Ruminants

Prolonged drought and resource scarcity have limited feed availability for livestock in arid and semi-arid regions, necessitating strategic resource management to sustain cattle productivity. This study evaluated the use of spineless cactus as an alternative feed ingredient for ruminants in dryland areas. The experiment assessed in vitro cumulative gas production from silages of Miúda forage cactus (Nopalea cochenillifera Salm-Dyck) combined with Tifton 85 Bermuda Grass (Cynodon sp.) hay and varying levels of urea (1%, 2%, and 3% on a dry matter basis) as a nitrogen source. Traditional supplements comprising Tifton hay, wheat bran, soybean meal, and urea served as controls. Kinetic organic matter degradation parameters exceeded 60%. Dry matter degradability was similar across all urea levels at six hours but diverged over time, with the 3% urea treatment showing lower degradability at 48 and 96 h. Organic matter degradability varied throughout incubation, with the 2% urea treatment performing best. Overall, these findings suggest that silage made from native Miúda forage cactus combined with Tifton hay and up to 2% urea can serve as an effective alternative roughage to meet the nutritional requirements of ruminants, particularly during periods of feed scarcity in arid environments. Full article

Precision livestock farming (PLF), by integrating multimodal sensor data, provides opportunities to enhance welfare monitoring and management in small ruminants. This study evaluated whether environmental, physiological, and behavioral measurements—including the temperature–humidity index (THI), carbon dioxide (CO₂) and ammonia (NH₃) concentrations measured at the barn level, body condition score (BCS), rectal and ocular temperatures, GPS-derived locomotion metrics, accelerometry data, and fixed animal traits—can serve as key predictors of welfare and productivity in dairy sheep. Data were collected from 90 ewes: all animals underwent the same repeated welfare assessments, while 30 of them were additionally equipped with GPS–accelerometer sensor collars; environmental conditions were continuously recorded for the entire flock, generating 773 complete multimodal records. All predictive models were developed using data from all 90 ewes; collar-derived behavioral variables were included only for individuals equipped with GPS–accelerometer collars. Nine regression methods (linear regression (LR), partial least square regression (PLSR), elastic net (EN), mixed-effects models, random forest (RF), extreme gradient boosting (XGBoost), support vector regression (SVR), neural networks (multilayer perceptron, MLP), and an ensemble of RF–XGBoost–EN were evaluated using a combination of nested cross-validation (CV) and leave-one-animal-out CV (LOAOCV) to ensure robustness and generalization at the individual animal level. Nonlinear models—particularly RF, XGBoost, SVR, and the ensemble—consistently delivered superior performance across traits. For behavioral (e.g., daily distance movement) and thermal indicators (e.g., medial canthus temperature), the highest predictive capacity (R² ≈ 0.60–0.70) was achieved, while moderate predictive capacity (R² ≈ 0.40–0.50 and ≈0.35–0.45), respectively, was observed for respiratory rate and milk yield, reflecting their multifactorial nature. Feature importance analyses underscored the relevance of THI, CO₂, NH₃, concentrations, and BCS across results. Overall, these findings demonstrate that multimodal sensor fusion can effectively support the prediction of welfare and productivity indicators in intensively reared dairy sheep and emphasize the need for larger and more diverse datasets to further enhance model generalizability and model transferability. Full article

