Seasons These are seasons that differ in weather and temperature. They change with the annual cycle. Plants and animals adapt perfectly to these seasonal changes.
Seasons on Earth
It is never very cold or very hot in the tropics, there are only two seasons: one is wet and rainy, the other is dry. At the equator (on the imaginary midline) it is hot and humid throughout the year.
AT temperate zones(outside the lines of the tropics) there is spring, summer, autumn and winter. Generally, the closer to the North or South Pole, the cooler the summer and the colder the winter.
Seasonal changes in plants
Green plants need sunlight and water to form nutrients and grow. They grow most in spring and summer or during the wet season. They tolerate winter or dry seasons differently. Many plants have a so-called rest period. Many plants store nutrients in thickened parts underground. Their aerial part dies, the plant rests until spring. Carrots, onions and potatoes are the type of nutrient storage plants that people use.
Such as oak and beech shed their leaves in autumn because at that time there is not enough sunlight to form in the leaves. nutrients. In winter, they rest, and in spring new leaves appear on them.
evergreen trees always covered with leaves that never fall. To learn more about evergreen and shedding trees.
Some evergreen trees, such as pine and spruce, have long, thin leaves called needles. Many of the evergreen trees grow far north, where summers are short and cool and winters are harsh. Keeping their foliage, they can start growing as soon as spring arrives.
Deserts are usually very dry, sometimes there is no rain at all, and sometimes there are very short rainy seasons. Seeds germinate and give new shoots only in the rainy season. Plants bloom and produce seeds very quickly. They store nutrients
Seasonal changes in animals
Some animals, such as reptiles, reduce their activity and go to sleep to survive the cold or dry season. When it gets warmer, they return to an active lifestyle. Other animals behave differently, they have their own ways of surviving in harsh periods.
Some animals, such as the dormouse, sleep through the winter. This phenomenon is called hibernation. All summer they eat, accumulating fat so that in winter they can sleep without eating.
Most mammals and birds hatch their young in the spring, when there is plenty of food everywhere, so that they have time to grow and get stronger for the winter.
Many animals and birds undertake long journeys each year, called migrations, to places where there is more food. For example, swallows build nests in Europe in the spring, and fly to Africa in the fall. In the spring, when it becomes very dry in Africa, they return.
Caribou (called reindeer in Europe and Asia) also migrate, spending their summers above the Arctic Circle. Huge herds eat grass and other small plants where the ice melts. In autumn they move south to the evergreen forest area and feed on plants such as moss and lichen under the snow.
The general study includes the following sections: 1) determination of the animal's habitus; 2) examination of mucous membranes; 3) examination of the skin, coat and subcutaneous tissue; 4) research lymph nodes; 5) temperature measurement.
Determining the habitus of an animal
Inspection is the main research method here. It is especially important when examining entire herds, breeding horses, evaluating animals, mass examination at exhibitions, etc. patients and those suspected of having a disease, groups are compiled to be rejected, selection is made according to one or another indicator, etc. An experienced doctor with good practical training performs such tasks so successfully that further research often makes only minor adjustments, emphasizing and shading the features each case.
Some details of the changes detected by inspection have to be established with the help of palpation, which, in a general study, finds a greater use. To determine body temperature, thermometry is used, which, instead of subjective sensations of examination and palpation, already delivers accurate data.
Regarding the diagnostic value of a general examination, it should be noted that in some fairly common diseases, the clinical picture is filled with symptoms from this side, and the diagnosis is thus based on examination data. These include: tetanus, rabies, morbus maculosus, bovine puerperal paresis, and acetonemia. In the vast majority of cases, however, a general examination gives only individual signs, perhaps important ones, especially in assessing the condition of the animal, such as, for example, temperature increase, the appearance of edema, but nevertheless completely insufficient to determine the nature of the disease. It can be hoped that further work over the patient and a special study will help to establish the picture of the disease so accurately that the purpose of the study - diagnosis - will be achieved. Finally, there are cases when a study conducted with all punctuality does not notice any changes at all. Not infrequently, in such circumstances, even a special study gives only extremely vague signals, regarding which it is impossible even to say where, from which organ they come. This is the position in which the doctor finds himself in case of chronic diseases. various bodies animals, with chronic virulent infections, etc. Careful observation of the patient, repeated studies of him and, finally, the use of certain methods from a number of specific ones similar cases often a tremendous service, pointing to the right path, delivering just the information that was missing in the process of making a diagnosis.
Definition of a gabit. si animal general research begins. Under the habitus understand the state of the patient at the time of research on physique, nutritional status, body position in space, temperament and constitution.
In creating the first impression of the patient and his condition, the habitus in general is of great importance, providing the kind of information that is important in any disease in general. In some cases, these data are guideline.
