Feeding strategies such as P and Ca depletion and repletion have been proposed to reduce the use of phosphate or improve P utilisation efficiency in pig diets, thereby contributing to the sustainability of the sector. A total of 48 entire male pigs (18.47 ± 3.18 kg BW) were fed a control diet (C = 100% of requirements) and a restricted diet (R = 80-90% of digestive requirements of P and Ca, respectively) in three growth phases, with the following feeding strategies: CCC, RCC, RRC and RRR. At each phase, growth performance and bone characteristics (proportion of low-, medium-, high- and very high-density bones, and total density) of live animals were analysed, as well as carcasses and individual bones, using computed tomography equipment. Additionally, carcass and meat quality were evaluated at slaughter. Although there were differences in some phases, the overall analysis showed that P and Ca depletion-repletion did not affect the animals' growth. Reducing dietary Ca and P caused an increase in the proportion of low-density bones, a decrease in the proportion of medium- and high-density bones, and a decrease in total bone density in depleted pigs compared with control animals at each phase. At the end of phase 2, bone characteristics of RC pigs tended to follow a similar pattern observed in RR pigs when compared with CC animals. However, at the end of phase 3, RCC and RRC pigs exhibited similar bone characteristics than CCC animals, due to the recovery in bone mineralisation. Additionally, body characteristics measured on tomograms of the repleted animals showed a quadratic effect, where RCC pigs exhibited a decrease in total body area, central subcutaneous fat thickness, and loin eye area in some body regions, demonstrating that P and Ca depletion-repletion affected the anatomical regions in different ways. On the other hand, carcass, head, 1st rib, and 4th last rib bone characteristics were affected by the R diet, where the RRR strategy showed significantly lower density than the CCC strategy. In the conditions of this study, the application of P and Ca depletion-repletion strategies, or full depletion (RRR), could be an alternative to reduce the use of phosphate in pig diets without impacting performances and bone characteristics.
Positive animal welfare (PAW) emphasises "a good life" marked by the experience of predominantly positive affective states, and the development of competence and resilience according to species-specific and individual capabilities. Even though the concept of PAW has received increasing attention in past years, guidance for shaping future PAW-friendly farming systems is lacking. As highly social species, farmed animals have the potential to experience a rich social life that can influence their welfare. This has often been studied through the lens of negative interactions. However, to advance research on PAW, a focus shift on how affiliative interactions can contribute to and maintain positive group dynamics is needed. Affiliative interactions are mostly based on social preferences that are, in turn, dependent on the individuals involved and their contribution to group cohesion. Acknowledging the uniqueness of each individual in their perception, cognition and appraisal is a challenge for ensuring PAW not only at the individual level but also at the group level. In this narrative review, we argue that combining the study of individuality and social life will generate practical knowledge that can be used for promoting PAW. We first examine how individual differences in sensory and cognitive capabilities shape vertebrate animals' appraisal of their environment and influence PAW. We then discuss key features of (intraspecific and interspecific) social life, such as affiliative interactions, social facilitation and socialisation, and their relevance for PAW. Finally, we explore how the interplay between individuality and social life can create conditions conducive to PAW. For this, we focus on the concepts of sociability and social competence as promising future research areas. Collectively, this review illustrates a complex framework emerging from the interplay between individuality and social life and paves the way for promoting PAW on farms and improving animal management.
Beta-glucan supplementation has been shown to have important immunomodulatory effects on both sows and pigs; however, there are discrepancies about the effect over piglets due to maternal supplementation. This study monitored the effect of 1-3 beta-glucans supplementation (from Euglena gracilis) in sows from the final third of gestation until the end of lactation by the health status (specifically, the immune and stress status) of the sows and their offspring using salivary biomarkers and piglet's growth performance. A total of 106 sows were randomly assigned to the basal diet (BD) or to the basal diet with 1-3 beta-glucans supplementation (GD) group at 1 g/sow per day. To evaluate the litter performance, the BW of all piglets was measured at birth and weaning and sow's performance data were recorded. Saliva samples were collected from a subset of sows, 35 from the BD group and 36 from the GD group, at different times during the trial: 21 and 7 days before the expected farrowing date (D-21 and D-7), the day after farrowing (D0), and at 7 (D7) and 21 days (D21) of lactation. Saliva was also collected from the heaviest and lightest piglets of each of the 71 litters the week before weaning. The health status of the sow and piglets was evaluated by the immune marker's interleukin 6, adenosine deaminase, calgranulin C, the acute phase proteins C-reactive protein, haptoglobin and immunoglobulin G; the stress marker's cortisol and α-amylase, and the oxidant status marker's total antioxidant capacity, total oxidant status and the calculation of the oxidative stress index. Piglets from sows fed GD showed higher BWs than those fed BD, both at birth and at weaning, with overall slightly lower levels of immune markers. All sows showed an increase in immune and oxidant markers at farrowing (D0) in comparison to previous times, with higher effects in the group of sows from the GD. Maternal supplementation with 1-3 beta-glucans showed improved immune activation in sows that could be properly evaluated using saliva biomarkers and an increase in piglet's BW at both birth and weaning.