The aim of this study was to evaluate the effects of oregano essential oil (OEO) as a replacement for monensin (MON) on performance, carcass characteristics and meat quality in heifers finished either in confinement or on pasture. Thirty-six Nellore heifers (252.44 kg ± 21.80 kg) were distributed in a completely randomised design in a 2 × 2 factorial scheme, with two types of additives and two finishing systems. In both systems, a concentrate at 1.5% of body weight (BW) on a dry matter (DM) basis containing MON (282.2 mg/animal/day) or OEO (300 mg/animal/day) was offered daily. The final BW (FBW) and average daily gain (ADG) were higher in confinement-finished animals than in those finished on pasture (p < 0.01). There was no effect from the finishing system (p ≥ 0.376) or additive (p ≥ 0.057) for hot-carcass weight, hot-carcass yield, subcutaneous fat thickness, or the Longissimus lumborum area. The pH and shear force of the meat did not differ between treatments (p ≥ 0.076). Finishing in confinement resulted in brighter meat than finishing on pasture (p ≤ 0.006). The use of OEO increased the redness of the meat (p ≤ 0.042). Consumer perception (n = 63) of the sensory attributes of aroma, colour, tenderness, flavour and juiciness was not affected by the treatments (p > 0.05). Heifers finished in confinement or on pasture, with the same proportion of concentrate in the diet and the addition of MON or OEO, presented similar characteristics for both the carcass and the meat. Full article

Barley is more extensively and more rapidly fermentable than maize, thus it is supposed to increase digestive disorders in ruminants. However, the effect of cereal type on animal performance and digestion may vary with processing degree. In the present experiment, the effect of dry-rolling or grinding barley and maize, as the main cereals in a concentrate containing a high proportion of starch with different rates of fermentation, on intensively reared beef cattle performance, diet digestibility, and feed intake amount and pattern, was studied. Thirty-six 3-month-old male calves were allocated to one of four diets consisting of barley straw (BS) and a concentrate with 60% cereals (barley and maize in proportions 75:25 or 25:75) presented dry-rolled or ground through a 3.5 mm sieve. The experimental period was divided into two phases of 10 weeks each: from start to 277 ± 3.6 kg live weight (LW; Growing), and from 289 ± 3.8 kg LW to slaughter (399 ± 4.6 kg; Finishing). For the Growing phase, there were no differences (p > 0.10) between the majority cereal in the concentrates, nor between their processing methods, in the daily intake of concentrate and BS, and in the animals’ final LW. With respect to Finishing, the interaction between cereal type and processing was significant (p < 0.05) for concentrate daily intake. As a result, animals consuming ground barley ate less concentrate than those fed rolled barley, whereas there were no differences between processing methods for animals fed maize-based diets. Animals consuming ground-barley concentrates consumed significantly more straw than those fed on dry-rolled-barley concentrates (p < 0.05 for Growing and p < 0.01 for Finishing) during the first four hours after feeding. No such differences appeared in animals consuming maize-based concentrates. Starch digestibility was higher in animals fed ground cereals vs. dry-rolled cereals during the Growing phase (p = 0.048), whereas NDF digestibility was also higher (p = 0.008) in animals fed ground cereals during the Finishing phase. The faeces from animals fed on rolled-maize concentrates showed a higher concentration of purine bases than the faeces of animals fed on rolled-barley concentrates (p = 0.016), although there were no differences for the ground cereals. Overall, the results reported indicated that replacing maize with barley in diets for feedlot beef cattle did not affect average daily gain, intake of straw or concentrate, or feed conversion ratios (total or considering just the concentrate); hence the inclusion of either cereal in greater proportions should be based on their market price and on the final cost of the compound feed (which may include different ingredients). The processing method of the cereals (grinding or dry-rolling) also had no influence on the above-mentioned variables, so the selection of the method should be based on their relative cost, exclusively in terms of feed efficiency. Full article

Edible trees, such as Bordão-de-velho (BVP; Samanea tubulosa), are being studied for their nutritional potential and the presence of bioactive compounds that influence ruminal fermentation. This study aimed to evaluate, using an in vitro assay, the effects of increasing the inclusion of BVP pods in dairy cow diets formulated with different energy levels. The experiment was conducted with eight treatments obtained from a 4 × 2 factorial arrangement, containing four levels of pod inclusion (0, 100, 200, and 300 g/kg dry matter) and two dietary energy levels (high and low). Increasing BVP levels resulted in a linear reduction in gas production from digestible organic matter in low-energy diets, without altering dry matter and organic matter digestibility or methane production. There was an increase in pH and in the acetate/propionate ratio, along with a reduction in the concentrations of short-chain fatty acids and isoacids. In conclusion, Samanea tubulosa pods improve fermentation efficiency and reduce gas production, making them a promising forage source for low-productivity animal diets. Full article