Rice. 1. Cretinism in a dog (according to Stang). Rice. 2. Rickets in a calf.
Body type determined by inspection according to the degree of development (mass) of the skeleton and muscular skeleton, and only in exceptionally rare cases, for example, when determining the details of the physique, the therapist has to resort to the help of measuring instruments.
Depending on the mass of bones and muscle tissue, they say either good or thin physique. A good physique gives the impression of strength and strength. A good physique is characterized by strong legs with wide joints and massive, voluminous muscles; the chest is wide and deep, the ribs are steep, wide, with large intercostal spaces; the back is short; a closed and short loin turns into a massive and wide croup; the head is large, sometimes heavy, with a fleshy, heavy and short neck. With a good physique, you can count on a good development of the lungs and heart, on a sufficient capacity of the intestines. An animal with a good physique shows maximum resistance to various harmful influences, and in case of diseases it turns out to be the most enduring, giving a significantly higher percentage of recovery. And only as an exception can be noted a few diseases (rheumatic hemoglobinemia of horses, morbus maculosus, puerperal paresis and acetonemia of cattle), which mainly affect animals of good constitution and good nutrition.
With a thin physique, the animals are weak, frail, fragile, weak; they seem to be flattened laterally. A long, narrow body, with a flat chest and a long back, a long loin and an open sigh, is set on long and thin (liquid) legs; light, dry, neat head suspended on a thin, long and flexible neck.
With a bad physique, cattle often become a victim of tuberculosis; calves are especially susceptible to paratyphoid, dictyocaulosis; horses die from catarrhal pneumonia, chronic alveolar emphysema and heart disease; poorly built puppies are often disfigured by rickets or die due to the plague.
Power status gives an idea of the balance of metabolism. Here, just as in assessing the physique, one should not begin with details. The state of nutrition is determined along the contour lines - their softness, roundness and completeness, or, conversely, rough angularity, sharpness; use in case of need
Rice. 3. Rickets. Softening of the bones. palpation, establishing the degree
high crest, belly under- Fig. 4. Wasting in the dog (according to Stang).
they pull, the pudendal olasty is deepened, the anus is far retracted.
Good fatness gives a reliable guarantee that the energy expenditure is fully balanced by its arrival. In cases where assimilation processes prevail over dissimilation processes, excess nutrient material is deposited in fat depots. Horses of heavy breeds, indoor dogs, cats, and especially pigs are especially predisposed to deposits of significant amounts of fat, as a result of which severe disorders of the function of certain organs sometimes develop. In such cases, one speaks of obesity.
Rice. 5. Squishy.
As a result of these or other influences, animals sometimes lose weight amazingly quickly, turning into real skeletons within some 3-5 days. This is observed in horses with an acute form of infectious anemia, with infectious encephalomyelitis, with acute glanders, in all animals with rabies, in calves and piglets with paratyphoid and white diarrhea. However higher degrees emaciation is more often the result of chronic infectious and
invasive diseases - tuberculosis and paratuberculosis,
chronic glanders, piroplasmosis, chronic infectious anemia, dictyo-caulosis, fascioliasis and gadfly disease of sheep. Sometimes emaciation is noted only on individual organs, even with good overall fatness. Here it should be noted atrophy of muscle groups with ankylosis of the joints, atrophy of the croup with flabby paraplegia.
The position of the body in space. The doctor has to observe and examine patients in various poses, with different positions of their bodies. When examining, the most comfortable position is the standing position, which guarantees flawless conduct of almost all details of the examination; small animals are more likely to be examined in a lying position or seated on a table. Sometimes some aspects of the study require observation of the animal while moving.
Healthy animals, left to their own devices, can easily change the position of their body at will, giving it those postures that correspond to volitional impulses. Unlike this kind voluntary provisions still distinguish forced positions, when the animal is forced to maintain the posture created by the painful process, without being able to change it at will. The reasons for this are loss of consciousness, certain pains, dizziness, weakness, perhaps fear or muscle or nerve paralysis. However, when analyzing forced positions, especially lying down, one should not lose sight of the fact that animals often do not rise simply because they do not want to get up, for example, after eating, hard work, at high external temperature, due to extreme phlegm, etc. To make sure that the animal is really not able to get up, one has to resort to various coercive measures - shouting, patting on the ears, croup, clicking with a whip, showing tasty food, etc. t. e. And only in those cases when, despite all the measures of influence and help in trying to get up, a change in position turns out to be impossible, it is recognized as forced. Forced positions are an extremely valuable sign, clearly characterizing the disease process and the patient's condition.
