11 research outputs found

    Genetic association between herd survival and linear type traits in Holstein cows under tropical conditions

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    The objective of this study was to estimate genetic parameters for survival measures from birth to 60 and 72 months of age, as well as survival up to 48 and 54 months after first calving. The genetic association of these measures with 20 linear type traits and final score in Holstein cows, born between years 1990 to 2004, was also evaluated. The components of (co)variance were estimated by Bayesian methods, using the programme THRGIBBS1F 90 in bivariate analyses, considering animal threshold model for measures of survival, and animal linear model for linear type traits. The mean posterior heritability for the measures of survival ranged from 0.09 to 0.15, and for those of the linear type traits ranged from 0.07 to 0.36. The posterior genetic correlation between linear type traits and measures of survival varied from -0.37 to 0.50, respectively. Indirect genetic selection for udder depth, rear teat placement, udder texture, bone quality, fore udder attachment, body depth and chest width may lead to correlated gains in longevity in Holstein cows under tropical conditions

    Sensitivity of South American tropical forests to an extreme climate anomaly

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    NERC Knowledge Exchange Fellowship (NE/V018760/1) to E.N.H.C.The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected.Publisher PDFPeer reviewe
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