Epidemiology and Management of BRD in Dairy Heifer Replacements

Alex Bach,1,2

1IRTA-Department of Ruminant Production2ICREA, Institut de Recerca i Estudis Avancats

Veterinarians represent a major piece in the sustainability chain:

Provide management advice

Care for the environment

Ensure economical performance of the herd

Foster data collection and use records to make management decisions

THE SUSTAINABLE VET

Introduction

0

15

30

45

60

Feed Labor Replacement Fixed costs Maintenance Misc. Energy

3.94.95.07.68.7

16.8

53.1

%

Introduction

Examine the operation holistically

Identify bottle necks and remove them

Introduction

Reducing AFC (w/o compromising BW at calving) implies:

1) the number of animals needed

2) the number of days on feed

100 x .30 x ((1-.03)x(1-.01)) x 2x(24/24) = 58 -> 46,000 €

100 x .30 x ((1-.03)x(1-.01)) x 2x(28/24) = 67 -> 53,000 €

100 x .30 x ((1-.03)x(1-.01)) x 2x(22/24) = 52 -> 41,000 €

Number of cows x replacement rate x ((1-mortality) x (1-heifer culling rate)) x 2x(Age first calving/24)

Introduction

For every kg of BW at calving, one could expect 14.5 l more milk in the first lactation

(70 Kg of BW mean 1,000 l of milk).

Bach et al., 2008

Introduction

For every 100 g ADG during the first 2 months of life, one could expect additional

300 l of milk in the first lactation.

Bach et al., 2008

Introduction

Item 1 2 3 4 5 6 7 8 9 10 11

Age range, d 1-65 66-110 111-158 159-229 230-307 308-336 337-415 416-483 484-546 547-639 640-660

Target BW, kg 80 125 175 250 325 530 390 454 510 590 610

Introduction

Item 1 2 3 4 5 6 7 8 9 10 11

Age range, d 1-65 66-110 111-158 159-229 230-307 308-336 337-415 416-483 484-546 547-639 640-660

Target BW, kg 80 125 175 250 325 530 390 454 510 590 610

Introduction

ZONE 1 ZONE 2

BRD Incidence

n=2,771 0 1 2 3 > 4 P-value

Final BW, kg 624 618 624 625 598 0.21

Final age, d 661 665 671 666 670 0.03

BRD

700

750

800

850

900

0 1 2 3 ≥4

Accumulated DIM

Number BRD

Bach, 2010

BRD Incidence

Heifers with 4 or more BRD cases had 1.87 greater odds of not finishing first lactation than heifers with no

BRD history.

Immune status of the animal (colostrum)

Vaccination program

Medication

Management

BRD Incidence

Immune Status

n=204 Low High P-value

BW at exit of Z1, kg 80.4 80.4 0.98

ADG in Z1, kg/d 0.7 0.7 0.91

BW at exit of Z2, kg 126.7 125.8 0.65

ADG in Z2, kg/d 1.0 1.0 0.52

BW at exit of Z3, kg 167.5 167.5 0.97

ADG in Z3, kg/d 0.8 0.9 0.63

Immune Status

The risk of having respiratory problems was only 8% lower in the animals with a high serum protein level compared to calves with a low protein serum level (P = 0.61).

Similarly, there were no differences in the incidence of diarrhea between the two groups.

Under the conditions of RLN, the use of serum protein levels provided no indication of risk of future pathologies or impaired performance.

Good management and environmental conditions may overcome immune deficiencies.

Immune Status

5 calves per hutch: 3 m2 and 7 m3 per calf6 calves per hutch: 2.5 m2 and 5.7 m3 per calf

7 calves per hutch: 2.1 m2 and 5 m3 per calf

- 16.6%

- 28.5%

BRD

7

6

5

0 15 30 45 60

22

38

58

Respiratory afflictions, %

Num

ber

of c

alve

s/pe

n

Item 5 6 7

n 50 60 70

BW entrance, kg 80 79 79

BW exit, kg 114 117 113

ADG, g/d 830 899 867

BRD

General recommendations for calf rearing advocate for keeping the animals individually housed and feeding milk replacer (or waste milk) twice daily.

The main purpose of keeping calves individually is to minimize the spread of infectious diseases (mainly diarrhea and pneumonia).

A recent survey (Fulwider et al., 2008) indicated that 50% of the producers send their calves to contract heifer operations.

BRD

The implementation of management schemes that reduce the spread of calf diseases is even more important in contract heifer operations (where animals from different origins are commingled).

Weaning time has been traditionally considered as a stressful moment for calves.

A common recommendation extensively implemented in the field is to keep calves individually-housed for at least one additional week after weaning (Quigley, 2001).

To our knowledge, there is no scientific evidence of the advantages or consequences of such a practice.

BRD

Several studies have evaluated the impact of weaning calves in groups or individually on performance (Terre et al., 2006), behavior (Warnick et al., 1977; Keil and Langhans, 2001), and health (Svensson and Liberg, 2006; Terré et al., 2006).

These studies have kept the animals either individually- or group-housed throughout the study.

An alternative weaning strategy would consist on keeping calves individually-housed for a period of time and, then form groups of calves for another period of time, and finally wean them while in groups.

BRD

Experiment 1. To evaluate whether allowing calves to remain for an additional 6 d individually-housed after weaning was beneficial in terms of performance and respiratory problems.

Experiment 2. To evaluate the effect on performance and incidence of disease of moving calves in groups before weaning.

BRD

Materials and Methods (Exp. 1) Three hundred and twenty female Holstein calves were assigned to two different treatments:

Allowing the calf to remain individually housed for an additional 6 d after weaning

Move the calf immediately after weaning to a different pen forming groups of 8 contemporaneous calves.