Forced lying position the horse enters clinical picture rheumatic and enzootic hemoglobinemia, the last phase of tetanus, the lethargic form of infectious encephalomyelitis, transverse lesions of the spinal cord and all diseases associated with loss of consciousness. In cattle, it characterizes the laying of cows before and after calving, puerperal paresis, the last phase of acetonemia, and transport sickness. Small cattle, pigs and carnivores during severe processes, especially febrile ones, generally prefer to lie, huddled in a corner (dogs), buried deep in the litter (pigs). When trying to pick them up, the animals get up, sluggishly and reluctantly take a few steps and lie down again, accepting the same
Rice. 6. Tetanus.
location. Thus, if for large animals forced lying is the central symptom of a limited range of diseases, determining the nature of suffering, then in small animals it is observed too often and shades only their condition.
Forced standing seen predominantly in horses. It is characteristic of tetanus, pleurisy, pleuropneumonia, all diseases associated with severe dyspnea, as well as a number of brain diseases.
Each of the described positions of the body, in space, both voluntary and forced, can be further: a) physiological and b) non-physiological. The latter is one of the most common symptoms of certain sufferings, involuntarily drawing attention to itself with its unusualness. Especially characteristic is the position of the body with tetanus, when the horses stand with legs apart, like goats, with an elongated head and neck, a tensely straightened back, ears pulled back and a raised tail. In severe febrile illnesses, they keep their heads helplessly lowered and stand with half-closed eyes, alien to everything. In the lethargic form of infectious encephalomyelitis and tetanus, horses lie stretched out with their head and neck extended, and the limbs sides of the body, facing upwards, are kept on weight, without touching the ground.
AT forced movement, differing in great diversity, are important in the pathology of the horse. These include: a) aimless wandering, b) arena movements, c) clockwise movements, d) forward movements, e) backward movements. In small animals, in addition, there are: e) roll-like movements. Forced movements are complex, sometimes well-coordinated, extremely monotonous movements that occur only under the influence of a pathological process, as a result of irritation of the corresponding centers. Since for the observer such movements appear to be completely unrelated to external influences, they really give the impression of being involuntary or forced.
Aimless wandering is usually observed with anatomical
Rice. 7. Elongated position of the head with pharyngitis.
brain damage and functional disorders. In Born's disease, equine encephalitis (American and French), infectious encephalomyelitis, bovine acetonemia, coenurosis, animals wander for hours, moving from one place to another in a state of some kind of stupefaction. Movements are poorly coordinated, animals
Rice. 8. Progressive osteitis.
they stagger, stumble, do not notice obstacles, climb walls, feeders, not responding at all to external stimuli, excluding, perhaps, auditory ones. Sometimes these movements are full of energy and strength and resemble the gait of a horse rushing to the house, horses, a foal, etc. Even obstacles are sometimes unable to stop the movement, only changing its shape. Stopping in front of a wall, falling into a ditch, lying on its side, the animal does not stop making habitual movements on the spot.
Manege movements are for the most part well-coordinated movements in a circle in a certain direction, and the diameter of the circle either remains unchanged or gradually decreases. In the first case, the animals sometimes walk in the accepted direction for hours; when the diameter of the circle decreases, the arena movements turn into clockwise movements, which more often end in an unexpected fall. They are usually the result of damage to the corresponding center of the cerebellum, thalamus opticus, ganglion big brain or unilateral shutdown of sensitive receptors in diseases associated with disorders of consciousness or increased intracranial pressure.
Movements of the hour hand are more often observed in the direction of rotation of the clock hand, sometimes in the opposite direction. They represent the rotation of the entire body of the animal around one of any legs as a fixed point. Similar movements are characteristic of paralysis of the item vestibularis and lesions of the cerebellum. Experimentally, they can be caused by destruction of the thalamus opticus, nucleus ruber, and anterior colliculus.
Rice. 9. Striving forward with brain diseases (but to Makarov).
my striving forward, which cannot be weakened or suspended. Movements are usually hurried and not always strictly coordinated. The limbs are often entwined, there is a staggering of the buttocks, stumbling, sometimes a fall or even overturning of the body. The localization of changes can be the centers of the occiput or torso, corpus striatum, as well as the retina.
Moving backwards is sometimes the only possible form of movement. It is observed occasionally in infectious encephalomyelitis and cerebrospinal meningitis and is usually associated with contractures of the occiput and spasms of the spinal muscles. Due to arching of the hind limbs, tilting of the head and severe coordination disorders, backward movement quickly leads to a fall or even capsizing of the animal. It is experimentally possible to induce this form of movement after the removal of the cerebellum.
