Secondary Trauma in Cage-Free Hens

Frederic J. Hoerr DVM

USPEA Live Production, Welfare, and Biosecurity Seminar

Nashville, TN

September 18, 2018

“Normal” mortality in commercial layers

• 6.4% to 11.6% to 80 weeks, depending on breed

• 64,000 to 116,000 hens lost in 1M bird farm

• At conservative loss of 100 eggs/hen

• 6.4 to 11.6M eggs

• Major target for improving welfare and profitability

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Assessing mortality

• Mortality survey examines every bird that dies on a given day

• Regular surveys establish trends that are important for health and welfare

• Mortality spikes are often a manifestation of “normal” mortality

• Focusing only on spikes in mortality may overlook existing information for prevention or mitigation

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Mortality survey vs. Normal bird/Wellness survey

• Mortality Survey

• Primary cause of death

• General categories not definitive diagnosis

• Can help focus further investigation

• Contributing or Additional Findings

• Parasites, injuries, non-lethal disease conditions

• Wellness exam

• Normal hens selected for sacrifice and assessment

• Weight, feathering, conformation, body condition, reproductive measurements

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A common problem……

Reports and spreadsheets that get filed and never analyzed

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Mortality Analytics Design

• Mortality “buckets”

• Cloud-based data and operations

• Keyboard, stylus, or voice data entry

• Infinitely expandable database

• Active and “retired/archived” flock data always accessible

• Rapid data analysis

• Graphs and tables

• Export to Excel

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•Primary Findings

•Beak Problem

•Bone - Skeletal Depletion

•Coccidiosis

•Cystic Oviduct - False Layer

•Decomposed

•Dehydration

•Emaciation

•Gout

•Gut, Enteritis

•Gut, Other

•Liver, Fatty or Hemorrhage

•Liver, Hepatitis

•Lung, Pneumonia or Air Sacculitis

•Lung, Respiratory, Other

•Omphalitis

•Other

•Peritonitis

•Prolapse

•Reproductive, Other

•Salpingitis

•Septicemia, Systemic Disease

•Suffocation/Piling

•Tetany, Metabolic (Calcium)

•Tracheitis or Tracheal Plug

•Trauma - Injury

•Tumor

•Undetermined

•Urolithiasis

•Vaccine Error, Reaction

•Vent Trauma

Mortality Survey Categories

• Individual body weight

• Flock body weight

• Individual or condition expressed as % of flock body weight

• Primary cause of mortality

• Secondary or contributing findings

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Analytics

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Company Complex Farm

House FlockHousing system

Breed Date Age

Individual bird tables

Top Findings: Primary diagnoses

1 month 1 year

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Secondary Findings: Oral ulcers

Feed Mill A, Farm A Feed Mill B, Farm B

Oral ulcers, presumptive evidence of mycotoxins or other irritating substances in feeds, show similar changes in incidence, regardless of feed mill or farm. This is suggestive that the problem may have a common source in purchased ingredients, or reflect annual variations in feed-associated stresses.

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Trauma - Injuries Primary and Contributing (Secondary)

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Why focus on trauma?

• Trauma reflects the interface of the hen with her environment• Equipment, handling, behavior

• Some trauma can be corrected

• Many hens in aviary systems have chronic lesion of trauma that may contribute to mortality

• Establish data to address consumer perceptions/misconceptions

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Criteria

• Trauma as primary diagnosis – 3 years of data• Broken bones, spur-capture, other wire capture, persecution, vaccine

handling injuries

• Pre-existing trauma diagnosis – 1 year of data• A significant disease process with evidence chronic pre-existing injury

• Peritonitis, salpingitis, pneumonia, tetany, gout

• Likely a contributing factor but trauma alone was not fatal

• Exceptions: Emaciation and Dehydration• If chronic pre-existing trauma present, then Trauma is the primary diagnosis

• Circumstantial evidence of failure to thrive in the production environment

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Primary Trauma

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Birds with severe coccidiosis were laying with head in feed trough; likely struck on the back or side of head by steel guard on traveling feeder.

Examples of fatal and nonfatal trauma

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Curved keel, likely fractured while flying into roosting perch. Nonfatal and common.

Broken clavicle (wishbone), likely from flying into aviary equipment. Nonfatal but the dark red muscle = dehydration.

