MVSc

The draught performance of Kangayam bullocks were compared with that of graded surti buffaloe bullocks, under the agro climatic conditions of Kerala, with a hot-humid tropical climate.

Two pairs of adult kangayam bullocks and two pairs of adult graded Surti buffaloe bullocks were used for ploughing both dry land and wet land at the rate of four hours a day during the summer season. Physiological responses like respiratory rate, pulse rate and rectal temperature and haemotological parameters like haemoglobin per cant, erythrocyte sedimentation rate, packed cell volume, lactic acid and plasma bicarbonate were estimated before work, immediately after work and after one hour of rest after work. The dry matter intake and water intake on days of work and on date of no work were also measured and compared. Other parameters like the area ploughed in one hour, average speed of walking, stride length and traction force developed during ploughing were also compared between the two species.

The buffaloe bullocks had significantly lower physiological responses before the start of work, when compared to that of indigenous bullocks. As a result of work the physiological responses increased significantly in both species. The values were higher for buffaloes during dry ploughing. The physiological responses including rectal temperature of buffaloes increased to a level indicative of distress due to heat stress. There were also other signs of distress like frothing and drooling of saliva and protrusion of tongue. But during wet ploughing the responses were not so marked in case of buffaloes and they did not show any apparent signs of distress. The physiological responses decreased but did not reach the pre-exercise values after one hour of rest.

The haemoglobin per cent of blood, packed cell volume and plasma bicarbonate content decreased significantly in cattle and buffaloes, during dry and wet ploughing. The erythrocyte sedimentation rate and blood lactic acid content showed a significant increase as a result of work. One hour of rest was not sufficient to bring these parameters to pre-exercise values.

Buffaloes consumed more DM when expressed in grams per kg metabolic body size. Both species consumed more on days of no work. The difference was more pronounced in case of buffaloes.

The water intake expressed as ml/kg metabolic body size significantly higher for buffaloes, both on days of work and on days of no work. In both the species, the water intake remained similar in days on which they were used for work and they were not used.

Kangayam bullocks ploughed significantly more area per unit than graded Surti buffaloe bullock. Cattle developed significantly more speed than buffaloes during dry ploughing. But during wet ploughing the speed was almost the same in both species. Cattle showed more stride length during dry and wet ploughing than baffaloes. But during wet ploughing the difference was negligible.

There was no significant difference in the traction power developed between cattle and buffaloes during dry or wet ploghings. But both species developed higher horse power during wet ploughing.

Overall, the results indicate that during summer in a hot-humid tropical environment, Kangayam bullocks can be used for dry as well as wet ploughings without any apparent ill effects. Graded Surti baffaloe bullocks are on par with Kangayam bullocks under wet-ploughing. However, they seem to be under severe heat stress and also their work out put inferior when used for a continues 4-hour period of dry land ploughing under similar climatic conditions.