Search Results (153)

The pharmacokinetics (PK) and pharmacokinetic–pharmacodynamic (PK/PD) relationships of cefquinome in small ruminants remain incompletely characterized, particularly for long-acting (LA) formulations. This study evaluated cefquinome disposition after intravenous (IV), subcutaneous (SC) and LA subcutaneous (SC-LA) administration in lactating sheep and goats using nonlinear mixed-effects models (NLMEs) and Monte Carlo (MC) simulations. Cefquinome exhibited low volumes of distribution (0.21–0.31 L/kg), with goats showing higher clearance and shorter terminal half-lives than sheep. The SC-LA formulation reduced the absorption rate constant and increased both the mean absorption time and terminal half-life by 4–6-fold, resulting in sustained systemic exposure over 48 h. PK/PD analysis showed higher PK/PD cut-off values for the LA formulation, with values of 0.125 μg/mL for the fT > MIC index and 0.25 μg/mL for the fAUC/MIC index, respectively, whereas IV and SC regimens achieved lower thresholds. MC simulations indicated that only the LA formulation achieved ≥ 90% probability of target attainment (PTA) values at MICs equivalent to tentative epidemiological cut-off values (TECOFF) for respiratory pathogens. Notably, fAUC/MIC provided a more informative descriptor of efficacy for the LA formulation. These findings highlight the advantage of LA formulations and demonstrate improved performance compared with conventional dosing regimens in sheep and goats. Full article

Seasonal variability in feed availability in Mediterranean dairy sheep systems can compromise animal performance and welfare, highlighting the need for reliable, high-frequency monitoring tools. Live weight (LW) is a key indicator of nutritional status, but conventional measurements are labour-intensive and poorly suited to dynamic conditions. Walk-over-weighing (WoW) systems integrated with electronic identification (EID) enable automated, continuous, individual-level LW monitoring. This study assessed the sensitivity of a WoW system to detect nutritionally driven LW changes in Sarda dairy ewes under indoor and grazing conditions. Two experiments were conducted: an indoor short-term nutritional challenge involving 24 non-lactating ewes and a grazing trial with contrasting pasture access times involving 48 lactating ewes. In both experiments, the WoW system detected consistent LW differences between nutritional treatments (p < 0.001), capturing both short-term responses and sustained LW dynamics. Differences were approximately 5%, indicating that the WoW system was sensitive to nutritionally induced LW variation under the experimental conditions of the present study, before marked changes in body condition score (BCS) became detectable. These results demonstrate that WoW systems can reliably capture LW trajectories in response to nutritional variation. However, LW responses should be interpreted cautiously, as short-term variation may also reflect gut fill and hydration dynamics, and intake information was not fully available at the individual level because some feed intake components were measured at the group level or estimated indirectly. Integrating automated LW data with production and management information may support group-level nutritional decisions and early detection of animals deviating from expected LW trajectories in precision dairy sheep systems. Full article

Shearing is a stressful procedure for sheep, combining isolation, restraint, and the mechanical action of shearing, which activates the hypothalamic–pituitary–adrenal axis and induces oxidative stress. This study investigated whether melatonin—a pleiotropic hormone with well-documented antioxidant properties—administration could modulate the stress response and oxidative stress in Sarda sheep during shearing. Forty lactating ewes (aged 3–5 years, mean body weight 41 ± 1.1 kg) were randomly assigned to four groups (n = 10 each): two groups received a subcutaneous melatonin implant (18 mg); two remained untreated as controls. Within each category, one group was shorn and the other subjected only to restraint. Blood samples were collected before, during, and after shearing to measure cortisol, glucose, reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), and oxidative stress index (OSI). Procedures elevated cortisol, glucose, ROMs, and OSI in all groups, but melatonin treatment significantly reduced these parameters and increased BAP relative to untreated animals at all sampling points (p < 0.05). No significant differences were observed between shorn and unshorn animals within the same treatment, suggesting that the handling, restraint, and isolation associated with the shearing procedure represent the major sources of stress, rather than the mechanical act of shearing itself. In conclusion, melatonin administration blunts the stress response and reduces oxidative stress in sheep during routine shearing-related handling procedures, suggesting its potential as a practical tool to improve animal welfare during routine management practices. Full article