Although in the minority, outdoor pig farming systems are experiencing a resurgence of interest in several countries such as France, systems that could contribute to the transition towards sustainable agriculture. Understanding farmers' motivations for adopting sustainable practices is crucial for transforming agricultural systems. Hence, this study aimed at identifying the motivational profiles of French farmers who chose to raise pigs on farms offering outdoor access to their animals. A total of 20 semi-structured interviews, lasting 1.25-2.25 h, were conducted among French farmers who raised pigs with various modalities of outdoor access (from simple courtyards to free-range farms). The topics addressed during the interviews included a historical overview, a description of the farm and practices, as well as opinions about the impact of outdoor access on farmers, animals, production and economic performance, environment, and society. Following a thematic analysis, farmers' motivational profiles were elaborated using multiple correspondence analysis and hierarchical clustering analysis. The study revealed three motivational profiles guiding farm management and system choices: The "Tradition" profile concerned farmers mainly motivated by relational values, emphasizing cultural heritage, landscape, and preservation of local breeds, and adopting free-range systems. The "Entrepreneurship" profile concerned farmers mainly driven by instrumental values, combining economic opportunities, innovation, and societal expectations, typically favouring indoor farms with outdoor courtyards. The "Naturalness" profile concerned farmers mainly animated by intrinsic and relational values, focusing on animal welfare, natural behaviours, environmental sustainability, and strong human-animal relationships, often expressed in full outdoor or mixed systems. These profiles demonstrate that outdoor access is not a single technical choice but an expression of diverse moral, cultural, and economic logics. Values and motivations shaped concrete farm decisions, influencing system type, management practices, and adoption of agroecological or innovative approaches. These findings highlight the importance of recognizing the diversity of farmers' motivations when designing support programmes across different agricultural contexts. Overall, tailored advisory services and training that align with underlying values could support diverse pathways while facilitating the adoption of outdoor pig farming systems viewed as more sustainable and acceptable agricultural systems.
The temporal distribution of hatching is an important factor affecting chick uniformity, welfare, and hatchery efficiency. Although preincubation has been successfully applied in several poultry species to improve hatchability and synchronise embryonic development, its effects on embryogenesis and hatch timing in pheasants remain poorly understood. The aim of the study was to evaluate the effect of pheasant egg preincubation on the temporal distribution of hatching and the course of embryogenesis, with particular emphasis on changes occurring in extraembryonic structures. The research involved 700 hatching eggs, which were divided into a control group (CON) and an experimental group (PRE), in which a preincubation protocol was applied consisting of 6 h of incubation (37.7 °C), 12 h of standard storage (17 °C ± 0.5 °C), 12 h of incubation (37.7 °C), and 6 h of standard storage (17 °C ± 0.5 °C). Eggs from the CON group were stored at 17 °C ± 0.5 °C during this time. Analyses included fresh egg quality, egg weight loss during incubation, incubation time, hatching parameters, chick quality, and the physicochemical properties of the eggshell, albumen, amniotic fluid, and yolk contents. The application of preincubation significantly shortened incubation time in the PRE group, where 87% of chicks hatched as early as 567 h of incubation. In the CON group, the hatching process was markedly prolonged and more temporally dispersed. The proportion of unhatched chicks was significantly lower in the preincubated group (P = 0.046). No differences were observed in egg weight loss or chick quality (P > 0.05). Eggshell thickness and the pH of albumen, yolk, and amniotic fluid changed during incubation. Significant differences in copper and manganese content were observed between groups (P = 0.047; P = 0.029), and differences in iron, zinc, and manganese content depending on the day of incubation (P < 0.001; P = 0.009; P = 0.017). Moreover, significantly higher lysozyme activity in the amniotic fluid was recorded on day 14 of incubation in the PRE group, which indicated enhancement of the developing embryo's natural antimicrobial barrier (P = 0.001). It can be concluded that preincubation is an effective method for shortening incubation time in pheasants without negatively affecting chick quality. The observed changes in extraembryonic structures and lysozyme activity suggest that preincubation may also influence physiological processes associated with embryonic development.