This narrative review aims to summarize, synthesize, and organize current knowledge on the adaptation of sheep and goats to stressful environments and to discuss how these adaptations contribute to food security in vulnerable communities. A structured search of Web of Science, Scopus, PubMed, and Google Scholar was conducted using combinations of terms related to sheep and goats, harsh environments (e.g., arid and semi-arid regions, heat stress, water restriction, poor-quality forage), and adaptation or resilience, combined with Boolean operators. A total of 1718 research publications were found, of which 86 were retained as the most relevant because they provided direct and detailed evidence on anatomical, physiological, digestive–microbiome, behavioral, and genomic adaptations of sheep and goats to stressful environments. The selected studies describe a wide range of phenotypic and integumentary traits, thermoregulatory and endocrine responses, digestive and microbial adjustments, behavioral strategies, and genomic signatures that, together, allow small ruminants to maintain basic functions, reproduction, and production under conditions of climatic and nutritional stress. Evidence from these studies also highlights how adaptive traits support herd productivity, economic stability of households, and the sustainable use of natural resources in regions where climatic variability and resource scarcity are common. Overall, the synthesis presented here underscores the importance of conserving and strategically using locally adapted sheep and goat breeds, incorporating resilience-related traits into breeding and management programs, and prioritizing further research on genomic, microbiome, and epigenetic mechanisms that underpin adaptation to harsh environments. Full article

The aim of this study was to evaluate the relationship between cows’ hepatic lipid content (HLC) at 10 days in milk (DIM) and their metabolic status, health, and production during transition and early lactation periods. HLC was determined in 103 cows from a grazing Chilean dairy herd via cytologic examination of the liver through fine needle biopsies, categorized as mild, moderate, or severe. Blood metabolites were evaluated in the transition period, together with diseases in the postpartum period and milk production during the first 90 DIM. In pre-partum and postpartum periods, primiparous cows with severe HLC showed higher plasma cholesterol than multiparous cows with mild HLC. Postpartum, cows with severe HLC had higher serum non-esterified fatty acids (NEFAs) and NEFA/cholesterol ratios than those with mild HLC. Similarly, cows with moderate and severe HLC presented higher plasma β-hydroxybutyrate and greater risk of subclinical ketosis than cows with mild HLC. Additionally, cows with severe HLC had higher milk production and lower milk protein content than those with mild HLC. These results indicate that moderate to severe HLC at 10 DIM was associated with negative energy balance and subclinical ketosis, whereas severe HLC was associated with increased milk production and decreased milk protein content. Full article

The present study aimed to apply machine learning algorithms to estimate respiratory rate (RR, breaths min⁻¹) and rectal temperature (RT, °C) as indicators of thermal stress in Dorper breeding rams, based on environmental and thermal variables obtained through infrared thermography. The algorithms Random Forest (RF) and Support Vector Regression (SVR) with radial kernel were employed, using ocular globe temperature (OGT), air temperature (AT), relative humidity (RH), and coat surface temperature (CST) as predictor variables, and rectal temperature (RT) and respiratory rate (RR) as response variables. Data were collected on a property located in Garanhuns, Pernambuco State, Brazil, under two environmental conditions (with and without climate control), totaling 20 monitored animals and 120 paired observations. Model performance was evaluated using the coefficient of determination (R²), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE), complemented by cross-validation (k-fold = 10), and model interpretability was assessed using SHapley Additive exPlanations (SHAP) to quantify the contribution of each predictor variable to model predictions. The results indicated that the RF model showed superior performance in predicting the physiological variables RR and RT, with higher coefficients (RR: R² = 0.858; RT: R² = 0.687) and lower error values. For RR, the RF model achieved RMSE = 16.38 and MAE = 13.33; while for RT, the errors were RMSE = 0.217 and MAE = 0.154. In contrast, the radial kernel SVR model showed lower performance, with R² values of 0.742 (RR) and 0.533 (RT), and RMSE and MAE values of 21.05 and 17.38 for RR, and 0.262 and 0.196 for RT, respectively. The application of machine learning-based models proved to be a viable and accurate alternative for estimating physiological indicators of thermal stress, contributing to the development of automated thermal management strategies for sheep in the Brazilian semi-arid region. The proposed data-driven approach demonstrates that low-cost thermal sensors combined with explainable artificial intelligence can support automatic decision-making for climate adaptation and animal welfare in semi-arid sheep production systems. Full article

