeding of mammalian meat/bone meal in animal feed
-prohibiting specified risk materials (neural from >30 m) in any product
-destroying animals showing signs or at high risk
Describe the control strategies for pseudorabies in the US
-All 50 states free but feral swine is a reservoir
-prevention with biosecurity, management - aka depopulation of infected herds
-can cross species
-there is a vaccine available- need USDA approval for use- controls spread but not infection
Describe the control of scrapie (transmissible spongiform encephalopathy) in the US
-70 year battle
-can test brain or lymphoid tissue
-remove overtime with selective depopulation
-codon testing (qq- susceptible to scrapie, qr– resistant but care needs to be taken when breeding, rr- resistant)
Surveillance- regulatory slaughter surveillance and scrapie free flock certification program
-if suspected- contact aphis and they will collect and test sample for free
Describe chronic wasting disease of cervids
-transmissible spongiform encephalopathy
-no cure of vaccine
-diagnosis: collect retropharyngeal lymph nodes and brainstem for ELISA and IHC
Control:
-voluntary herd certification of farmed herds (USDA)
-wildlife services strategic plan - usda aphis wildlife services
What are cattle fever ticks?
Rhipicephalus annulatus and microplus
- vector for babesiosis (foreign animal disease) and anaplasmosis
- eradication for babesiosis in US started in 1906
- control now confined to tx/mexico border- includes dipping and tick riders (cowboys looking for cattle crossing the border)
What agencies are involved in protecting against foreign animal diseases?
- world organization for animal health (OIE)
- food and agriculture organization (FAO)
- USDA APHIS- vet services unit
- department of homeland security
What control measures should backyard flocks use to protect against avian influenza?
-get poultry from certified disease free sources
-quarantine new birds for 21 days minimum
-limit your birds access to wild birds- bird feeders, waterers
-dont mix ducks, chickens and turkeys
-BIOSECURITY
Defend the flock - good resource for clients
How is newcastle different than avian influenza?
- very similar clinical signs to HPAI aka sudden death
- much more rarely zoonotic- causes conjunctivitis in humans (less severe)
-there is a vaccine available- doesnt stop spread but reduces effects
What are the main tools to control foot and mouth disease?
-enhanced biosecurity
-rapid diagnostics
-national movement standstill (72 hour period where any cloven hooved animals can move in the US)
-trace backward/forward
-depopulate and carcass disposal
-vaccination is available- held in stockpiles as a pre-vaccine which will produce a lot of doses very quickly (no strains of vaccine are cross-protective)
Long intubation and lots of modes of transmission make this very hard to control
Describe how FMD shows up in sheep/goats vs swine vs cattle
Sheep/goats: maintenance hosts, silent spreaders
-can carry/shed virus for up to 12 months in sheep, 4 months in goats
-limited signs
Swine: amplifying host
- produce 10^6-10^9 infective virus doses daily which are shed in all excretions
-hoof lesions, vesicles, sudden death in piglets
Cattle: host that shows the most
- often first species to show clinical signs
-can carry virus for up to 6 months- some may remain infected for up to 3.5 years
-signs: vesicles, teat lesions, foot lesions, heavy calf loss
*in all groups, babies are the ones that die
*not a zoonosis
Describe classical swine fever
-highly contagious viral disease- aka hog cholera
-once endemic in US, eradicated in 1978
-reservoir is wild boar and domestic swine
-variable virulence and clinical signs
Control: stockpile vaccines
- MLV effective but does not allow for differentiation between vaccination and exposed
*can be spread through feeding uncooked garbage (insufficiently cooked meat)
What is african swine fever?
-contagious viral disease of swine only
-spread via soft ticks, feral and domestic swine
-4 forms of disease based on virulence (signs can be insidious or severe with mortality approaching 100%)
-recently has been found in haiti and dominican republic
-no vaccines available- chinese failed with vaccines and created new strains of virus by accident
What are the 3 main goals of the FAD response?
-detect, control and contain
-eradicate- stabilize animal ag, food supply
-provide: science/risk based approaches and information
Whos in charge of FAD outbreaks?
USDA area veterinarian in charge and state animal health official
- assign a FADD (foreign animal disease diagnostician) which took a course- only person allowed to collect samples in FAD investigation
What is the center for food security and public health and how do they play a role in FAD outbreaks?
-collaboration between industry, state governments, USDA and academia
-provide guidance to livestock producers to voluntarily prepare for a FAD outbreak
What is the role of VDACS?
-state level animal disease control and prevention
- they investigate outbreaks, contain the spread, and play a role in preparedness
- they overlook CVI (certificates of veterinary inspections)
- they have oversight of livestock marketing facilities
- and they are in control of the animal disease traceability program
How long do CVIs last?
30 days
What is important to remember about statements on a CVI?
State requirements vary- some require specific statements about certain diseases
-also test requirements and permit numbers may vary per state
T/F: the dirtier the cows, the higher the SCC
True
What are the steps of the milking procedure?
- Provide a low stress environment
- adrenalin can interfere with release of oxytocin which is required for milk let down - Check foremilk and udder for mastitis
- pre-dip teats with an effective disinfectant
- steps 2 and 3 can be interchanged - Completely dry teats with a single use towel
- Attach milking unit within 120 seconds of teat stimulation
- Adjust milking units as necessary
- Shut off vacuum before removing milking unit
- Dip teats with an approved post-dip disinfectant
What is the purpose of stripping the teats?
-visually checking for mastitis into strip cup
- removing highest somatic cell count milk
- stimulating milk let down
-ideally want unit on within 60-120 seconds of stimulation of the teat to avoid milk losses
What are the ideal characteristics of pre-dip?
-something that both sanitizes and disinfects
-decreases the number of bacteria at the teat end
-must be an approved dip
-purpose is to kill any bacteria/fungi at teat end (environmental pathogens)
-must use an approved dip
-contact time is a minimum of 30 seconds
What is the mechanism of action of most teat dips?
