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Tools to stop the Gumboro CycleThe poultry industry has faced enormous technological changes, one of them is the further introduction and expansion of in-ovo vaccination technology at the hatchery and the development of more vaccines that can be applied through the in-ovo route.

By Guillermo Gonzalez, Carlos Gonzalez and Miren Arbe, Ceva Veterinary Services and Ceva Vaccination Services &

Equipment, Ceva Santé Animale (Ceva)

Egginject Dual Pressure System technology (Ecat-ID) is a clear example of how in-ovo technology can improve protection against different poultry diseases such as Marek’s disease, Gumboro disease, and Newcastle disease, etc. The Egginject patented

Dual Pressure Injection System allows automatic and individu-al adaptation of the injection to each single chicken embryo, and therefore, a better vaccination can be achieved. This ensures a more accurate and safer vaccination process requir-ing less labour compared to drinking water in the farm or the subcutaneous vaccination route at hatch. Additionally, day old chick stress and processing time at hatch is greatly reduced allowing faster delivery at the farm and earlier access to feed.

Spanish field exampleSince 2009, Ceva’s veterinary services team in Spain has been monitoring vaccination in the field in different locations for their customers. This service, called Global Protection Services or GPS, is a tool to monitor vaccine application and the level of protection in a flock. It also enables detecting epidemiological evolutions, identify risks and propose corrective actions in

order to help poultry producers to make quick decisions.A retrospective study compared and analysed 2,283 broiler flocks delivered from a single hatchery located in Spain, equipped with an Egginject in-ovo machine. The day old chicks (DOC) were delivered from the hatchery to farms located in the nearby regions in the Northeast of Spain. Hatchery and growing farms were set up under the same integration. The age of the birds ranged from 24 to 69 days of age, with a mean age of 41 days. Antibodies against Gumboro disease were tested using an ELISA kit (Biochek), in 10 to 20 birds per flock. Cobb 500 and Ross 308 genetic lines, at an approximate 50/50% rate, were being reared at the time of the study.

Vaccination techniques analysedThe original Gumboro vaccination program for this producer was a commercial live vaccine containing the Lukert infectious bursal disease virus strain (intermediate IBDv strain). The birds were vaccinated twice, once in-ovo and again in drinking water at 15 days of age. The intermediate Gumboro Lukert strain vaccine is made of conventional technology, therefore it is quickly neutralised by the maternally-derived antibodies (MDA) after injection, con-trary to an immune IBD complex vaccine. As a result this group was regarded as actually being vaccinated by drinking water at 15 days of age. In this study 138 broiler flocks were

G U M B O R O S P E C I A L

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0 1000 2000

22%

3000 4000 5000 6000 7000 8000 9000 10000 12000

Figure 6 - Titre distribution of the drinking water vaccinated flocks.

Quartile 25

4%

0%

2% 2% 2%2% 1% 2%3%4% 4% 4% 4%

7%7%6%

4% 4%4%5%5%

1% 1% 1%

monitored from January to June 2009 with this vaccination program.Afterwards, between November 2009 and July 2016, 2,145 flocks were vaccinated in-ovo (Egginject system) with Transmune. After collection, all the blood samples were deliv-ered to the laboratory for sera processing. The results were interpreted according to the ELISA kit manufacturer’s recom-mendations and analysed with statistical software.

Bird responses to vaccinationWithin the group of broilers vaccinated twice with the inter-mediate Gumboro vaccine, a very wide spread of titres from 0 to above 12,000 was found (Figure 6). The results in Table 4 indicate that only 46% of the flocks showed titres between 4000 to 9000 which is regarded as the expected titre range. In addi-tion, 22% of the flocks had very low IBD titres, below 391,

which were considered negative or non-vaccinated. In the group of broilers vaccinated in-ovo with Transmune using Egginject, a much more homogenous spread of the IBD mean titres was observed with 71% of the flocks having titres between 4000 to 9000. Only 3% of the flocks vaccinated with

Table 4 – Results overview of titres.

Rate of broiler flocks showing:

Vaccination program Expected titres (4,000-9,000) Negative titres (< 391)

Drinking Water 46% 20%

Transmune 71% 3%

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Figure 8 - Distribution of titres in the drinking water vaccinated group. 37% of the birds are out of the acceptable range.

22%

4%

0%

2% 2%4%

4%6%

7% 7%5% 5%

4% 4% 4% 4%4%

1%

0 20001000 3000 4000 5000 6000 7000 8000 9000 10000 12000

Figure 9 - Median value of the CV(%) in theTransmune in-ovo vaccinated group.

