ruminant herd health Flashcards
What is monitoring?
a continuous effort to collect data to detect changes or trends int he occurence in order to inform descisions
What is surveillance?
a special case of monitoring where data is used to assess a a status in response to a pre-define threshold
what are the 8 steps in surveillance?
1) objectives
2) hazard selection
3) case definition, diagnostic methods
4) target pop’n
5) timing, sapling interval
6) data management, analysis
7) methods for data analysis
8) feedback
How is incidence calculated?
incidence (rate) = no of new cases / pop’n at risk x time at risk
how is prevalence calculated?
prevalence (proportion) = no of exsisting cases / pop’n at risk
what is bias?
a systematic error due to the design, implementation or the analysis of the surveillance program
What is a zoonoses?
disease which are naturally transmitted between vertebrate animals and humans
what is a carrier?
pathogens isolated from animal/human without causing clinical signs of diesease in the host ( 1sample)
what is a colonised host?
no clinical signs on the host but implies that microbes are multiplying on the host .. need longitudinal sampling
what is a reservoir?
the spread of an organism within the reservoir host to maintain the pathogen indefinitely
What are our responsibilities to zoonoses?
1) early suspicion and correct diagnosis
2) client communication
3) prevent spread
how in food animals is the risk assessment for zoonoses carried out?
risk assessment = probability of inf ( prevalance of hazard and transmission pathway) + consequence of exposure
What is a hazard?
an agent, substance or action that has the potential to cause an undesired event
What is a risk?
the probability of an undesired event and the consequences of it
What is risk management?
interrupting, preventing or eliminating transmission pathways identified in the assessment
4 mains strategies for risk management
1) risk transfer (insure)
2) risk avoidance (dont perform hazardous activities)
3) risk mitigation / reduction (agree target)
4) risk acceptance ( do nothing if below target)
why do we carry out surveillance?
1) effetiveness of statutory disease control
2) protect public health
3) understand and measure the impact of animal disease on climate change
4) detection of new / re-emerging disease, infection and toxicity
5) providing assurance of freedom from specified disease
6) detection of incursion of an exotic disease
7 steps in a herd / flock investigation
1) define the problem
2) history taking
3) a - environment exam
b - distance flock exam
4) a - individual animal exam (full vs basic - mucus membranes, weight, BCS)
b - post mortem exam
5) further diagnostic test
6) data analysis and decision making
7) reporting back and future monitoring
problem with poor thrift in young animals?
longer to reach slaughter weight so more expensive
target calf / lamb growth rates
calf = 1-3 kg / day lamb = 100-300 g/ day
problem with adults being thin at mating
longer anoestrus
lower conception rates
less ovulation rate (fewer twins)
problem with adults being thin in early pregnancy
less placental development
problem with adults being thin in late pregnancy
increased risk of metabolic disease
problem with adults being thin during lactation
less milk yield
Main questions to ask when examining poor thrift
whole herd?
appetite normal?
YES - good nutrition? - yes (maldigestion / malabsorption) - no (under fed / trace element deficiencies)
NO - wont eat (parasites ) / cant eat ( dental /lame)
What is the role of cobalt?
rumen microbes incoporate it into vit B12 which is part of the co-enzyme needed to convert propionate into the glucose pathway
what are the signs seen with cobalt deficiency? and what species esp?
weaned lambs poor thrift concurrent parasitism / under fed eye discharge anaemia
what is the role of selenium / vit E?
protects cells from free radicals and maintains resistance to infection
what are the signs of selenium / vit E deficiency? what species?
any species white muscle disease (congenital or delayed) embryonic death increase disease susceptibility reduced milk yield
What is copper used for?
essential part of myelin formation,
iron release into plasma during erythropoiesis,
elastin and collagen synthesis,
pigementation
what are the signs of copper deficiency? what species esp?
growing cattle
poor thrift , diarrhoes, poor coat colour, swayback, bone fragility
what is seen with iodine deficiencies?
goitre
lack of thyroid hormone
how to you test for copper?
7-10 liver biopsies
how do you test for cobalt
7-10 blood / liver
how do you test for selenium?
3-6 bloods
how do you implement a treatment for trace element deficiencies?
give it to half the herd first had measure growth rates to see if economically viable
how is gross margin calculated?
gross margin = output - variable costs
how is change assessed economically?
partial budget analysis = (new cost + revenue foregone) - ( cost saved - new revenue)
What are the groups of causes of sudden death?
infectious ( septicaemia, toxaemia, anaemia)
toxicity (plants , minerals, lead, cyanide)
climatic (lightening , hypothermia)
trauma (foreign body etc)
nutritional (eat weird things)
metabolic ( hypo Mg , hypo Ca)
how is sudden death defined?
death within 24hrs of last observation
what are the major parasites in the abomasum?
teladorsagia
haemonchus
nematodes
what are the major parasites in the S.int?
trichostrongylus
nematodirus
nematodes
what are the major parasites in the liver?
fasciola hepatica
trematode
what is the nematode life cycle?
sheep – eggs on grass – hatch – eaten
ppp=3 w
what are the clinical signs of nematode infection?
diarrhoea weight loss death anaemia reduced appetite -- change GIT structure -- infl -- protein loss
trematode life cycle?
eggs in faeces – miricidium – mud snail – vegetation – eaten – liver – mature
ppp = 8-10 w
what are the exceptions to immunity to parasites?
goats
immuno - compromised animals
ewes PPR
liver fluke
what is the main parasite threat in spring?
lambs - N.battus
calves - ostertagiosis
FEC not much use
what is the main parasite threat in summer?
calves - nematodes (teladorsagia, haemonchus)
lambs / goats - telodorsagia
FEC valuable
what is the main parasite threat in autumn?
calves - nematodes (trichostrongylus)
lambs / goats - trichostrongylus
acute liver fluke
what is the main parasite threat in winter?
chronic liver fluke
what are the groups of broad spectrum anthelmintics?
yellow - levamisoles white - benzimadozole clear - macrcyclic lactones orange - amino - acetonitrile derivatives purple - spiroinodoles
5 flukicides
triclabendazole (kills everything over 1 wo, rest do 8 wo) oxyclozanide nitroxynil closantel albendazole
what would you give new animals on the farm?
- orange / purple incase they have any resistance
- triclabendazole and one other flukicide
