Galleau S. -HamersC. –Blosse A. – Bolon A. Blanchet M. - Duboeuf M. – Goutebroze S. / Merial S.A.S. – 69007 Lyon, France

1. SAFETY OF A BIVALENT BTV-4/BTV-8 INACTIVATED
VACCINE IN PREGNANT AND LACTATING CATTLE
Galleau S.1 - Hamers C.1 – Blosse A.1 – Bolon A. 2
Blanchet M.1 - Duboeuf M.1 – Goutebroze S.1
1 Merial S.A.S. – 69007 Lyon, France
2 Independent Investigator, c/o MERIAL
Introduction
Bluetongue (BT) is an infectious OIE listed disease of wild and domestic ruminants. Recent Bluetongue virus serotype 8 (BTV-8) outbreaks in
Northern Europe have seriously affected cattle and sheep industries. To control BT epizooty, several countries have implemented large-scale
compulsory vaccination campaigns in ruminant populations, including a large number of pregnant and/or lactating animals.
The present study assessed the safety of an overdosed vaccine from the BTVPUR ALSAP® range (Merial S.A.S) administered to pregnant dairy
cows, through monitoring of reproductive performances and milk production in field conditions.
Material & Methods Calving data
Study design: The number of calvings and abortions/stillbirth were similar between
the treatment groups whatever the stage (trimester) of pregnancy at
Field study conducted in a BTV-free dairy farm located in the French Prealps
first vaccination. In both groups, causes of abortion could not be
(department of Ain).
evidenced.
Inclusion of 96 pregnant dairy cows allocated to 2 groups according to their
age and their pregnancy stage: Among the born alive calves, few deaths occurred before 15 days of
age (4 in G0 and 3 in G1) but none was related to the treatment.
G1 (n=48) : vaccinated twice at a 4-week interval (D0/D28) with a BTV-4 /
BTV-8 inactivated and overformulated vaccine (1 mL; SC route) In total, the number of cows which delivered a live calf were identical
G0 (n=48) : controls injected with placebo (physiological saline) in the in the two treatment groups (p=0.714, Fisher’s exact test).
same conditions as for G1
Figure 2 : Number of gestation fulfilled and abortions/stillbirth, according to the
pregnancy stage at first injection
Monitoring:
Animals were monitored by the farmers (blinded procedure) as follows: 20 19
Pregancy fulfilled in G0
18
- Individual clinical observation and daily recording of rectal temperature 18 (placebo)
during 4 days following each injection Pregancy fulfilled in G1
16 15 15 (vaccinates)
- Monitoring of pregnancy and health status of the offsprings until 15 days
Abortions in G0 (placebo)
of age 14
Abortions in G1 (vaccinates)
- Recording of the monthly milk yield (official milk production control) 12
No. of cows
before vaccination and during the 4 subsequent months
10 9
Results
8
8
6
Clinical monitoring 4
4 3
No treatment-related general reaction was observed after each vaccination.
2 1
After the first injection, vaccinates presented a slightly higher rectal 0 0 0
temperature than controls (+0.4°C in G1 vs +0.2°C in G0; p=0.042, Student t-test). 0
First injectio n during the 1st First injectio n during the 2nd First injectio n during the 3rd
trimester o f pregnancy trimester o f pregnancy trimester o f pregnancy
After the second injection, no difference between the treatment groups was
observed (p=0.534, Student t-test). Milk yield
Figure 1 : Evolution of mean rectal temperature following each injection The 2 treatment groups were homogeneous for their stage of
lactation. The milk yield was equivalent in both treatment groups
before vaccination (March; p=0.849, Mann-Whitney W test) and during the 4
38.8
G0 (placebo)
subsequent months (Sum April-July; p=0.673, Student t-test) .
G1 (vaccinates)
Figure 3 : Monthly milk yield recorded before vaccination (March) and during the 4
subsequent months (April-July).
Mean rectal temperature (°C)
Second injection
First injection
38.6 1st G1 (vaccinates)
1st
2 nd G0 (placebo)
30 2 nd
25
Milk yield (kg)
20
38.4
15
10
5
0
38.2
D0 D1 D2 D3 D4 D28 D29 D30 D31 D32 March
April
Day of protocol May
June
July
Conclusion
The results of the study demonstrated the safety in pregnant and lactating cows of the administration of an overformulated BTV-4 /BTV-8
inactivated vaccine through:
• a very limited and transient temperature increase following the first vaccine injection,
• an absence of treatment-related general reaction,
• an absence of impairment of the reproductive performance whatever the stage of pregnancy,
• an absence of impairment of the milk production in lactating cows.
® : BTVPUR ALSAP is a registered trademark of Merial in the European Union and Elsewhere.
This product can be used ONLY under governmental direction.