Animal hygiene deck II Flashcards
particulate matter quantitites are higher in which season?
slightly higher in winter (rooms often closed, ventilation
rate lower)
Highest dust concentration detected in ?
aviaries and pig farms, less dust can be found in cattle and sheep housing.
The approximate dust amount (airborne particles in total) in
conventional animal facilities is often measured in the range of
0.25 - 25 mg/m3.
Note: these are measured at times but are NOT safe. Dust content exceeding 10 mg/m3 seriously damages any living organism.
The size of dust particles ranges greatly but is between
0.2 - 100 μm.
The size of the majority of the dust particles ranges between
0.3 - 20 μm.
Indirect impact of dust: (5)
enhances condensation of humidity;
inhibits the effect of sunlight, especially UV radiation;
accumulates on windows’ glass;
affects the work of the ventilation system;
serves favourable environment for the development of microbes and mould
fungi.
Direct impact of dust: (3)
skin: itching, skin inflammation, disorders in thermoregulation, the
protective function of the skin and skin sensitivity decreases;
eyes: irritant effect, conjunctivitis;
respiratory tract (especially <5 μm, originating from excreta!).
Most respiratory reactions in pigs are
allergic (antibodies in blood).
Pneumoconiosis
The pneumoconioses are a group of lung diseases caused by the lung’s reaction inhaling certain dusts.
What can dust inhalation cause in birds?
Acute alveolitis
What common bacterial infection can horses contract via dust inhalation?
Rhodococcus equi in horses: bacteria lives on the ground → horses inhale
it with the dust → zoonotic pneumonia (mainly foals).
Commonish airway disease in horses
Horses → Recurrent airway obstruction (RAO), 2 forms.
Dust allergic effect:
respiratory hypersensitivity to antigens
(AID)
Dogs → Allergic inhalant dermatitis (AID) – genetic disposition to produce IgE antibodies to inhaled allergens (frequent cause of dermatitis).
Dust content exceeding ? seriously damages any living organism.
10 mg/m3
Most air microflora are
harmless saprophytes.
However, Fungi spores may also disseminate without anchoring to a substrate.
Favourable factors in a farm for air microflora include: (3)
no direct solar radiation, indoor humidity exceeds outdoor humidity preventing drying, enough nutrients.
The highest bacteria and fungi concentrations in
broiler and pig houses.
Examples of diseases that spread via wet carrier (droplet infection): (4)
Foot-and-mouth disease,
bovine spongiform encephalopathy,
tuberculosis,
glanders and strangles in horses, etc.
Examples of diseases that spread via dry carrier (dust infection): (3)
Anthrax,
tuberculosis,
aspergillosis, etc.
(spores!)
Biological aerosols consist of
living and non-living airborne biological particles and their fragments (e.g. endotoxins, i.e. lipopolysaccharides.
Bioaerosols are formed by suspension of particles of biological origin in the air.
Bacteria are most numerous in what species’ housing?
poultry housing.
The prevention and control of bioaerosols’ exposure is based on the three levels of intervention:
elimination of the source;
controlling the source;
controlling exposure.
Lipopolysaccharides originate from?
from the outer membrane of gram-negative bacteria
CFU
colony-forming unit
Harmful gases in the air of farms (6)
CO (carbon monoxide)
CO2 (carbon dioxide)
N2O (nitrous oxide)
NH3 (ammonia)
H2S (hydrogen sulfide)
CH4 (methane)
The air density at normal conditions is
~ 1.29 kg/m³.
The air composition in animal facilities is influenced by (2)
1) the vital activity of animals
2) the degradation of manure, urine and feed.
O3
Ozone – O3 an allotrope of oxygen
Unstable gas with a specific pungent smell, formed by UV radiation.
Atmospheric air contains very little ozone (0.00002–0.00004 ppm), and rarely (usually after thunderstorms).
It cleans the air by oxidizing gases and organic compounds.
CO2
Carbon dioxide is a colourless gas with a slightly acidic odour; ~1.5 times heavier than air.
Is a greenhouse gas.
The concentrations 300–3000 ppm do not impair animal health or performance.
N2O
Nitrous oxide, laughing gas, is a colourless gas with a slightly sweetish odour and slight metallic taste; ~1.5 times heavier than air.
In atmospheric air ~330 ppm. 30% in the atmosphere is the result of human activity – the main origin is well-fertilized agricultural land.
NH4 transforms to nitrogen gas (N2) in nitrification and denitrification. N2O is an intermediate product. Barns with straw as litter, particularly straw matrasses emit more
N2O than slatted floor systems.
It is the third most important greenhouse gas, substantially contributes to destruction of ozone layer and global warming. It has a long residence time in the atmosphere of about 120 years.
Its toxicological potential is negligibly small. When inhaled in concentrations of 20% and more it has an analgesic and weak narcotic effect.
CO
Permissible concentration?
Carbon monoxide is a colourless and odourless; slightly lighter than air.
Formed by incomplete combustion: combustion and exhaust gases.
Human: 1000 ppm → lethal in 20 min; 5000 ppm → lethal in 5–10 min.
Harmful to animal health from 50–60 ppm.
Lethal for adult birds – 2000 ppm, for adult pigs – 4000 ppm.
Permissible concentration 10 ppm
CO mechanism for lethal effect
Binds the haemoglobin into a relatively stable compound called carboxyhaemoglobin (COHb) which is a 300 times more stable bond than between Hb and O2.
