Selection for increased longevity in dairy cows can enhance farm profitability and animal welfare. The main objective of this study was to estimate variance components and genetic parameters for 8 functional longevity indicators defined based on different culling reasons recorded in 7,188,910 Holstein cows. Culling reason groups included age, workability issues, economic reasons, conformation problems, production level, health issues, reproduction performance, and unknown factors. Longevity was analyzed longitudinally, assigning a score of 1 or 2 based on the cow's lifetime in the herd across age classes ranging from 1 (12-23 mo) to 15 (180 mo) years. A single-trait random regression model (RRM) using fifth-order Legendre orthogonal polynomial provided the optimal fit, and it was used in subsequent analyses. Heritability estimates varied according to age and culling reasons: 0.17 to 0.38 (age-related), 0.04 to 0.52 (workability issues), 0.002 to 0.20 (economic reasons), 0.02 to 0.28 (conformation), 0.02 to 0.26 (production), 0.02 to 0.25 (health issues), 0.02 to 0.24 (reproduction), and 0.02 to 0.22 (unknown reasons). The genetic correlations between adjacent ages were high and positive (≈1.0) but became negative (≈-1.0) between more distant ages. The average genetic correlations among the culling reasons were generally low or moderate (≈-0.50 to ≈0.80). However, the age-related culling, workability, and economic reason groups showed the lowest correlations among them compared with the others. In contrast, health, reproduction, and unknown reason groups exhibited the highest correlations, reaching values close to 0.80. Genetic trends showed similar patterns across culling reasons, with genetic gains being observed at younger ages and losses at older ages. Overall, this study demonstrates that cow longevity in Canadian Holstein cattle is heritable with substantial additive genetic variance. The heritability estimates varied depending on the culling reason, but at least one age always had a moderate heritability estimate. Moreover, cow longevity defined based on different culling reasons may represent genetically distinct traits. Therefore, it is recommended to consider culling reasons when genetically evaluating cow longevity in Holstein cattle populations.
This review evaluates the effectiveness of culling and birth control interventions for managing free-roaming dogs (FRD) and cats (FRC) worldwide across key outcome domains-population metrics, zoonotic disease indicators, shelter indicators, public metrics, animal welfare, ecological externalities, and cost-effectiveness-and identifies contextual conditions determining intervention effectiveness. Following PRISMA, we conducted three separate systematic searches in PubMed, Web of Science, and Scopus (up to 16 October 2025) addressing culling, birth control, and modelling studies. Empirical evidence was synthesised using descriptive, stratified analyses. Modelling studies were synthesised to identify conditions associated with effectiveness. Ninety-one empirical studies were included (33 culling; 58 birth control), alongside 18 modelling studies. Birth control interventions were more frequently classified as effective than culling, with statistically significant differences in effectiveness distributions between intervention types (p = 0.045). Culling effectiveness was context-dependent and largely confined to island systems, particularly for FRC, while FRD-targeted culling was rarely effective, especially for zoonotic disease indicators and public metrics. Birth control-particularly multi-component, long-term programmes-showed higher effectiveness across domains and in open mainland settings. Temporal analyses showed a decline in both the volume and reported effectiveness of culling studies since 2010, alongside increasing and geographically broader evidence for birth control. Modelling studies identified high population coverage, sustained implementation, and control of population inflow as key conditions for effectiveness. Culling has limited, context-dependent effectiveness, whereas birth control within integrated strategies more consistently achieves sustained outcomes across domains. Effectiveness depends on coverage, duration, and addressing drivers of population inflow, including abandonment and uncontrolled breeding.
The objective of this retrospective cohort study was to evaluate the association between body weight (BW) at first calving and growth, health, and reproductive performance during the rearing period, as well as subsequent milk production, calving related events, transition cow health, and culling risk in the first and second lactation in dairy cows from a single commercial dairy herd in northern Germany. The final data set consisted of 3,891 primiparous cows that calved between 2017 and 2021 and 1,894 of which were followed until their second lactation. Data were extracted from a commercial dairy herd management software system including information from 1) the heifer rearing phase: growth, calfhood morbidity and reproductive performance as nulliparous heifers and from 2) first lactation and second lactation: including age at first calving, calving related events, transition cow health, milk yield, culling risk, and growth from lactation 1 until 2. The animals were categorized into 4 quartiles based on their BW at first calving Body weight quartile 1-4 (BW_Q1): 394 - 564 kg (n = 1,019), BW_Q2: 566 - 588 kg (n = 996), BW_Q3: 589 - 612 kg (n = 923), BW_Q4: 614 - 768 kg (n = 953). Mixed effect models were used for continuous outcomes, multiple logistic regression for binary risk outcomes and Cox-proportional hazard models were used for time to event outcomes. Cows in BW_Q1 were already lighter at birth by 1.5 kg compared with cows from BW_Q4 and experienced higher pre-weaning morbidity (BW_Q1: 40.5% vs. BW_Q3: 34.3%) without showing a difference in failed transfer of passive immunity. Although lighter heifers in BW_Q1 had reduced pre-weaning growth, and therefore lower BW at weaning and at d 360 they showed better reproductive performance as nulliparous heifers, resulting in an 18-d reduction in age at conception and a 19-d reduction in age at first calving compared with heavier heifers in BW_Q4. In the first and second lactation, lighter cows had an approximately 2 kg/d lower milk production during the first 8 weeks of each lactation than heavier cows. Average daily gain in lactation 1 was significantly higher in BW_Q1 (0.359 ± 0.006 kg/d) compared with BW_Q4 (0.253 ± 0.006 kg/d) suggesting some compensatory growth. Further, in lactation 1, lighter cows from BW_Q1 had an approximately 43% greater risk for culling within 300d in milk, compared with the heavier cows from all other quartiles. Overall, body weight at first calving was associated with subsequent performance, with lighter cows producing less milk but exhibiting greater post-calving growth, while reproductive performance differed during rearing but not after calving.