Phytoestrogens are plant-derived phenolic compounds that structurally resemble endogenous estrogens and can exert both estrogenic and anti-estrogenic effects in animals. In ruminant nutrition, the main classes of phytoestrogens (isoflavones, lignans, stilbenes, coumestans and selected flavonoids) are supplied predominantly by legume forages and soybean-based feeds, in which concentrations can reach several mg/g of dry matter. After ingestion, these compounds are extensively metabolized by the rumen microbiota to derivatives with altered biological potency, such as equol and p-ethyl-phenol, which influence endocrine, immune and metabolic pathways. Experimental and field studies in cattle, sheep and goats indicate that dietary phytoestrogens may improve nitrogen utilization, immune competence, growth performance, antioxidant status and milk yield. However, they can also impair fertility, modify hormone profiles and compromise embryo survival in a compound-, dose-, and species-dependent manner. In this review, we summarize current knowledge on the botanical and nutritional sources, ruminal metabolism and transfer of phytoestrogens in ruminants, and critically examine their effects on blood metabolites, immune responses, growth and carcass traits and lactational performance and reproductive function. A structured literature search based on PRISMA principles was used to identify and appraise experimental and observational studies in both grazing and intensive production systems up to 2025. Remaining knowledge gaps and practical implications for the safe use of phytoestrogen-rich feeds in livestock production are highlighted. Full article

Using alternative energy sources for animal feed, such as hybrid corn varieties rather than genetically modified ones, is important. Therefore, the objective of this work was to assess the effects of supplementation at the end of gestation with Mexican Puma hybrid corn grain on productive and behavioral parameters in sheep. Twenty Columbia multiparous ewes were used; along with their diet, they were provided 600 g/animal/day of cracked corn during the last 20 days of pregnancy and the first week of lactation. The animals were divided into two groups: one fed commercial cracked corn (n = 11) and the other Mexican Tlaoli Puma hybrid cracked corn (n = 9). The productive parameters evaluated in the mother were: body weight, body condition score (BCS), feed intake, weight change, glucose, and ketone body levels, as well as the estimated quality of milk using Brix refractometer values on days 15 and 30 of lactation. In lambs, their rectal and external temperature was measured 2 h after birth, while their weight was measured 2 h after birth and every week until week 6 postpartum. Behavioral parameters were measured in the first two hours postpartum, including the maternal latency of cleaning the offspring, duration of the first cleaning episode, the lamb’s latencies of standing and nursing, and vocalizations in mother and lamb. Weight, BCS and weight change were not affected by the group but were affected by time; these parameters increased at the end of gestation and decreased significantly after delivery (p < 0.05). Ketone body levels were not affected by group or time (p > 0.05) and remained at low values. Glucose levels were not affected by the group but were affected by time; they increased significantly after birth (p < 0.05). Feed intake was similar in both groups (p > 0.05) and decreased as parturition approached (p < 0.05). The estimated milk quality was not affected by the group, nor by the time (p > 0.05). Mothers in both groups began cleaning their offspring within the first three minutes after giving birth and emitted a similar frequency of vocalizations (p > 0.05). However, mothers in the commercial maize group had a longer cleaning episode than those in the hybrid maize group (p < 0.05). The lambs in both groups stood up within the first half hour of birth, suckled before one hour after birth and emitted a similar number of vocalizations (p > 0.05). Temperatures and lamb weight were similar in both groups (p > 0.05); however, lamb weight increased as they aged (p < 0.05). It is concluded that supplementing sheep at the end of gestation with Puma hybrid Mexican corn grain can yield similar productive and behavioral benefits as supplementing with commercial grain. Full article

