CC BY
34
UDC 636.0364:612
ON THE INFLUENCE OF HIGH TEMPERATURE OF ENVIRONMENT AND SOLAR RADIATION ON PHYSIOLOGICAL FUNCTIONS OF ANIMALS WITH DIFFERENT ECOGENESIS
Stepanov D.V., Doctor of Agricultural Sciences Rodina N.D., Assistant Professor Mamaev A.V., Doctor of Biological Sciences Stepanova S.S., Candidate of Biological Sciences Orel State Agrarian University, Orel City, Russia E-mail: shatone@mail.ru
ABSTRACT
In order to point out differences in adaptive ability of the animals born in the conditions of subtropical climate and imported from the arias of moderate climate both kinds were simultaneously exposed to high ambient temperature and solar radiation. The analysis of materials of experiments on studying of influence of high temperature of the environment and solar radiation on the animals born in the conditions of subtropical climate and imported from the European part at young age, showed that they, is generally similar react to influence of extreme conditions of the environment. The carried-out researches showed that the smallest differences (generally on body temperature and frequency of respiration) were observed in the first year of adaptation of the delivered animals.
KEY WORDS
European breeds; Adaptations; Animal; Solar radiation; Extreme conditions; Environment.
There is always hope that animals could accommodate to new climatic conditions. Most expectations are laid upon new generations that appear in a new climatic zone. There is a variety of opinions on adaptability of animals to new climatic conditions. Slonim A.D., 1967; Soldatenkov N.I., 1969; Sukhomlin K.G., 1971 and others show that in hot climate -due to the adaptability to heat - hyporeaction to high temperatures is observed and the process of individual adaptation is finished by the age of four years, that is - by the grown-up state. Raushenbach Y.O. and Kiselev Y.A. (1975) state, that comparative study of reactive specifics of black spotted cattle breed from Middle Asia (Tashkent District) and Siberia (Omsk District) did not show essential difference in thermal regulation specifics of these breeds under high ambient temperature.
In order to point out differences in adaptive ability of the animals born in the conditions of subtropical climate and imported from the arias of moderate climate experiments were conducted when both kinds were simultaneously exposed to high ambient temperature and solar radiation.
MATERIAL AND METHODS OF STUDY
The study was being held throughout 4 years on the animals of black spotted breed born in hot climate from previously imported and initially imported from moderate climate specimen. The experiment was held on heifers of 12-15 months old, after 2-3 months after their relocation from moderate climate, and then on the same specimen after their 1 calving and 3 calving. Control specimens had been born in subtropical climate and were the third generation of imported animals of the same breed.
The study was held in the morning under moderate ambient temperature (15-22 °C) and in the afternoon after 2 hour (2 to 4 p.m.) exposure in the sunlit field at 35,5-39,5 °C. Throughout the period of experiments animals’ clinical state, lung respiration and gaseous metabolism, perspiration and topography of skin temperature were tested.
The analysis of materials of experiments on studying of influence of high temperature of the environment and solar radiation on the animals born in the conditions of subtropical climate and imported from the European part at young age, showed that they, is generally similar react to influence of extreme conditions of the environment.
RESULTS AND DISCUSSION
The study on the heifers of 12-15 months old, after 2-3 months after their relocation from moderate climate showed that after their 2-hours exposure in the field their body temperature raised up to 40,2 °C (1,8 °C more in comparison with the morning temperature). In the meantime, the body temperature of control subjects born in hot climate boy temperature rose from 38,4 to 39,3 (by 0,9 °C only - See Table 1). Respiration rate of imported heifers raised by 2,7 times, of born in hot climate - only by 2,2 times. However, pulse rate in the first group raised from 83,8 to 89,9; in the second group - from 79,9 to 87,7, that is - a little bit more.
Table 1 - Levels of clinical data of black spotted animals of different exogenesis under the exposure
on the insolated field during the adaptation
Animal’s Age Group Atmospheric temperature , 0C Air Humidity, % Body temperature 0C Pulse rate per minute Respiration rate per minute
a.m. p.m. a.m. p.m. a.m. p.m. a.m. p.m. a.m. p.m.