Germicide action
- iodine oxidative is commonly used- damages all bacteria (65% of what is used)
What percent is the best you can do to reduce bacteria during milking procedure?
85%
- relative risk is better with proper hygeine prior to milking
What are the 4 hygiene scores?
1: free of dirt
2: slightly dirty
3: moderately covered with dirt
4: covered with caked on dirt
Similar scores for teat end cleanliness- due to presence of pre-dip or dirt after wiping
Why are hoses never recommended for cleaning teats?
washes all the bacteria from higher on the udder to the teat end
What type of commonly used milking system do not dry cows?
Robots
- not good for reducing bacteria
How can we make sure that milk let down is ok?
-well stimulated teat
-proper lag time (largest influence on rapid and complete milk out)
- watch milk bowl- if milk isnt filling this is a problem
What is lag time?
The time from stimulation to when the milking unit is attached
- 90 seconds is ideal
- long lag times= losing milk
-low lag times= redisposed risk of mastitis
Why may cows have a dry/blind quarter?
Usually secondary to chronic mastitis and scarring of the teat
- seen very commonly
How do you differentiate an abscessed quarter from regular mastitis?
Looks like pus- smells foul
- usually caused by trueparella
- often also have sloughing material
Treatment: open up and debride
- teat amputation
- kill quarter with 10% iodine
- utilize pain meds as needed
How should the milking unit be placed?
-one teat at a time
-try to avoid squawking- indicates improper seal
-position of liner should be up to the base of the udder (covering whole teat end)
How fast should a cow milk out/how long does milk let down last?
4-6 minutes ideal
- high milking times are a reason for culling
-milk letdown lasts 6 minutes
*milking time is the same regardless of milking volume
Describe how the milking unit should be removed?
-automatic takeoffs- when milking <0.5 L/min
- manual- when there is little milk entering the bowl
- turn off the vacuum to teat and allow unit to fall off- DO NOT PULL OFF
What would be a sign that automatic takeoffs are coming off too late?
Hyperkeratosis
- amount of milk left in the quarter- should have at least 1/4 cup left after removal
What can you measure in a parlor without any machines?
Pre-dip time, lag time, teat end scores, hygiene, residual milk, teat end cleanliness, turn times
What is the purpose of post dip?
Reducing contagious pathogens
- often contain conditioning agents
- provide bactericidal agents between milking (ideally cows should stand for a couple hours after)
Describe the different types of post dips
Bactericidal agent- 1% iodine most common
Emollients: glycerol
Barrier dips to seal off the end of teat- thicker
Powder for freezing conditions- not the best but otherwise they will freeze
How long does it take for the teat sphincter to close?
2 hours
- keep cow standing- provide feed and water
How do you know the milk line vs the vaccum line in most barn types?
Milk line- will be stainless steel
Vaccum- will be white
Long blue line- carries milk
Black line- where vacuum goes to the pulsator
What is the difference between parallel and herringbone parlors?
Parallel: can fit more cows, harder to get them in, fairly efficient
Herringbone: less space efficient, easier for cows to get in, working from side of animal vs back
What is a tandem parlor?
Cows go in horizontally
- gate closes in from the side
- takes up a lot of space
What do flowmeters measure?
-conductivity
-pounds of production
-flow for automatic takeoffs
What are the main goals of winter ventilation?
- control humidity (goal between 50-70%)
- control drafts (unwanted air movements)
- control heat
- control noxious gases (ammonia, methane, carbon monoxide)
- control disease agents
- control dust (from bedding, animals, feed)
- air exchange 5 X/hour
What happens if humidity is too high during the winter? If too low?
High:
- makes the air feel colder
- bacteria and viruses survive better
Low:
- makes it harder to breath- decreases mucociliary apparatus function
What is the main source of ammonia in the environment around dairy cows?
Feces
-contains high amounts of undegraded protein which are degraded into ammonia through bacterial breakdown
-best way to avoid high ammonia levels is to remove feces
How can you remove dust from feed?
-Add fat
-pelleted feed
Adding water not recommended- will spoil quickly
What are the main goals of summer ventilation?
-controlling heat- 50 exchanges per hour
-control gases
-control disease agents
- control dust (not as much of a problem due to higher humidity levels)
Why is production lowered through heat stress?
These animals eat less
How do animals create moisture and heat?
Moisture through sweat, urine, feces, respiration
Heat- body generates it
What does ventilation remove?
Moisture, heat, dust, gases, disease agents
T/F: pressure inside the building must equal the pressure outside the building
True
- if higher in inside - the barn would explode
- if higher outside- would implode
What are the primary principles of natural ventilation?
Hot air rises and cold air sinks
Why do hot fires burn faster?
More hot air leaving quicker= more oxygen coming in from surrounding areas
What is the purpose of a ventilated ridge on the top of modern barns?
Allows hot air to escape
From what direction is the prevailing wind in north america? How does this impact the direction we want our barns to be built in?
From southwest
Want barns to run east to west so building is either facing south or north
T/F: the deeper the slope of a roof, the slower air can travel
False- faster
What allows for airflow into a barn?
A gap between the walls and the roof
- roof always extends a foot or two beyond the wall
- allows air to flow in
Wind allows the warm air to be removed faster
What is done with the side curtains on the walls during the summer?
They are lowered to allow more air to enter, and thus more hot air can be removed
What occurs to the moisture as air is removed?
- moisture is also removed
Why does condensation occur?
Due to a cold hot interface
- always occurs on the warm side as warm air contains more moisture than cold air
When is condensation a problem in buildings?
When it causes mold to build up on the roof
- can be controlled with insulation
T/F: cold air expands when it enters a warmer area
True
- it spreads out and therefore holds less water/humidity
- can be used to reduce humidity in a barn during the winter
How can you aid in ventilation when there is no natural breeze?
Mechanical ventilation
- positive= air pushed or blown in
- negative= air is pulled or sucked out
What is the venturi effect/bernoullis principle?
