6 – Feedlot Additives + Implants

Question 1

What is the importance of processing of newly arrived cattle to the feedlot?

Answer 1

• First opportunity to have an affect on cattle’s health and performance in feedlot
• Busiest time of year at feedlot (but maybe not as seasonal when buying dairy cattle)
• Boring, repetitious task
• *priority

Question 2

Processing: general considerations

Answer 2

• Faster is NOT always better
• Handle them quietly and calmly
• Avoid injuries to both cattle and crew
• Restrain animals adequately in chute while processing
• Animal welfare guidelines
• *we are producing food NOT cattle=quality assurance
• Ideally within 12-24 hrs
• Delayed processing can result in disease ‘wrecks’
• ‘risk class specific’ and ‘feedlot specific’
  o SLOWER FILL=GREATER RISK

Question 3

What are the components of a processing protocol?

Answer 3

• ID
• Vaccinations
• Early treatment/prevention of BRD: ‘metaphylaxis’
• Parasite control products
• Implanting
• Castration/dehorning (usually leave horns on)
• Quality assurance
  o Injection sties/changing needles/withdrawal times, etc.

Question 4

What are the 3 common health issues in feedlot cattle?

Answer 4

1. Bovine respiratory disease:
   a. Mostly early in feed period
2. Lameness
   a. Happen throughout
3. Nutritional related diseases (bloat, acidosis)
   a. Mostly later in feed period

Question 5

Bovine respiratory disease

Answer 5

• MOST important disease concern in feedlot cattle
• Grouped into ‘risk categories’ based on ‘risk factors’
  o Weaning
  o Age/weight
  o Mixing
  o Transport
  o Weather
  o Gender
  o Vaccination history
  o Previous exposure to bunks and feed

Question 6

Ultra high risk calve

Answer 6

• Young
• Light weight
• “Holstein calves’
• Recently weaned
• No feed or vaccine history
• Not castrated
• Auction
• *likely to get metaphylaxis

Question 7

Low risk calves

Answer 7

• Yearling
• Higher weight
• Vaccinated
• Background and feed history
• Castrated
• Direct market

Question 8

BRD ‘stats’

Answer 8

• Morbidity and mortality dependent on combination of risk factors present
• Morbidity peaks within first 7-10days
  o Can reach 35-50%
• Case fatality: 5-10%
• *many arrive already incubating disease

Question 9

What are the challenges of BRD management?

Answer 9

• High risk animals are cheaper=makes for a more profitable return
  o If can manage risk=can make more money
  o Every $1/cwt reduction can afford an additional 1% death loss
• Seasonal industry in Canada
• *level of mixing is significant and inevitable
• Majority of cow-calf producers sell calves DIRECTLY at weaning
• Many already incubating disease or become sick within a few days
• Many are in ‘witness protection program’ (we don’t know history)

Question 10

How is it being a seasonal industry in Canada?

Answer 10

• Fall run
• Many trailers arrive at one time
• Challenge to deal with processing within 24hrs of arrival and treating sick calves
• Hard to differentiate between sick and ‘homesick calf’

Question 11

What are some of the management strategies employed to deal with diseases?

Answer 11

• Vaccination on arrival
  o Reduced disease, but not ideal
• Pre-vaccination
• Preconditioning

Question 12

What is pre-vaccination?

Answer 12

• Specific sales and programs
• Does provide reduction in disease but doesn’t mitigate all risk factors
• Cow-calf producer should be paid more
• *hard to fill a whole pen though with those calves

Question 13

What is preconditioning?

Answer 13

• Step beyond pre-vaccination
  o Weaned minimum 45d prior to sale
  o Accustomed to eating from feedback
  o Vaccinated
  o Castrated and dehorned prior to weaning
  o Treated for parasites at least 3 weeks prior to sale
• *cow-calf producer benefits from increased sale weight and premium price

Question 14

What are some challenges with preconditioning?

Answer 14

• Low numbers of pre-conditioned calves available
• Price premiums not always enough for cow-calf producer
• Purchase prices vs. BRD risk dilemma
• *not as common anymore=just can’t fill enough pens

Question 15

What is metaphylaxis?

Answer 15

• Administration of injectable long acting microbial to control BRD upon arrival
• 1. Treating early cases: those incubating
• 2. Prophylaxis to cases that may develop in next few days
• *many label claims (ML or oxytetracycline
• 50% reduction in treatments and significant drops in mortality
• Resistance concerns

Question 16

What are the factors in choosing metaphylaxis?