Agricultural activities place pressure on the environment through the demand of land, water, and nutrients, as well as the subsequent potential generation of emissions and pollutants. However, agriculture is essential to feed the growing population. Nutrient leakage from the food system in the form of food loss and waste (FLW) makes food production inefficient. The FLW refers to the deterioration of food quality anywhere in the food system that makes it unsuitable for human consumption. This includes vegetable and fruit leftovers, bakery leftovers and former foodstuffs products and properly processed food waste, depending on the legislation. A one-nutrition approach advocates for repurposing FLW into feed, thereby reducing nutrient leakage and food-feed competition. However, the evaluation of FLW in feed to produce a clear guideline for feeding FLW to livestock is not yet well established. Therefore, this review examines the use of FLW as a direct feed for livestock and FLW biotransformation via insects or microbes. These scenarios were evaluated based on their nutritional value and impact on livestock health, performance, and safety. After minimal to moderate processing of FLW, direct feeding offers a safe, nutrient-rich, and economically viable option for feeding FLW to livestock. Insects and microbes biotransform FLW into protein- and energy-rich biomass, providing macronutrients and supporting livestock performance under well-designed diet formulations and conditions. However, safety issues such as the presence of contaminants, spoilage and microbial risk in FLW can negatively impact livestock health and performance. Hence, beyond nutritional values, assessing the safety of using FLW as feed is mandatory, as discussed in this review. As of now, a full replacement of ingredients such as corn or soy is not possible due to a decrease in livestock performance in some instances and limitations in regulatory guidelines and infrastructure. This review proposes a categorisation of FLW based on the intensity of processing required to inactivate pathogens in the raw FLW, nutritional value, moisture content, logistics, and target species. The proposed categorisation offers a decision-making guideline for including FLW in feed. Further research is needed to prioritise a comprehensive assessment of the economic and environmental impacts of FLW use before reconsidering regulatory frameworks and substantially replacing conventional forage crops.
Pig welfare around slaughter remains a sensitive issue, as animals are exposed to multiple hazards within a short period. The objective of this review was to provide a comprehensive assessment of the key factors affecting pig welfare in commercial slaughterhouses, to evaluate their impact on meat quality, and to examine contemporary alternatives to high-concentration CO2 stunning with respect to their implications for both animal welfare and meat quality. During lairage, exposure to a novel environment and unfamiliar animals can hinder recovery from transport stress. Limited space allowance negatively impacts welfare by impairing rest, exacerbating heat stress, and increasing agonistic behaviours. Cooling strategies, such as intermittent water spraying, can improve thermal comfort and reduce stress within groups. Although feed withdrawal is necessary for food safety, it should be limited to less than 16 h to avoid prolonged hunger and additional stress. Handling practices during movement to the stunning point are another significant source of stress when poorly executed. Effective stunning is essential to ensure that pigs are rendered unconscious without pain before exsanguination. While electroencephalography remains the most accurate method to assess consciousness, practical evaluation in commercial settings relies on animal- and resource-based indicators, whose reliability depends on standardised protocols and proper training. The two most widely used stunning methods are electrical stunning and exposure to high concentrations of CO2. Electrical stunning induces immediate unconsciousness but raises welfare concerns due to handling and restraint, particularly in high-throughput systems. In addition, the use of electric goads to move pigs from groups into raceways, although reducible, cannot yet be eliminated, highlighting the need for improved facility design. CO2 stunning, although widely adopted, is aversive, as it induces hyperventilation and irritation of mucous membranes. Alternatives such as improved electrical systems and inert gas stunning using argon, nitrogen, or helium at residual oxygen levels below 2% show potential welfare benefits by reducing pain, fear, and respiratory distress. However, these systems typically result in slower induction of unconsciousness and faster recovery, posing practical challenges. Preslaughter stress significantly affects carcass and meat quality, leading to defects such as bruising, blood spots, and alterations in colour, firmness, and water-holding capacity. In severe cases, this results in conditions such as pale, soft, and exudative or dark, firm, and dry pork, reducing product quality and economic value. Implementing low-stress handling and optimised stunning practices can improve both animal welfare and meat quality outcomes.
This study investigated the temporal dynamics of bromoform (CHBr3) dehalogenation from Asparagopsis taxiformis and its effects on fermentation characteristics and microbial composition in an in vitro batch culture system, generating data relevant to the safety and efficacy assessment of A. taxiformis as a methane (CH4) inhibitor. Per treatment, six bottles were incubated with individual rumen fluid from three rumen fistulated lactating Holstein-Friesian dairy cows, with duplicate bottles per biological replicate (3 biological × 2 technical replicates). These bottles were used for continuous measurement of gas production, spot CH4 measurements at 0, 1, 2, 4, 8, 12, 24, 36, 48, 60, and 72 h of incubation, as well as for sampling (at 72 h) of volatile fatty acids (VFAs), CHBr3 metabolites, total bromine, iodine and arsenic concentration, and microbiome composition. Substrate (0.5 g DM) comprised 60% grass and 40% corn (DM basis) with or without 0.01 g DM A. taxiformis (Asparagopsis and Control, respectively). Samples for CHBr3 metabolites, bromine, iodine, arsenic, and microbiome analyses were taken to study changes over time (at 1, 2, 4, 8, 12, 24, 36, 48, and 60 h) from extra bottles incubated at the same starting time containing the Asparagopsis treatment. Cumulative gas production was not affected by the addition of A. taxiformis, while cumulative CH4 production was reduced by 94 and 78% after 24 and 72 h of fermentation, respectively. Total VFA concentration and molar proportion of acetate decreased, and molar proportion of propionate increased in Asparagopsis compared to Control. After 1 h of fermentation, only 5.3% of the added CHBr3 was detectable, and it was below the detection limit after 8 h. The concentration of dibromomethane (CH2Br2) increased markedly within 1 h and remained relatively stable up to 72 h of fermentation. No bromomethane was detected. The lack of stoichiometric conversion between CHBr3 and CH2Br2 suggests that additional, unidentified brominated metabolites may have formed. Total bromine, iodine, and arsenic concentrations remained relatively stable over time. Supplementation of A. taxiformis resulted in large shifts in microbial community, including a decrease in the relative abundance of archaeal and ciliate species. Longitudinal microbiome analyses confirmed a progressive microbial community restructuring over time. The shifts in bacterial community generally indicate an adaptation to elevated hydrogen concentrations or alternative fermentation pathways. Further in vivo research is needed on the absorption, metabolism, distribution, and excretion of CHBr3 and its derivatives in ruminants, including potential metabolism in organs beyond the rumen.