Air travels faster through a smaller opening
- air travelling fast travels farther due to momentum
*like a thumb over a water hose
What should you do to best evaluate the ventilation in a facility?
Get at the level of the animals
T/F: barns are designed for a certain number of cows in order to ensure adequate ventilation
True
What is the best way to maximize the use of fans?
Have them pointed down onto the animals
-keep them clean- dirt on fans can reduce the amount of air that can be pushed by 10%
- use larger fans to accomplish greater air turnover
What are the main goals of milking systems?
-harvest milk as fast, efficient and safe as physiologically possible
-important to maintain equipment to optimize milking and milk quality
-dysfunction of milking machines may influence development of mastitis
-dysfunction or improper technique can damage teat end or teat canal and can be a risk factor for mastitis
What are the 6 basic parts of a milking system?
- The vacuum pump- removes air from system to pull milk from the claw (rated in cubic feet per minute)
- vacuum regulator or controller- keeps the vacuum at a consistent level to avoid teat end issues
- receiver- where milk first enters
- pulsator- allows vacuum into and out of the milking unit- important for rest phase
- milking units
- vacuum lines
What is the vacuum usually set to?
13 “ mercury
What does the number of vacuum pumps depend on?
The size of the parlor
- goal is to maintain vacuum without large fluctuations
What is the vacuum reserve/balance tank?
-provides vacuum reserve to minimize fluctuations across the system
- makes up for air let into system
-collects moisture and dirt to protect the pump (newer units may have separate filtering unit)
T/F: the vacuum regulator controls vacuum level by admitting/restricting air into the vacuum system
True
Why is the vacuum at the teat end lower than what the system is set to?
To avoid teat end damage
What are some causes of vacuum fluctuations?
-Inadequate vacuum reserve
-pump being too small for system
-malfunctioning vacuum regulator
-inherent leaks in system
- this can introduce bacteria into teat end and set up micro air currents that mobilize bacteria and bacteria can blow into teat canal
How are vacuum levels measured?
-across the system with a vacuum recording device
- measure under load, in claw at peak milk, fall off levels, with 1-2 units open etc
What should the vacuum level be at peak milk?
11.5-12.5 Hg
Describe the milks trip through the system
Teat end–> inflation/liner–> short milk tube –> bowl–> long milk tube–> milk line–> receiver jar–> milk sock–> plate cooler–> bulk tank
What do the pulsators do?
- they regulate the milk/massage phases of the teat cup liners
- allows alternating vacuum/atmospheric pressure into teat cup chamber
- attached to pulsator vacuum line
- manual, digital (what most of them are)
- the space in between the inflation and shell allows for the buildup of atmopsheric air
- the vacuum removes atmospheric air and allow milk to flow out of the teat
- short pulsator tube sets the vacuum between the shell and liner
What is the function of the short milk tube?
Transfers milk from the shell into the milk bowl
What is the difference between the pulsator rate and ratio?
Rate= number of complete milk/massage cycles per minute (45-60)
Ratio = % of time that the teat is being milked (milk: rest ratio)
What is the vacuum doing during your milk phase and rest phase?
milk phase- vacuum is at its highest (B)
rest phase- vacuum is at its lowest (D)
Should be graphed to make sure they are opening and closing correctly
What does bimodal milk flow indicate?
A cow that was not stimulated correctly
- can also see when flow out of the canal is greater than flow into teat cistern (late automatic take offs
What do you use to assess when a cow is done milking in a system without automatic takeoffs?
- flow into the milk bowl
What is conductivity of milk?
- how many sodium ions there are in milk
- goes up with mastitis
What should be the slope of the milk line so that it can flow by gravity into the reciever jar?
At least 1 inch per 10 ft
- from the receiver jar, the milk pump takes it to the bulk tank after moving through the milk sock
What is the purpose of the milk sock?
It is a filter
- cleans out hair, dirt and garget
should clean out between milkings
- lots of chunks= milking mastitis cows
- also lets you know cleanliness of cows
- can culture material to see what pathogens may be present in herd
Describe the function of the plate cooler
- cools milk through a counter current exchange
- milk is cooled from 100 F to 40 F through plate cooler and bulk tank (often refrigerated, if insulated well can cool without refrigeration)
What does the agitator in the bulk tank allow for?
Periodically turns on to stir milk
- keeps the milk from separating
-helps with thermoregulation within the tank
When should the teat cup liners be changed?
Every 1200 milkings
How often should the milk lines be washed?
At least twice a day
What is the maximum amount of time animals should be in the holding pen?
1 hour
What is the leading cause of lameness in dairy cattle in the US?
Digital dermatitis
What is the classic location of the M2 lesions aka acute lesions?
At the heel bulb, interdigital
- want to treat these
- ideally treat multiple times
What are the main risk factors for digital dermatitis?
New animals in herd, poor hygeine, trauma, young animals, poor micromineral supplementation, management
What is the chronic form of digital dermatitis?
“hairy warts”
- M4 proliferative lesions
- these cows are carriers within the herd
If you have continuous cycling between M2-M4-M2 what may be the management issue?
Foot baths
- need to be done on a regular basis
- make sure they are clean and you are using appropriate substances
What is the treatment for digital dermatitis?
Superficial lesion
- painful and causes them to walk on toes
What are the bacteria responsible for digital dermatitis?
Treponema and other anaerobes
- treat topically with oxytet powder in place for 48 hrs minimum
What is the spectrum of tetracyclines?
Spirochetes, rickettsial
- broad spectrum
What are the top 3 areas for controlling DD?
Management, hygiene and nutrition
Is DD seen in beef cattle?
Not as much as in dairies
- moisture is a big risk factor
- very big problem on feedlots
How long does it take for an M2 lesion to occur?
Can take 3-4 months
- why it is hard to keep out of herd
- new animals may not show lesions
What are some overall success factors to reduce lameness?