Roll-like movements are often observed in small animals: dogs, cats, and especially birds. They represent the rotation of the animal's body around the longitudinal axis. At the same time, everything is often limited to only one turn or even half a turn, in other cases, movements continue until they are stopped by some obstacle on the way. They are usually associated with unilateral lesions n. vestibularis, cerebellar peduncles or their surrounding parts.
Temperament determined by the speed and degree of reaction to external stimuli. The criterion is the expression of the eyes, the reciprocal movements, for example, the play of the ears, and the whole behavior of the animal. Distinguish between lively and sluggish temperaments.
Horses of a lively temperament are distinguished by the ability to quickly perceive: they are always attentive, vigilantly watching their surroundings, sensitively responding with playing with their ears, changing their gaze, and facial expressions to perceived impressions from outside world, show impatience before work, before giving food, haste in eating; their movements are full of energy and strength, they are the most valuable workers in almost every economy.
However, a sharply pronounced lively temperament at the same time presents some inconvenience, and sometimes makes the animal completely unsuitable for work. Horses of a lively temperament are often too impressionable, disobedient, stubborn, angry, shy, sometimes maim people, animals, often break the harness.
The phlegmatic temperament is manifested by just the opposite properties. Animals are lazy, lethargic, little mobile and stupid.
For the therapist, temperament is important in the sense that, in severe suffering, it is sharply reflected in the behavior of the animal. Strong pain sensations are especially painful for animals of a lively temperament and, conversely, are less disturbing for phlegmatic people. And vice versa, with severe febrile illnesses, horses of a lively temperament at first glance do not give the impression of being seriously ill, retaining their appetite and vigor for a longer time, while phlegmatic people under these conditions do not pay any attention to their surroundings and seem hopeless. Thus, when evaluating the forecast, it is necessary to take into account the peculiarities of temperament.
Constitution. The constitution is understood in veterinary medicine as a combination of all influences that determine one or another degree of resistance of tissues, organs and the whole organism in the fight against harmful factors. This general resistance is very different and depends on the resistance of each individual tissue and the nature of each individual stimulus, and thus is far from being always a constant value.
Astrakhan sheep is considered extremely resistant, as it easily tolerates the harsh conditions of Central Asia - lack of water, tropical heat, dry and scarce food, but, transferred to a humid climate and abundant green vegetation, it does not acclimatize well and often dies from inflammation of the gastrointestinal tract. intestinal tract, dictyocaulosis.
When evaluating the constitution, it must be remembered that, along with morphological features of an organism, which are easy to measure and evaluate, here the purely biological properties of tissues matter and, in addition, the properties of the germ plasm, its genotinic structure, which determines the development of the cell. It is about this direction. Thus, the constitution is determined by three factors: exterior, interior and heredity.
According to Bogomolets, the constitution "leaves its mark on the whole organism in its whole, reflecting not only on the morphology of the individual, but also on the individual nature of his physiological reactions.” For the therapist, the reaction to the influence of various painful factors is especially important. From this point of view, since the time of Hippocrates, a strong and a weak constitution have been distinguished. Animals with a strong constitution easily put up with the adverse effects of temperature, high humidity, the action of cold winds, drafts, tolerate deprivation, hunger, strong stress, and are less sensitive to a number of infectious diseases, and after infection they easily recover. Animals of a weak constitution in this respect are the exact opposite.
The desire to give a more accurate description of constitutional types, which could be widely used in in practical terms, led to the creation of various kinds of numerous classifications. Of these, Shigo's (Sigaud) classification has become widespread in myo-icin, which distinguishes 4 main types: respiratory, muscular, digestive and cerebral. Attempts to transfer this classification to animals have not been successful, since within one species, for example, in cattle, it is not possible to establish enough characteristic features for each type. Thus, in relation to animals, this classification, as a four-term one, cannot withstand empirical verification, and is also inconvenient when constructing variational series.
From this point of view, the classification of Kretschmer (Kretschmer) is more consistent, which distinguishes three main types: 1) asthenic ^ (lep-tosompy), 2) athletic (muscular) and 3) pyknic.
Rice. 10. Asthenic type.
Zaitsev, who worked on the study of constitutional types in horses, gives them the following characteristics.
Asthenic type characterized by a long chest, long neck, light head, with a relatively poorly developed lower jaw and chewing muscles, and a tucked up abdomen. Well developed lung of considerable size poor development connective interlobular tissue. A voluminous massive heart but in relation to the total body weight is much larger than in other types. Network blood vessels well branched. The liver is relatively small. The small intestine is shorter than other types. Representatives of this type are Arabian and English horses, as well as American and Russian-American trotters.
For picnic type characterized by a short chest, a massive croup with wide-set mokloks, a massive head with a strongly developed lower jaw and chewing muscles, a short neck and a voluminous belly. Animals are distinguished by great strength, but far from being so mobile. Ardennes, percherons, and partly heavy artillery horses fit this characteristic.