Baroque horses represent a distinctive group of breeds that emerged mainly between the 16th and 18th centuries, shaped by the demands of European royalty and their courts. Although recognised as separate breeds, they share common ancestry, breeding goals, and historical gene flow. This study aimed to evaluate their genomic diversity, population structure, and admixture patterns. We analysed 1 160 individuals from eight breeds - Lipizzan, Old Kladruby Horse, Pura Raza Española, Lusitano, Friesian, Criollo, Peruvian Paso, and Puerto Rican Paso Fino - using 34 026 single-nucleotide polymorphisms, with the Croatian Arab horse included as an outgroup. The Lipizzan was further divided into national subpopulations, the two Old Kladruby subpopulations defined by colour (black and grey), and within the Pura Raza Española, the Carthusian strain was treated as a distinct subpopulation. Observed genetic diversity, measured by heterozygosity and haplotype richness, was broadly comparable across breeds, although clear differences were observed between breeds with the lowest values (Friesian) and those with the highest values (Lusitano and Criollo). Genomic inbreeding coefficients, estimated using runs of homozygosity (FROH>2Mb) and homozygosity-by-descent segments (FHBD), ranged from ∼0.06 to ∼0.29 and ∼0.14 to ∼0.27, respectively. These values indicate relatively high levels of inbreeding, which may reflect the closed breeding structure of the populations and their relatively limited effective population sizes. In contrast, most individual inbreeding coefficient (FIS) values were negative, reflecting deliberate avoidance of close-relative matings. Estimates of contemporary effective population size (NeLD) ranged from ∼50 to ∼240 across breeds, depending on the method. Historical NeLD trajectories revealed two distinct demographic decline patterns: one occurring around 12 generations ago and the other around 22 generations ago. Evidence of recent between-breed gene flow was detected among Iberian breeds and between Croatian Arab and Lusitano, whereas shared historical ancestry among Baroque breeds was evident across populations. These results provide new insights into the genomic architecture of Baroque horses and offer valuable guidance for managing their genetic diversity.
Selection for uniformity in livestock species is desirable because it is associated with welfare and robustness. To address variability, it is essential to have more than one record per animal; therefore, the number of records per individual is crucial. The guinea pig, characterised by its low litter size, is a species of notable economic and nutritional importance, especially in the Andean region of South America. The objective of this study was to evaluate, through simulation, the impact of low record numbers on the performance of heteroscedastic models used in selection for uniformity, using guinea pig birth weight as an example. Different data structures that modulated litter size (LS), number of litters (NL), number of breeding animals (BAs), and number of generations of records were evaluated. The analysis of simulated data was performed under Frequentist and Bayesian statistical approaches. In general, the model was able to adequately estimate the variance components and predict genetic values, although its performance depended on the data structure. Under the Frequentist approach, the litter variance affecting the residual variance was biased downward in LS = 2 and LS = 3 (between -69 and -96%), although the bias decreased in LS = 5 and LS = 7 (between -10 and -44%). The BAs did not influence the bias. At NL = 2, the bias ranged from -68 to -76%, and at NL = 6, from -35 to -69%. The Bayesian method failed to converge in the scenario with two generations and NL = 2. The accuracy of the genetic values for both the trait and the residual variance was identical regardless of the statistical approach used. An increase in BAs did not lead to favourable changes in accuracy, but higher LS and NL tended to improve the accuracy of the genetic values of the trait and the residual variance. We conclude that selection for uniformity under a low number of repeated records, such as the limited number of within-litter birth weight data in guinea pigs, is feasible. However, it is recommended to carefully monitor the data structure to predict the expected response and, if possible, to use populations with the highest possible litter sizes.