Lower infection pressure: cleanliness (hygiene scoring), foot bath management
Low forces on feet: improving cow comfort
- try to maintain 12-14 h resting time
Early detection and treatment
- have a person responsible for finding lame cows
Good horn quality and shape
- regular trimming and balanced nutrition
T/F: The goal for hygiene scores should be that <50% of cows are graded 3s and 4s
F- should be less than 25%
What are the main minerals essential to maintaining hoof health?
- trace minerals
- zinc acts as bricks, biotin acts as mortar
- Mn supports joint structure and bone density
- Cu supports synthesis and maintenance of ligaments, tendons, bones and cartilage
- Se: antioxidant and immunity, protects cell membranes
How should lesions be recorded on a farm?
- Infectious (digital dermatitis and foot rot)
- Sole ulcers
- White line disease
- Upper leg lameness
What are the main uses of lameness scoring?
- early detection and ranking severity of lameness
-monitoring prevalence of lameness in a herd
-can help estimate loss of profits in a herd
-benchmarks can be established to determine whether established prevention measures are effective
-comparing the incidence and severity of lameness between herds
-identifying individual cows for functional claw trimming
What are the lameness scores?
1- stands and walks normally with a flat back, long confident strides
2 - stands with flat back, arches when walks, slightly abnormal gait
3- stands and walks with arched back, short strides
4 - arched back standing and walking, favors certain legs
5- constant arched back, great difficulty moving
What is the ideal level of clinical lameness in a herd?
<10-15%
What is the key for management of lameness?
Foot trimming!
- ideally done twice a year
What are some of the guidelines for hoof trimming?
-start with the hindlimbs
- trim toe length to 3 inches
- start on lateral claw and trim starting at toe (dont trim much from heel- usually overgrow at toe)
- trim medial claw from toe
- try to balance claws all the way across- to avoid sole ulcers (sole should be flat all the way across both medial and lateral claws)
-dish out ulcer sites to transfer weight to surrounding areas (weight shifted onto wall, toe and heel)
- find any lesions and correctively trim the foot (look at white line, soft tissues)
What is the ideal heel depth?
At least 1.5 inches
What are the most common trimming errors?
-trimming toes too short
- trimming soles too thin
- rounding the toe- ok
- failure to remove sufficient thickness of the sole at the toe in overgrown claws
- over trimming the heels
- over trimming the inside claw heel
- trimming abaxial wall for cosmetic reasons
- removal of axial wall at the toe
- sloping the sole
- excessive trimming or thinning of axial wall
- failure to trim the sole flat from heel to toe
- failure to balance weight bearing surfaces between the two claws
*trimming is an art, not a science
Where is foot rot found most commonly- what is the treatment?
Interdigital space- deep lesion
- treatment is systemic oxytet or macrolides
T/F: sole ulcers are seen more commonly in dairy
False- beef
- very common in feedlots
T/F: if in doubt with upper leg lesions, try meloxicam and rest
True
- though cant do in lactating dairy cows due to long milk withdrawal
Describe some of the main features of alpacas
-domesticated versions of vicunas (from south america- adapted to high elevation, cool areas)
-spear shaped ears and smooshed face
-weigh an average of 150 lbs
-herd animals=skittish
-produce finer fiber, more fleece, come in large variety of colors
Describe some of the main features of llamas
- domesticated version of the Andean guanaco
- have banana shaped ears and longer face
- larger stature (up to 400 lbs)
- more independent minded- good guard animals
- more commonly used as gaurd animals or for meat
T/F: alpaca wool lacks lanolin
True- makes it hypoallergenic
- their wool is also flame and water resistant
What is the difference betweeen the huacaya and suri types of alpacas?
Huacaya- wooly dense crimped fleece
- most commonly seen in US
Suri- long/silky dreadlock fiber
T/F: llamas and alpacas can cross- breed
True
- create huarizo offspring
What does it mean when your alpaca is humming?
They may be curious, content, worried, bored, fearful or cautious
T/F: llamas are ok being the solo animal
No- they are social and like to be in packs
- should have at least 2
Describe some of the basic husbandry principles for llamas and alpacas
- they prefer cool dry winters and mild dry summers
- heat stress is a major concern, so ventilation/air flow and shade is essential
- dry ground ideal- straw bedding in winter
- ensure enough space in barns due to herd hierarchy
- need separate facilities for hospital/maternity/quarantine
What is the humidity and temp where you dont want to work llamas or alpacas?
If the temp and humidity additive is greater than 120- unnecessary handling should be avoided
- if greater than 160 dont do anything with them
Describe the nutrition of llamas/alpacas
-eat 2% BW in dry matter, if pregnant lactating or growing should get 1.5-2X maintenance
-offer fresh hay daily
-use camelid or sheep labeled mineral mix (have a risk of copper toxicity)
What is the recommended stocking density of camelids?
No more than 5-7 camelids per acre if there full time
- parasite management is made easier as they create a dung pile (usually created near feeders or inside shelter)
Describe how camelid shearing/trimming should be conducted
- thermal window for heat dissipation at the minimal (ventral thorax and abdomen) but full body is preferred
- should be done by July 1st at the latest
-trimming should be done 2-3 times per year - mouth examinations should be performed at shearing
- perform monthly BCS
How should you manage lacerations, burns or sunburns related to shearing?
Lacerations- common in areas with loose folds of skin
- clean and allow to heal by second intention
Burns from hot shears
- lead to thick scaps, usually on dorsum
- resembles wool rot
- treat with antibiotic ointment
Sunburn
- more common in light skinned animals
- protect from further exposure and treat with aloe vera
What is one of the main contributor to hyperthermia in camelids?
Obesity
What are some of the main signs of heat stroke in camelids? What steps should you take?
- open mouth breathing and inability to maintain neck/body upright
- hyperthermia, recumbency, edema of ventrum, perineum, legs
Diagnostics: HCT, renal function markers, severity of hyperlactemia and metabolic acidosis
Treatment: move to cool shady area
- IV fluids with peracute form- risk of shock
-with subacute recommend shearing, pools of water, chilled fluids, supportive care
What is one of the main hoof conditions seen with camelids?