Background: Cortisol is known as the main hormone released during stress responses in cattle and has been used to assess various stressors, including heat stress. This study investigated hair cortisol concentration (HCC) in different hair coat colors in dairy cows under natural heat stress conditions (temperature humidity index = 75). Methods: Hair samples were collected from the forehead region of ten multiparous cows (Brown Swiss, Montbéliarde, and Holstein) per group color at both the beginning and end of a three-week peak summer period in 2024 in the region of Jendouba, North Tunisia. Cows were grouped according to hair coat color (black, brown, red, white, and yellow) for subsequent analysis. Hair samples were prepared using a methanol-based separation protocol and analyzed via enzyme-linked immunosorbent assay (ELISA). Results: Meteorological data confirmed that cows were sustained under heat stress, with an average temperature humidity index value of 75; results indicated that black hair had considerably more HCC than white hair (p < 0.05). The results showed that there is a significant difference between HCC under three clusters (p < 0.05) according to hair color. Conclusions: The study emphasizes that hair color, along with factors such as breed and environmental conditions, should be carefully considered when using HCC to assess stress in cattle beyond simply black or white hair color. Full article

Studies in taurine breeds have shown that genetic selection can improve the fatty acid (FA) profile of bovine milk, but studies are scarce considering Zebu animals. In this study, genetic parameters for FA concentrations and unsaturation indexes in the milk fat of Zebu cows were estimated, with emphasis on Gir and Guzerá breeds. Milk samples from 299 Gir and 266 Guzerá cows belonging to 22 herds distributed throughout Brazil were analyzed using gas chromatography. Fourteen individual FAs, 11 FA groups, four nutritional indexes, and five unsaturation indexes were evaluated. Tri-trait Bayesian models were applied, including 305-day milk and fat yields as “anchor” traits. Systematic effects such as contemporary group, age at calving, diet, sampling age class, and days in milk were considered. Palmitic acid was the most abundant FA, followed by oleic, stearic, and myristic acids. Heritability estimates ranged from moderate to high: 0.28–0.66 in Gir cows, and 0.25–0.74 in Guzerá cows, for individual FAs and FA groups. Unsaturation indexes also showed moderate to high heritability. Genetic correlations were generally strong, with long-chain FAs negatively correlated with short- and medium-chain FAs. The results suggest that genetic selection can be applied to improve the nutritional profile of milk fat in Zebu cattle. Full article

Climate change poses significant challenges to livestock, particularly in tropical regions. The Amazon biome, which hosts one of the world’s largest cattle populations, faces growing risks of nutritional, metabolic, and infectious diseases driven by heat stress (HS) and environmental instability. This systematic review synthesizes evidence from primary studies, international reports (IPCC, FAO), and peer-reviewed literature on cattle physiology, disease dynamics, and climate adaptation. HS reduces feed intake, disrupts endocrine–metabolic homeostasis, and suppresses immunity, increasing susceptibility to metabolic, deficiency and infectious diseases. Breed-specific immune responses offer opportunities for genetic and management-based adaptation. Socio-economic impacts disproportionately affect smallholders, linking livestock health to food security and poverty. Ensuring sustainable cattle production in the Amazon will require climate-smart strategies integrating nutrition, genetics, reproduction, and health management, supported by policies that align adaptation and mitigation. Future research should prioritize immune-metabolic biomarkers, periparturient disease monitoring, and genomic tools for thermotolerance. Full article

