Lecture 12: Beef Feedlot Flashcards
What is life post weaning?
-Weaning goal: calves 7-8 months of age ~500-700lbs
-Backgrounding (some farms don’t do this): Hay based diet, fed until 800-900lbs (9-11 months of age)
-Feedlot: reach finishing weight of ~ 1,300-1,500lbs approx. 15-17 months of age
What is the purpose of a feedlot?
Goal: Rapid and efficient gain of lean muscle mass
-Typically 200d on feed (varies with feed cost and type of cattle)
-Finishing has decreasing nutritional efficiency (younger generally has higher feed efficiency so feedlot get more “investment” at beginning
What are feedlot economic considerations?
-Key is COST OF GRAIN, purchasing and selling prices (feed cost is biggest driver of profitability bc most $$)
-Unless mortality is excessive (>2%) main cost of disease is slowed growth (immune response)
-Early successful treatment of respiratory disease still = a 5-10% decrease in ADG
-If prices low/costs high, disease may make difference b/w profit and loss (big economic reason to limit disease specifically respiratory)
What are feedlot disease problems?
- RESPIRATORY DISEASE
- Lameness
- Bloat
- Clostridial diseases
- Urolithiasis (urinary stones, slow or stop urine)
- Polio (Nutritional deficiency of thymine causes brain issues)
- Pregnancy (don’t want pregnant animals in feedlot number of issues 1. feed efficiency not enough for her requirements 2. problems at calving)
What are some challenges of the feedlot?
-Calves from numerous sources (transported from many different areas)
-Mixed at sale
-Mixed on arrival
-Transport stress
-Weather stress (cold, wet)
-Lack of adaptation to dry or ensiled feeds (diff diet background have better response to new diet than one coming directly from cow/calf)
-Lack of vaccination
-Relatively high animal density
What does the triad look like for respiratory disease in beef feedlots?
Host
-Immunocompromised (not passive bc older animals)
-Transport and social stress
-Decrease dry matter intake (held feed on transport influence immune fxn
Environment
-Animal density
-Cold, wet, weather
Agent
-BVD
-BRSV
-M. Haemolytica
etc
What is undifferentiated Bovine Respiratory Disease (UBRD) pathogenesis?
- Imuunocomprized animal (typical at animal arrival)
- Clinical/subclinical viral respiratory disease (damages respiratory tract)
- Mannheimia haemolytica moves from pharynx to lung, replicates, causes damage (present in nasal cavity but vial damage deeper in lung tissue)
4.Fibrinous pneumonia (animals may die or recover with treatment, but often have chronic lung damage)
Review: what is Mannheimia Haemolytica?
-Bacteria normally resident in the naso-pharyngeal area
-Opportunistic cause of fibrinous pneumonia (classical “shipping fever”)
-Leukotoxin damages lungs and causes systemic illness
TRUE OR FALSE: It is possible to clinically differentiate b/w agents?
FALSE
-just know that animal has reparatory disease unless specific signs for that individual agent
What are UBRD viruses, histophilus somni, mycoplasma bovis?
Viruses
-BVD. Infectious Bovine Rhinotrachetitis (IBR), (BRSV), Parainfluenza 3 virus (PI3)
-Generally predispose to or occur with bacterial pneumonia
-Can be primary pathogen (esp IBR, BRSV)
Histophilus somni
-Pneumonia, fibrinous pleurites, myocarditis
Mycoplasma bovis
-Opportunities cause of pneumonia and arthritis
What are the clinical signs of UBRD?
-Depression
-Anorexia (Won’t come to bunk, belly concave/sunken rumen)
-Temperature >40 C (virus can causes fever abnormal > 39.5C)
-Cough/nasal dischage
-Increased respiratory rate and effort (back to lungs half lung not functional)
-Weight loss/no gain
-Death (if untreated) 2-7d d/t response. distress +- toxaemia
-If large amounts (>2/3) of lung tissue is damaged or if less so (20-50%) with toxaemia (blood infection surplus of bacteria in blood), animals often die
-In untreated 33% case fatality
-Expect 80-90% success with early treatment
What are the epidemic curve ‘trends’ with UBRD?
-Home vs auction hers
Home: local operations with in vicinity of feed lot, has less incidence of UBRD
Auction: Further away being exported with others more chance of pathogen and have longer “incubation” period before coming to feedlot
Both: Show an increase for UBRD in the first 3 w therefore biggest risk is fist couple days - 3w after arrival
What is the treatment for UBRD?
-Close observation, esp first month after arrival (most risk 3w after arrival) in small pens makes it easier
Pull claves that appear:
-Gaunt (lack of rumen fill)
-Depressed (not at bunk eating)
-Laboured breathing (would segregate and do physical testing/exam
-Treatment based on fever and absence of signs of other diseases
-Single dose for long acting (1 treatment for full disease course which is helpful for management) injectable antibiotic
-For first treatment return to home pen
-Re-assess in 3-7d
-Chronics moved to hospital pen
-Protocols for prudent use of antibiotics
-Disease definitions
-treatment protocols (be consistent when is a respiratory disease and how we treat is consistent)
-First and second line therapy
-Meat withdrawals (labeled products have a meat withdrawal period on them arrival can’t be slaughtered before medication out of system)
Why do producers give antibiotics to herds if they have a virus?
-An iamb could have a virus and is given an antibiotic so they dont get a bacterial infection in additional to virus when their immune system is low
-Less likely to be chronic and spread disease/shedding overall disease
-Viral damage first then bacteria causes damage
What types of vaccinations/vax strategies are used with UBRD?
viral vax recommended
-Timing is important ideally calves are pre-vaccinated at least 3w+ prior to weaning welfare ahead of arrival
-However-parental vaccination on arrival often practiced
-Intranasal on-arrival–> local immune response
Both viral and bacterial vaccines are commercially available