Ulcerative pododermatitis aka immersion foot
- moist conditions predispose
- causes footpad blistering/sloughing
Treatment: debridement, antiseptics, foot protection, systemic pencillin
- long healing period
Describe how you manage the teeth of camelids
-lower incisors grow continuously
-underbite common- lower incisors should meet rosttral end of superior dental pad
- trim using dermel, powdered incisor trimmers or gigli wire
- they have 3 pairs of fighting teeth that you may need to trim to protect injury to humans (remove sharp point with dremel or gigli wire, leaving 2-4 mm of the crown above gumline to prevent abscessation, extraction not recommended due to nerve proximity and risk of mandibular fracture)
- molars should be examined for abnormal wear and points- float only if abnormal wear and weight loss are noted
-tooth root abscesses are common
When should castration be performed in camelids?
-around 18-24 months
-wait until after they have reached skeletal maturity to avoid orthopedic problems
- can do standing or anesthetized
What is the only core vaccine in camelids?
CD & T- same as sheep
- should get twice at a 3-6 week interval when they are 3-4 months old (earlier if concern about passive immunity)
-booster annually or at times of wounds or surgery
7-8 way clostridial can be given if risk is present
Lepto- endemic areas as needed
- not labeled for camelids- can use sheep/cattle vaccines
Rabies- in endemic areas
West nile - naive young or immunocompromised in endemic areas
Can consider EEE, EHV-1, rota/corona
BVD vaccine NOT recommended
What should be done to manage internal parasites in camelids?
-deworming recommendations are constantly changing
- when parasites are an issue, should evaluate fecal egg count- repeat 2 weeks after deworming, stocking density and dung pile management
Note: FAMACHA not as helpful- lots of things can cause anemia
What is the main parasite of concern in camelids other than H contortus?
EMac- eimeria spp
- if you see even 1- pathogenic (must use special float)
- treat with amprolium, ponazuril, sulfadimethoxine
Why is blanket deworming not recommended?
Want to maintain a refugia population
- pair FAMACHA with fecal egg counts
- dont deworm unless Famacha score is high with high parasite load
Which dewormer should you avoid in the first 30 days of pregnancy?
Albendazole
What is the main concern associated with levamisole?
Overdose
- requires very accurate dosing/weights
What is bioworma?
A product containing a fungus that stops larvae from hatching in feces
- only works if >50 degrees outside
What should be the first test that you run in an older animal with chronic weight loss?
Johnes
What are the common causes of colic in alpacas?
C3 ulcers most common, impactions also common, but many other things can cause
When do camelids tend to get uterine torsions?
At 6-8 month mark
- unlike cows that get these near parturition
What is the cause of third compartment (C3) ulcers in camelids?
-little is known, associated with stress, high grain diets, NSAID use, concurrent GI disease, grazing lush pasture
-most ulcers occur around greater curvature of caudal flexure near pylorus
-risk of anemia or perforation
-best trt is injectable pantoprazole
-depending on severity can consider blood transfusions, antibiotics, surgery or euthanasia
What are the main differential diagnoses for anemia in camelids?
- haemonchus contortus
- bleeding gastric ulcer
- mycoplasma haemolamae
- anemia of chronic disease
- neoplasia
Describe the main clinical features of meningeal worm
-P tenuis
- one of the most common causes of neuro illness and death in camelids
-causes ataxia–> difficulty standing–> ascending paralysis
- after ingestion worm enters spinal cord caudally and migrates cranially
- exposed to intermediate larval stages through accidental ingestion of infected terrestrial slugs and snails
- natural host is white tailed deer
Treat with panacur
Describe the lifecycle of P tenuis
-adult worms lay eggs in meninges of white tailed deer which are passed into venous circulation and travel to lungs where they hatch into 1st larval stage
- deer cough up L1, swallow and pass in feces
-larvae invade or are ingested by snails/slugs where they develop into the third larval stage over 24 weeks
- infected snails are ingested by accidental hosts
-signs begin 45-53 days after infection
What testing is done for P tenuis? what is the treatment?
-no good antemortem tests, though eosinophilic inflammation in CSF is highly suggestive
- nested PCR from formalin fixed tissues
Treatment: high dose fenbendazole (10x normal dose) for 5 days, can also add parenteral ivermectin and anti-inflammatories
Prevention: monthly dewormers in areas where it is endemic, minimizing deer populations, use of molluscicides on outer fence rocks
What are the main skin disorders of camelids?
Pediculosis, dermatophilosis, clipper burn
What is pediculosis
Lice- affects heavily fleeced areas
- if sucking lice, treat with injectable ivermectin + maybe blood transfusions if severe, if biting lice (more common) treat topically with pyrethroids
What skin conditions tend to affect the more lightly fleeced areas of camelids?
Bacterial folliculitis
- staph most common
- leads to erythema, and patchy crusty or exudative hair loss on head, back, ventrum or distal extremities
- culture ideal
- use systemic antibiotics and antiseptic shampoo
What areas of the body are most affected by ringworm?
Legs, head and perineum
- usually not pruritic
How do you diagnose mange? What is the treatment?
Deep skin scrape to look for sarcoptes (causes most intense pruritis), chorioptes (most common in north america), psoroptes (mainly affects ears) or demodex
Treatment: parenteral doses of ivermectin, may need higher doses with chorioptes + topical products (may have to treat entire herd)
What are some non infectious skin disorders of camelids?
-zinc responsive dermatosis (occurs in likely haired regions- non pruritic, treat with zinc or minimum of 2 months)
-idiopathic nasal or perioral hyperkeratotic dermatitis
-idiopathic necrolytic, neutrophilic, hyperkeratotic dermatosis
-dorsal nasal alopecia (alopecia over bridge of nose, seen more commonly in dark faces animals, treat with systemic or topical therapies)
When do you tend to see munge?
