Effects of the termination of non-therapeutic antimicrobials (NTA) on overall drug usage, resistance and productivity in the Danish swine and broiler industry

Hanne-Dorthe Emborg, DVM, PhD National Food Institute, Technical University of Denmark

National Food Institute, Technical University of Denmark

Development in pig herd structure in Denmark

• Denmark has– The world’s largest export of

pork– Highly modern production – Well educated farmers– High level of animal welfare,

hygiene and management– 80% increase in production in

20 years

1988 1998 2008Number of farms with pigs 35,000 18,000 6,000Heads (1000) 15,000 22,700 27,078

1988 1998 20080

20

40

60

80

100

1-5,000 heads 5,001-10,000 heads

>10,000 heads

Perc

enta

ge o

f pro

duct

ion

National Food Institute, Technical University of Denmark

The Danish broiler production• Broilers are intensively raised with

several flocks produced per house per year

• All-in/all-out production• Modern production with high levels

of hygiene, welfare and management

• From 1990 to 2008 the production increased from 116 million kg to 186 million kg, a 38% increase

• From 1993 to 2008 the average number of broilers produced pr farm pr year increased by 49%

Farm

House HouseHouse

Broiler flockBroiler flock

Broiler flock

Farm

House HouseHouse

Broiler flockBroiler flock

Broiler flock

Farm

House HouseHouse

Broiler flockBroiler flockBroiler flockBroiler flock

Broiler flockBroiler flock

Rotations

1993 1998 2008Number of farms with broilers 343 314 214Average production pr. farm (1000) 349 430 520

National Food Institute, Technical University of Denmark

Termination of non-therapeutic antimicrobial (NTA) use in Denmark

• In 1995, the Danish Minister for Food, Agriculture and Fisheries banned the glycopeptide avoparcin

• In 1997, avoparcin was suspended in EU• In 1998, virginiamycin, a streptogramin, was banned in Denmark • Early 1998, the Danish cattle and broiler industries voluntarily decided to

stopped all use of NTA’s, and the pig industry stopped all use of NTA’s in pigs over 35 kg (Fines imposed on those not agreeing to phase out.)

• In July 1999, 4 NTA’s were suspended in EU: spiramycin, tylosin, bacitracin and virginiamycin

• In 1999, EU banned olaquindox and carbadox due to toxicity to humans • The remaining use of NTA’s in Danish pigs was voluntarily phased out

during 1999 (Fines imposed on those not agreeing to phase out.)• In the European Union, all NTA’s were phased out by the end of 2005

National Food Institute, Technical University of Denmark

Antimicrobial use in Danish swine production

No sales profit

Avoparcin ban Virginiamycinban

Ban on NTA usefor finishing pigs

Ban on NTA usefor weaning pigs

NTA

National Food Institute, Technical University of Denmark

Comparisons of tetracycline and macrolide consumption in danish pig production 1992-2008

1992

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

0

5

10

15

20

25

30

35

40

45

50

Tetracyclines Macrolides total

Mg

an

tim

icro

bia

l / kg

pork

pro

du

ced

NTA stop finishers

NTA stop weaners

National Food Institute, Technical University of Denmark

Production of poultry and consumption of NTA and therapeutic antimicrobials

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 20080

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0

50

100

150

200

250

Production (mill. Kg) NTA Therapeutic

Kg

act

ive

su

bst

an

ce

Pro

du

cti

on

(m

ill. k

g)

National Food Institute, Technical University of Denmark

Consumption of antimicrobials in Denmark

1992

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2008

*0

50

100

150

200

250

300

Therapeutic NTA USA

mg

an

tim

icro

bia

ls p

er

kg

pro

du

ced

me

at

National Food Institute, Technical University of Denmark

* Based on data from Animal Health Institute and USDA

Consumption of antimicrobials in Denmark and the USA

National Food Institute, Technical University of Denmark

Effects on resistance• The purpose of the interventions were to reduce a reservoir of

antimicrobial resistance in food animals

• The NTA’s used in Europe had mainly activity against Gram positive bacteria. Thus, susceptibility in Salmonella and E. coli are not relevant as an indicator for NTA termination

National Food Institute, Technical University of Denmark

Occurrence of VREAvoparcin consumption and resistanceto avoparcin among E. faecium

National Food Institute, Technical University of Denmark

Macrolide consumption and resistance to macrolides among entorococci from pigs

0

10

20

30

40

50

60

0

10

20

30

40

50

60

70

80

90

100

Con

sum

ptio

n(m

g/K

g)

Per

cent

resi

stan

ce

Macrolide use E. faecium E. faecalis

National Food Institute, Technical University of Denmark

Macrolide consumption and resistance to macrolides among Campylobacter coli from pigs

National Food Institute, Technical University of Denmark

Macrolide consumption and resistance to macrolides among Staphylococcus hyicus from pigs

National Food Institute, Technical University of Denmark

Virginiamycin consumption and resistance to virginiamycin among E. faecium from pigs and broilers

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

0

20

40

60

80

100

0

2,000

4,000

6,000

8,000

10,000

12,000

Virginiamycin E. faecium Pigs E. faecium broilers

% r

esis

tant

isol

ates

Kg

activ

e co

mpo

und

National Food Institute, Technical University of Denmark

Conclusions

• Major increase in Danish food animal production

• Total antimicrobial consumption reduced from 100 to 49 mg/kg (51%) from 1992 to 2008

• Major reductions in resistance to the antimicrobial agents which were reduced, among animal pathogens, indicator bacteria and zoonotic bacteria

National Food Institute, Technical University of Denmark

Broiler production Percent dead broilers in total (Nov. 1995 – June 2002)

Data: Danish Poultry Council

0

1

2

3

4

5

6

7

8

No

v95

Jan

-96

Ma

r96

Ma

y96

Jul9

6

Se

p9

6

No

v96

Jan

97

Ma

r97

Ma

y97

Jul9

7

Se

p9

7

No

v97

Jan

98

Ma

r98

Ma

y98

Jul9

8

Se

p9

8

No

v98

Jan

99

Ma

r99

Ma

y99

Jul9

9

Se

p9

9

No

v99

Jan

00

Ma

r00

Ma

y00

Jul0

0

Se

p0

0

No

v00

Jan

01

Ma

r01

Ma

y01

Jul0

1

Se

p0

1

No

v01

Jan

02

Ma

r02

Ma

y02

Time

Pe

rce

nt d

ea

d b

roile

rs

NTA stop

National Food Institute, Technical University of Denmark

0

1

2

3

4

5

360

380

400

420

440

460

480

Mo

rta

lity

(%)

Da

ily g

ain

(g/d

ay)

Daily gain (weaners) Weaner mortality

NTA term.weaners

Temporal association between NTA termination in weaners and productivity measures in weaners

Data: National Committee for pig production

National Food Institute, Technical University of Denmark

Conclusions

• The NTA stop had minor influence on the productivity in both the broiler and the pig production

• Economic impact

• No impact in the broiler production

• Short term impact on number of pigs treated for diarrhoea in a minor part of the herds, after that no economic impact