Broken leg, with malunion and scar tissue deposition. Fatal injury over time due to insufficient feed intake. Red muscle = dehydration

Trauma, healed fractures and emaciated & dehydrated hens

Pre-existing injury and emaciationRecorded as Primary Trauma

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Trauma, caught in cage, +/- spur

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Wing with chronic trauma with infected skin and likely deeper

involvement of the joint.

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Persecution trauma

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Pre-existing trauma of keel

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Clavicle (wishbone) fractures

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Pre-existing keel trauma and peritonitis

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Pre-existing keel trauma and peritonitis

Pre-existing trauma and salpingitis (oviduct inflammation)

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Injury, pre-existing, with emaciation and dehydration; recorded as Primary Trauma

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Emaciated & dehydrated; failure to thrive. No other lesion identified

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Trauma as Primary Diagnosis Secondary Findings: Pre-existing Trauma with Primary Diagnosis

Pre-existing trauma in

aviaries - % affected

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Pre-existing trauma in

the aviary by age – count

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Pre-existing trauma in the

aviary by breed, % affected

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A sampling of a growing number of studies on keel fractures• No difference between free-range siblings and conventional cages

• Traumatic in origin• Bone mass is lower in fractured keels (lower bone breaking threshold) • Bone ash, collagen no difference • Fleming et al, Brit Poult Sci 2003

• Up to 60% affected at 50 weeks, Floor > Cage• Petrik et al, Poult Sci 94, 2015

• Ramps effective in preventing keel and foot pad problems in non-cage systems• Heerkens, et al, Poult Sci 95, 2016

• Fracture prevalence increases with age, to 50 weeks and beyond• Cages > Floor, until 72 weeks+, then Floor > Cage• Brown > White• Eusemann, BK, et al, 2018, PLOS one, https://doi.org/10.1371/journal.pone.0194974

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Mike T. Petrik Michele T. Guerin Tina M. Widowski

Poultry Science, Volume 94, Issue 4, 1 April 2015, Pages 579–

585,https://doi.org/10.3382/ps/pev039

Eusemann BK, Baulain U, Schrader L, Thöne-Reineke C, Patt A, Petow S (2018) Radiographic examination of keel bone damage in living laying hens of different strains kept in two housing systems. PLoS ONE 13(5): e0194974. https://doi.org/10.1371/journal.pone.0194974

Floor > CagesCage > Floor

Keel Fractures

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Syste

m A

Syste

m B

0

1 0

2 0

3 0

4 0

P re -E x is t in g T ra u m a - F a rm A

A v ia ry S y s te m

% o

f M

orta

lity

Syste

m A

Syste

m B

0

1 0

2 0

3 0

4 0

P re -E x is t in g T ra u m a - F a rm s A , B , C

A v ia ry S y s te m

% o

f M

orta

lity

Conclusions

• Regular mortality surveys reveal trauma to be a primary cause of death, • Acute fatal trauma

• Chronic pre-existing trauma is detected along with other primary causes of death

• Fractures of keel and clavicle are the most common pre-existing lesions of trauma in dead hens examined in surveys• Peritonitis > emaciation > pneumonia > prolapse > tetany > salpingitis

• Pre-existing fractures• Have greater occurrence in aviaries than conventional cages• Appear in mortality by 35 weeks and continue to 100+ weeks• Detected in 7 genetic strains (100%) in aviaries, at 12- to 30% of total mortality• Aviary systems may be a significant influence

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Discussion

• This problem was detected and defined by regular mortality surveys and related extended discussion of findings

• Data analysis was possible because of a disciplined approach to examining “normal” mortality

• Survey method was modified to accommodate pre-existing trauma as contributing factor in mortality

• Ongoing assessment of• Interactive pathogeneses with primary diagnoses (infectious and metabolic)• Understanding the influence of aviary design

• Pullet training and layer management may be mitigation points

• Breed differences

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ENDFred.hoerr@gmail.com

www.vetdx.com

334-750-7566

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Acknowledgements• Steve Taylor• Paul Williams• Dr. Mark Blakely• Dr. Bernie Beckman, Dr. Danielle Botting,

Frank Johndrew, Bill Snow• Dr. Kelli Jones• Mark Tilbury• Management and Staff at Midwest Poultry

Services LP• John Hoerr