12-15 I 19 37,9 80 26 38,4 40,2 84 90 40 109
months II 19 37,9 80 26 38,4 39,3 80 87 40 86
1 calving I 15 35,5 66 18 38,5 39,6 72 88 31 78
II 15 35,5 66 18 38,4 39,4 74 80 31 77
3 calving I 22 39,5 68 25 38,5 40,9 72 76 52 116
II 22 39,5 68 25 38,2 40,0 70,5 81 46 100
Groups: I - imported, II - born in subtropical climate.
Experiments that were held in a year after the import of the animals to hot climate conditions on the heifers after their first calving proved that between groups of animals born in different climates no principal difference showed in the reactions on simultaneous exposure to high temperature and solar radiation. After exposure at the insolated field first-calvers’ body temperature raised by 1,1°, and the body temperature of the cows born in hot climate - by 1,0 °C, pulse rate raised 2,5 times and 2,4 times correspondingly.
Approximately the same reaction to extreme conditions remained in the experimental groups in their fourth year in the subtropical climate.
Under the exposure to high temperature and solar radiation imported cows after 3d calving showed the increase of body temperature by 2,4 °C in comparison to the morning temperature, born in the hot climate - by 1,8°; pulse rate of the first group increased by 5,5 %, of the second - by 15,3%; respiration rate of both groups increased 2,2 times.
Thereby judging by the clinical rates it should be stated that under simultaneous exposure to high ambient temperature and solar radiation newly imported animals show a stronger reaction that control subjects born in hot climate. However according to some indications imported subjects have advantage over the subjects born in hot climate.
Animals of the same breed but born in different conditions show even more similarity in the pattern of their respiratory function and gaseous metabolism (see Table 2).
Under the exposure to high ambient temperature and solar radiation of imported first-calvers of a black spotted breed (1 group) the respiratory rate lowered by 25% and lung ventilation increased by 50% in comparison to the data acquired under the moderate exposure during morning hours. Under the same conditions the specimens of the 2 group born in hot climate showed lowered respiratory rate by 22% and increased lung ventilation by only 33%. O2 consumption and heat production changed insignificantly and were almost the same for both groups of test subjects. Respiratory quotient lowered for the 1 test group - by 10,1%; for the second test-group - by 9,2%.
The data proves almost identical reaction to extreme environment of the heifers born in hot climate and heifers relocated from moderate climatic areas. There is no significant difference in reaction to extreme environment of the animals of different ecogenesis (both groups) stated even a year in the conditions of hot climate (after their first calving).
Table 2 - Age dependent changes of physiological functions of black spotted animals of different exogenesis under the exposure on the insolated field
Data Imported Born in hot climate
Age Age
12-15 months 1 calving 3 calving 12-15 months 1 calving 3 calving
a.m. p.m. a.m. p.m. a.m. p.m. a.m. p.m. a.m. p.m. a.m. p.m.
Atmospheric temperature , 0C 19,0 37,9 15,0 35.5 21,7 39,7 19,0 37,9 15,0 35,5 21,7 39,7
Air Humidity, % 79,6 25,6 66,0 18,5 68,0 25,0 79,6 25,6 66,0 18,5 68,0 25,0
Respiration depth, ml/kg 6,0 4,5 11,0 5,4 6,6 4,6 5,9 4,6 10,2 5,2 5,4 3,6
Pulmonary ventilation, l/kg/hour 9,8 14,7 15,6 16,2 11,4 12,57 9,3 12,2 14,2 14,7 9,4 12,0
O2 Consumption, ml/kg/hour 191 181 390 299 286 189 185 178 380 282 301 195
CO2 Excretion, ml/kg/hour 152 128 351 242 239 177 149 130 335 226 239 150
Heat emission, kilojoule/kg/hour 0,426 0,416 0,452 0,343 0,336 0,200 0,425 0,421 0,440 0,332 0,345 0,219
Respiratory quotient 0,78 0.70 0,88 0,80 0,82 0,63 0,78 0,71 0,87 0,80 0,81 0,76
Both groups of animals showed similar changes in their respiratory functions and gaseous metabolism under the exposure in the insolated field in comparison to their morning rates. P.M. rates showed respiratory depth decrease by 49% for the animals of the first group and by 51% for the animals of the second group; lung ventilation - by 4,0 and 3,5 % respectively; O2 consumption decreased by 23,3% for the animals of the first group and by 25,7% for the animals of the second group; heat production decreased by 24,7 and 28% respectively. The decrease of respiratory quotient proved the same for both groups.
