Effects of restricting water to growing, lactating and pregnant buffaloes reared in a hot and humid environment
| Autor: | A. Srikandakumar, S. S. E. Ranawana, N. Tilakaratne |
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| Rok vydání: | 1983 |
| Předmět: | |
| Zdroj: | Journal of the National Science Foundation of Sri Lanka. 11:25 |
| ISSN: | 2362-0161 1391-4588 |
| DOI: | 10.4038/jnsfsr.v11i1.8398 |
| Popis: | An experiment was carried out to examine the effects on certain physiological indices of heat stress in buffaloes subjected to restriction of water in a hot (Atr temperature = 27.6 - 32.8oC) and humid (Relative humidity = 62- 84%) environment. Five each of growing (Mean age = 10 months). lactating (Mean milk yield = 5 litreslday) and pregnant (8 - 9th month of gestation) Surti buffalo& were grazed under young coconut palms and subjected to three treatments in successive periods, each of three week duration. Each treatment was imposcd 011 all g~ouys of al~irrlals sirnultanenusly. In treatment t referred to as the normal management, animals were allowed drinking water ad libitum and wahwed for 1.5 hours daily. In treatment I1 wallowing was denied, and treatment 111 comprised restriction of drinking water in addition to denial of wallowing. Thermal stress was monitored by measuring rectal and skin temperature, respiration, pulse and cutaneous evaporation rates nf each animal several times a day. A11 physiological variabies studied showed a progressive increase from 0700 hours till 1400 hours and declined towards 1800 houn. The time effect was very highly significant (PC 0.001). Under normal management, growing heifers were found to bemorestressed than the adults. Denial of wa'lowing and restriction of drinking water caused an aggravation of heat stress wlth an average elevation of 0.9 - 1.2" in rectal temperature and 16 - 18 respirations per mtnutc at mid day over their respective base values. No significant group difference was observed during the latter treatments. The average rate of cutaneous evaporation of 310 ' 15 during treatment I decreased to 271 t 15 g/ml/hour in treatments 11 and 111. Heifers generally showed a lower rate of cutaneous evaporation and higher rate of respiration The results indicate that despite shade the buffaloes suffered from heat stress as the ambient temperatures increased. Lack of wallowing and restriction of drinklng water aggravated the stress. Younganlmals were possibly moredependent on the pulmonary route forevaporat~vecooling. Adult buffaloes did show a capacity to lose moisture through theskin at rates comparable to those of zebu cattle. |
| Databáze: | OpenAIRE |
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