Improving feed efficiency and reducing enteric methane emissions are key priorities for enhancing the sustainability of ruminant production systems. This study examined the genetic architecture of dry matter intake (DMI), residual feed intake (RFI), methane emissions (MEs), and BW in Merino sheep using weighted single-step genome-wide association studies. Phenotypic records were collected from 1 247 Merino sheep for DMI, 1 231 for RFI, and 1 219 for ME, all of which were genotyped using the GeneSeek® Genomic Profiler™ 50K single-nucleotide polymorphism (SNP) array, as well as BW records from 78 466 animals, of which 1 626 were genotyped. Genomic regions explaining at least 0.5% of the additive genetic variance were identified for all traits, with several regions shared by at least two traits. Shared regions on chromosomes 5, 6, 10, 19, and 21 were further evaluated using the Close Linkage versus Pleiotropism (CLIP) test to distinguish pleiotropy from close linkage, revealing pleiotropic loci (chromosome 10 shared between DMI and RFI; chromosome 19 shared between DMI and ME) and closely linked loci influencing multiple traits. Candidate genes located within these regions include RXFP2, members of the ITIH gene family, and FADS1-2, which have been previously associated with growth, metabolism, and tissue development, reflecting potential biological mechanisms underlying feed intake, growth, and methane production. No single genomic window exceeded 6.73% of the additive genetic variance, and even within regions showing the strongest window-based signals, the combined effect of the five most informative SNPs accounted for less than 0.23% of the genetic variance, supporting a highly polygenic architecture across all traits, with ME exhibiting the most pronounced polygenic pattern. Several of the candidate genes identified here have also been reported in other ruminant and non-ruminant species, suggesting partially conserved biological mechanisms of potential relevance beyond Merino sheep. These findings provide a foundation for future studies aimed at refining genomic prediction models and support the use of multitrait evaluations and Bayesian approaches incorporating GWAS-derived priors for traits that are difficult and expensive to measure, such as feed efficiency and methane emissions.
Ruminant products contain fatty acids (FAs) with recognised benefits for human health, such as vaccenic (t11-18:1) and rumenic (c9,t11-18:2) acids, especially in animals fed forage-based diets due to the ruminal biohydrogenation of dietary polyunsaturated FAs. In contrast, high-cereal diets alter normal ruminal biohydrogenation pathways, favouring the production of t10-18:1 instead of t11-18:1 (termed as the t10-shift), resulting in a less favourable FA profile from a nutritional perspective. Replacing cereals with alternative resources rich in non-structural carbohydrates other than starch, such as almond hulls (AHs), which are characterised by high sugar content, in a diet containing a 40% forage diet, could be an effective approach to prevent t10-shift. However, there is limited information about the potential of replacing cereals with AHs to prevent the t10-shift and promote the formation and deposition of t11-18:1 and c9,t11-18:2 in lamb meat, as well as their effects on ruminal fermentation. Therefore, the effect of partially replacing cereals with increasing levels of AHs was evaluated in twenty-four lambs, distributed into three dietary treatments. In these treatments, cereals were progressively replaced with AHs, reaching 0, 9 and 18% of AHs in the diet composed of 40% dehydrated lucerne and supplemented with 5% soybean oil. The analyses of volatile fatty acid (VFA), FA, and dimethyl acetal (DMA) composition of the rumen content, and FA of Longissimus thoracis muscle were performed. Orthogonal polynomial contrasts were applied to evaluate the linear and quadratic effects of replacing dietary cereal with AHs. Replacing cereals with AHs up to levels of 18% did not substantially affect rumen activity, assessed by the lack of effect on rumen pH, VFA composition, or on the branched-chain FAs or DMAs from microbial origin. The most relevant effects of treatments were observed on C18 FAs. In rumen content, the proportions of t10-18:1 decreased linearly with increasing levels of AHs in diets, while t11-18:1 quadratically increased. Regarding the t10-shift, defined as the ratio of t10-18:1/t11-18:1 > 1, only two lambs in the 0AH diet had a ratio > 1, whereas all lambs fed AHs had a ratio < 1. In intramuscular fat, the proportions of t11-18:1 (+52.5%) and c9,t11-18:2 (+40.5%) increased with increasing levels of AHs in diets. No relevant differences were observed for n-6 or n-3 polyunsaturated FAs in lamb meat. Partially replacing cereals with AHs in a diet composed of 60:40 concentrate-to-forage prevented the occurrence of t10-shift and increased the health-beneficial C18 FAs, i.e. t11-18:1 and c9,t11-18:2.
Essential oils (EOs) are widely used as phytogenic feed additives in livestock systems; however, evidence for their benefits in preweaning dairy calves remains inconsistent. We conducted a systematic review and meta-analysis to quantify the effects of EO supplementation on growth performance, feed utilisation, rumen fermentation, and blood immune and biochemical indices in preweaning dairy calves, and to explore potential sources of heterogeneity. Web of Science, ScienceDirect, PubMed, Scopus, China National Knowledge Infrastructure (CNKI), VIP Chinese Journal Database (CQVIP), and WanFang Data were searched from inception to 8 October 2024. Twenty-nine studies (48 treatment arms; 1 048 calves) met the inclusion criteria. Risk of bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation tool. Random-effects meta-analyses were performed, with prespecified subgroup analyses by supplementation route (liquid feed versus starter feed), dominant bioactive group (phenolic, cineole/terpene, aldehyde-containing, and mixed/other), supplementation duration, and estimated harmonised dose category. Leave-one-out sensitivity analyses were used to assess robustness; publication bias was evaluated using Egger's and Begg's tests when ≥ 10 effect sizes were available. Overall, EO supplementation was associated with higher average daily gain and several body measurements, higher DM intake, lower feed conversion ratio, improved apparent nutrient digestibility, and lower faecal score. In rumen fermentation, acetate decreased and butyrate increased, while other rumen parameters showed no consistent changes. In blood indices, EO supplementation increased immunoglobulin G and immunoglobulin A as well as total protein and triglycerides, and decreased albumin, total cholesterol, and blood urea nitrogen, whereas glucose and β-hydroxybutyrate were not significantly affected. Exploratory subgroup analyses suggested that the magnitude and direction of responses may vary with supplementation route, dominant bioactive group, duration, and estimated harmonised dose category; however, several strata were supported by limited numbers of studies and should be interpreted cautiously. In conclusion, EO supplementation is associated with improved growth and feed utilisation in preweaning dairy calves, with response patterns that may vary according to EO composition and feeding strategy; further well-designed trials are needed to refine practical recommendations.
