Method of reducing stress level in animals

Abstract

A method of reducing stress level in animals such as pigs may include: sealable enclosing the animals in at least one chamber; exposing the animals to a gas mixture comprising oxygen and at least one type of physiologically inert gas; gradually decreasing the oxygen concentration from a maximum level, to a minimum level; gradually increasing the at least one physiologically inert gas concentration from a minimum level to a maximum level; wherein the minimum level of the oxygen concentration is higher than the anaesthetic causing concentration for the animals.

Claims

1. A method of reducing stress level in animals, the method comprising: sealable enclosing the animals in at least one chamber, exposing the animals to a gas mixture comprising oxygen and at least one type of physiologically inert gas, gradually decreasing oxygen concentration from a maximum level to a minimum level, gradually increasing the at least one physiologically inert gas concentration from a minimum level to a maximum level, and avoiding bringing the animals to a state of unconsciousness or death by the gas mixture throughout the at least one chamber; wherein the minimum level of the oxygen concentration is higher than an anesthetic causing concentration of oxygen for the animals, wherein the maximum level of the at least one physiologically inert gas concentration is between 90 to 97%, and wherein the gas mixture comprises a CO2 concentration lower than 5%; wherein the at least one chamber extends from a first position where the animals are received to a second position where at least one subsequent process takes place, where exposure to the gas is while the animals move from the first position towards the second position, the first position being the position where the concentration of the oxygen is maximum and where the concentration of the at least one physiologically inert gas is minimum, the second position being the position where the concentration of the oxygen is minimum and the concentration of the at least one physiologically inert gas is maximum; and wherein the at least one subsequent process includes at least one of a transport process, an examination process, and a treatment process.

2. The method according to claim 1, wherein the maximum level of oxygen is between 17 to 25%.

3. The method according to claim 1, wherein the minimum level of oxygen is between 3 to 10%.

4. The method according to claim 1, wherein the minimum level of the at least one physiologically inert gas concentration is between 75 to 83%.

5. The method according to claim 1, wherein an initial exposed gas mixture is atmospheric air.

6. The method according to claim 1, wherein the at least one physiologically inert gas comprises N2 gas and/or Ar.

7. The method according to claim 1, wherein the CO2 concentration of the gas mixture is in the range from 0.1% up to a maximum concentration level, wherein the maximum concentration level is lower than an anesthetic causing concentration of CO2 for the animals.

8. The method according to claim 1, wherein exposing the animals to the gas mixture is while the animals are standstill.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

(2) FIG. 1 shows a flowchart of a method according to the present invention.

(3) FIG. 2 shows one type of a chamber wherein the method according to the present invention may be performed.

DESCRIPTION OF EMBODIMENTS

(4) FIG. 1 is a flowchart of a method according to the present invention to reduce stress level in animals such as pigs for at least one subsequent process.

(5) In step (S1) 101, the animals are sealable enclosed in at least one chamber. In one embodiment, the chamber may be considered as a space where e.g. few animas at a time, e.g. a pre-fixed number or number range of animals, is standing more or less stationary. In another embodiment, the at least one chamber extends from a first position where the animals, e.g. a pre-fixed number or number range, are received to a second position where the at least one subsequent process takes place.

(6) In a second step (S2) 102, the animals are exposed to a gas mixture comprising oxygen and at least one type of physiologically inert gas.

(7) In a step (S3) 103, the oxygen concentration level is gradually decreased from a maximum level, to a minimum level.

(8) In a step (S4) 105, the concentration level of the at least one physiologically inert gas is gradually increased from a minimum level to a maximum level.

(9) The minimum level of the oxygen concentration is selected such that it is higher than the anaesthetic-causing concentration for the animals.

(10) In one embodiment, the maximum level of oxygen is between 17 to 25%, preferably between 19 to 23%, preferably around 21%. In another embodiment, the minimum level of oxygen is between 3 to 10%, preferably between 4 to 8%, preferably around 6%. In still another embodiment, the minimal concentration of the at least one physiologically inert gas concentration is between 75 to 83%, preferably between 77 to 81%, preferably around 79%. In yet another embodiment, the maximal concentration of the at least one physiologically inert gas concentration is between 90 to 97%, preferably between 92 to 96%, preferably around 94%. In an embodiment, the initial exposed gas mixture is atmosphere.

(11) Referring to the embodiment above, the exposure to the gas while the animals are standstill, or while they move from the first position towards the second position, the first position is the position where the concentration of the oxygen is maximum and where the concentration of the at least one inert gas is minimum. The second position is the position where the concentration of the oxygen is minimum and the concentration of the at least one physiologically inert gas is maximum

(12) FIG. 2 illustrates ways of performing the method to reduce stress level in animals. Here the method is performed in a sealable chamber (1) with an openable inlet area (2) and an openable outlet area (3). The chamber extends at least from a first position (4) to a second position (5). Animals (not shown) can be positioned into a transport chamber (7). The transport chamber (7) is initially located in the first position (4) with a maximum oxygen concentration and a minimum concentration of at least one physiologically inert gas. The transport chamber (7) is transported as indicated by arrow (6) from the first position (4) to the second position (5) and during this transport the gas mixture can be changed such that in the second position (5) there is a minimum oxygen concentration and a maximum concentrating of at least one physiologically inert gas. The animals may be in a reduced stress level when the transport chamber (7) reaches the second position (5) or the animals may be in a reduced stress level after the transport chamber (7) has been located for a period in the second position (5).

(13) The sealable chamber (1) may be a stand alone equipment, The sealable chamber (1) may also be located next to an equipment where the animals are subjected to a subsequent process. This subsequent process may be stunning in a stunning equipment. The sealable chamber (1) may also be an integrated part of an equipment where the animals are subjected to a subsequent process, such as a stunning equipment for stunning the animals. This subsequent process (e.g. stunning) may take place at the second position (5), which requires the gas inlet is controlled such that the animals are in a reduced stress level when reaching the second position (5). In the figure the sealable chamber (1) is illustrated as being horizontally arranged, though it may also be vertically arranged or inclined up-wardly or inclined down-wardly and where the transport chamber (7) in a vertically arrangement can be moved down-wards and/or up-wards, and up-wardly or down-wardly if the sealable chamber (1) inclines up-wardly or inclines down-wardly, respectively.

(14) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.