Silvopastoral System Mitigates the Thermal Stress and Benefits Water Buffaloes’ Comfort in the Eastern Amazon, Brazil

Abstract

Twenty female Murrah buffaloes between four and five years old were randomly distributed into two groups (traditional system - TS and silvopastoral system - SPS) with 10 animals each and an average weight of 377.78 kg and 356.10 kg, respectively, for the TS and the SPS. The TS had a management regime with no canopy cover and no shade coverage over the drinking and feeding troughs. In the SPS, Racosperma mangium (Fabaceae) trees were used to provide shade, with an estimated 10% shading. The physiological variables studied were rectal temperature and respiratory frequency measured every three days from 6 to 7 AM and from 12 to 1 PM. The following environmental indices were calculated: Temperature Humidity Index (THI), Black Globe Humidity Comfort Index (BGHI), and Benezra’s Index of Adaptability (BIA). The THI values were high in both management systems, between 76.27 and 86.73, higher than the limit of comfort level for buffaloes, which is 75. The maximum values of BGHI for the afternoon were 92.0 and 87.62, for TS and SPS, respectively, and the maximum values of BIA for the afternoon were 4.4 and 3.8, for TS and SPS respectively, which were higher than the critical level of adaptability and represented an uncomfortable condition that causes a reduction in animal performance. It was concluded that the silvopastoral management system is more efficient in terms of animal comfort for the female buffaloes as a result of the shade that provides a more amenable microclimate.

Thermoregulatory reactions of female buffaloes raised in the sun and in the shade, in the climatic conditions of the rainy season of the Island of Marajó, Pará, Brazil

“…These results demonstrate that exposure to full sun, due to the incidence of solar radiation, raised the body surface temperature by 1.6 • C, compared to the treatment with availability of shade, at 14:00 h, as buffaloes prefer to feed in shaded areas (10). With similar results, Santos et al (26), in the Amazon, observed that buffalo heifers looked for shaded areas, especially in the hottest hours of the day, to ruminate, both standing and lying down, in search of the most suitable place for their well-being. The radiant energy load incident on the animal, in tropical regions, can be greater than three times the total endogenous heat produced by the animal itself.…”

“…Thus, the absorption of solar radiation by the animal and the ambient temperature can increase the production of metabolic heat, resulting in thermal discomfort ( 11 ). Research carried out evaluating the thermoregulatory mechanism of buffaloes describes shade as a relevant component to enhance heat dissipation in different environments ( 26 , 28 , 72 , 73 ). In this sense, heat stress can promote a reduction in grazing activity ( 74 ), which can cause weight loss in cattle ( 75 ).…”

“…Both groups had access to water and mineral salt ad libitum . The sample used in this study of 10 buffaloes per group was the same used in the Santos et al ( 26 ) and Athaide et al ( 27 ). In this study, only clinically healthy buffaloes were selected.…”

Water buffalo production in the Brazilian Amazon Basin: a review

“…Silvopastoral systems have been validated in experimental fields of the Brazilian Amazon, with outstanding results in terms of forest and forage production (Oliveira 2011), animal performance (Lourenço Magalhães et al 2011;Joele et al 2013), thermal comfort (Garcia et al 2011;Santos et al 2020), and animal health (Moraes Júnior et al 2010). The favorable results achieved with buffalo production in silvopastoral systems reveal the importance of management for the productivity and sustainability of livestock raising in the Amazon (Castro et al 2008).…”

“…Fortunately, it has been shown that immersion in water is not essential for the survival of buffaloes since they can normally maintain all physiological and behavioral features as long as adequate shade is available (Moraes Júnior et al 2010;Garcia et al 2011;. The adoption of silvopastoral systems, a productive strategy that incorporates the use of tree in pastures, reduces the negative effects of solar radiation, provides greater thermal comfort to the animals, and increases animal welfare and productivity (Silva et al 2014;Santos et al 2020). A recent study carried on Marajó Island proved that buffaloes graze and ruminate longer when they are raised in pastures in which shaded areas are available (Almeida et al 2019).…”