Rice. 11. Picnic type
Muscular type occupies a middle position between those just described. The best representatives of this type are mestizos of trotting and heavy horses, and
Rice. 12. Muscular type.
also convoy and well-built working horses, which are distinguished by well-developed muscles, strong bones, sufficient snares and mobility.
Zaitsev's measurements of height, torso length, chest girth behind the shoulder blades and metacarpus girth according to six main indices, processed using the method of variation statistics, made it possible to establish a profile for each type.
At the same time, “in horses of a muscular type, the profile is usually located close to the midline, while in picnics it will go above the midline and only at the end drops down. The corresponding curve for asthenics, on the contrary, goes below the middle line, at the end rising up ”(Zaitsev). However, the differences between the main constitutional types are not limited to purely morphological features of the body structure. These differences go much deeper, reflecting on the function of the main systems. According to "Chernorutsky, there is known kind correlation between the constitutional type and the functional power of the organism. So, the respiratory capacity of the lung in asthenics is higher than in picnics; their blood pressure, on the contrary, is somewhat lower, and their calcium and uric acid levels are also significantly lower.
Significant differences are further established by hematological examination. In trotters, according to Zaitsev, the number of erythrocytes and hemoglobin is higher than in draft horses and working horses. The diameters of erythrocytes, their surface and volume in trotting horses are also greater than in draft horses.
Thus, the exterior of the animal is closely related to its internal features (interior). This makes it possible to use constitutional features as a criterion not only in assessing the performance of an animal and its productivity, but also in a therapeutic sense.
With delivery across Novosibirsk.
Under cellular conditions under the influence psychological factors and with improper feeding, the resistance of the body of animals to diseases is greatly reduced, therefore proteins, like other animals, are susceptible to various diseases. When keeping animals at home, you must strictly follow the basic rules of sanitary regime and personal hygiene in order to protect your pets from disease. In addition, during childbirth and during the period of rearing offspring, there are often inexplicable cases of death of young animals and females, which occur in connection with new living conditions that differ from those in nature.
First of all, so that your animals feel good and never get sick, need to take proper care of them.. In addition, it is necessary to keep the newly acquired squirrel in quarantine for one month and only then transplant the new animal into common cage with your other pets.
Change of scenery, as a rule, also greatly affects the general condition of the animal. He may feel sad, his appetite decreases and lethargy appears. special attention and care requires animals in the first month of stay in your apartment. During this time, they wean from the old conditions and get used to the new home environment and to people. During this period, try to give them especially a lot of time so that the animals get used to you and consider you theirs.
At keeping animals in quarantine you need to carefully monitor his health for a month and measure his body temperature. If you know the normal body temperature of your pet, then any deviation from the norm will indicate that the animal does not feel well.
If there are several animals in quarantine, for example, a male and a female, the sick animal must be transferred to another cage.
Very often, young females refuse or are reluctant to feed their young with milk. In such cases, the mammary glands are examined, and if the female turns out to be healthy and she has milk, then it is recommended to leave her at the brood, and so that the babies do not die of hunger, they should be fed with milk through a pipette for several days. If the female begins to feed the cubs normally during this time, artificial feeding can be stopped.
If the mammary gland does not secrete milk or the female stubbornly refuses to feed the offspring, then she is rejected, and the cubs are placed with another female (it can be of a different species, for example, with a rat that has cubs), and she feeds the foundlings until they are independent.
If there is no female suitable for these purposes, then the cubs are artificially fed with boiled milk, first through a pipette, and then with the help of a nipple. The following accessories are required for this purpose. A heat emitter, which can be used as a heating pad used in medicine. This device is used to heat orphans and sick animals.
1. Plastic syringes without needles for feeding newborn orphans and cubs who, for some reason, do not have enough female milk.
2. Lots of soft and absorbent paper towels.
Goat's or cow's milk can be used as a milk substitute for squirrels ( feed warm), and also at the age of several days, you can feed gruel, to which a little glucose or condensed milk is added ( for one part of baby food 50 ml of condensed milk with a fat content of 12%). Later, a small amount of calcium powder (such as calcium gluconate) is added to this mixture, as well as a small amount of sugar at the tip of a teaspoon. When feeding orphaned cubs, substitutes for cat and dog milk have proven themselves well.