6 mo-2 years
- lesions may wax and wane
- may be associated with underlying immunodeficiency
- will see lot more erythema compared to zinc responsive dermatosis
-treat with topicals or systemic antibiotics, in severe cases steroids
T/F: camelids are induced ovulators
True
- require introduction of seminal plasma to induce LH surge or can give GnRH agonist (but AI is uncommon)
How long is the gestation length of camelids?
11 months
- prolonged pregnancy is common- do not induce unless medically justified
-most pregnancies are in the left horn
What type of placenta do camelids have?
Diffuse epitheliochorial placentation
- considered retained after 3 hours
T/F: there are multiple ways to get to the same diagnosis
True
- younger vets tend to take a longer path, doesnt make it wrong
What is the difference between intuition an analysis?
Intuition- based on experience
- where most errors occur in medicine, didn’t think about it enough
Analysis- hypothetico-deductive
-where decision making should happen
With both- dual process theory
What are some questions you should ask yourself when collecting information about a scours outbreak?
- is this piece of information important or irrelevant to you or the client
- does this piece of data make the hypothesis more or less likely
- how does the data interrelate with the other data already gathered
- which data is the most critical
If you look hard enough in any dairy herd, will you find crypto?
Yes
Is it important to know the difference between rota and corona?
Not really- will treat the same
Do you care about differentiating coccidia from other causes of scours?
Yes- impacts treatment
If all calves are getting sick before 2 weeks of age, what pathogen can you rule out?
Coccidia
When do Ecoli, rota, corona, clostridium, coccidia and salmonella tend to cause diarrhea in calves?
Ecoli- 1-3 days
Rota- 5-14 days
Corona- 5-30 days
Clostridium- 7-28 days
crypto- 7-21 days
coccidia- 21 days +
salmonella- 5-18 days
What is the first thing you should do when arriving at a farm for a scours outbreak?
Look at records
What may a client need help with in scours outbreaks?
-early detection of scours or dehydration
-treatment protocols for calves with scours
-management of calves without scours
-management of cows yet to calve
-detection of pathogens
*must remember goals of the client- need to help client prioritize what they want most
What is R0?
The reproductive ratio of an infectious disease
- risk an infected animal will spread its disease to another
-depends on animal, agent and environment
-it is not a fixed number- changes depends on where you are in the calving interval
What is the generic sours plan?
Clean calving area, make sure they get colostrum, early detection and treatment, oral fluids then IV, potentially antimicrobials and NSAIDs
- need to know how this plan needs to change depending on client goals
What is the sandhill calving system?
Every 2 weeks, cows yet to calve are moved to a new pasture
- cow calf groups are put back together after calving season
- every cow gives birth in a clean pasture
*breaks pattern of scours
What are some general characteristics of scours cases?
-you will usually find one or multiple pathogens
-fecal-oral s the primary route of transmission
-need to divide clients time between early detection and treatment and infection control measures (clean pastures, clean personnel and equipment, segregation of calve groups)
How can you categorize abortions?
By trimester, causative agents, or characteristics of infections
What is the most host adapted pathogen that results in abortions?
Lepto
What are some natural causes of abortion in the 1st, 2nd and third trimester?
1st- hyperthermia, trauma/palpation, twins, progesterone deficiency, prostaglandins, cortisol, loss of body condition, previous retained placenta, pyometra or mastitis
-usually see resorption, maybe maceration or mummification
2nd- not much of anything
-may see mummification, abortion, or autolysis
3rd- twins, surgery, stress/cortisol, xylazine
-may see abortion, premature birth or stillbirth
T/F: if you can determine when the abortions are happening and the nature of the presentation I can narrow my list of rule-outs
True
T/F: if I identify a pathogen in an abortion outbreak, my plan will be better
Not necessarily, unless zoonotic
Which pathogens tend to be more problematic during 1st, 2nd and 3rd trimester?
1st- BVDV, bluetounge, campylobacter, tritrichomonas
2nd- brucella, listeria, neospora
3rd- IBR, BVDV, salmonella, lepto, aspergillus, anaplasma, epizootic foothill abortion
When infectious cause of abortion, when does the infection occur relative to when the cow aborts the calf?
days, weeks or months
How good are diagnostic labs at finding pathogens in aborted fetuses?
Poor - only find agent in about 20% of cases
- commonly will not find a pathogen
-need to submit both fetus, placenta and blood to increase sensitivity
T/F: it is less important to move cows that have aborted into a clean pasture compared to scours
T- still not a bad idea
- not spread feco-oral like scours
Which should you sample first in a BVD outbreak- the cows or calves?
Cows!
Why do labs want you to send abomasal fluid for abortion workups?
Can do dark field microscopy to look for spirochetes
- good evidence of lepto
Can cows have lepto in their kidney and give birth to a normal healthy calf?
Yes
What two things are different about the bovine immune system compared to other species?
Limited/ no IgG transfer prior to birth
Secretion of IgG and IgA on surfaces
Intense innate response- PMNs
- cattle love to make abscesses
T/F: Lymphocytes are more numerous than neutrophils in a normal CBC
True
What is the unique class of lymphocytes that ruminants have?
Gamma delta T lymphocytes
- present at birth and decline with age
- function is still unknown- may help with resistance to m bovis, lepto and m avian paratuberculosis
- more sensitive to dexamethasone
What is the clients expectation with vaccines?
-they eliminate the chance of getting a particular illness
What are the actual goals of vaccination?
-To develop increased resistance to a pathogen
- a group of vaccinated individuals limits the spread of a pathogen within the group and potentially protects unvaccinated or immunosuppressed individuals
What is herd immunity?
Indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection
What are some potential outcomes of increased immunity?
-minimize clinical disease in an individual or a herd
-prevent clinical disease in an individual or herd
- minimize or prevent infection
- promote productivity
Which is one of the most successful vaccines in cattle?