Results in anoxemia because hemaglobin cannot transport oxygen while carbon monoxide is bound to it.
Permissible concentration 10 ppm.
NH3
Ammonia is a colourless, characterized by its sharp pungent smell, much lighter than the air.
Ammonia is found in trace quantities in atmospheric air. Out of the number of detrimental gases found in animal facilities, excess ammonia is most common.
The principal origin of ammonia in the animal environment is dietary nitrogen. As a rule, the metabolic nitrogen is excreted immediately after its formation.
NH3 odor detection threshold
15 ppm – odour detection threshold (for some people it is already
as low as 5 ppm)
NH3 level lethal within a few minutes.
5000 ppm
level of NH3 exposure with negative effect in case of prolonged exposure
10 ppm
H2S
Hydrogen sulphide is a Colourless gas with the characteristic pungent foul odour (rotten eggs), about 1.19× heavier than air.
10 ppm – the borderline concentration for eye irritation;
150 ppm – paralysis of the olfactory nerve in human, lethal in 8–48 h.
In animals, the lethal dose varies (depending on the size and weight)
between 200–5,000 ppm.
Normally, the concentration in animal facilities is low/undetectable.
H2S Is produced as a result of
anaerobic (microbial) breakdown of sulphur-containing long-standing organic matter such as faeces, urine, uric acid
Can be detected when long-time stored manure or slurry is
removed from the barn, especially when mixed up too much.
Is found in the intestinal tract gases of animals (protein-rich feed,
digestive disorders!).
Permissible concentration of H2S
0.5 ppm (5 ppm).
CH4
Methaneis a Colourless, odourless, flammable; much lighter than air.
Generally harmless gas but one of the greenhouse gases. Is formed in the anaerobic degradation of organic matter (cellulose, hemicellulose).
Explosive in high concentrations: 5000–15000 ppm.
Permissible concentration of CH4
300 ppm.
Odours are formed as a result of
microbial activity, especially in the anaerobic degradation of the mixture of urine and faeces.
Ventilation affects animal health and productivity mainly via three
mechanisms of animal and environment interaction:
air quality of animal facilities;
animal thermoregulation;
spread of pathogens and (sex) pheromones.
The main aim of ventilation is to
secure certain climatic conditions in an animal facility that would beneficially affect animal health and productivity level.
Ventilation capacity is
the amount of air in a m3, that during 1 hour is to either enter or be removed from a housing facility to maintain air parameters within the required boundaries. It shows ventilation intensity.
Unregulated air circulation occurs:
Through pores, gaps, and cracks of the housing facility/ barn →
walls, ceilings, doors, windows.
Natural ventilation is based on the physical principles of
chimney (stack) effect (particularly in winter) and wind effect (particularly in summer).
Stack (buoyancy force) effect is predominant!
Chimney effect →
variation in air weights (temperatures); ventilation is more efficient in case of a longer (higher) chimney.
Wind effect →
pressure on and inside the room; depends on wind direction and force, as well as the shape and size of the room; roof pitch/slope is also important (the higher the better).
As a general guideline, the total area of the air inlets
should be twice that of outlets!
In conventional (warm) barns:
The areas of the air inlet and outlet openings are usually
equal.
In cold free housing barns:
What is often used as an outlet opening.
An open roof ridge
Photoperiodism is
the reaction of an organism to the duration and proportions of dark and light periods within a 24-hour daily cycle.
An animal senses electromagnetic radiation of ? nm as light:
360–760 nm as light
360–450 nm → purple
450─500 nm → blue
500–570 nm → green
570–591 nm → yellow
591─610 nm → orange
610─760 nm → red
The colour of an object depends on
the length of the waves the light absorbs and reflects.
Accommodation ability of an eye is
the ability to focus on the objects
→ relatively weak in farm animals (esp. sheep).
Stimulating effect of direct solar radiation/light on the functions
of an organism:
the number of cellular elements and haemoglobin concentration in
blood increase;
cardiac function and blood circulation improve;
metabolism, particularly mineral metabolism, intensifies;
epidermis becomes thicker and skin function improves;
respiration becomes deeper → gas exchange improves;
oxidation processes intensify;
impact on the central nervous system – activity and mobility ↑;
sociability increases.
Impact of excessive direct solar radiation:
the irradiated area temperature increases (4–9 oC);
biochemical changes in blood – disturbed metabolism of tissue cells;
histamine–like substances in blood – disturbed metabolism;
photoelectric effect – tissues ionize;
erythema – short–term, no pigment deposition.
Sunstroke
Noise is defined as
aperiodic sound majorly consisting of simple tones of various pitch (frequency) and strength.
Exposure to high frequency impulsive noise is most harmful.
The noise level standard recommended by Swedish researchers
is 45 dB-A per 24 hours.
Swedish research showed that the noise produced by animals in a
barn does not exceed 55 dB-A (especially if noiseless equipment is
used).
Exposure to long-term noise can cause:
heartbeat accelerates,
respiratory rate increases and becomes shallower,
heat production decreases,
gastric motor activity decreases,
body temperature increases,
rumination activity decreases (the cow chews portion of feed 50-70×),
production/growth drops.
Noise is a particularly powerful stressor for birds and pigs. Which species is the least sensitive?
Cattle are least sensitive.
Persistent noise results in:
lasting agitation,
increased injury incidence,
increased mortality rate,
decrease in animal yield.