Calf nutrition research has undergone a paradigm shift over the past two decades, moving from practices focused on cost efficiency and early weaning toward a deeper appreciation of the long-term biological and economic value of early-life feeding. This review synthesizes advances in energy and protein nutrition of dairy calves, with particular attention to how milk allowance, liquid feed composition, weaning strategies, and postweaning diets shape growth, health, and lifetime productivity. Evidence consistently demonstrates that higher planes of whole milk or milk replacer feeding improve growth, welfare, and gastrointestinal development. However, milk replacer formulations often diverge from whole milk in fat, protein, and carbohydrate profiles, raising concerns about metabolic imbalances and morbidity risk. In this review, we highlight how macronutrient quality, fat composition and structure, and protein quality and composition can influence digestion, metabolism, and health. Weaning outcomes are shown to depend not only on the timing and amount of milk but also on the quality and formulation of the entire diet (including starter feed) across preweaning, weaning, and postweaning phases. Starter feed composition, including starch source, effective fiber, protein-to-energy balance, and rumen undegradable protein fraction, plays a central role in sustaining growth and ensuring a smooth transition. Postweaning and peri-pubertal nutrition influence mammary gland development, age at puberty, and body composition, underscoring the importance of aligning heifer targets with lifetime productivity goals. We conclude that calf nutrition should be engineered as a continuum from birth to breeding, with each period's diet designed to prepare for the next. The integration of precision feeding technologies, improved nutrient requirement models, and longitudinal studies that link early-life strategies to lactation and longevity will be critical to refine recommendations. This review positions calf nutrition not simply as a management tool for short-term performance but as a biological lever with far-reaching impacts on lifelong animal health, efficiency, and sustainability.
Dietary betaine (BET) supplementation enhances production performance of dairy cows, improves ruminal fermentation, and increases efficiency of feed utilisation. However, the precise mechanism underlying betaine-mediated regulation of physiological functions in periparturient dairy goats remains unclear. Therefore, this study investigated the effects of betaine supplementation on apparent nutrient digestibility, production performance, serum physiological and biochemical parameters, antioxidant capacity, and immune function of periparturient Wendeng dairy goats. A total of 48 healthy primiparous Wendeng dairy goats at 130  days of gestation (BW, 43.93 ± 9.96  kg) were selected and divided into four groups, according to their initial BW using a randomised block design. Each group contained four replicates, with three goats per replicate. Goats in the control group (CG) were fed a basal diet, whereas those in the experimental groups received betaine for 6, 12, or 18 g/day per goat, designated as the BET1, BET2, or BET3 group, respectively. The experiment comprised a 7-day adaptation period followed by a 50-day experimental period. Throughout the postpartum period, DM intake, average daily milk production, and 4% fat-corrected milk production were significantly higher in the BET groups. The feed-to-milk ratio was also significantly lower in the BET groups than in the CG. In contrast, the apparent digestibility of ADL was lower in BET2 and BET3, and lactose percentage was higher in BET2. On the 1st day of the postpartum period, creatinine (CRE) content was significantly higher in BET3 than in other groups, while blood urea nitrogen (BUN) was lower in BET1. Total cholesterol was also lower in BET1 than in CG and BET2. In terms of antioxidant status, total antioxidant capacity was lower in BET3, whereas total superoxide dismutase (T-SOD) was higher in BET2 and BET3. Glutathione peroxidase (GSH-PX) activity and malondialdehyde content were lower in BET1 and BET2. On the 35th day of the postpartum period, BW and high-density lipoprotein cholesterol levels were lower in all BET groups compared to CG. The BUN/CRE ratio was reduced in BET2 and BET3. T-SOD levels remained higher in BET1 and BET3, but GSH-PX activity was lower in all BET groups. Therefore, betaine supplementation enhances milk-production performance, milk composition, antioxidant capacity, and immune function in periparturient dairy goats.