Blackleg
Which government sector is responsible for the development of vaccines?
USDA
- FDA does drugs
T/F: you can see the data for vaccine trials prior to 2007
False
What is Dr. Sweckers theory for why none of the pinkeye vaccines are effective?
It does help, but pinkeye lesions are so obvious that nothing “works”
- other vaccine efficacy may be similar but we dont see the disease so we view it as being more effective
What are some potential mechanisms for vaccine efficacy?
-prevent the pathogen from gaining entry
-build a strong titer, prevent infection/disease even if pathogen gets into body
-manage negative clinical outcomes
-manage severity of disease
Which vaccines prevent pathogens from gaining entry?
-surface vaccines: IBR, PI3 +/- BRSV
-rota/corona and scours
Goals are to increase surface specific IgA and increase non specific immunity
Which vaccines build a strong titer, prevent infection even if pathogen gets into body?
Multi system pathogens: IBR, BVDV
- concept is a certain titer protects the animal
- indirectly measured by the serum neutralization assay
- harder to establish breakpoints with ELISA
Which vaccines are designed to manage negative clinical outcomes?
Lepto hardjo, Pinkeye Vaccines
Which is more pathogenic: moraxella bovis or boviculi?
Bovis
- boviculi alone cannot cause infection experimentally
Which vaccines aim to protect the individual and not the herd?
- Endovac bovi against endotoxin
- tetanus toxoid
- C perfringes toxoid
- M hemolytica
- rabies
T/F: if youve done a good job at vaccinating heifers and cows you should not have fear of using a modified live vaccine in a pregnant cow
True
- if vaccinated pre-breeding, dont need to boost during pregnancy anyways
T/F: modified live vaccines are typically cheaper
True
- less virus needed - replicates in body
- does not usually require booster
What are some common reasons for vaccine failure?
-bottle is empty
-wrong site
- wrong timing
How does stress alter immunity?
- decreases it
- dont vaccinate neonates until 4-7 days- fetal cortisol will interfere
- acute and chronic stress is thought to be immunosuppressive
*heat stress significantly increases cortisol
What happens if you select for disease resistance to a particular disease?
Animal will become more susceptible to other diseases
Why are cows preg checked?
To find open cows!
- these cows need something to happen!
- need to eliminate costs of assuming she is pregnant- consider rebreeding or culling
To determine days pregnant, presence of twins, sex of fetus
On herd level- evaluating breeding program
When is the term conception rate used more commonly?
The number of cows pregnant after a single event
When is the term pregnancy rate commonly used?
The number of cows pregnant after a period of time
What is the number of services per conception?
The number of straws of semen it took to get a cow pregnant
What is the percent of cows pregnant after AI called?
AI conception rate
Over what time period is the pregnancy rate over in dairy and beef?
Dairy: 21 day period
Beef: season long (usually 60 days)
If you want to find more pregnant cows, what should you do?
Check them earlier
- there is a large amount of early embryonic loss
Describe continuous variables
Production metrics fall into this category
- ex: lbs milk/day
- some percentages can look continuous (ex lambing percentages can be over 100%) but in reality they are not
What is a binomial variable?
Yes/no variable
- commonly converted to pregnancy or rates
- what you should really be looking for is rates
When looking at preg rates, what should be considered besides the percentage?
Odds or risk ratio
If you want to use chi squared to prove the difference between percentages, what do you need?
A very high sample size
T/F: odds make low or high percentages look better than odds in the middle (around 50%)
True
T/F: differences appear greater when looking at smaller numbers
True
- if it easier to prove a change at high and low percentages than to prove a change on rates around 50%
What is the number needed to treat?
Number of patients you need to treat to prevent one additional bad outcome or promote one additional good outcome
NNT= 1/ ARR (absolute risk reduction)
ARR= control rate- experimental rate
- can use this to explain the economics of treatment to a client
When is survival curve analysis useful?
Comparing certain data between farms, such as lameness, vaccination/not vaccination
- looking at number of days
T/F: it is easier to compare continuous variables than binomial variables
True
What diseases should be vaccinated for?
IBR, BVDV, rota, corona, lepto, clostridials
-cannot be eradicated
When should your focus be on minimizing pathogen exposure and focusing on treatment, cleanliness and testing?
Those that cannot be eradicated and there is not a good vaccine
- ostertagia, coccidia, salmonella, BVDV- PI, lice, flies, scours
What diseases do you have to focus energy on treatment alone- no way to get rid of?
-BRDC, pink eye, foot rot, listeria
T/F: when is way more important than what when it comes to vaccines, antibiotics and dewormers
True
With beef cows, what is the main goal to reduce pathogen load?
Boost immunity to repro pathogens PRIOR to breeding
- all cows should get IBR, BVDV, lepto
- give 10-21 days prior to breeding- concern for modified lives in naiive herds on fertility
Bull bred herds need campylobacter vaccine
AI and using virgin/yearling bulls - can reduce STDs
- test mature bulls for trich
Cow herd needs to be isolated from new additions
- and new animals need to be tested for BVD PI
What is one of the main challenges with vaccinations in beef herds?
There is a 60 day breeding season so it is hard to find the perfect day to vaccinate when all cows have calved
- some boost lepto at preg check
If using killed products, need to boost at some point during the year
How do you know if a beef calf has gotten colostrum?
-you have watched it happen
-cow has a large developed udder
-one teat is smaller/cleaner
What are the cons of unrolling hay over snow?
Often providing bedding and not feed
- can lead to dirty udders
When should scours vaccines be given?
3 and 6 weeks before calving in heifers, one dose in cows
- there is a risk of putting heavy pregnant cows through a chute
- vaccines include rota, corona, and clostridium/ecoli
Vaccination at birth is commonly done but there is little evidence that this is beneficial due to high cortisol
What vaccines should be given between 3 weeks to weaning?
