Silvopastoral systems integrating tree cover into pasturelands offer promising strategies to mitigate heat stress in tropical livestock production. This study evaluated the effects of shade from Eucalyptus urograndis on thermal comfort indices in Gyr and Girolando dairy cattle in the Brazilian Cerrado. Forty-eight lactating cows (24 Gir, 24 Girolando) were monitored over two years in two contrasting environments: no shade (full sun) and shade (silvopasture). Thermal indices, including rectal and surface temperatures (measured via infrared thermography), respiration rates, and panting scores, were analyzed alongside environmental data, such as the Temperature-Humidity Index (THI). Cattle under shade consistently exhibited lower body temperatures, respiration rates, and panting scores, with significant differences amplified under heat stress conditions (THI > 74). Though both benefited from shade, Gyr cattle demonstrated better thermoregulatory responses than Girolando. Discriminant analysis accurately classified animals by system (> 92
O objetivo principal deste trabalho foi apresentar as principais explicações para a persistência da informalidade no sistema produtivo do Queijo Artesanal Serrano (QAS) e quais são as implicações desse cenário para o desenvolvimento territorial sustentável. A pesquisa de campo foi realizada em municípios catarinenses durante os meses de março a maio de 2023, com a aplicação de 59 entrevistas e 39 questionários, em quinze municípios. A informalidade se manifesta enquanto uma alternativa viável para a continuidade da comercialização do QAS, principalmente em canais comerciais tradicionais, frente às barreiras normativas sanitárias. A sua relevância com para o Desenvolvimento Territorial Sustentável se dá ao reforçar a valorização de um recurso territorial específico e as relações de confiança e proximidade que mantêm um mercado territorial de grande vitalidade.
ABSTRACT The phyllochron is a key developmental parameter used to predict leaf appearance in crop simulation models. This study estimated the phyllochron of field-grown cut sunflower genotypes across tropical, subtropical, and temperate environments using single-linear and bilinear models, and tested the hypothesis that a distinct breakpoint reflects a change in phyllochron during ontogeny. Leaf appearance was monitored in twelve genotypes across multiple trials conducted between 2020 and 2023 in Brazil and Italy. The phyllochron was estimated using linear and bilinear regressions relating leaf number to accumulated thermal time and expressed in °C day per leaf. Field observations revealed a breakpoint in leaf appearance, with a longer phyllochron up to stage V6 (34.87 °C day per leaf) and a shorter phyllochron from stage V7 onward (21.82 °C day per leaf). This shift was associated with changes in leaf phyllotaxy and the onset of stem elongation. Phyllochron phases were consistent across genotypes and influenced by environmental factors, particularly air temperature, whereas planting method showed no significant effect. These findings improve understanding of phyllochron dynamics and provide an ecophysiological basis for incorporating a bilinear chronological response function into process-based models for cut sunflower.
This study evaluated reproductive performance of gilts classified as in anestrus in a batch farrowing system. Thirty-three gilts not expressing estrus within 40 days post-arrival were treated with chorionic gonadotropins, with blood collected for progesterone (P4) analysis on the same day. Thirteen gilts expressed estrus within 7 days, and 12 were inseminated (232.8 ± 2.1 days old), with 11 farrowing (91.7%; 14.2 ± 0.83 total piglets). Nineteen gilts had P4 ≤ 2.6 ng/mL at treatment; among the 20 non-responders, 10 had P4 > 2.6 ng/mL. A strong association was observed between P4 levels (≤ 2.6; > 2.6 and < 19; ≥ 19 ng/mL) and the responsiveness of gilts to gonadotropin treatment (P < 0.01; Cramér's V = 0.63), with greater responsiveness in gilts with P4 levels ≤ 2.6 ng/mL. Non-responsive gilts (n = 20) received Altrenogest for 10 - 11 days, with 17 showing estrus within 10 days and 15 farrowing (88.2%; 14.3 ± 0.84 total piglets). Estrus detection failures and silent heat likely caused misdiagnosis. Gonadotropin, with or without Altrenogest, reduced culling ~8-fold, allowing 41-58% of gilts to reach at least the 3rd farrowing.