0 50 100

38% 38%

10%

5%3% 2% 2% 1% 1%0% 0% 0% 0% 0% 0%

150 200 250 300 350

Figure 7 - Titre distribution of the Transmune in-ovovaccinated flocks.

Quartile 25

0

7%

3% 3%4%

7%

15%

19% 9%

1%

6%3%

2% 1% 1% 0% 0% 0%

2000 3000 6000 8000 12000 16000

Transmune showed a titre below 391 (Figure 7). At the same time, the normal distribution in both groups was very differ-ent. The distribution of the titres in the drinking water vacci-nated birds is very variable, on the contrary, the titres of the Transmune vaccinated birds using Egginject in-ovo vaccination were showing a much better distribution with 50% of the titres between 5142 and 7886.When analysing the titres again, it’s important to observe that more than 12% of the drinking water vaccinated birds showed a value >9000 (Figure 8). Interestingly, 37% of the birds vacci-nated with the drinking water vaccine showed either a very high titre or a very low titre (quartile 25). When looking at the coefficient of variation (CV) (%) of the titres, the Transmune/Egginject group showed an excellent median value of 31% (Figure 9), whereas the drinking water vaccine showed a value of 56% (Figure 10). A remarkable difference could be noticed, especially around 31 to 33 days in the drinking water vaccinat-ed group, as in this group the titers were below 2000 which is considered low (Figures 10 and 11). No data was available before 31 days of age, but the polynomial curve in the analysis for the drinking water group estimated a probability that between 27-28 days of age the titres were very low. The Transmune and Egginject group did not show any average

mean titre lower than 2000 at day 27.Basically, drinking water Gumboro vaccination in these results showed much more erratic figures, includ-ing negative titres which suggest-ed a vaccination failure. When using Transmune applied by the Egginject in-ovo equip-ment, average mean titres were much more even, and strongly positive, regardless of the age of sampling. Antibody titres of flocks using the drink-ing water vaccination technique were low or even negative in between 31-33 days. On the contrary antibody titres in the Transmune-vaccinated birds were clearly positive at that age, suggesting an earlier and more uni-form vaccine take.

Conclusions of the field trialThis retrospective field trial compared Transmune vaccinated flocks using the in-ovo Egginject equipment and previous flocks which were vaccinated using a drinking water vac-cine. The main points could be summarised as stated below:

• Clear differences in mean titres and CV’s between the drinking water vaccination group and the in-ovo group using Transmune and Egginject were observed. The Transmune vaccinated flocks demonstrated more uni-form vaccination titres and a lower CV value.

• In many cases the Maternally Derived Antibody titre (MDA) is not homogenous in a given flock of day old chicks. Therefore, it’s is practically impossible to find a vaccination date when almost 100% of the birds are able to build up an immune response to vaccination. This makes Transmune, with its ability to adapt to different MDA levels per chick, the best option.

• With drinking water vaccination, a high proportion of

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Figure 11 - Evolution of serological titres per flock agein the drinking water intermediate IBD vaccine group.

31

O - Lowesttiter

observed32

16500150001350012000

Mea

n of

ave

rage

10500900075006000450030001500

33 34 35 36 37 38 39 40

Age (Days)

41 45 46 47 48 49 51 52 53

Avg = 4761,86

Figure 12 - Evolution of serological titres per flock age in the in ovoTransmune group.

24

Mea

n of

ave

rage

16500

15000

13500

12000

10500

9000

7500

6000

4500

3000

15002000 - Lowest titerobserved

0

Avg = 6298,99

26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Age (days)

43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 60 69

Figure 10 - Median value of the CV(%) in the drinking water vaccinated group.

0 50 100 150 200 250 300

1%1%1%1%3%

5%5%10%9%

24%

41%

0%0%

birds non- or partially-protected, amounted up to approximately 37% or the flock. This percentage of birds is at high risk of facing a field IBD infection with a poten-tial loss of 10% of net income per bird (McIlroy et al. 1992).

Advanced technology like the Egginject in-ovo equipment and new technology vaccines, like Transmune, are becoming more popular among hatcheries, since they enable fast, safe and wel-fare friendly vaccination of chicken embryos. The time between hatch and delivery to the farms is reduced, and less handling is needed in the field due to extra vaccinations. This vaccination application needs specific high quality equip-ment, close support, maintenance and monitoring of correct vaccine application. It also needs specific vaccines which are able to overcome the presence of MDA, while inducing an active immunity. Transmune is able to do this.

The Egginject patented dual pressure injection system allows automatic and individual adaptation of the injection to each single chicken embryo.