Individually Housed

Group HousedIndividually Housed

Starter.. 4 L of MR 2 L of MR Dry TMR

Starter.. 4 L of MR 2 L of MR

49 d 56 d 62 d

Group Housed

Dry TMR

98 d

104 d

Results (Exp. 1)

0

17.5

35

52.5

70

Grouped 6 d after weaning Grouped at weaning

41.4

61.2

1.691.72

Before Grouping After Grouping

Pro

port

ion

of c

alve

s af

fect

ed, %

a

b

Incidence of Respiratory Problems

Bach et al., 2010

Materials and Methods (Exp. 2)Two hundred and forty female Holstein calves were assigned to two different treatments in three different periods:

Remained until the age of 56 d individually housed

Moved to groups of 8 calves in super-hutches at 49 d of age

Group HousedIndividually

Group HousedIndividually Housed

.. 4 L of MR

.. 4 L of MR

49 d 56 d 63 d 112 d70 d

Starter

Starter

Dry TMR

Dry TMR

2 L of MR

2 L of MR

Materials and Methods (Exp. 2)

Results (Exp. 2)

1.2

1.8

2.4

3

3.6

49-56 57-63 63-70 71-77

3.36

2.73

2.3

1.57

3.42

2.812.41

1.79

Grouped at 49 d Grouped at 56 d

Sol

id fe

ed in

take

, kg/

d

Age, d

P < 0.05

*

Grouped calves consumed more solid feed than those individually housed.

Results (Exp. 2)

Grouped at 49 d

Grouped at 56 d

15 18 21 24 27

25.8

25.2

Proportion of calves affected, %

0 0.325 0.65 0.975 1.3

1.23

0.87

Cases/calf

P < 0.05

Incidence of Respiratory Problems

Bach et al., 2010

Can we use records to cope with BRD?

BRD

Materials and Methods (Exp. 1) Two hundred and forty female Holstein calves were raised in individual hutches and were checked for respiratory afflictions once daily starting at 5 d of age.

At weaning time calves were allocated into different groups of 8 calves based on their previous BRD history. Within each period, 2 superhutches housed:

8 calves with no previous record of BRD

6 animals with no previous BRD record and 2 calves with previous episode of BRD

5 calves without a history of BRD and 3 calves with previous

0

13.75

27.50

41.25

55.00

Cases/hutch Calves affected, % Time to 1st case, d

11

52

911

38

5

2324

4

0-8 2-6 3-5

RatioNo previous case-Previous case

Bach et al., 2010

BRD

Materials and Methods (Exp. 2) Two hundred and forty female Holstein calves were raised in individual hutches.

Calves with no previous record of BRD were randomly allocated to 3 superhutches containing 8 calves

Calves with a previous case of BRD were randomly allocated to 3 different superhutches (RRR).

0

13.75

27.50

41.25

55.00

Cases/hutch Calves affected, % Time to 1st case, d

9

99

11

19

38

4

0-8 8-8

RatioNo previous case-Previous case

Bach et al., 2010

BRD

120.00

125.50

131.00

136.50

142.00

Final BW, kg

136

141

0-8 8-8

RatioNo previous case-Previous case

1.12

1.15

1.17

1.20

1.22

ADG, kg/d

1.13

1.21

Bach et al., 2010

BRD

0.9

1.025

1.15

1.275

1.4

0 1 2 3 ≥4

ADG, kg/d

Bach et al., 2010

120

127.5

135

142.5

150

0 1 2 3 ≥4

BW, kg

BRD

Materials and Methods 140 Holstein calves were housed in individual hutches until 49 d of age and moved to super-hutches in groups of 8-10 animals.

The Control group did not receive any antibiotic treatment I.M. unless needed.

Calves in the Zactran group were treated with gamithromycin at 6 mg/kg (1 mL/25kg BE) one week after being moved from individual to group housing (at the age of 56 d).

0

0.3

0.6

0.9

1.2

BRD Incidence Cases/calf

0.74

0.452

1.16

0.449

Control Zactran

BRD

P = 0.18

There were no differences (P = 0.81) in growth rate

Materials and Methods 157 Holstein calves were housed in individual hutches until 52 d of age.

At weaning they were moved to super-hutches in groups of 8-10

The Control group did not receive any antibiotic treatment unless needed.

The calves in the other group were treated with gamithromycin at 6 mg/kg (1 mL Zactran/25 kg BW) at the time of movement from individual to group housing at the age of 56 d.

0

0.225

0.45

0.675

0.9

BRD Incidence Cases/calf

0.44

0.301

0.81

0.516

Control Zactran

BRD

P < 0.05

There were no differences (P = 0.62) in growth rate

Combining the results from Experiments 1 and 2 the overall response to Zactran could be assessed with a bit more precision (more than 300 animals).

Overall, there were no differences (P = 0.38) in animal performance between the Control (1.2±0.04 kg/d) and Zactran (1.2±0.04 kg/d) calves.

The incidence of respiratory problems was greater (P < 0.05) in Control (49.5±0.04 %) than in Zactran (37.0±0.04 %) calves.

The number of respiratory cases per calf was also greater (P < 0.05) in Control (1.0±0.18 cases/calf) than in Zactran (0.60±0.18 cases/calf) calves.

BRD

ConclusionsMonitoring health aspects is crucial

BRD incidence my compromise overall productive life of dairy cows

Action must be taken rapidly

Start with symptomatic treatment and move to antibiotic if no response is seen

Use an adequate vaccination program

Calves that are moved to groups immediately after weaning grow better and have less BRD incidence than those that are kept isolated for one additional week.

Calves that are grouped at pre-weaning time and continue to receive MR in groups improve ADG, solid feed intake, and suffer less BRD relapses.

Offering milk in groups does not affect CV of BW or ADG.

Conclusions

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