-respiratory diseases- summer pneumonia (often occurs at 2-3 months of age when moms are getting pre-breeding vaccines)- there is a concern with maternal interference, may be better to give killed
- clostridial diseases
2-4 weeks prior to weaning give BRDC vaccines
- for replacement heifers give brucella and lepto
When should cows be dewormed?
In the spring
- parasite loads are the highest in the summer
Who needs deworming the most?
The first-time grazer
- weaned calf new to pasture
Adult cows often dont need to be dewormed
- need refugia- adult cows often arent clinically affected by worms
When do lice cause the most problems?
In the winter
- spend their life on the cow
- treat the animals with pyrethrins and avermectins between thanskgiving and Christmas
What is the difference between horn flies, face flies and stable flies?
Horn flies= haemotobia irritans
- easiest to control as they spend most time on cattle
-usually on back
Face flies= musca autumnalis
- harder to control with insecticides as they travel
Stable flies- stomoxys calcitrans
- hang out around belly and legs
- tags and pour ons are ineffective- must spray cattle
- helps to clean up old hay piles, and feed around bunks
What are some of the fly control options that are commonly used?
- tags (after 200 horn flies)
-pour ons (permethrins and avermectins)
-back rubbers or dust
-feed through minerals
-parasitic wasps
-fly traps
What are the main goals for cow comfort?
-clean, dry, comfortable resting area
- unobstructed access to feed and free-choice water
- confident injury free flooring
- proper ventilation
- heat stress relief (general public thinks cold is more of a problem)
What are the 5 freedoms?
Freedom from hunger and thirst, freedom from discomfort, freedom from pain injury and disease, freedom to express normal behavior, freedom from fear and distress
What needs to be considered when designing a barn?
There needs to be adequate alleys, crossovers and no dead ends
Which costs more per cow- a 4 row or a 6 row?
4 row
- but also gives cows more room
- early production cows need more space, and need more feedbunk space
What is the purpose of the brisket board and the neck rail?
- to prevent from laying down/standing too far forward in the stall and getting stuck
- allows for a forward lunge space
Why are the dividers between free stalls open and not solid?
So cows can look at each other and gives more space to move head in order to stand up
T/F: head to head stalls can be shorter
True
- can stick head into neighbors stall to give room to stand up
T/F: cows will lay down more on mats compared to sand or matresses
False
- they lay down on sand and mattresses moreso
- they also tend to stand more on mattresses than sand when lame
Do cows prefer flexible or solid dividers?
Flexible- but lying time does not differ
- preference does not necessarily mean better welfare
T/F: no matter what barn you build you will have alley cows
True
What does perching behavior indicate?
Either stall isnt big enough, brisket board not far enough ahead, or she is lame
What are some indications that there is not enough bedding in a stall?
Cows arent spending a lot of time lying down
- callous and hygroma formation
What is the perfect pattern for concrete?
Hexagons
- allows for good traction
What is the problem with concrete floors?
They wear down over time
- always eventually need replacement
Compare and contrast headlocks and rails
Headlocks allow for fewer aggressive events, especially when feedbunk space is limit
Rails are less expensive and allow more cow freedom
Which cow on the pecking order is the most stressed?
Number 2-5
- they are competing for the top spot
T/F: late gestation/early lactation cows should be understocked
True
- should fill 80%
Can overstock mid gestation cows if necessary
How do you avoid social stress when moving groups of cows?
Consider all in all out transfer of animals
What are the main signs of heat stress in cattle?
- increased resp rate
-decreasing feed intake–> decreased milk production
Occurs above 75-85 F (humidity dependent)
What are some methods to reduce heat stress?
-provide shade- align it N-S, barn aligned EW
- cool cow with water and air movement (want water on the cow before air on the cow- works best in low humidity environment)
* ideally put fan over the bunk
What is the cause of most metabolic diseases?
Nutrition
- there can be metabolic diseases that are not nutritional, such as developmental orthopedic disease
What is the difference between complicated vs complex?
Complicated= many steps, each have predictable outcome
Complex= multiple steps, but outcomes are not always predictable or there may be multiple outcomes (usually involve humans)
- most metabolic diseases fall into this category
What is heritability?
The chances that a trait will be passed on through generations
- percent of the phenotype due to the genotype
T/F: it is easier to select for milk fat/protein than it is to select against ketosis, milk fever or retained placentas
True
T/F: DA’s are fairly heritable
True
What diseases occur most commonly during the transition period in heifers? What about cows?
1 rule out for down heifer= retained placenta
- metritis also occurs more commonly in heifers than cows
- in general retained placenta and milk fever occur a lot more commonly than displaced abomasum and clinical ketosis
What are the risk factors for retained placenta? What are the treatments?
Risk factors: hypocalcemia, twins/dystocia, low vit E and selenium, poor transition ration
Treatments: prostaglandin within 1 hr on induced cows (in cows that calve normally this does not help)
- frequent, low dose oxytocin
- antibiotics if she gets metritis (broad spectrum trt in every case is not recommended)
Describe the poster child DA case
- 4-6 yr holstein cow in the first 6 weeks of lactation
- owners report ketosis, metritis, retained placenta and hypocalcemia, twins in history
- clinical findings: metritis, mastitis, enteritis and retained placenta
-often starts with excess fluid and gas accumulation in abomasum
Generally guernseys are affected more than holsteins which are affected more than brown swiss
What are some factors affecting abomasal motility and GI emptying?
Increased bile acid in the abomasum (duodenoabomasal reflux)
- abdominal muscle from cows with DAs have decreased contractility
-dysfunction of the enteric nervous system
-product of fermentation - decreased abomasal motility due to high grain diets- also result in abomasal gas production (unsure whether accumulation of gas leads to poor motility or poor motility leads to accumulation of gas)
-ration associated- grain fed late gestation, low roughage diets, pelleted rations, high NEFA at calving
T/F: cows that have gotten DA surgery catch up in milk production over time
True
- takes 10-15 more days to get them pregnant