Modern genetic selection for high productivity has created a physiological conflict in ruminants, where the metabolic demands of lactation compete directly with the energy requirements of reproduction. This review provides a mechanistic synthesis of how key nutritional factors modulate the endocrine and cellular pathways governing reproductive success in cattle and sheep. Negative energy balance (NEB), characteristic of the early postpartum period, suppresses the hypothalamic–pituitary–gonadal (HPG) axis by impairing the pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH), mediated through reduced kisspeptin signaling, growth hormone (GH) resistance, and decreased circulating insulin, insulin-like growth factor-1 (IGF-1), and leptin. At the macronutrient level, excess rumen-degradable protein elevates blood urea nitrogen and impairs the uterine environment, while omega-3 polyunsaturated fatty acids inhibit prostaglandin F2α synthesis to support corpus luteum maintenance. At the micronutrient level, selenium, copper, and zinc are essential antioxidant cofactors protecting gametes and embryos from oxidative stress, while vitamins A, D, and E regulate gene expression in reproductive tissues. Furthermore, maternal nutrition during critical gestational windows programs the reproductive capacity of offspring through epigenetic modifications, with profound implications for long-term herd fertility. Understanding these nutritional–reproductive interactions is crucial for developing precision feeding strategies that optimize herd fertility, improve animal welfare, and ensure the economic sustainability of livestock management. A thorough understanding of these nutritional–reproductive interactions is essential for developing precision feeding strategies that optimize fertility in high-producing ruminants. Full article

The objective of the present study is to evaluate the effects of lactation stage, age, somatic cell count (SCC), and daily milk yield on plasmin–plasminogen (PL–PG) system activity and physicochemical milk traits in intensively reared Chios and Frizarta ewes. A total of 52 purebred ewes (26 ewes per breed and farm) were randomly selected and prospectively monitored during the 3rd, 5th, and 6th month post-lambing. Daily milk yield and body condition score (BCS) were recorded, and individual milk samples were collected for the assessment of PL–PG activities using enzymatic assays, SCC, electrical conductivity (EC), refractive index (RI), and pH. Correlation analysis and mixed linear regression models were used for the assessment of the effects. Lactation stage significantly affected PL–PG system traits in both breeds, but in opposite direction; plasmin and plasminogen plus plasmin declined toward late lactation in Chios ewes, whereas it increased in Frizarta ewes. Lower SCC was associated with reduced plasmin system activity in Chios ewes, whereas no effect was observed in Frizarta ewes. The plasminogen-to-plasmin ratio remained stable across lactation, breeds, and SCC classes, indicating coordinated regulation of the system. BCS was positively associated with plasmin activity during late lactation, suggesting a stage-dependent metabolic modulation. EC and pH were closely associated with SCC, while RI mainly reflected compositional variation. Our findings underline that, although the PL–PG system is primarily affected by lactation stage and mammary health status in sheep, there are breed-specific regulatory patterns which should be further investigated. Full article

Oxidative stress contributes to reproductive disorders, immune dysfunction, and reduced productivity in livestock during periods of high metabolic demand and environmental challenge. Selenium supports antioxidant defense systems because it is incorporated as selenocysteine into selenoproteins, including glutathione peroxidases and thioredoxin reductases that detoxify peroxides and sustain redox balance. The review summarizes selenium occurrence and chemical forms in feeds, as well as its absorption, transportation, and storage. The review also outlines the major features of selenoprotein biosynthesis and its prioritized allocation, with an emphasis on cattle, pigs, sheep, and goats. Evidence from multiple sources indicates that selenium status and supplementation interacts with antioxidant capacity, immune competence, thyroid hormone metabolism, reproductive performance, and the transfer of selenium to milk and offspring. In ruminants, rumen microbial transformations can reduce the bioavailability of inorganic selenium salts, and organic sources, such as selenium-enriched yeast, hydroxy-selenomethionine, and selenitetriglycerides, often increase blood and milk selenium more effectively. In pigs, organic selenium is commonly associated with enhanced antioxidant and immune indices in sows and piglets during late gestation, lactation, and weaning, whereas effects on growth performance are inconsistent. The review emphasizes the narrow margin between adequacy and excess and outlines practical considerations for supplementation and monitoring, alongside research needs for emerging selenium forms and functional biomarkers. Full article