Despite the critical importance of nutritional assessment in veterinary medicine, internationally recognized guidelines for compromised ruminants remain absent. This paper addresses this significant gap by presenting comprehensive nutritional assessment protocols adapted from small animal and equine guidelines, combined with clinical experience and ruminant-specific considerations. Therefore, the objective of this article is to establish standardized nutritional assessment guidelines for compromised ruminants that facilitate early detection of risk factors and nutritional imbalances affecting animal welfare and productivity, while guiding appropriate clinical nutritional interventions. The guidelines integrate systematic screening and extended evaluation protocols encompassing patient signalment, comprehensive health interviews, environmental examination, and nutrition-focused clinical assessments. The framework incorporates validated scoring systems including body condition scoring, fecal consistency and digestibility scores, rumen fill assessment, and muscle scoring. Laboratory evaluations including blood biochemistry, hematology, milk quality records, and metabolite profiling support clinical decision-making. The proposed assessment framework addresses animal-specific factors, diet-related considerations, feeding management practices, and environmental influences on nutritional status. Critical evaluation points include alimentary system function and integrity, forestomach assessment, and detection of malabsorption syndromes. The guidelines emphasize that many nutritional abnormalities manifest non-specifically, and detection limitations exist, particularly in peracute presentations. In conclusion, successful clinical nutritional interventions require comprehensive assessment protocols that prioritize rumen health maintenance and oral diet delivery whenever possible. The guidelines we suggest will provide veterinary and nutritional practitioners with systematic tools for evaluating compromised ruminants, establishing appropriate interventions, and monitoring outcomes using SMART goals. Further research is warranted to refine specific dietary requirements for compromised ruminants and validate intervention protocols across diverse production systems. Full article

The present study determined the effects of varying inclusion levels of baobab oilseed cake (BOSC) combined with fossil shell flour (FSF) diets on body condition scores, body weight gain, and nutritionally related blood metabolites of Angora goats. Twenty-four Angora goat wethers aged 5–6 months, weighing 12.75 ± 1.5 kg, were kept in individual pens for 105 days of successive feeding, including a 14-day adaptation period. Goats were randomly allocated to four dietary treatments: 0%, 5%, 10%, and 15% BOSC (n = 6). Each goat was offered experimental diets at 4% of its body weight daily at 08:00. Goats were then released to graze on natural pastures at 10:00 and returned to their respective pens at 16:00 daily. Body weight gain, body condition scores, and blood concentrations were determined. Angora wethers BCS linearly increased (p < 0.05) as weeks progressed in all inclusion levels of BOSC. Body weight gain increased linearly (p < 0.05) in goats fed 0% and 10% BOSC across the 13-week feeding period, while goats fed 5% BOSC showed a sharp quadratic increase (p < 0.05) between weeks 5–6 and those fed 15% BOSC between weeks 3–8. Creatinine levels showed a sharp quadratic decline (p < 0.05) between 10–15% BOSC inclusion, while urea levels quadratically declined (p < 0.05) between 0–5% inclusion. Phosphorus concentrations also decreased quadratically (p < 0.05), reaching their lowest values between 5% and 10% BOSC, while total protein, glucose, magnesium, albumin, and calcium remained unchanged (p > 0.05) across dietary treatments. In conclusion, this preliminary study suggests that the inclusion of 15% BOSC improves BWG, BCS, and nutritionally associated blood metabolites in Angora goats. Further studies with a larger number of animals are recommended to confirm these findings. Full article