Cases of the birth of dead cubs in healthy females are extremely rare. They occur with malnutrition or malnutrition, due to a lack of vitamins and trace elements, as well as some infections, such as listeriosis or brucellosis. Females during childbirth, if they are fed a balanced diet, die very rarely. Their death can occur as a result of a spasm of the unpaired uterus, caused, for example, by a strong fright. To prevent stress, you should always approach the nesting house with a pregnant female carefully and without much noise. Real pathological births occur mainly for two reasons - in violation of the asynchrony of labor from the right and left sections of the uterus or the wrong position of the embryos. There are also cases of death of pregnant females from sepsis due to the decomposition of dead embryos, as well as as a result of ectopic pregnancy.
It is easy to confuse with stillborn cubs that were born normal, but died already on the nest litter for some reason, for example, because their mother did not accept them, which happens not only during the first birth in a cage, but also in wild females who were caught already pregnant. In the first case, the cause is the insufficient development of the maternal instinct, in the second, the lack of milk as a result of strong, prolonged stress. In addition, the female may accidentally trample the newly born cub. It often happens that a young female, who killed the first brood due to inexperience, successfully raises the next ones.
Animals forced to live in a cramped cage are often at enmity with each other. At the same time, the behavior of animals of different sexes and temperaments sometimes differs quite strongly: the male, as a rule, guards the area of the entire cage. Females act differently: one cannot calm down until " alien"is in a cage, which ultimately leads her to death from hunger and persecution, the other is limited to the fact that, having driven her rival into a corner, she goes to the house and rests there. The female guards only the nest and can be aggressive even to the male.
An interesting trip, a seaside vacation, and even just a change of scenery treat stress for a reason - new experiences trigger active neurogenesis which helps to hide old memories behind new impressions.
hippocampus The subcortical region of the brain is shaped like a seahorse (from which it got its name). It is extremely important for memory formation and spatial learning.
When scientists discovered certain area hippocampal stem cells dividing to form new neurons, they thus proved that nerve cells are restored. Then it was possible to show that neurogenesis occurs not only in the children's brain, but also in the adult brain (both in animals and in humans). It remains only to prove that it affects the growth of neurons. For example, there is now an active hypothesis according to which there is a connection between neurogenesis, the ability to survive stress and the influence environment. This time it was experimentally confirmed by American specialists Michael Lehmann and Robert Schloesser from the National Institute of Mental Health and the National Institutes of Health in Bethesda, USA.
Neurogenesis occurs in the so-called subgranular zone of the dentate gyrus of the hippocampus. Here the stem cells nervous tissue differentiate into new nerve cells, which are incorporated into nerve connections hippocampus, and also migrate to other parts of the brain.
To find out if this process affects the behavior of animals in stressful situation, scientists used transgenic laboratory mice in which, with the help of genetic manipulation, the formation of new nerve cells is blocked. The control group consisted of ordinary laboratory mice.
How Mice Received the Prey Complex
The mice were subjected to severe social stress. To do this, they were placed in a strange cage, in which an unfamiliar male lived, controlling his territory. At the first stage, the owner and the stranger were separated by a perforated partition, so that the animals saw each other and smelled someone else's smell, but did not physically touch.
At the second stage, the partition was opened for five minutes, and the owner attacked the stranger. The planted mice defended themselves from the aggressor as best they could: they took a fighting stance, tried to repel attacks and hit the floor hard with their tails. But the owner, defending his territory, always won, and from time to time the behavior of the placed mice changed. They fought back less and less, more and more often huddled in a corner and assumed a pose of submission. For two weeks of fights on foreign territory, they developed a victim complex - a severe depressive state.
New experiences save you from depression
After the end of the mouse fights, the groups of both transgenic and control animals were divided in half. The first half of the groups were housed in their home cages, and the other half in cages with enriched media. They contained the most interesting objects for mice: soft material for the nest, wheels for running, ladders, as well as different size plastic tubes in which mice could hide.
After a three-week rest period under normal or improved conditions, the mice were challenged again to see if their behavior had changed during that time. Mice resting from fights under normal conditions behaved in the same way during new encounters with the aggressor as after the first experience of defeat. They hid in a corner, took a subordinate posture and froze. Everything indicated that their depressed, depressed state - the victim complex - had not disappeared anywhere.
The same behavior was demonstrated by transgenic mice (which did not produce new neurons). And everyone, even vacationers in enriched conditions.
But the mice control group, who had been in improved cells, showed much greater activity: they resisted the aggressor and behaved as if they had forgotten about their negative experience defeats.
Biologists spent with mice additional tests to assess their condition. Control mice, after being in an enriched environment, differed in all tests from other animals in depression. They did not lose their exploratory interest in unfamiliar surroundings, they did not lose their desire for pleasure - they preferred water sweetened with saccharin to plain water, they showed less fear when spending time in a lighted cell. Depressed mice from the rest of the groups did not show curiosity, did not want to drink sweet water and sat in the dark.
