Young females, sentinels of viral circulation in beef cattle herd - - PowerPoint PPT Presentation

Young females, sentinels of viral circulation in beef cattle herd

Results of BVD monitoring in Cher & Loir-et-Cher

PSAl

Objective

• To develop a general monitoring tool like in

dairy herd

• No additionnal constraint for breeders :

⇒ Requires only prophylaxis blood samples

• Low cost:

=> Pooled blood serum

Device development

• Thesis of Benjamin SAUTEREAU (NANTES

2005) in Cher department.

• Test = Elisa p80 LSI :

– Antibodies witnesses of viral multiplication ; – Only 1 vaccinal crosstalk : Mucosiffa (/mucobovin);

• Objective = to find a representative sample
• f the herd.

– Comparative study : herd seroprevalence vs. age group seroprevalence – Test used out of instruction for use : exploitation of the raw results of inhibition percentage

Device development

• Pools of 5 blood serums are too sensitive and doesn’t

represent the group’s seroprevalence.

Device development

• Serologies on pools of 20 blood serum, sampled within

the whole herd are not correlated to herd seroprevalence

Device development

• Serologies on pools of 20 blood serum are correlated

in intragroup seroprevalence (age group)

Device development

• For big herds, serological results on young animals (1

year-old heifers) are not a good indicator of BVD’s circulation in the rest of the herd (breeding in a separate group).

Device development

• Serological results of 3 years-old heifers (G3 = 24-36

months) are a good indicator of herd seroprevalence.

Seroprevalence/G3 > 60% Herd seroprevalence > 55% ⇒G3 are sentinels of viral circulation ! (linked with presence

• f IPI animals or several transitory

viremic animals)

Raw results of screening

=> Threshold determination to discriminate both populations with our results

Distribution of inhibition percentages of pooled blood samples of Loir-et-Cher beef cattle herds Distribution of inhibition percentages classes of pooled blood samples of Loir-et-Cher beef cattle herds

Raw results of screening

100 200 300 400 500 600 700

By inhibition percentage classes ⇒ Both populations are more difficult to discriminate, many « intermediate » situations. ⇒ Representative of an high prevalence «open» system .

Multiannual evolution

⇒ Best segregation

• f populations and

higher «favorable» proportion. ⇒ Effect of control plans (since 2006).

(we hope)

Multiannual evolution

=> Stability of the distributions (low farm density), thus stability of chosen thresholds

Thresholds (re)validation

2 1 65% 35% Agrees with B Sautereau’s Thesis (ENVN 2005 – GDS18) ⇒ Implementation of a rating system 0/1/2 (ABD in Cher).

Obstinacy of ratings

⇒ Implementation of a monitoring system, in order to decrease the variations

• f intermediate rating = sequences 0/1/2 such as BVD monitoring in dairy herds

Distribution livestock/rating Evolution rating « 0 » Evolution rating « 2 »

Comparison of dairy and beef cattle device

séquence Statut commentaire 000 A non infecté récemment 100 A non infecté récemment 010 A non infecté récemment 001 A non infecté récemment 011 B infection limitée (stoppée ?) 111 B infection limitée (stoppée ?) 012 B infection limitée (stoppée ?) 112 B infection limitée (stoppée ?) 021 B infection limitée (stoppée ?) 121 B infection limitée (stoppée ?) 101 B infection limitée (stoppée ?) 210 B infection limitée (stoppée ?) 110 B infection limitée (stoppée ?) 211 B infection limitée (stoppée ?) 002 C séroconversion ? 102 C séroconversion ? 222 D contaminé 122 D contaminé 212 D contaminé 221 D contaminé 022 D contaminé 020 E cas particuliers 201 E cas particuliers 120 E cas particuliers 202 E cas particuliers 200 E cas particuliers 220 E cas particuliers

2 9 2013 A B C D E A

61% 1%

B

3% 1% 1%

C

1% 1%

D

9% 2%

E

5% 1% 16%

2 9 2013 A B C D E A

83% 2% 1%

B

3% 2% 1%

C

1% 1%

D

2% 2%

E

2%

Costs and Feasibility

Loir et Cher Cher Feasibility : Realization on prophylaxis blood samples (no additional intervention of the veterinarian). « Mass programming » DAP / DAI in Sigal. = AUTOMATIC (1 minute programming / year) Results out of Sigal (specific informatic data exchange) and out of prophylaxis reports Results out of Sigal (specific informatic data exchange) Cost : 12,5 € / livestock /year (8 € for dairy herds) Cost : 14,7 € / livestock /year

Prospects

Loir et Cher Cher Preservation of the alert device Implementation of a personnalized BVD assessment Preservation of the devices:

• «targeted assanation» ;
• personnalized BVD assessment.

Be capable of establishing statutes Non_IPI on the basis of these epidemiological criteria, such as for the dairy livestocks of the CDC ACERSA: Females > x months in " Super A " (AAAA) (research needed)

Conclusion

• A simple and low cost device for BVD

monitoring in beef cattle herds

• Adaptable (and needs to be adapted) to the

epidemiologic situation.

• Exploitable as a guarantee criteria : further

investigations needed

Aknowledgments

• Daniel Parizot
• Benjamin Sautereau
• Rémi Vermesse
• Esthel Thieri-pigé

Contact : serge.nouzieres.gds41@reseaugds.com