The most recent National Research Council Nutrient Requirements for Sheep and Goats was published in 2007, one of the most consequential nutrient requirement recommendations for sheep and goats in the world. The enhancement of production efficiency, minimization of carbon footprint, and maximization of resource economy, among others, motivate the continuing discussion of nutrient utilization and refinement of nutrient requirements in sheep and goats that are increasingly important in various parts of the world. Progress has been made in the estimation of energy and protein requirements in sheep and goats, mainly utilizing empirical feeding experimentation, comparative slaughter techniques and minimum endogenous loss methods. In sheep, newer estimates of energy and protein requirements for maintenance and growth and partial efficiencies has been reported since 2007. There were suggestions that energy and protein requirements could have been affected by breed, wool growth, gender and size, with these reported values being similar or lower than the recommended values in international feeding systems such as NRC, ARC, INRA and AFRC. In goats, energy and protein requirements for growing goats were reported to be either higher or lower than the established recommendations, depending upon meat or dairy breeds. Effect of gender on energy requirement appeared to be related to the stage of growth or degree of maturity. Newer data also suggested that existing recommendations on nutrient requirements may not be adequate for non-pregnant and non-lactating pubertal females. In multiparous pregnant goats, energy and protein requirements for maintenance did not appear to be affected by days of pregnancy, but efficiencies of metabolizable energy and metabolizable protein utilization for pregnancy were. There were suggestions that metabolizable protein can be predicted from energy intake using equations that encompass both sheep and goats, but more data on goats were called for to account for specific differences in nutrition. In addition to sulfur, there has been progress made on the estimation of maintenance and growth requirements of calcium, phosphorus, potassium and magnesium in goats, with suggestions on the consideration of gender and breed differences. While conventional factors such as breeds and species, genotype, stage of maturity, gender, body composition, mobilization of tissue energy for production, and additional activity energy required due to resource limitation and acclimatization remain as important considerations for the estimation of nutrient requirements in sheep and goats, emerging factors such as climate change, heat stress, parasitism and secondary plant compounds that can affect nutrient utilization should also be considered in the estimation of nutrient requirements. Model equations and partial efficiencies used by NRC to predict energy and protein requirements for maintenance, growth, lactation, and fiber have been highlighted and discussed for the purpose of a more focus discussion and refinement for the future. Potential limitations of both traditional and emerging methodologies in determining the nutrient requirements in sheep and goats were discussed. The advancement in nutrigenomics can potentially move nutrient requirements beyond its population-based guidelines. To justify the research investment, emerging methodologies such as nutrigenomics will have to be linked more directly to the improvement of production efficiency via more precise prediction of nutrient requirement. With the assistance of artificial intelligence and more data obtained from sensor technology, precision nutrition has the potential to deliver nutrients precisely to individual animals and meet nutrient requirements in sheep and goats. Full article

Footrot is one of the top five globally important diseases of sheep and causes lameness, leading to poor welfare and productivity. Transmission of Dichelobacter nodosus, the causative agent, occurs via surfaces such as pasture or bedding and persistence occurs from diseased sheep shedding bacteria into the environment; D. nodosus cannot replicate off host. High resolution proximity sensors were deployed on a flock of Poll Dorset sheep for 10–17 days at several points of the production cycle (teasing, tupping, pregnancy, and lactation (<6-week-old lambs)) between July 2018 and May 2021. Association indices between pairs of sheep were calculated, and outbreaks of footrot were simulated using a network-based susceptible-exposed-infected-recovered model. Two management approaches were modelled (1) where sheep were treated either not promptly, or effectively, resulting in long recovery times (28–100 days) and (2) where sheep were treated and recovered within 15 days, assuming ‘active management’ of footrot by the farmer using ‘best practice’ of prompt recognition of lame sheep and parenteral and topical antibiotics. Under ‘active management’ conditions (scenario 2), outbreak sizes were smaller at all points of the production cycle. This adds to existing evidence that prompt, effective treatment of sheep at all stages of the production cycle is key to reducing the prevalence of footrot in the flock, including at breeding when sheep are more likely to be in close contact. Full article

Photoperiod and seasonality influence reproduction and lactation in sheep, but their effects on milk hormones, milk composition, and lamb growth are not fully understood. This study assessed the effect of season on milk prolactin, leptin, and insulin concentrations, milk chemical composition, lactation performance, and lamb growth in Polish Mountain ewes. Forty ewes were divided into the following two groups: short-day (lambing in December, n = 20) and long-day (lambing in May, n = 20). Milk samples were collected on days 5, 15, 25, 35, and 45 of lactation. Ewes in the long-day photoperiod had higher milk yield (p < 0.01) and higher prolactin and insulin concentrations (p < 0.01), whereas leptin concentrations did not differ seasonally. Milk from short-day ewes was characterized by higher dry matter and fat content (p < 0.01) and higher protein and lactose content (p < 0.05). Lambs from the long-day group achieved higher mean daily gain (p < 0.01). These results indicate that photoperiod influences lactation performance, milk composition, and offspring growth through seasonal hormonal and metabolic mechanisms, suggesting that appropriate lambing timing and day length manipulation can improve milk production efficiency and lamb growth in practical sheep production systems. Full article

