Scour in sheep and parasitic gastroenteritis Flashcards
List 4 causes of scour in neonatal lambs
nutritional- incorrect mixing of milk replacer
Bacterial- E.coli, Clostridium perfringens type B, salmonella
Viral - Rotavirus
Parasitic- cryptosporidium
List 4 causes of D+ in lambs
rumen acidosis
coccidiosis
nematodirus
parasitic gastroenteritis
List 3 causes of D+ in adult sheep
rumen acidosis/ lush pasture
salmonella
(Johnes)
At what age do lambs generally get affected by E.coli
watery mouth
< 4 days old
desribe what E.coli tends to look like in lambs
pyrexia
lethargic
may scour
mortality rates high
watery mouth
rattle belly- have a pot belly
what is watery mouth associated with
poor hygiene and failure of passive transfer
Decribe how to prevent watery mouth in lambs
good hygiene
hospital pen for sick lambs/ ewes
good colostrum management
ewe nutrition/ BCS- so colostrum good quality
How much colostrum should a lamb get
50ml/kg colostrum ASAP after birth (definitely by 6 hours) 5kg lamb = 250ml.
200ml/kg in first 24hrs (5kg lamb = 1litre)
What causes lamb dysentery
clostridium perfringens type B
what do you see with lamb dysentery
sudden death in lambs
may see blood tinged diarrhoea
How do we control clostridial diseases
Vaccination- given pre-lambing (lambs can be vaccinated from 2-3 weeks old)
they are opportunistic infections
what age does lamb dysentery tend to affect
< 3 weeks old
List the 2 species of coccidia which are pathogenic in sheep
E.ovinoidalis and E.crandallis
at what age are sheep most at risk for cocci
3-12 weeks old most at risk
tend to see more in housed lambs and later born lambs more at risk due to high challenge
List 4 risk factors of coccidiosis infection in lambs
mixing age groups of lambs
moving young lambs to shed/pasture where older lambs were kept
intensively stocked systems
faecal contamination in/around feed/water troughs
List the clinical signs of coccidiosis in lambs
straining
abdominal pain
diarrhoea +/- mucus and blood
death in severe cases
describe how to prevent coccidosis infection in lambs
colostrum management
maintain good hygiene
prevent faecal-oral transmission
what age lambs tend to be affected by cryptospordium
<10 days old
List the clinical signs seen with crypto in lambs
diarrhoea, inappetence, abdominal pain and mild pyrexia. In mild infections may see reduced growth rates and general poor performance
describe how to diagnose cryptospordisum in lambs
faecal sample/ PM
Describe prevention of cryptospordium in lambs
colostrum
fence off water courses- can be transmitted through this
don’t mix age groups
check disinfectants are effective against cryptosporidium
List the GI nematodes that affect sheep
Trichostrongylus
Teladorsagia
Nematodirus battus
Haemonchus
Name the trematode that can affect sheep
Fasicola hepatica
List the GI nematodes that can affect cattle
Ostertagia ostertagi
Cooperia oncophora
Trichostrongylus axei
List 2 parasites that sheep don’t develop immunity to
Fluke (sheep and cattle)
Haemonchus (sheep)
Which lungworms affect sheep
D filaria
M capillaris
where does nematodirus over winter
on the pasture (viable up to 2 years) - not in EWES
what weather conditions are needed for N. battus to hatch
cold period followed by a mean day/night temp of 10 degree
What can be seen on faecal egg count with N. battus
No eggs found - but cause disease before eggs are found
Describe how to control N. battus in lambs
climate modelling- to help predict which pastures most risky
what anthelmintic should be used against N. battus
BZ (white)- worm all lambs
Describe the clinical signs of Teladorsagia and Trichostrongylus in sheep
scouring
weight loss
poor fleece quality
dull depressed
dehydration
death
what are the sub-clinical signs of Teladorsagia and Trichostrongylus in sheep
lower DLWG
reduced feed conversion
reduced immunity to other infections
what is Periparturient relaxation in immunity (PPRI) in sheep
immunity reduces near end of gestation this can allow L4 larvae to reactivate and shed eggs in faeces
when lambs goes out there is increased burden on pasture
when is PPRI in ewes
2-4 weeks pre lambing to 6 – 8wks post- lambing
Which ewes are at more risk of PPRI
triplets
low BCS
young (ewe lambs and shearlings)
These will generate most of the pasture contamination
Describe type 1 gastroenteritis
Wet summers cause eggs to hatch and infect stock early and cause disease in the same season
Describe type 2 parasitic gastroenteritis
Dry summers cause eggs to remain unhatched until autumn wet conditions at which point the infectious larvae enter hypobiosis inside the stock rather than completing development to adulthood.