Producing more ethical and animal-welfare friendly eggs is a public demand. This study was carried out to provide more insight into the environmental impacts of no-culling of male chicks (NCMC) in a laying hen (white and brown breeds) production system in the Netherlands. A life cycle assessment was conducted and three phases including i) the rearing and laying periods of parent stocks, ii) the hatchery stage, and iii) the rearing and laying periods of hens, were assessed. Based on the obtained results, the carbon footprint (CF) of market egg equipped with NCMC was 2.31 and 2.74 kg CO2eq/kg eggs for white and brown breeds, respectively . Feed production and land use change were the main contributors to the total greenhouse gas (GHG) emissions of parent stocks and hens phases. According to our findings, application of NCMC technique increased GHG emissions at hatchery stage by 98 and 56% for white and brown breeds. However, use of NCMC led to less than 1% higher CF of market eggs at the end of laying period of hens 1%. The higher GHG emissions were due to i) higher energy consumption, ii) higher egg losses, iii) higher errors in the sex determination process, and iv) lower hatchability. This modest rise in emissions showed that more animal friendly and ethical production can be achieved through the implementation of NCMC with minimal environmental trade-offs. Integrating such practices with improved feed techniques may offset the extra emissions while delivering higher sustainability outcome in overall. Comparison of different allocation methods demonstrated that the choice of allocation method influences the estimated effect of implementing the NCMC strategy on the CF of market eggs.
Biological invasions threaten ecosystems worldwide, with invasive predators such as lionfish (Pterois spp.) altering marine communities through predation, competition, and habitat disruption. Since their introduction to the western Atlantic in the 1980s, lionfish have rapidly expanded their range and contributed to declines in native reef fish populations. In response, management agencies have implemented targeted removal programs, although their effectiveness, particularly across broad spatial and temporal scales, remains uncertain. We evaluated the effects of removals (culls) at two temporal frequencies by quantifying the densities of both lionfish and potential prey over two years at experimental and non-removal control sites in Florida's Biscayne National Park (BNP). Removals conducted at one-month intervals resulted in moderate reductions in lionfish density but removals at four-month removals did not result in appreciable changes in density. Neither treatment produced substantial changes in lionfish biomass or native prey abundance. Importantly, the magnitude of change in lionfish density following removals depended on the initial lionfish density at a site. Together with previous work, these results suggest that removals are less effective at reducing lionfish densities and enhancing prey assemblages once lionfish densities are already low. Our findings underscore the importance of monitoring lionfish density when evaluating the ecological efficacy of removal programs.
Although the productive lifespan is a key factor for the sustainability of dairy farming, it has decreased in European countries over many years. We aimed to study the development of production level (2.22 million cows) and productive lifespan (2.31 million cows) from 1999 to 2019 by analysing Swiss herdbook data of Holstein cows (from two different herdbooks: HO_HOS from Holstein Switzerland, HO_SHB from swissherdbook), Swiss Fleckvieh (SF), Brown Swiss (BS), Simmental (SI) and Original Braunvieh (OB) breeds, as well as culling reasons (limited to the period from 2008 to 2019, n = 149 033). Average lifetime daily milk yield (LDMY, kg) continuously increased in all breeds studied: in 1999, it ranged from 6.4 ± 3.6 kg/d (SI) to 8.5 ± 4.0 kg/d (HO_HOS), while until 2019, it had significantly increased to values between 7.6 ± 4.1 (SI) and 12.1 ± 5.5 (HO_HOS) kg/d. Contrary to the prevailing European trend, average productive lifespan (PL, years) increased significantly (and stabilised) in all breeds except OB from 1999 to 2019: in 1999, it ranged between 1.9 ± 1.7 (HO_SHB) and 3.5 ± 2.7 years (BS), and increased to a range between 3.0 ± 2.1 (HO_HOS) and 3.8 ± 2.8 years (SF) in 2019. In contrast, PL in OB decreased from 4.6 ± 3.3 to 3.6 ± 2.8 years over the same period. Culling rates until the second lactation ranged from 40% (SF) to 51% (HO_SHB). For specialised dairy breeds, fertility and udder health problems were the main culling reasons, while insufficient milk production was more relevant in the dual-purpose breeds OB and SI. Long-living cows were characterised by a lower average milk yield in first lactations, a slower average milk yield increase across subsequent lactations, lower average somatic cell counts and shorter calving intervals. An increase in LDMY through extended PL was most pronounced in early lactations but persisted beyond the 10th lactation in all breeds. When comparing the development of LDMY over 20 years with differences in LDMY among cows culled at different lactations, it becomes evident that the phenotypic increase in LDMY observed over the past two decades is comparable in magnitude to the increase achievable by extending PL of young cows by approximately two lactations, regardless of the breed considered. We conclude that increasing the proportion of mature cows within the herd could yield substantial improvements in the economic and ecological efficiency of dairy production.
