Ewes bred for resistance to gastrointestinal nematodes have lower parasite egg
output during the peri-parturient period.
Morgan, E. Baber, P. and White, T. 2014.
800
Farm 1
700
600
500
400
High
300
Low
200
100
Mean faecal egg count (epg)
Mean faecal egg count (epg)
Mean faecal egg count (epg)
Introduction
Ewe’s experience a peri-parturient rise (PPR) in faecal egg count (FEC)
around the lambing period which contaminates pasture with nematode
eggs and subsequently increases the infection pressure of new born
lambs. Breeding ewes with a lower PPR has the potential to alleviate the
need for anthelmintic use; saving money and slowing resistance build up.
The aim of this project was to quantify the value of EBV’s on reducing FEC output during PPR in
adult ewes and assess if there are any effects on ewe performance.
Materials and Methods
 The study lasted for 8 weeks (Farm 1) and 11 weeks (Farm 2), both farms replicated the
same trial with a similar number of ewes (n=47) and
800 (n=53) respectively.
700 of high (positive) and low
Farm
1
 Exlana sheep were selected to get a similar number
(negative)
600
FEC EBV’S.
500
 All ewes gave birth within 10 days and were managed
as a cohort during the trial period.
400
 Faecal samples were taken at four intervals and analysed within five days using the
High
300
McMaster technique. Trichostrongyloid nematode eggs and coccidial oocysts were
Low
200
counted separately.
100
 Ewes were weighed in late pregnancy and at the end
0 of the study to monitor condition
0
5 effect6on ewe8 milk yield.
change. Lambs were weighed at 8 weeks of age to determine
the
Weeks
after lambing
Results
600
500
*
Farm 2
400
300
200
High
Low
100
0
Figure 1.
0
5
7
11
5
6
8
Mean faecal
egg count (FEC) in eggs
per gram
Weeks after lambing
Weeks after lambing
(epg) in Exlana ewes with high (positive or zero) and low (negative) estimated breeding value for nematode FEC, at
600and three occasions into lactation. (*) Significant difference.
lambing
0
0
Mean faecal egg count (epg)
*
Farm
o500 Both farms FEC peaked at
5-6 2weeks after lambing and declined thereafter.
o400 On farm one the correlation between EBV and average FEC was positive but not
300 significant.
High
o On farm two the low EBV ewes had a significantly
(P=0.041) lower FEC count in week 5
200
and on average 47% lower than the highLow
EBV ewes.
o100 Overall, farm two had a 30% reduction in average FEC over the PPR.
o 0 On farm two low EBV’s were not correlated with ewe weight loss (p = 0.65).
5
7
11
Conclusion 0
Weeks after lambing
This study shows that low EBV ewes had a 30-50% lower egg output compared to high EBV
ewes during the peri-parturient period (PPR), with no significant effect on ewe performance.
Further study is needed to determine the physiological difference in low and high FEC EBV
maternal breeding lines which reduces the prevalence of worm burdens. Finally this paper
provides evidence that selecting low EBV maternal breeding lines for flock improvement could
reduce on farm anthelmintic use and slow resistance build up in the national sheep flock.