Oxidative stress impairs the productivity and welfare of heat-stressed hair sheep; however, the key factors contributing to its occurrence remain unclear. Twenty-two Dorper × Katahdin ewe lambs weighing 23.5 ± 2.8 kg and experiencing outdoor heat stress in a desert region were used to establish the contribution of climatic variables, physiological responses, metabolism, and feedlot performance to the oxidant-antioxidant imbalance. Pearson’s correlation, principal component analysis, and multiple linear regression were applied to the datasets. Oxidative stress biomarkers showed positive relationships with average and minimum climatic variables, morning rectal temperature, serum triglycerides and insulin, and feed efficiency. Still, these biomarkers were negatively correlated with maximum ambient temperature (Te) and temperature-humidity index (THI), morning and afternoon respiratory rate (RR), total protein, and feed intake. While total oxidant capacity and fat oxidation were mainly associated with decreased maximum Te, protein oxidation was primarily associated with increased morning RR. Total antioxidant capacity was favored by a reduction in maximum THI and oxidative stress index (OSI) by an increase in maximum relative humidity. With minimal contribution (≤6%), protein and fat oxidation were also explained by increased serum insulin and feed intake, respectively, whereas OSI was explained by increased weight gain. Overall, the presence of oxidative stress in feedlot hair sheep experiencing outdoor heat stress was regulated by a combination of climatic conditions, morning RR, and, to a lesser extent, productive performance. Full article

Spineless cactus, known for its high heat tolerance and low water requirements, offers a sustainable alternative for animal feed in regions where conventional crops struggle to thrive. This study aimed to evaluate the carcass characteristics, leg tissue composition, and non-carcass constituents of lambs fed increasing levels (0, 15, 30, and 45% based on dry matter) of spineless cactus as a replacement for Tifton hay. Additionally, we estimated body weight and carcass traits using biometric measurements (BM). Forty male lambs, with an average initial body weight of 23.6 ± 2.58 kg, were subjected to a feedlot regime. Empty body weight was the only variable that showed a significant orthogonal contrast between the control group (0%) and those fed spineless cactus (p < 0.05). A quadratic regression effect (p < 0.05) was observed for the weights of the cold half carcass, neck, shoulder, and leg cuts. No significant effects were found on non-carcass components or biometric measurements. Biometric measurements showed strong positive correlations with slaughter weight and carcass characteristics. Based on these findings, replacing 30% of Tifton hay with spineless cactus is recommended as the optimal level, as it maintains carcass quality, tissue composition, and non-carcass traits. Moreover, biometric measurements prove to be effective tools for predicting slaughter weight and carcass characteristics, offering practical value for farmers seeking efficient and sustainable production strategies. The inclusion levels of 24.25% to 27.50% of spineless cactus in the diet of confined sheep appear to be the most efficient, promoting high-value commercial cuts without compromising carcass quality parameters. These levels balance productive performance and sustainability, especially in semi-arid regions. Full article

Individual vocal recognition is essential for social cohesion and survival among conspecifics. In sheep, it facilitates postnatal identification and strengthens the mother–offspring bond. Although vocal individuality has been well-documented in lambs and ewes, little is known about whether rams—typically reared separately in farming systems—exhibit acoustic distinctiveness. This study investigated whether rams express vocal individuality across different emotional contexts and whether their calls convey contextual information. Adult rams’ vocalizations were recorded across five emotionally distinct contexts: physical and visual isolation (morning and evening), auditory exposure to ewes’ bells without visual contact, feed anticipation, and feed denial. Implementing discriminant function analyses and linear mixed models, we assessed individual distinctiveness and contextual variation in acoustic parameters. Rams exhibited vocal individuality ranging from 59% to 80%, with higher distinctiveness in negative contexts compared to positive ones. Vocal distinctiveness persisted across contexts, albeit to a lesser degree, suggesting some degree of acoustic stability. Calls were classified above chance by context, suggesting rams use vocalizations to convey affective states. Formant dispersion and amplitude variation were the most informative raw acoustic parameters under negative from positive contexts. The findings indicate that rams exhibit context-dependent vocal individuality, potentially conveying affective states through vocalizations. Full article

