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Infrared thermography has been investigated in recent studies to monitor body surface temperature and correlate it with animal welfare and performance factors. In this context, this study proposes the use of the thermal signature method as a feature extractor from the temperature matrix obtained from regions of the body surface of laying hens (face, eye, wattle, comb, leg, and foot) to enable the construction of a computational model for heat stress level classification. In an experiment conducted in climate-controlled chambers, 192 laying hens, 34 weeks old, from two different strains (Dekalb White and Dekalb Brown) were divided into groups and housed under conditions of heat stress (35 °C and 60% humidity) and thermal comfort (26 °C and 60% humidity). Weekly, individual thermal images of the hens were collected using a thermographic camera, along with their respective rectal temperatures. Surface temperatures of the six featherless image areas of the hens' bodies were cut out. Rectal temperature was used to label each infrared thermography data as "Danger" or "Normal", and five different classifier models (Random Forest, Random Tree, Multilayer Perceptron, K-Nearest Neighbors, and Logistic Regression) for rectal temperature class were generated using the respective thermal signatures. No differences between the strains were observed in the thermal signature of surface temperature and rectal temperature. It was evidenced that the rectal temperature and the thermal signature express heat stress and comfort conditions. The Random Forest model for the face area of the laying hen achieved the highest performance (89.0%). For the wattle area, a Random Forest model also demonstrated high performance (88.3%), indicating the significance of this area in strains where it is more developed. These findings validate the method of extracting characteristics from infrared thermography. When combined with machine learning, this method has proven promising for generating classifier models of thermal stress levels in laying hen production environments.

RESUMO

This study aims to evaluate water, land, and nutrient efficiencies in a tropical beef feedlot system by providing artificial shading and considering local conditions and feed cultivation. The study was conducted at the Experimental Feedlot of Embrapa Southeast Livestock in Brazil. Forty-eight Nellore bulls were divided into two groups, with one group having shade (GS) and the other without shade (GWS). The animals' body weights, water intake, and dry matter intake were recorded. The water footprint was calculated using a product-focused assessment, considering water consumed in feed production and animal drinking. The nutrient balance and land footprint were also assessed. To both treatments, the crop scenario with soybean and corn first crop produced in Maringa resulted in the lowest water and land footprint values. Corn was the main contributor to green water consumption. The efficiency in water use for corn decreased between the first and second crops. The water footprint of soybean meal varied between production locations. GWS had slightly higher average blue water consumption than GS. In terms of nutrient balance, the GS treatment exhibited lower nitrogen and phosphorus balance values, indicating higher efficiency in the use of these elements. The provision of artificial shading was found to reduce the water footprint and improve nutrient use efficiency. The location of grain production and the timing of corn planting were identified as key factors influencing water and land footprint values.

Assuntos

RESUMO

This study aimed to evaluate the change in the air temperature and the impacts of heat waves using Climate Change Indexes on the physiological and productive responses of lactating Holstein cows. Daily data of maximum and minimum air temperature for 1981-2021 were used. Heat waves were determined using six Climate Change Indexes. Individual data on respiratory rate, rectal temperature, and milk yield were collected in the summers of 2018, 2019, and 2021. The temperature trend analysis showed a significant (p < 0.0001) increase in maximum temperature, minimum temperature, and days in a heat wave. All six indexes increased significantly (p > 0.01). The increase in warm nights (> 20 °C) and the hottest days (> 35 °C) was the highest since 2010. Heat waves were classified into short (< 5 days) and long (> 5 days) of greater (> 36 °C) or lesser (< 36 °C) intensity. During the long and short heat waves of greater intensity, the respiratory rate increased (p < 0.05) until the fourth day. On the other hand, rectal temperature was higher (p < 0.05) from the fourth day until the end of the long heat waves. Therefore, the decrease in milk yield was significantly greater from the fourth or fifth day onwards. Finally, the evaluation method based on indexes was efficient to demonstrate the negative effects on physiological parameters and milk yield and can be indicated to evaluate heat stress in lactating cows.

