This study aimed to assess the variation over time in thermal comfort indices and the behavior of physiological parameters related to thermolysis, blood parameters, and semen in natura of buffalo bulls reared in tropical climate. The study was carried out in an artificial insemination station under a humid tropical climate (Afi according to Köppen). Ten water buffalo bulls (Bubalus bubalis) were used during the 5 months (April to August) of study. The environmental Temperature Humidity Index (THId) and the pen microclimate Temperature Humidity Index (THIp) were calculated. Every 25 days, respiratory rate (RR), heart rate (HR), rectal temperature (RT), and Benezra's thermal comfort index (BTCI) were assessed in the morning and in the afternoon. A blood assay was performed every month, while semen was collected weekly. THIp did not vary over the months (P > 0.05) and was higher in the afternoon than in the morning (77.7 ± 2.6 versus 81.8 ± 2.1, P < 0.05). RR, HR, and BTCI significantly increased over the months and were different between the periods of the day (P > 0.05) but within the physiological limits. RT varied between the periods of the day and decreased over the months, being the lowest in August (37.8 ± 0.7 °C), time-impacted hematocrit, mean corpuscular volume, hemoglobin levels, and spermatic gross motility and vigor (P < 0.05). Thus, buffalo bulls reared under a humid tropical climate may have variations in thermal comfort during the hotter periods but are able to efficiently activate thermoregulatory mechanisms and maintain homeothermy, hence preserving their physiological and seminal parameters at normal levels.
Thermal stress causes severe effects on the wellbeing and reproduction of cattle, including changes in oogenesis and spermatogenesis, generating great concerns, which last for decades. In cattle, the occurrence of thermal stress is associated with a reduction in the production of spermatozoids and ovarian follicles, in addition to the increase of major and minor defects in gametes or in their intermediate stages. In bovine females able to reproduce, a reduction in the rate of estrus manifestation and an increase in embryonic mortality has been observed. Therefore, keeping animals on good welfare conditions, with water supply and in shaded areas can favor the improvement of different reproductive parameters. For all this, the present study aimed to gather, synthesize and argue recent studies related to animal welfare, focusing on the effects of thermal stress on the reproduction of cattle, aiming to support possible strategies to mitigate the harmful effects of thermal stress in this species.
6RESUMO -Objetivou-se com o experimento demonstrar a composição bromatológica e avaliar a cinética de fermentação e degradabilidade ruminal efetiva in vitro, por meio da técnica "Hohenheim Gas Test", da farinha do mesocarpo do babaçu I ® e II ® (FMBI e FMBII) e de rações com diferentes níveis de inclusão. Foram conduzidos dois ensaios: um com os subprodutos puros e milho e outro com rações com inclusões da FMBI e FMBII nas seguintes proporções: 0; 7,5; 15,0 e 22,5% da matéria seca total. O delineamento foi o de blocos casualizados sendo seis blocos no primeiro e cinco no segundo ensaio. Os tempos de mensuração dos gases produzidos foram 3; 6; 9; 12; 24; 48; 72 e 96 horas. As farinhas FMBI e FMBII apresentaram composições bromatológicas diferentes, em relação aos constituintes da fibra (FDN, FDA e Lignina). As farinhas FMBI e FMBII apresentaram padrões de cinética de fermentação inferiores aos padrões de fermentação do milho grão. Com o aumento da proporção de FMBI e FMBII na ração, reduz-se a produção de gases por tempo de incubação. Em virtude do exposto, pode-se afirmar que as farinhas do mesocarpo I e II, apesar de serem fontes de amido, não apresentaram fermentação ruminal semelhante à fonte amilácea padrão, o grão de milho. Palavras-chave:Alimentação. Orbignya martiana. Produção de gases. Ruminantes. Subprodutos. ABSTRACT -The objective of the experiment was to demonstrate the bromatological composition, and evaluate the fermentation kinetics and effective ruminal degradability in vitro, using the "Hohenheim Gas Test" technique, of babassu mesocarp flour I ® and II ® (FMBI and FMBII) and of feeds at different levels of inclusion. Two trials were carried out: one of pure byproducts and corn, and another of feeds with inclusions of FMBI and FMBII in the following proportions: 0, 7.5, 15.0 and 22.5% of the total dry matter. The experimental design was of randomized blocks, with six blocks in the first trial and five in the second. Measurement times for the gases produced were 3, 6, 9, 12, 24, 48, 72 and 96 hours. The FMBI and FMBII flours showed different bromatological composition for the fibre components (FDN, FDA and Lignin). The FMBI and FMBII flours also showed patterns for fermentation kinetics inferior to the fermentation patterns of corn grain. Increasing the ratio of FMBI and FMBII in the feed reduces gas production for time of incubation. In view of the above, it can be said that mesocarp flours I and II, despite being sources of starch, did not present ruminal fermentation similar to corn grain, the standard source of starch.
This study evaluates the production behavior and prices in the beef cattle industry in the Brazilian Amazon. We used time series data obtained from various sources and employed multiple regression and polynomial regression analysis. For the price analysis, we used the classical time series model and separated the seasonal and cyclic indices based on the 12-month centered moving average. The analyses covered the period from 1990 to 2015, when the regional cattle population grew at a rate of 5% per year, compared to the national growth rate of 1.7%. The price analysis reveals the existence of cycles in regional cattle ranching, defined mainly by an inverse correlation between the price of fattened cattle and the slaughter of matrices. As for the variables determining the growth of the cattle population, we find that rural credit policy assumes an important role in enabling the supply of resources for financing livestock projects that are more popular than investments in agriculture. The creation and structuring of state agricultural defense agencies in the late 1990s represents an important measure in the institutional sphere, as the implementation of animal health policies and programs has generated a favorable environment for the expansion of investments in meat production and processing, in addition to opening up opportunities for trade in the domestic and international markets.
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