Improving livestock nutrition with natural supplements can enhance productivity and meat quality. This study evaluated whether a clayey micromineral compound (CMC) in lamb diets improves feed efficiency, health, and meat traits. Twenty-four 60-day-old Dorper/Santa Inês crossbred lambs (28.41 ± 4.147 kg initial weight) were randomly assigned to four CMC doses (0%, 0.4%, 0.8%, or 1.2% of dry matter intake/day) for 90 days, following a 15-day adaptation. The lambs were individually housed, with daily feed intake monitoring, weekly weight measurements, and blood analyses at the start and end. On day 89, rumen fluid was sampled for digestion analysis, and post-mortem evaluations were used to assess meat quality and rumen health. The results showed that 0.8% CMC optimized fat and fiber digestion (p < 0.05), while higher doses linearly improved meat color intensity (p < 0.05). Blood tests indicated better liver function at intermediate doses (p < 0.05). However, the CMC did not affect overall growth, feed intake, or carcass traits. The supplement was safe but provided selective benefits. These findings suggest that CMCs could enhance feed efficiency and meat appeal, although further research is needed to refine dosing for maximum impact. Full article

A significant gap in specific nutritional guidelines for ruminants with compromised health exists. Due to their unique anatomy, physiology, and metabolic processes, further research is needed to establish accurate, evidence-based recommendations tailored to these animals. This review highlights the critical role of clinical ruminant nutrition and provides provisional recommendations based on studies in other species (e.g., changes in nutrient requirements in different morbidities available for humans and less for companion animals). These suggestions should be interpreted cautiously until more definitive, species-specific data become available. The review includes the foundational principles of clinical nutrition in ruminants, with particular emphasis on the pathophysiology of nutrient utilization. It explores the roles of energy, protein, vitamins, and minerals during illness or injury and discusses how these nutrients can be strategically applied in clinical interventions. Considerations for designing diets for compromised ruminants are also addressed, considering both physiological needs and the challenges posed by illness and injury states. Practical aspects of diet delivery during treatment are examined, including the indications, benefits, limitations, and potential side effects of route of feeding. Clinical nutrition can be administered orally, enterally (including rumen delivery) or parenteral, depending on the localization of the pathology and the integrity of the alimentary tract. Nutrients should be provided based on livestock requirements and pathophysiology and severity of the primary morbidity. Oral or ruminal provision of diet should be prioritized to maintain rumen functionality. Additionally, a list of pharmaconutrients with potential clinical applications in ruminant medicine is presented to encourage future research and integration into veterinary practice. The success of clinical nutritional interventions can be measured by improvements in appetite, behavior, and health of the compromised ruminant. Full article

Urea is one of the most widely used sources of non-protein nitrogen (NPN) in ruminant diets due to its low cost and high availability. However, its rapid solubilization in the rumen can result in abrupt ammonia release, leading to toxicity risks and low nitrogen utilization efficiency. In this context, slow-release technologies, particularly microencapsulation, have been developed to synchronize NPN release with fermentable carbohydrate availability, thereby enhancing microbial protein synthesis, improving animal performance, and reducing environmental impacts. This review compiles recent advances in urea microencapsulation, emphasizing different wall materials such as waxes, lipids, polysaccharides, and fatty acids, as well as drying techniques and formulation strategies. Slow-release urea (SRU) addition in small ruminants’ diet may increase nutrient intake and digestibility, improve N balance, and reduce urinary excretion losses. Regarding performance, positive responses are observed when nitrogen release is properly synchronized with energy availability, although the results may vary depending on the encapsulant type, forage-to-concentrate ratio, and ruminal passage rate. Additionally, effects on meat quality and environmental parameters indicate that this technology holds not only zootechnical but also socio-environmental potential. It is concluded that urea microencapsulation can represent a promising alternative to optimize NPN use efficiency in ruminant production systems, though greater methodological standardization, long-term evaluations, and comparative economic analyses are required to encourage its broader adoption. Full article