All the larvae emerge from hypobiosis at the same time in the spring in the gut
RARE
what are the clinical signs of haemonchus
anaemia, weakness, weight loss and sub-mandibular oedema in chronic cases. Fertility, fecundity, milk yield may all be affected by the infection in the same way as any other debilitating disease.
Describe how to control haemonchus
Closantel to treat Haemonchus infections
as well as other BZ, LV & ML groups (these are ore broad spec so more likely to generate resistance)\
which organs do ostertagi ostertagi affect
abomasum
which organ does cooperia oncophora affect
small intestine
how long does it take for cow to develop imunity to C. oncophera
one full grazing season
how long does it take for cow to develop imunity to O. ostertagi
up to 2 grazing seasons
when is the risk periods for parasitic gastroenteritis in cattle
mid-july until housing
describe one way to reduce risk of parasitic gastroenteritis in cattle
graze cattle on hay/silage aftermath in second half of grazing season to reduce risk of parasites
What are the 3 groups of anthelmintics that can be used in sheep and cattle
BZ- group 1 - white
LV- group 2 - yellow
ML- group 3 - clear
What are the 2 extra types of anthelminitcs that can be used in sheep
AD- group 4- orange
SI- group 5- purple
used to try and extend lives of group 1,2 and 3
List 3 non-chemical methods of parasite control
genetics
grazing management
bioactive forage (chicory)
Name a narrow spectrum anthelminitc that can be used against fluke and haemonchus
Closantel (Nitroxynil)
Name a narrow spectrum anthelminitc that is effective OMNLY against fluke
Oxyclozanide
Describe how to perform faecal egg count reduction test
FEC before treatment
FEC sample 7-14 days after treatment- depends on which used
then work out percentage efficacy
what level on FECRT is considered resistant
Less than 95% reduction in FEC = resistance
Less than 50% reduction in FEC = obvious drench failure
List 4 things that drive anthelminitic resistance
Buying in resistant worms.
Under dosing individuals.
Over treating the population.
Allowing resistant worms the chance to dominate.
Describe how to prevent anthelminitic resistance
Quarantine treatments for purchased stock
Dose for the heaviest in the group and calibrate equipment
Minimise number of treatments
Administer the correct (narrow spectrum) product correctly!
Dilute out any AR worms
Use non-chemical means of control (inc clean grazing)
Describe what is meant buy maintaining an ‘in refugia’ population
Maintain an in-refugia population that is not exposed to treatment (free-living on pasture and adults/immature in untreated sheep), this will dilute the eggs produced by AR worms.
Whole flock or whole group treatments to be discouraged.
Describe what happens when you treat all group for worms then move onto low contamination pasture
fewer parasites around so lambs appear to be growing better, but they are mainly resistant worms.
Describe what happens when you treat all group for worms then move onto high contamination pasture
more parasites around but mixed population of susceptible and resistant, so anthelmintics remain effective.
what happens when using targeted selective treatment and/or dose delay move statergy
maximise anthelmintic efficacy whilst minimising negative impacts on production due to parasites
at what point on FEC do we see reduced DLWG
> 300 eggs per gram
what should you consider if lambs have high egg count but not scouring
Haemonchus contortus
what DLWG do we expect in lambs
pre-weaning >300g/d
weaning 200-300g/d
150g/d autumn/winter
how does co-grazing reduce parasite burden on pasture
reducing stocking density of host species
describe how we assess pasture risk
based on field type
and grazing history
how can delayed turnout reduce parasite burden on pasture
pasture contamination low by july if not grazed that season
Describe what estimated breeding values are
measure of breeding potential of an animal for a specific trait.
Take into account performance data of relatives and heritability of trait.
use rams that have been selected for worm resistance can be useful in flocks