Conserving farmed animal genetic resources is essential for addressing global challenges such as climate change, emerging diseases, resource scarcity, and evolving market demands. Among mammalian species, sheep represent one of the groups with the highest proportion of breeds at risk. One such breed is the Uruguayan Creole sheep, which is well adapted to its natural environment and primarily found in Uruguay's temperate native grassland regions. Although this breed is believed to have originated from European breeds, the extent of its genetic divergence and distinctiveness remains unknown. Understanding its genetic relationships with other breeds, as well as assessing its within-breed genetic diversity, is crucial for identifying conservation priorities. In the present study, we used high-density single-nucleotide polymorphism panels to (i) determine the phylogenetic relationships between Uruguayan Creole sheep and potential ancestral breeds that may have contributed to its development; and (ii) assess the current genetic status of the breed. Two Uruguayan Creole populations were compared with 36 populations representing different breeds selected for their potential historical or genetic connections to the Creole. Different analytical methods, including Principal Component Analysis, phylogenetic reconstruction, admixture analysis and Wright's fixation index, were applied to investigate interbreed relationships. Historical and recent effective population sizes were estimated from the observed spectrum of linkage disequilibrium. The analyses show that the Uruguayan Creole sheep is genetically distinct from other breeds, including the Spanish breeds from which it is theoretically derived. This divergence is likely the result of genetic drift and natural selection. The two Creole populations also differed from each other and displayed distinct population structures, probably reflecting their differing selection histories. Critically, the Uruguayan Creole showed a very low effective population size (fewer than 50 individuals). Given these findings, the establishment of a genetic conservation programme is strongly recommended to prevent the extinction of this valuable breed. Such a programme should be informed by genetic relationships data and should implement strategies aimed at reducing rates of coancestry and inbreeding and enhancing effective population size. More broadly, these recommendations are applicable to the conservation of endangered livestock breeds across species.
Excessive lipolysis and enhanced inflammation in periparturient dairy cows may lead to metabolic disorders and diseases. Membrane phospholipids and lipid mobilisation-released polyunsaturated fatty acids (PUFAs) can be oxidised into oxylipins that have pro- and/or anti-inflammatory roles. Selenium has immunomodulatory and anti-inflammatory effects, but the mechanisms are not yet fully understood. The objective of this study was to examine the effects of prepartum selenium-yeast (SY) supplementation on the inflammatory response in dairy cows during the periparturient period by regulating plasma oxylipin profiles. Fourteen cows were randomly assigned to two groups. Cows in one group were provided with a TMR containing sodium selenite at 0.3 mg Se/kg DM. Cows in the other group received SY at a dosage of 0.2 mg Se/kg DM during the last 4 weeks of pregnancy, in addition to being fed the same TMR as the control group. Blood was sampled on d -28, 1, 7, 14, and 28 relative to parturition for targeted oxylipin assays. A total of 53 of 134 oxylipins were detected in plasma. Dietary treatment mainly affected plasma linoleic acid-, arachidonic acid-, and eicosapentaenoic acid-derived oxylipins. For linoleic acid-derived oxylipins, anti-inflammatory 13-oxo-octadecadienoic acid was increased in the SY supplemented group as compared with the control. For arachidonic acid-derived oxylipins, prepartum SY supplementation decreased pro-inflammatory prostaglandin (PG) E2, 5- and 12-hydroxyeicosatetraenoic acid (HETE), as well as 5-oxo-eicosatetraenoic acid, while increasing or tending to increase anti-inflammatory 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids. The increased 15-keto-PGF2α and 20-Carboxy-arachidonic acid in the SY-supplemented group indicate that selenium may promote the conversion of pro-inflammatory PGF2α and 20-HETE into their respective inactive metabolites. For eicosapentaenoic acid-derived oxylipins, prepartum SY supplementation increased or tended to increase anti-inflammatory 5-, 15-, and 18-hydroxyeicosapentaenoic acids, as well as 14,15- and 17,18-epoxyeicosatetraenoic acids. Prepartum SY supplementation also increased or tended to increase the ratios of linoleic acid- and arachidonic acid-derived epoxy fatty acids to their corresponding diols, suggesting that selenium may stimulate a shift in the cytochrome P450 epoxygenase-derived oxylipin profile towards anti-inflammatory activity. Additionally, an increased plasma total PUFA and a reduced ratio of n-6 to n-3 PUFA in response to SY supplementation were observed in this study. Taken together, our study demonstrates that prepartum SY supplementation attenuates bovine postpartum inflammation by promoting the production of anti-inflammatory oxylipins and inhibiting that of pro-inflammatory oxylipins. These effects may be associated with selenium-mediated regulation of substrate availability, enzymatic oxidation pathways, and the degree of oxylipin metabolism.