Assuntos

RESUMO

Bos taurus indicus temperament is variable and affects beef tenderization. Our objective was to investigate temperament and performance of non­castrated Nellore and identify groups based on Longissimus lumborum (LL) pH decline as well as beef characteristics produced by those groups. We investigated 94 animals with a subset of carcasses (n = 24) selected based on LL pH at 24 h postmortem (pm) to represent two groups: resistant to pH decline (> 5.8 called pH­Res; n = 10) and normal (< 5.7 called pH­Nor; n = 14). Steaks were fabricated from the LL muscle and randomly assigned to aging (2, 7, 14, and 21 days). Sarcomere length, cooking loss, myofibrillar fragmentation index (MFI), and Warner­Bratzler shear force (WBSF) were determined. Data on temperament were investigated in a multivariate approach, while beef data were compared between groups using the analysis of variance. Rectal temperature at the beginning of the finishing phase and total weight gain were greater and related to animals in the pH­Res group (p < 0.01 and p = 0.03, respectively). Temperature and pH decline curves, sarcomere length, and cooking loss revealed that pH­Res produced beef with lower quality compared to the pH­Nor group. Results for MFI and WBSF did not show differences between groups within each time pm; however, overall steaks from pH­Res were tougher (p = 0.06). Incidence of LL pH between 5.8 and 5.9 at 24 h pm did not compromise the tenderization rate or extension; however, it affected the water holding capacity in this population of Nellore cattle.(AU)

Assuntos

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OBJECTIVE: This work was carried out to evaluate the effects of zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RH) combined with immunocastration on the welfare traits of feedlot Nellore cattle. METHODS: Ninety-six Nellore males (average body weight [BW] = 409±50 kg; average 20 mo of age) were divided into two groups according to BW; half of the animals in each group received two doses of an immunocastration (ImC) vaccine in a 30 day interval, and the other half did not receive the vaccine (NoC). Afterward, the animals were housed and fed a common diet for 70 days. Then, they were split into three groups and fed one of the following diets for 30 additional days: control (CO) diet, with no ß-AA; ZH diet, containing 80 mg/d ZH; and RH diet, containing 300 mg/d RH. Welfare traits were assessed by monitoring body surface temperature using infrared thermography (IRT) and plasma cortisol and temperament measurements. RESULTS: There was no interaction between sexual condition and diet for any trait. The ImC and NoC groups did not differ in rectal and ocular temperatures. The ImC animals had higher flight speeds (p = 0.022) and tended to have higher cortisol levels (p = 0.059) than the NoC animals. Animals fed ZH and RH did not differ in cortisol levels, respiratory rate, rectal temperature, temperature measured by IRT, or temperament behaviour. CONCLUSION: The ImC animals showed a less stable temperament during handling practices than NoC, whereas ZH and RH supplementation had no adverse effects on animal welfare.

RESUMO

Ninety-six feedlot-finished Nellore steers were used to verify the relationship between temperament indicators and meat tenderization. Temperament index (TI), chute score (CS), and average of exit velocity (EV) with CS (AT) presented low positive correlations (P≤0.05) with shear force, either at 2 or 16days postmortem (WBSF-16). The rectal temperature was consistently correlated with temperament indicators (TI, CS, and AT) and WBSF-16. Two groups (n=12) representing the most tender (39.2±4.9N) and most tough meat (94.1±11.8N), based on WBSF-16, were compared for temperament, and calpastatin activity (CASTa) was determined 48h postmortem. The tender group presented lower EV, TI, and AT (P≤0.05). The tender group exhibited lower (P≤0.05) CASTa in the triceps brachii muscle, but there was no difference in CASTa in the longissimus lumborum muscle between WBSF groups. Meat tenderness and inhibitory activity of calpastatin may be associated with divergent temperament indices in zebu cattle.

Assuntos

RESUMO

The aims of this study were to evaluate the use of infrared thermography (IRT) images as a tool for monitoring body surface temperature and to study its relationship with residual feed intake (RFI) in Nellore cattle. We also evaluated IRT as an indicator of feed efficiency in Bos indicus cattle. In this study, 144 Nellore steers were fed high-concentrate diets for 70 days to evaluate feedlot performance. We examined nine animals classified as high RFI and nine animals classified as low RFI by measuring rectal temperature (RT), respiratory frequency (RF), and IRT in the front, eye, ocular area, cheek, flank, ribs, rump, and front feet. The measurements were taken at 0700, 1200, and 1600 hours. The IRT temperatures measured at the eye, cheek, flank, ribs, rump, and front feet were positively associated with RF and RT. These results indicate that increases in the temperatures are associated with increased RF and RT. There was an effect in the RFI group in the front region where IRT correlates with RT. The front IRT for high-RFI cattle was lower (P < 0.01) than that for low-RFI cattle. The higher skin temperature measured by IRT for animals in the RFI group may be related to improved efficiency of thermoregulatory mechanisms because the RT remained lower in the low-RFI group. IRT can be used in the head for studies related to RFI in beef cattle.

Assuntos