But it needs new neurons
The experiment showed that exposure to an enriched environment cured mice of depression caused by defeat in conflicts. But in order for such a treatment to work, there must be neurogenesis in the brain - the formation of new neurons. If you block it, the enriched environment does not work.
Discussing the mechanisms of action of an enriched environment, the authors suggest that it reduces the emotional reactivity of animals and enhances emotional stability. This conclusion is confirmed by a decrease in the production of stress hormones under these conditions. And apparently, the formation of new neurons - necessary condition for the ability to cope with stress. And besides, new neurons are included in the formation of new memory, which is necessary for the development of an enriched environment.
According to the authors of the article in the journal Molecular Psychiatry, The symptoms and manifestations of murine depression are similar to post-traumatic depression in humans. And, therefore, in the treatment of the latter, the same methods can be used.
Behavioral work
Animal
The main objectives of the work on observing the behavior of the animal are:
√ in developing the method of observation and improving the skills of students to observe;
√ in the formation of ideas about the behavior of animals;
√ in obtaining and improving practical skills in describing, recording and interpreting externally observed activities, mental states of animals.
After doing homework a seminar is held with an analysis of the observations made, an analysis of typical shortcomings and a discussion of the most successfully completed work.
In this work, the method of "participated observation" is used, that is, the observer is present in the field of view of the animal (does not hide), communications between the animal and the observer are not excluded (if they occur during the observation period, they must be recorded).
The observer influences the observation situation by introducing a new object into the field of view of the animal. The choice of the nature of the object depends on the type and temperament of the animal and the general situation of observation. The observer himself decides which object will be introduced into the field of view of the animal. An important condition observation of the animal in this task is to change the behavior of the animal. If the animal ignores the introduction of a new object into the field of view, i.e. new item does not cause any change in the behavior of the object of observation, you need to record this in the protocol and choose another object.
Observation is carried out using continuous time-based logging. In other words, the observation protocol records all the external manifestations of the animal per unit of time. The protocol is filled out every minute.
You can observe any animal (domestic, wild, familiar or not familiar to the observer), in any environment (natural or specially organized by the observer).
Animal observation is carried out from 10-30 minutes (depending on the type of animal and the observed activity) to 2-3 hours.
The conditions for starting filling out the observation protocol are that the observer himself must cease to be a new object for the observed animal by the beginning of fixing the behavioral reactions of the animal. When modeling the situation in the third or fourth minute of observation, the animal is provided with a new object. The introduction of an object into the field of view of the animal IS RECORDED in the protocol.
If necessary (clarification of the obtained data, expansion of the experience of observing various types of animals), repeated observations for the same animal or for others. Comparison of observations of two animals allows for an additional estimate.
General principles keeping records of observations.
First of all, it is necessary to build records in such a way that each observation protocol is provided with the following information:
1) date of observation (indicating the year);
2) start time and end time of observation;
3) place of observation;
4) observation conditions (temperature, and if the animal is outside, then wind, cloudiness, precipitation; the presence and number of people near the enclosure, the presence of other animals);
5) the general condition of the animal at the beginning of the observation - normal, inactive, agitated, in pain, etc.;
6) sufficiently detailed data on the observed animals (species, sex, name and/or number);
7) surname and signature of the person who conducted the observations.
If observations are made on separate sheets, then all information should be on each sheet, if the entry is in a journal, then the data common to all observations, as well as the abbreviations used, can be placed on the title page.
Secondly, the records should reflect objective changes in the external state of the animal, while the same external manifestations should be equally reflected in the records in all cases.
EXAMPLE: Let's take an example to illustrate this point. Assume that the observer uses three expressions to indicate the posture of a lion lying with its head on its paws and closing its eyes: "The lion is lying", "The lion is sleeping", "The lion is resting". With external similarity, these records do not mean the same thing at all. In the first case we are talking about the posture of the animal, that is, about its position in space, which is recorded completely objectively; the second statement characterizes the physiological (or mental) state of the animal; both objective (in obvious cases) and subjective assessments are possible here; finally, the third phrase contains an assumption about the reasons why the animal exhibits certain forms of behavior, it is clear that all assumptions of this kind are purely subjective character. If, moreover, the observer writes each time what seems to him the most suitable, then, wanting to find out how often the lion manifests this or that state, the observer actually learns only how often it seemed to him. In addition, no quantitative comparison of the frequencies of manifestations of such diverse elements (which in this case completely overlap) can be justified at all.
The situation becomes even more complicated if the observer applies estimates of the 2nd and 3rd kind, not being able to understand the essence of the occurring phenomenon. For example, a person who does not know that the wide opening of the mouth - "yawning" - in monkeys is a sign of an aggressive mood, is likely to regard these actions, by analogy with human yawning, as a sign of a state of drowsiness.
