2x2x2 factorial design with the factors of breeds; Murrah x swamp crossbreds and swamp buffaloes, non and feed supplementation, and work and non-work, was used in this study. Sixteen Murrah x swamp crossbreds and 16 swamp buffaloes were randomly allotted into 8 treatment combinations. The study period was 6 nonths; however, the animals in the working groups only started plowing at the beginning of week 5 and finished at the end of the experimental period. It was found that the average daily gain of Murrah x swamp crossbreds was not significantly different from that of swamp buffaloes. With out regard to other factors, the feed supplemented group gained more weight than the non-feed supplemented (P0.01), while the working and non-working groups were not statistically different in growth rate. No interaction among factors was found. For plowing ability, the crossbreds, the non-supplemented and supplemented groups could plow an area of 0.23 rai (0.09 acre) per hour while swamp buffaloes, the non-supplemented and supplemented groups, could plow 0.24 rai (0.10 acre) and 0.30 rai, (0.12 acre) respectively (P0.01). For the speed of plowing, the crossbreds, the non-supplemented and supplemented groups, could travel 40.71 and 48.42 metres per minute, respectively (P0.05) while the swamp buffaloes, the non-supplemented and supplemented groups, could travel at a speed of 43.86 and 53.32 metres per minute, respectively (P0.05). Within the non-feed supplemented groups, crossbred and swamp buffaloes could plow the area of 0.23 rai (0.09 acre) and 0.24 rai (0.10 acre) per hour, respectively (P0.05). Within the feed supplemented groups, the crossbred and swamp buffalo could plow the area of 0.23 rai (0.09 acre) and 0.30 rai (0.12 acre) per hour, respectively (P0.01). As for the speed of plowing, the performance of all the groups was not significantly different, i.e. 40.71, 48.42, 43.86 and 53.32 m/min for crossbred non-supplemented, crossbred supplemented, swamp non-supplemented and swamp supplemented groups, respectively (P0.05). However, the supplemented groups could plow faster than the non-supplemented ones (P0.05).

The study examined changes in the body-weight of mature buffaloes at the Surin Buffalo Breeding Center due to seasonal fluctuation in feed supplies. It also investigated the effect of parturition on buffalo cow body-weight. The effect of feed scarcity started to show in January when the buffalo body-weight began to decline, and continued to decline to the lowest average in April, the hottest and dryest month of the year. The monthly weight change of the mature buffaloes could well be explained by the annual rainfall pattern. The data on monthly records of the body-weight of buffalo cows during the five months before calving and the four months after indicated that the animals gained 33.1 kg during the five-month pre-partum and lost 34.5 kg from one month after, with the average calf birth weigth of 30.8 kg. The nursing cows continued to lose weight during the four-month post-partum. The cows calved from May to October and regained their body-weight faster than those calved from November to April