The study on the physiological functions of the heifers after the 3d calving (after 4 years in the conditions of hot climate) showed minor difference in reactions to high temperature and solar radiation among the cows imported from the European part of the country and those born in the hotter climate. Under the exposure to high temperature and solar radiation the respiratory depth of the imported black spotted cows decreased by 30% (from 6.6 ml/kg to 4.6 ml/kg); among the cows born in hot climate - by 33% (from 5.4 ml/kg to 3.6 ml/kg) and lung ventilation increased by 12,7%. Imported cows after the 3d calving showed decrease of O2 consumption by 33.8% and heat production - by 40.2% after the exposure to the sun; those born in hot climate - by 35.4 and 35.8% respectively.
The data gathered on gaseous metabolism - one of the most important indicators to rate the physiological state of an animal - did not prove major difference in reaction to high temperature and solar radiation among the specimens of the same breed born in different climatic conditions. That proves minor different in adaptability to hot climate between animals newly imported to this climate and those bred in hot conditions for 2-3 ecological generations. The nature of perspiration and topography of skin temperature also indicates similarities in reactions to extreme environmental conditions among the animals of different ecogenesis (See Table 3).
Judging by the intensity of perspiration which stimulates heat emission imported animals showed the same and sometimes even better results than animals born in hot climate. Perspiration rate of imported heifers after exposure in the field increased by 41% in
comparison with morning rate, whereas the rate of the heifers born in hot climate - only by the 17%.
Table 3 - Perspiration and skin temperature rate of the animals of black spotted breed of different ecogenesis under the exposure in the insolated field
Age Genesis Atmospheric temperature , 0C Air humidity % Perspiration, g/m2/hour Skin Temperature, 0C
night day night day night day night day
12-15 months Imported 19,0 37,9 79,6 25,6 33,7 47,5 31,1 37,4
Born in Tajikistan 19,0 37,9 79,6 25,6 37,9 44,2 31,8 36,8
1 calving Imported 15,0 35,5 15,0 35,5 20,9 37,9 35,5 38,3
Born in Tajikistan 15,0 35,5 15,0 35,5 19.7 38,3 36,0 38,0
3 calving Imported 21,7 39,5 68,0 25,0 43,3 48,0 34,8 38,9
Born in Tajikistan 21,7 39,5 68,0 25,0 47,7 53,7 34,9 38,9
Under the same conditions the perspiration rate of imported first-calvers increased by 80% and after the 3d calving - by 11,5%; subjects born in hot climate showed a higher rate under the same conditions - 93 and 12,5% respectively.
Imported animals of the first and second years of experiment showed a higher body temperature increase in comparison to the subjects born in hot climate. Subjects of the fourth year of experiment (after their 3d calving) showed the same skin temperature under moderate and under high ambient temperature.
Experiments proved the least difference (in body temperature and respiratory rate) is displayed during the first year of the animals’ adaptation. Later - in the second and the fourth year, after the first and the third calving - the difference in their reaction to high ambient temperature and solar radiation proved uncertain or invalid.
CONCLUSIONS
1. In the arias of subtropical climate under the simultaneous exposure to high ambient temperature and solar radiation animals of European cattle breed do not cope with heat load well.
2. Breed that comes from imported parents does not differ much from imported parents in terms of tolerance.
3. In order to preserve European cattle breeds from simultaneous exposure to high temperature and solar radiation in the field it is necessary to put up sun blinds.
REFERENCES
1. Raushenbach Y.O., Kiselev Y.A. Influence of temperature conditions of individual genesis on the formation of productive traits and specifics of cattle thermoregulation. - In the book: Heat resistance and cold resistance of domestic animals. Ecological and genetic nature of animals’ difference. Novosibirsk, 1975.
2. Slonim A.D. Physiology of thermal regulation and thermal adaptation of farm animals. -M.-L. Nauka, 1966.
3. Soldatenkov N.I. Influence of hot climate on cattle physiological functions. Scientific tradition of Tajik Scientific Agriculture. Dushanbe, 1972, vol. IV.
4. Sukhomlin K.G. On the mechanism of thermal regulation of farm animals - Spb. Physiological basis of pedigree zoning . «Nauka», L. 1968.
