set 6 Flashcards
Advantages to stockers/backgrounders
- growth phase put on weight cheaply
- high forage diets(less expensive)
- good for producers who like to manage this period
Disadvantages to stockers
very risky period health wise
Reasons for disease spike post arrival
- recently weaned(stressful)
- commingled with calves from many sources
- exposed to many diseases for the first time
- off-feed for few days
Biggest issue for stockers
respiratory disease
Bovine respiratory disease
shipping fever
- lung infections(pneumonia) caused by pathogens normally residing in the nose and throat of sick animals
- mutli agent( virus+bacteria+ high stress= BRD)
Clinical signs of BRD arise when?
7-10 days after arriving
Clinical signs of BRD include?
- depression
- decreased food intake
- no signs of other disease
- high temperature >40C
- +/- cough and nasal discharge
- +/- increased respiratory effort
- +/- weight loss
Consequences of BRD
- if untreated case fatality of 30%
- early treatment has 80-90% success
- death if 2/3 of lung damaged or if toxemia occurs
Primary respiratory pathogens of BRD
- cause significant disease by themselves
- IBR
- Bovine respiratory syncytial virus(BRSV)
- Parainfluenza type 3(PI3)
Secondary pathogens
bovine viral diarrhea virus(BVDV)
-viral infections further depress immune function, don’t actually cause pneumonia itself
Mannheimiahemolytica
most severe
- commensal organism- part of resident flora in upper respiratory tract
- becomes pathogenic(replicates quickly in lungs)
- produces leukotoxin that destroys WBC , inflames lung tissue
- causes most severe damaage of the bacterial respiratory pathogens
Pasteurellamultocida
commensal- found in 20-60% of clinically normal calves
implicated in fatal BRD second to m. haemolytica
Histophilissomni
commensal
virulence factors on cell wall- inflame blood vessels
-early pneumonia- BRD in recently weaned calves
Mycoplasma bovis
not commensal- passed from calf-calf
- causes other conditions as well- mastitis, arthritis, abortion
- chronic carries(hard to culture/diagnose)
- respond poorly to antibiotics- sensative to tetracyclines
BRD Prevention
Increase immunity
- buy pre-weaned, bunk adjusted calves
- vaccinate on arrival or in 4 weeks NOT IN BETWEEN
- provide higher quality feed/forage
Most important health management tools
- animal records
- pen location
- farm source
- medication given, withdrawl times
- response to treatment - post-mortem
- large scale testing may not be feasible
- knowing the cause of death-critical
- aids in planning preventative medicine programs
Health management objectives for feedlots
- rapid growth rate
- maximization of feed conversion efficiency
- reduction in morbidity, mortality, culling rates
- optimization of health expenditures
- reduction in antimicrobial residues
Finished product sold to?
market- packers buy live animal
direct to packer- packer buys graded carcass weight cattle
direct to consumer- freezer beef, send to butcher and sell to friends
For direct to packer and direct to consumer, the price is influenced by?
- carcass yield
- grade
- maturity
- meat colour
- fat colour
When trimming the carcass the following are removed
- bruises- caused during transport, horns,
- injection sites
- head condemned- squamous cell carcinoma
Subacute Ruminal Acidosis economic issue
- condemnation liver
- suboptimal weight gains
Prevention of subactue ruminal acidosis
- careful ration formulation, mixing and delivery
- PM deads to determine level of liver abscesses
- keep records of slaughter condemnation
- prophylactic antibiotics in feed
Meat grade
-based on marbling
Marbling
-genetics plays a role(angus )
heifers more than steers
-starts accumulating at a young age
increased when calves weaned younger on grain diet
-reduced in sick animals
-male calves left intact longer=less marbling
-more aggressive animals= reduced
Why do we castrate bulls in feedlots?
inappropriate management for calving on feedlot
risk of complications/death at calving
often younger heifers- likely to have fetal maternal disproportion
poor feed:gain ratio
less uniform growth
welfare issue
