Silvopastoral systems as a strategy to attenuate the negative effects of heat stress on productivity of beef cows grazing natural grassland

• Published in: Agroforestry systems Vol. 98; no. 7; pp. 1995 - 2011
• Main Authors: Goncherenko, G. A., Báez, F., Fedrigo, J. K., Santa Cruz, R., Claramunt, M., Mercadante, V. R. G., Viñoles, C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-10-2024; Springer Nature B.V
• Subjects: Agriculture; Beef cattle; Biomedical and Life Sciences; Calves; Cattle; Forestry; Gametocytes; Grasslands; Grazing; Heat; Heat stress; Heat tolerance; Hormones; Insulin-like growth factor I; Life Sciences; Physiological effects; Productivity; Temperature effects; Thermal environments; Vagina; Weaning; Heat stress; Temporary weaning; Reproductive performance; Weaning weight
• ISSN: 0167-4366; 1572-9680
• DOI: 10.1007/s10457-024-01081-9

Heat stress affects cow-calf performance during the summer; thus, it is relevant to study attenuation strategies. The thermal environment, physiological response to heat stress, concentrations of metabolic hormones and productivity of cow-calf pairs grazing silvopastoral (SPS) and full sun (FS) systems, associated or not with temporary weaning (TW) were evaluated. Eighty-four Braford crosses cow-calf pairs were randomly assigned to four treatments in two years: (1) SPS + TW (n = 15), (2) SPS − TW (n = 28), (3) FS + TW (n = 18) and (4) FS − TW (n = 23). The black globe temperature humidity index was lower under the trees shade, thus SPS cows explored a larger area (
P
 < 0.01) and grazed longer (
P
 < 0.05). Live weight of cows and calves and body condition score of cows were greater in SPS than FS (
P
 < 0.01). IGF-I concentrations were greater in SPS than FS (
P
 = 0.001), but decreased in SPS + TW cow-calf pairs (
P
 < 0.01). TW decreased insulin concentration in cows and increased its concentrations in calves (
P
 = 0.01). Cows grazing SPS had less observations with vaginal temperature ≥ 39.1°C compared to FS cows (
P
 < 0.001). SPS + TW cows tended to ovulate earlier postpartum (
P
 ≤ 0.1), but days to conception and pregnancy were similar between groups. In conclusion, SPS provided a more comfortable thermal environment, associated to a decrease in the vaginal temperature of cows. This resulted in longer grazing sessions and hormone dynamics compatible with greater animal productivity and earlier reinitiation of cyclicity. TW decreased IGF-I concentrations in cows grazing SPS, thus the lack of its protective effect on the oocyte impeded the advancement of conception.