Thirdly, entries must be made neat enough so that they can be easily read, all symbols (icons, letters) must be deciphered.
Fourth to observe behavior is to notice changes in external state animal. These changes can be extremely diverse (in principle, any, the most insignificant movement is a change in the external state).
If any movements and changes in appearance animal fit into a complex of fixed external manifestations species-typical reaction, it is permissible to use an abbreviated description of this reaction. At the same time, it is necessary to describe in the notes to the observed phenomena what is included in the observed reaction. Let's look at this situation with an example.
EXAMPLE: The cat reared its fur - a change; raised her hair, arched her back, flattened her ears, bared her teeth and hissed. All this together can be called "assumed a menacing posture." It is possible to indicate in the protocol of observation the common name of all behavioral manifestations(“assumed a threatening posture”). BUT in the notes it is necessary to decipher what objectively observed changes are included in the concept of "threatening posture":
“The classic menacing posture of a cat: All four legs of the cat are tensely extended, it seems to be standing on tiptoe, the back is arched in a hump, the tail is curved, and the hair on the back and tail stands on end. The threat is complemented by appropriate facial expressions: the ears are pressed to the back of the head, the nose is wrinkled, the fangs are bared, the corners of the mouth are pulled back. The cat purrs and periodically hisses"
All the actions of the same cat during a fight with another cat (and these actions include “furry rearing”, and “threat posture” and much more), if compared with the state of the animal before meeting with an individual of its own species, are also a change.
This example demonstrates the ability to describe behavior on various levels- from elementary movements separate parts bodies to complex and long-term unfolding behavioral ensembles (for example, the reproductive behavior of the stickleback includes building a nest, guarding it, attracting a female, courtship ritual, fertilization of eggs, etc.).
At what level to carry out the description - it depends on the objectives of the study, on the questions posed, however, in order to be able to quantitatively compare the results obtained with each other, all units of behavior used in describing the actions of the animal must have the same dimension, i.e. .one of them should not be included in others as constituent parts(as, for example, "raising the wool" is included in the "pose of threat").
The most common way to describe the actions of an animal is with the help of conventional icons, each of which corresponds to one of the selected elements of the ethogram. When designing an icon system, you should choose simple, easy-to-write symbols. Significantly increases the possibility of recording the use of additional service icons (for example, double underlining of the icon indicates the mutual orientation of actions, question mark after the action icon - failed attempt taking this action; Exclamation point- the coercive nature of the action in relation to the recipient, etc.).
A well-thought-out recording order allows you to quickly, compactly and conveniently “stack” information for subsequent reading. For example, at the beginning of the record, the time of the beginning of the action is indicated, then its initiator (No., letter index, nickname or other short designation of a particular animal). Further - the symbols of actions in their natural sequence; after the description of the actions indicate the object to which they were directed (in the case of social interactions), concludes the record with the end time of the action.
Video recording can be used to record observations. This allows you to keep an eye on the animal without looking away. The records made must be deciphered and rewritten in the diary of observations, while the time for decoding is spent approximately twice as much as for the observations themselves. The presence of video recording allows you to increase the rating.
Part of the time of observation, the animal may hide in a shelter, or for other reasons be inaccessible to the observer. We recommend immediately, in the course of observation, to note how long the animal was in the observer's field of view. If the animal disappeared from view before the introduction of a new object into the field of view, the observation of the animals should be repeated or the observation time should be increased, marking in the protocol the period of time when the animal was not available for observation.
The work is done according to the template below.
Purpose of observation(for example: to follow the dog's orienting and exploratory activity in a new environment).
Observation conditions(for example: observing the behavior of a dog in natural conditions during the first visit to a summer cottage).
Observation Protocol
Observer (full name) _________________________________________________
Date __________ Start and end time of observation _______ – _______
Place of observation _____________________________________________
Conditions (temperature; and if the animal is outside, then wind, cloudiness, precipitation; the presence and number of people near the enclosure, etc.) ___________
___________________________________________________________
general characteristics animal:
View _________________________________________________________
Gender __________ Age ___________
Nickname or number: ___________________________
Animal status (active, passive, health status) ____________
Simulation of the situation:
Characteristics of an object new to the animal, to which it is supposed to cause an orienting reaction: __________________________________
__________________________________________________________________
Significance for the animal (food, frightening object, toy, neutral object) ____________________________________________________________
The size.____________________________________________________________
Method of introduction into the field of view of the animal _____________________________
__________________________________________________________________
Distance ________________________________________________________
Description of the animal's behavior at each time interval (minimum 10 minutes): Time (per minute) Animal behavior, change in appearance
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Page creation date: 2017-10-25
