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Cutaneous evaporation is the main avenue by which cattle dissipate heat via the involvement of sweat glands and other skin components. The difference in skin morphology between B. indicus and B. taurus has been recognized, as well as differences in their ability to tolerate heat. The objective of this study was to compare skin morphology between B. indicus, B. taurus, and their crossbreds. Skin samples of Sahiwal ( B. indicus) ( n = 10, reddish brown skin) and Holstein Friesian (HF) ( B. taurus) ( n = 10, black and white skin) and crossbred of HF75% ( n = 10, black and white skin) and HF87.5 % ( n = 10, black and white skin) were biopsied for histological study, followed by measurement of skin components. The results indicated that breed significantly affected sweat gland morphology. The shape of the sweat gland, as indicated by the ratio of length/diameter, in Sahiwal was baggier in shape compared to HF (5.99 and 9.52) while values for crossbreds were intermediate (7.82, 8.45). The density and volume of sweat glands in Sahiwal (1,058 glands/cm; 1.60 μ × 10) were higher than in HF (920 glands/cm; 0.51 μx10) and crossbreds, both HF 75 % (709 glands/cm; 0.68 μ × 10) and HF 87.5 % (691 glands/cm; 0.61 μ × 10) respectively. However, capillary surface area was greater for HF (2.07 cm) compared to Sahiwal (1.79 cm); accordingly, the lower genetic fraction of HF in crossbred cattle showed less capillary surface area (1.83 and 1.9 cm for HF75% and HF87.5 %) ( P < 0.01). Nerve density was not significantly different between Sahiwal and HF but was higher in the crossbred ( P < 0.01) cattle. Moreover, the effect of skin color (black and white) was evaluated and it was found that there was an interaction ( P < 0.01) between breed and skin color on the skin components. This study reveals that there are differences in skin morphology among B. indicus, B. taurus and their crossbreds, with these differences being more or less related to the genetic fraction of HF. This may imply that capability for cutaneous evaporative heat loss and tolerance to heat in crossbred cattle could be related to skin morphology. [ABSTRACT FROM AUTHOR]

The objective of the experiments reported here was to measure the effects of cooling techniques (Modified roof vs Normal roof) on the performance and physiology of 12 young male buffaloes with a similar live weight of 160 kg. The study was conducted at Chainat Agriculture and Technology College, Chainat Province, Thailand. The animals were divided randomly into two groups, each group comprising six buffaloes, and the two groups were studied to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects' physiological responses to heat stress under hot humid conditions. The modified roof resulted in lowered heat stress in buffaloes compared to those under a standard roof. The difference was shown by the buffaloes having a significantly lower mean rectal temperature (39.14 ± 0.07 vs 40.00 ± 0.10°C) and plasma cortisol (2.14 ± 0.24 vs 3.38 ± 0.37 ng/ml). The average daily water consumption was significantly lower in the MR group (MR, 29.71 ± 0.86 vs NR, 34.14 ± 1.06 L head day), while there was a tendency for the roughage intake to be higher in the MR group compared to that of the NR group (MR, 5.88 ± 0.18 vs NR, 6.44 ± 0.19 kg head-1 day; P = 0.0508). It was concluded that roof modification facilitated a reduction in heat load from roof re-radiation, and was an effective means of alleviating thermal stress in young buffaloes. [ABSTRACT FROM AUTHOR]

Total moisture losses (TML) from 2 Large White X Landrace pigs sprinkled (800 ml/min) for 0, 30, 60, 90 or 120 seconds at 35C ambient temperature were measured in a hygrometric tent. TML increased to peak values of 5-6 g/min after sprinkling for 60-120 seconds. Irrespective of duration, TML declined to control levels within 60-70 minutes. To obtain most benefit in terms of feed intake and growth in a hot climate it is suggested that pigs should be sprinkled with approximately 800 ml water every 30 minutes. [ABSTRACT FROM AUTHOR]

Field and climatic chamber studies revealed that walking at 4.5 km/h elicited greater thermoregulatory responses in Hereford cattle than did the possession of a wooly hair coat. Under mild field conditions, walking caused sweating rate to increase to 150-200 g/m/h within one hour (P<0.001); no significant differences were recorded between wooly-coated and clipped cattle. Walking at 4.5 km/h on a treadmill in a climate chamber at 38°C and 34 mm Hg water vapour pressure elevated rectal (P<0.001) and skin (P<0.05) temperatures to levels considerably above those in stationary controls. There were no differential effects on sweating or respiratory rates, though the latter were generally higher in the exercising group. Differences in skin temperature, sweating and respiratory rates between coat-types and exercise groups in the climate chamber were similar, but exercise resulted in a much greater rectal temperature response. Overall, exercise represented a more potent thermoregulatory stimulus than a wooly hair coat. [ABSTRACT FROM AUTHOR]