Fertility traits are crucial economic traits in dairy cattle production, with a substantial influence on farm profitability. As quantitative traits, fertility traits are affected by both genetic and environmental factors. While previous studies have primarily focused on additive genetic effects, the contribution of dominance effects on key economic traits in Holstein cattle remains insufficiently explored. This study employed a genome-wide association study to simultaneously evaluate additive and dominance effects. The objectives were to identify Single-Nucleotide Polymorphism (SNP) loci and genes associated with fertility traits, detect genetic markers affecting fertility traits in Chinese southern Holstein cattle, and enhance the understanding of their underlying genetic mechanisms. Using high-quality imputed whole-genome sequence data from 3 439 individuals, we analysed eight fertility traits. Genome-wide association analyses identified 720 SNPs exhibiting significant additive effects and 505 with significant dominance effects, among which 465 SNPs overlapped. Notably, dominance effects independently captured 13 candidate genes (including 3 regulated exclusively by dominance) and uncovered non-additive variation that additive-only analyses missed. Functional annotation highlighted 21 candidate genes, such as LY6E, LY6K, GPR12, PSME4, CYP11B1, CHAC1, and GUSB. Among these, ten genes were regulated by both effects, eight by additive effects alone, and three by dominance effects alone. Gene ontology and kyoto encyclopedia of genes and genomes analyses showed these genes are involved in reproductive biological processes-such as steroid hormone synthesis, fertilisation, gastrulation, primary germ layer development and are enriched in pathways related to reproductive endocrine regulation, fatty acid metabolism, neural signal transduction, and oxidative stress. Fine-mapping and Linkage Disequilibrium (LD) analysis further refined key genomic regions, including a locus on chromosome 11 at position 36.3-36.9 Mb associated with conception rate, and identified core candidate SNPs such as chr14:1525338 near LY6E. This study demonstrates that incorporating dominance effects enhances the detection power of genetic associations and provides a more complete characterisation of the genetic architecture of fertility traits. Our findings offer a robust foundation for genomic prediction, advancing the accuracy of breeding programmes targeting fertility improvement in Holstein cattle.
A recently published model for litter weight in multiparous species defines genetic dam and sire effects as linear random regression slopes on litter size. Building on the interpretation of these effects in terms of maternal and direct breeding values for birth weight, we show how to convert estimates of genetic covariance parameters from that model into direct and maternal genetic (co-)variances for birth weight. Additionally, we introduce a modification of the random regression model that directly provides the same results. As a case study, litter weights from two unselected mouse control lines were first analyzed separately using a univariate approach. Then, bivariate analyses were conducted, adding litter size or one of several body mass traits at later ages as a second trait. The DUKb line contributed weights for 7 241 litters (87 641 pups) from 116 generations, and the DUKssi line 14 496 litter weights (160 334 pups) from 152 generations. The maternal genetic variance of individual birth weight was 2-3 times that of the direct genetic variance. Strong correlations (0.78 and 0.77, respectively) were estimated between direct and maternal genetic effects on birth weight; however, SEs were high at 0.45 and 0.36. Estimates of genetic correlations between the maternal effect on birth weight and LS were negative (-0.63 and -0.59) and of similar magnitude in both lines; their SEs were moderate at 0.05 and 0.06. Genetic correlations between maternal genetic effects on birth weight and body mass traits at later ages (day 21, day 42, and at mating) were strong, ranging from 0.82 to 0.95, depending on line and trait; SEs for these estimates ranged from 0.03 to 0.15. Results obtained by applying the modified random regression model were identical, as expected given its equivalence. In conclusion, litter weight data provide information on the genetic (co-)variability of direct and maternal effects on birth weight and on their (co-)variability with additive-genetic effects on other traits. Previously applied models, in contrast, suffer from confounding with litter size and do not account for sire effects, limiting their ability to extract the full information on birth weight. Thus, litter weight should be regarded as a trait characterising prenatal growth of newborns, and any version of the random regression model should be employed for meaningful analyses.
The complete replacement of soybean meal with alternative plant-derived protein sources in poultry diets represents a promising strategy to improve the environmental sustainability of feed formulations. This study investigated the effects of a soybean meal-free diet on growth performance, meat quality, lipid composition, proteomic profile, and sensory traits in the Italian native slow-growing chicken breed Bianca di Saluzzo. Ninety-six males were reared under identical semi-extensive conditions and fed either a conventional soybean meal-based diet (C) or an experimental soybean meal-free formulation based on field bean, pea protein, sunflower meal, and maize gluten as the protein sources. Birds were slaughtered at 147 and 174 days of age. Growth performance, carcass yield, and proximate meat composition were not affected by diet or slaughter age, confirming that the soybean meal-free feed ensured adequate nutrient supply. The experimental diet significantly increased linoleic (C18:2n6) and α-linolenic (C18:3n3) acid concentrations and enhanced the total essential fatty acid index in both breast and thigh meat, while reducing lipid oxidation and thrombogenicity index values, indicating improved oxidative stability and nutritional quality. Proteomic analyses showed no diet- or age-dependent clustering, suggesting stable muscle proteome expression in the birds fed the alternative feed. Higher scores for overall odour, sweetness, umami, and pungency were attributed to the meat from birds fed a soybean meal-free diet, indicating a richer flavour profile of this meat. Altogether, the complete dietary exclusion of soybean meal did not impair production performance or the technological quality of the meat, while enhancing health-related lipid indices and sensory attributes. These results demonstrate that a mixture of alternative protein sources can sustain productive efficiency and meat quality in native poultry breeds, supporting the development of resilient and environmentally responsible feeding strategies aligned with agroecological principles.