Sawdust represents a locally available lignocellulosic resource that may complement ruminant diets during periods of forage shortage. This study evaluated the feeding value of birch (Betula pendula) sawdust subjected to physical and chemical processing using a stepwise experimental approach. Steam-exploded and fresh sawdust were treated with 0, 4% ammonia, or 4% sodium hydroxide in a 2 × 3 factorial design and initially evaluated by in vitro gas production, dry matter digestibility, and fermentation pH. Based on these results, selected materials were further assessed for rumen dry matter and fiber degradation using the in sacco technique in cannulated dairy cows, with untreated and ammonia-treated wheat straw included for comparison. In addition, steam-exploded sawdust was compared with wheat straw and grass silage for in vivo digestibility in sheep. A pilot study also tested aspen (Populus tremula) sawdust in lactating cow diets. Steam explosion substantially reduced fiber fractions, particularly hemicellulose, and increased residual carbohydrates, resulting in higher gas production and in vitro digestibility compared with fresh sawdust (p < 0.05). Ammonia treatment markedly increased crude protein content, whereas sodium hydroxide primarily increased ash concentration. In sacco, steam-exploded birch showed similar or higher ruminal dry matter and neutral detergent fiber degradation compared with ammonia-treated wheat straw, while untreated fresh birch remained largely undegraded. In vivo, steam-exploded sawdust exhibited greater organic matter digestibility and net energy than untreated wheat straw but remained less digestible than grass silage (p < 0.0001). A pilot feeding test with lactating dairy cows demonstrated good acceptance of untreated aspen sawdust as a partial roughage substitute under non-standardized conditions. Overall, the results indicate that steam-exploded sawdust has potential as a complementary roughage source for ruminants when conventional forages are limited. Full article

The effects of pelleting a total mixed ration (TMR) for dairy sheep were investigated in an experiment involving 24 lactating Assaf ewes, which were assigned to two groups and fed the same TMR ad libitum, offered either in pelleted (PTMR group, n = 12) or in unpelleted form (CTMR group, n = 12). The experiment lasted 28 days, during which feed intake, eating behavior (including meal frequency and size, meal duration, eating rate, between-meal interval), and milk yield were recorded daily. Body weight (BW) was recorded on days 1 and 28 and milk samples were collected on days 1, 8, 15, 22 and 28 for milk composition analysis. Blood acid-base status was determined at the beginning and at the end of the trial. Ewes fed the CTMR diet exhibited (p < 0.05) a higher meal frequency and longer meal duration, along with a smaller meal size and slower eating rate. However, feed intake in this group was less than that in ewes fed PTMR only during the final two weeks of the experimental period. Total eating time was also longer (p < 0.001) in the CTMR group, whereas the average time between meals was shorter (p < 0.002). No differences (p > 0.05) were observed between dietary treatments in blood acid-base status, milk yield or milk composition. However, a diet x day interaction (p < 0.05) was detected for milk yield, as during the last 2 weeks of the experimental period the ewes fed the PTMR yielded more milk than those fed the CTMR. Feed conversion ratio did not differ between groups (p > 0.05), but body weight loss was greater in ewes fed the CTMR diet (−3.00 vs. −0.58 kg; p < 0.05). A trend toward improved feed efficiency was observed in the PTMR group when calculated based on milk yield corrected for that theoretically derived from the mobilization of body reserves (1.98 vs. 1.41 g DMI/kg milk; p = 0.077), with estimated contributions from body reserves of 485 g/day in the CTMR group and 70 g/day in the PTMR group. In conclusion, the use of pelleted total mixed rations in high-yielding dairy ewes enhances feed intake, feed efficiency, milk yield, and energy balance without adversely affecting milk composition or animal health in the short term. Full article

