Growth curves of campolina horses using nonlinear models

Teixeira, Glaciane Lopes; Fernandes, Tales Jesus; Muniz, Joel Augusto; Souza, Felipe Amorim Caetano de; Moura, Regina; Melo, Raquel Moreira Pires dos Santos

doi:10.1016/j.livsci.2021.104631

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…This might also apply to the Przewalski’s horse, as for example females of the closely related feral horse (e.g., in Australia: Csurhes et al 2016 ) usually do not reach their maximum adult size until an age of around 4 years. Similar results have been obtained by studies in different breeds of domestic horses, in which females are reaching adult body size and mass at an age of around 4–5 years (Fernandes et al 2020 ; Lopes Teixeira et al 2021 ). A further key mechanism leading to such an age-specific sensitivity in female Przewalski’s horses, and possibly also in other group-living ungulates, could be based on the association between the females’ age and their social rank position.…”

Section: Discussionsupporting

confidence: 86%

Age-specific effects of density and weather on body condition and birth rates in a large herbivore, the Przewalski’s horse

Rödel,

Ibler,

Ozogány

et al. 2023

Oecologia

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Reproduction in young females can show a particularly sensitive response to environmental challenges, although empirical support from individual-based long-term studies is scarce. Based on a 20-year data set from a free-roaming Przewalski’s horse population (Equus ferus przewalskii), we studied effects of large-herbivore density (horses + cattle) and weather conditions experienced during different life stages on females’ annual birth rates. Foaling probability was very low in 2-year-olds, reaching maximum values in 5 to 10-year-olds, followed by a decrease in older females indicating reproductive senescence. Mother’s previous reproductive investment affected her current reproduction; young and old mothers (as opposed to middle-aged ones), which had nursed a foal for at least 60 days during the previous year, reproduced with a lower probability. Foaling probability and body condition of young females were lower when large-herbivore density was high. Reproduction was also influenced by interactive weather effects during different life stages. Low late-summer precipitation during the females’ year of birth was associated with a pronounced decrease in foaling probability in response to harsh late-winter temperatures prior to the mating season. In turn, increased amounts of late-summer rain during this early age together with more late-summer rain during the females’ current pregnancy led to an increased reproductive probability in 2–3-year-olds. These results were corroborated by the ameliorating effects of late-summer rain on body condition in such females. In conclusion, our findings highlight the interactive importance of weather conditions experienced during early life, and of density and weather during current pregnancy on foaling probability, particularly in young females.

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Section: Discussionsupporting

confidence: 86%

Age-specific effects of density and weather on body condition and birth rates in a large herbivore, the Przewalski’s horse

Rödel,

Ibler,

Ozogány

et al. 2023

Oecologia

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“…where y is the dependent variable (i.e., aerenchyma percentage) at the distances from the root apex, x is the distance from the root apex, A is the parameter that represents the asymptotic value, B is the parameter related to the growth rate, and C is the parameter that represents the distance between the initial value and the asymptote ( Tjørve and Tjørve, 2017 ; Sari et al, 2019 ; Teixeira et al, 2021 ).…”

Section: Methodsmentioning

confidence: 99%

Longitudinal Pattern of Aerenchyma Formation Using the Ti-Gompertz Model in Rice Adventitious Roots

Chen

BuHong³

et al. 2021

Front. Plant Sci.

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The longitudinal pattern of root aerenchyma formation of its relationship with the function of adventitious roots in rice remains unclear. In this study, the percentage of the aerenchyma area to the cross-sectional area (i.e., aerenchyma percentage) was fit with four non-linear models, namely, W0-Gompertz, Ti-Gompertz, logistic, and von Bertalanffy. Goodness-of-fit criteria such as the R2, the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) were used to select the model. The bias of the parameters was evaluated using the difference between the ordinary least squares-based parameter estimates and the mean of 1,000 bootstrap-based parameter estimates and the symmetry of the distributions of these parameters. The results showed that the Ti-Gompertz model, which had a high goodness-of-fit with an R2 close to 1, lower AIC and BIC values, parameter estimates close to being unbiased, and good linear approximation, provided the best fit for the longitude pattern of rice aerenchyma formation with different root lengths among the competing models. Using the second- and third-order derivatives according to the distance from the root apex, the critical points of Ti-Gompertz were calculated. The rapid stage for aerenchyma formation was from the maximum acceleration point (1.38–1.76 cm from the root apex) to the maximum deceleration point (3.13–4.19 cm from the root apex). In this stage, the aerenchyma percentage increased by 5.3–15.7% per cm, suggesting that the cortical cells tended to die rapidly for the aerenchyma formation rather than for the respiration cost during this stage. Meanwhile, the volume of the aerenchyma of the entire roots could be computed using the integral function of the Ti-Gompertz model. We proposed that the longitudinal pattern of root aerenchyma formation modeled by the Ti-Gompertz model helped to deeply understand the relationship between the anatomical traits and physiological function in rice adventitious roots.

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