Answer 16

• Expected disease risk (high, ultra high risk)
• Risk tolerance of owner
• Product efficacy based on clinical trial data
• Labour availability and skill
• Cost of treatment and cost of mortality
• Cost of metaphylaxis program

Question 17

Lameness: major contributors

Answer 17

• Bigger issue in dairy industry
• Major contributors
  o *Foot rot
  o Laminitis: due to high levels of grain
  o Arthritis: mycoplasma bovis
  o Toe-trip necrosis
  o Digitial dermatitis
• *1/3 of treatments=foot related

Question 18

What is toe tip necrosis?

Answer 18

• Unknown cause
• Occasionally occurs in outbreaks of feedlot calves from one source farm or auction yard
• Often severely lame after arrival at feedyard
• May be simply due to abrasion of toes during handling
• *treatment unrewarding
• Many animals eventually destroyed

Question 19

What foot and animals are more likely to get toe-tip necrosis?

Answer 19

• Hind feet
• Infection with environmental bacteria
• More common in excitable or wild animals
• Scrambling on rough footing
• Excessive wear on APICAL WHITE LINE
• Ascending infection

Question 20

Nutritional diseases and grain fed cattle: what can be added to help/minimize them?

Answer 20

• Finishing rations=90% grain
• *sequela of rumen acidosis
  o Liver abscesses to post-venal caval thrombosis
  o Laminitis
  o Mycotic rumenitis
• **ionophores are important additive to help with bloat and acidosis

Question 21

What are some examples of not managing nutrition well?

Answer 21

• Moving cattle to quickly up step-up program
• Delivering wrong ration to cattle
• Failing to keep feed available at all times
• Increasing amount of particular ration too quickly

Question 22

What’s ‘natural’ program in Canada?

Answer 22

• Not a specific label
  o Likely implies minimal human intervention
• Niche programs to limit use of
  o Ionophores
  o Antimicrobials
  o Bet agonist
  o Roughage level/grass fed programs
  o Hormone implants

Question 23

Conventional grain fed vs. grass based diets

Answer 23

• Grain
  o 3lbs/day
  o 7lbs feed efficiency (1lb on animal)
  o 171d to slaughter
  o Lower feed and yardage costs
• Grass
  o 1lb/day
  o 21lbs feed efficiency
  o 488d to slaughter
  o *need to get more money to actually make a profit or break even

Question 24

Identify the factors that have a major impact on profitability in the feeding industry

Answer 24

• Feed efficiency
  o If change by 10%=43% change in profit
• Cost of feeders and slaughter price: 20% change in profit each
• Death loses=much lower change in profit

Question 25

What are some feed additives?

Answer 25

• Ionophores
• Melengesterol acetate to heifers
• Antimicrobials

Question 26

Ionophores

Answer 26

• Widespread use
• Effect cell membrane of specific rumens and change flora of rumen
• Ex. monensin, salinomycin, alpharma
• *no prescription required if fed at label dosage and not in combo with other products

Question 27

What are the effects of ionophores?

Answer 27

• *Decrease feed intake, but improve feed efficiency and average daily gain
  o Increased propionate
  o Reduced acetate, methane, hydrogen ion and lactate production
• Sloer rate of food passage
• Reduced protein degradation in rumen
• *aids in control of coccidiosis and decreases incidence of bloat

Question 28

Melengestrol acetate (MGA premix)

Answer 28

• 125x progesterone activity
  o Prevents estrus
  o ADG INCREASED and feed efficiency improved
• Used in feedlot heifers
• Occasionally used to synchronize estrus in breeding
• NOT approved for concurrent use with hormone implants
• 24hr withdrawal prior to slaughter

Question 29

Antimicrobials as feed additives

Answer 29

• Can cause significant change in rumen flora resulting in growth benefits as well
• *growth promotion claims are all ELIMINATED
• Antimicrobial resistance=significant!
• *all added now require a vet feed prescription
• **Primary used is to feed to prevent liver abscess

Question 30

Liver abscess

Answer 30

• Accounts for 2% carcass weight
• Packing plant=not happy if condemned
  o 16% condemnation rate
  o Culled dairy cows: 24%
• *severe ones can affect performance
  o Decrease ADG and feed efficiency
  o $50-60/head loss in affected animal

Question 31

What can be used to reduce liver abscesses? Most common

Answer 31

• Tylosin
  o 40-70% reduction
  o Improved ADG by 2%
  o Improved feed efficiency by 2.6%

Question 32

What are some other antimicrobials used in feedlot rations?

Answer 32

• Tylosin
• Chlortetracycline
• Oxytetracycline
• Chlortetracycline + sulfamethazine
• *some tetracyclines used at higher doses to prevent H. somni or respiratory disease

Question 33

What are chlortetracycline + sulfamethazine used for?

Answer 33

• Prevention of foot rot
• Reduction of bloat
• Maintenance of weight grains during periods of stress: shipping/handling