Background/Objectives: In the context of increasing consumer demand for high-quality meat, this study aimed to evaluate the effects of 4% fermented goji berry residue supplementation on meat quality and flavor characteristics in finishing Tan sheep. Methods: Thirty-six male lambs were randomly assigned to a control and FGB group and fed for 68 days. Results: FGB supplementation significantly enhanced Longissimus Dorsi (LD) brightness (L*), redness (a*), and crude protein content, while reducing crude fat (p < 0.05). Amino acid analysis revealed significant increases in lysine, methionine, histidine, glycine, proline, arginine, cysteine, and total sweet-tasting amino acids in the FGB group (p < 0.05). Lactate and inosine monophosphate (IMP) levels were significantly elevated, whereas hypoxanthine levels decreased (p < 0.05). Metabolomics identified 189 metabolites, with 12 differentially expressed, mainly enriched in butanoate metabolism, glycolysis/gluconeogenesis, PI3K-Akt, and HIF-1 signaling pathways. Transcriptomics revealed 382 differentially expressed genes, including key regulators of lipid metabolism (FOXO1, SLC2A4, LPIN1, IGF1, SPP1) and amino acid metabolism (COL3A1, GLUL, PSMC1). Conclusions: Fermented goji residue altered amino acid and lipid metabolism in the LD muscle of Tan sheep, affecting meat quality and flavor traits. However, effects on color (L*, a*, b*), protein content, and shear force varied across the four muscles studied, indicating that responses to supplementation are muscle-specific. These findings offer a sustainable strategy for improving meat quality and provide insights into the molecular mechanisms underlying flavor development in ruminants. Full article

Staphylococcus aureus (S. aureus)-induced mastitis poses a significant threat to animal husbandry. This condition triggers sustained mammary inflammation, oxidative stress, and disrupts mitochondrial homeostasis, ultimately impairing mammary gland function and milk yield. Conjugated linoleic acid (CLA) is a long-chain fatty acid found in meat and dairy products derived from ruminants. It exhibits multiple biological activities, including anti-cancer, anti-inflammatory, and antioxidative stress-alleviating effects. Thus, this study sought to determine whether CLA alleviates S. aureus-induced mastitis in Hu sheep through the PPARG-UCP2 axis. Fifteen lactating Hu sheep were randomly allocated into three groups (n = 5): control group, model group, and CLA group. The CLA group received 1 mg/mammary gland of CLA via intramammary infusion for seven days, followed by S. aureus challenge (5 × 10⁷ cells/mL, 2 mL/mammary gland) in the model and CLA groups, while the control group received saline. Venous blood and mammary tissue samples were collected at two days post-infection. The results demonstrated that S. aureus infection significantly upregulated the expression of inflammatory factors (IL-1β, IL-6, and NF-κB) in the mammary tissue of Hu sheep, p < 0.01. Relative to the control, the model group showed increased ROS and MDA levels, a diminished NAD+/NADH ratio, and downregulated expression of the antioxidant factors SOD, Nrf2, HO-1, and SIRT3, p < 0.01. Furthermore, the expression of p-AMPK and mitophagy-related factors (PARKIN, PINK1, and LC3b) showed a statistically significant increase in the model group than in the control group, p < 0.01. S. aureus infection also suppressed the expression of PPARG and UCP2, p < 0.01. In contrast, the CLA group showed lower levels of inflammatory factors (IL-1β, IL-6, and NF-κB), ROS and MDA, while the NAD+/NADH ratio and the expression of antioxidant factors (SOD, p-Nrf2, HO-1, and SIRT3) were elevated compared with the model group, p < 0.01. Moreover, the expression of p-AMPK and mitophagy-related factors (PARKIN, PINK1, and LC3b) was reduced in the CLA group relative to the model group, p < 0.05. Concurrently, the expression of PPARG and UCP2 was higher in the CLA group than in the model group, p < 0.001. These findings demonstrated that S. aureus infection induced mastitis in Hu sheep mammary tissue, whereas CLA alleviated the infection by upregulating the PPARG-UCP2 pathway, thereby reducing inflammation, oxidative stress, and mitophagy levels. This study offers a novel perspective on mammary tissue repair during mastitis and expands the understanding of UCP2’s biological role. Full article