Blood biochemical, hormonal, and hematological responses of native sheep submitted to different environmental conditions

The aim of this study was to evaluate the biochemical, hormonal, and hematological blood responses of native sheep subjected to five temperatures (20°, 24°, 28°, 32°, and 36 °C), using 24 sheep of the following breeds: Santa Inês (SI), Morada Nova (MN), Soinga (SO) and no defined racial pattern (NDRP), kept in collective pens inside the climatic chamber. The experimental design was completely randomized, in a 5 × 4 factorial scheme (5 temperatures and 4 breeds) with 6 animals of each breed at each temperature. There was interaction for urea (P < .0001), glucose (P < .0001), cholesterol (P < .0001), and magnesium (P < .0001) as a function of breed and air temperature. Urea (P = .001), glucose (P < .0001), triglycerides (P = .033), cholesterol (P = .004), and magnesium (P < .0001) showed differences according to breed. It was observed that T4 (P < .0001) and cortisol (P < .0001) showed an interaction between breed and temperature, while T4 (P = .001) and cortisol (P = .001) an effect of breed. The highest magnesium concentration was observed in MN, and the lowest was in NDRP, SO, and SI, which are statistically similar, and SI and NDRP are statistically similar. The hormones showed a significant effect (P < .0001) for temperature, where cortisol increased, and thyroid hormones decreased with increasing temperature. Temperatures of 32° and 36 °C contribute to changes in blood, hormone, and hematological biochemical responses of native sheep.

Thermal stress index for native sheep

The first objective of this study was to develop a thermal stress index for sheep based on environmental and animal data collected in a climate chamber under various environmental conditions. The second objective was to compare published indices of thermal comfort and the proposed index, testing them with the data from this study, with the objective of pointing out the most adequate index to be used by breeders when choosing management procedures. A total of 3024 data were obtained for the physiological variables of the sheep exposed to the eight thermal conditions in the climatic chamber and in ambient condition, kept three days in each thermal condition. A principal component analysis summarized the measurements of physiological variables into only one variable (y1). Using SigmaPlot software, multiple regression of y1 with the environmental variables and their combinations produced a number of indices. The equation chosen was the heat stress index for sheep, TSI = 24.153 - (0.0523*A_T) + (0.746*B_GT) + (4.104*Vp), with R² = 0.668. The correlations presented high values, where these correlation values were assumed to indicate the efficiency of each index as indicators of the animals' response to the environment. Thus, it was assumed that the TSI presents a high efficiency.

Chicken bed reuse

Aviculture is a developed and important industry worldwide. However, it is an industry that produces solid waste such as bedding. As an attempt to reduce environmental impact and productive activity costs, beds are reused by several consecutive lots which can increase microorganism concentration and lead to unsanitary conditions. In this regard, it is essential to adopt a litter pre-treatment during the gap sanitary period between lots to avoid passing problems to the birds from the current flock to the subsequent flock and to guarantee the litter quality. Several factors must be considered to guarantee that there is minimal damage to chicken production. Therefore, this literature review aims to approach the main factors that affect the thermal comfort and chicken litter quality, as well as alternatives used as an alternative biological treatment to guarantee its reuse quality.

Morphology of coat and skin of small ruminants reared in the Brazilian semi-arid region

The structure of the coat and integument of small ruminants reared in semi-arid regions have valuable characteristics that favor their adaptation to the region. The objective of this study was to evaluate the structural characteristics of the coat and integument and sweating capacity of goats and sheep in the Brazilian semi-arid region, using 20 animals, 10 of each breed, 5 males and 5 females of each species, grouped in a completely randomized design in a 2 x 2 factorial scheme (2 species and 2 genders) with 5 replicates. The animals were already being kept under the influence of high temperatures and levels of direct solar radiation before the day of the collections. At the time of the evaluations, ambient temperature was high, with low relative humidity. The pattern of epidermal thickness and sweat glands per body region was superior in sheep (P < 0.05), and the number of hair follicles and sweat rate were similar (P > 0.05) between the species. There was no difference (P > 0.05) in the evaluated characteristics between the genders, showing that they are not influenced by hormones. The morphology of the coat and skin of these animals showed a superiority of goats compared to sheep.

Biogas from poultry waste-production and energy potential

The objective of this study was to evaluate the effect of heat treatment on poultry litter with different levels of reutilisation for potential generation of biogas in experimental biodigesters. Chicken litter used was obtained from two small-scale poultry houses where 14 birds m^-2 were housed for a period of 42 days per cycle. Litter from aviary 1 received no heat treatment while each batch of litter produced from aviary 2 underwent a fermentation process. For each batch taken, two biodigesters were set for each aviary, with hydraulic retention time of 35 days. The efficiency of the biodigestion process was evaluated by biogas production in relation to total solids (TS) added, as well as the potential for power generation. Quantified volumes ranged from 8.9 to 41.1 L of biogas for aviary 1, and 6.7 to 33.9 L of biogas for aviary 2, with the sixth bed reused from both aviaries registering the largest biogas potential. Average potential biogas in m³ kg^-1 of TS added were 0.022 to 0.034 for aviary 1 and 0.015 to 0.022 for aviary 2. Energy values ​​of biogas produced were calculated based on calorific value and ranged from 0.06 to 0.33 kWh for chicken litter without fermentation and from 0.05 to 0.27 kWh for chicken litter with fermentation. It was concluded that the re-use of poultry litter resulted in an increase in biogas production, and the use of fermentation in the microbiological treatment of poultry litter seems to have negatively influenced production of biogas.