Visceral leishmaniasis (VL) remains a lethal parasitic disease, disproportionately affecting resource-limited regions where sustained control measures are often economically and logistically impractical. Consequently, cost-effective and sustainable strategies tailored to seasonal transmission patterns are urgently needed. Because temperature and rainfall strongly influence sandfly populations, aligning control efforts with seasonal transmission dynamics may enhance effectiveness while reducing costs. This study proposes an impulsive control strategy within a temperature- and rainfall-dependent VL transmission model to assess how strategically timed, short-term interventions optimize disease control. We examine the effects of intervention timing, frequency, and coverage for measures including sandfly breeding site elimination, insecticide spraying, and culling infected reservoir animals. Theoretical analysis shows that the disease-free periodic solution is locally asymptotically stable when the basic reproduction number ([Formula: see text]) is below one, while endemic persistence occurs when [Formula: see text]. The calibrated model closely reproduced observed seasonal transmission patterns, providing a robust basis for evaluating interventions under climatic forcing. Global sensitivity analysis revealed that vector-related parameters consistently drive infection burden, while reservoir parameters show negligible effects, indicating that vector control should be prioritized over reservoir culling for cost-effective VL management. Simulations indicate that targeted interventions implemented for only a few weeks annually substantially reduce transmission. Although vector control and reservoir culling independently decrease cases, their combined application is more effective. A biannual one-week intervention reduces human cases by 95.11%, increasing to 96.6% when extended to two weeks. Initiating interventions six weeks after peak infection yields the most substantial long-term impact, achieving a 98.89% reduction at 85% coverage.
This report describes the epidemiological characteristics of animal influenza (AI) outbreaks and the features of high-risk human populations in the Honam region during the 2024-2025 epidemic season. It also aims to identify limitations observed in field responses and to propose areas for improvement to inform future strategies for the prevention and control of human AI infections. AI detection data from animal health authorities were examined according to pathogenicity, occurrence site, and administrative district, with monthly trends derived from specimen collection dates. High-risk individuals were identified using exposure investigation forms reported to national infectious disease information system, and were evaluated by occupation, age, and nationality. Suspected human cases were reviewed for clinical manifestations, epidemiologic links, and results of real-time reverse transcription polymerase chain reaction (RT-PCR) testing. A total of 184 AI events were documented in the Honam region. Jeonbuk and Jeonnam primarily exhibited poultry farm-associated cases, whereas Gwangju predominantly showed cases associated with live bird markets. Initial detections occurred among wild birds, followed by a peak in poultry farm outbreaks in December. A total of 2,961 high-risk individuals were identified; over 80% were culling workers and 61.5% were foreign nationals. Four suspected human cases were recorded, all of which tested negative by RT-PCR. During the 2024-2025 epidemic season, AI outbreaks in the Honam region increased in scale compared with previous seasons, and occurrence patterns and the size of the high-risk population were closely associated with outbreak magnitude. Although no human AI infections were identified, the predominance of culling workers and the high proportion of foreign workers among high-risk groups, along with inadequate implementation of preventive measures, highlighted vulnerabilities in field-level response capacity. These findings call for strengthened information sharing between animal and human health authorities before the epidemic season, systematized culling procedures, enhanced multilingual education for foreign workers, and advanced stockpiling of preventive resources for high-risk populations.
To explore how market supply-demand dynamics mediate seasonal brucellosis transmission, a non-autonomous periodic model with market feedback is developed, addressing the oversight of market-driven dynamics in existing models by integrating seasonal fluctuations of core market factors with epidemiological processes. Theoretically, coincidence degree and evolution operator theories confirm the existence and global asymptotic stability of periodic solutions in the market-disease framework, achieving methodological and socio-epidemiological modeling innovations. Validated with Xinjiang's 2018-2022 brucellosis surveillance data, numerical simulations show seasonal fluctuations in livestock off-take rates and breeding recruitment potential drive the disease's periodic transmission, revealing a unique market-mediated pathway independent of biological and climatic factors. A key insight is that disease detection efficiency critically depends on the market-culling competition ratio with temporal heterogeneity, challenging the universal optimality of stricter detection and highlighting market mechanisms' non-negligible role. Policy analysis finds strengthening environmental disinfection is more feasible and cost-effective for regional control than only improving detection/culling rates. The model also identifies a bidirectional feedback loop: epidemic policies reshape livestock supply and market prices, while price signals regulate farmers' herd management via profit incentives, further modulating transmission risk. In conclusion, effective brucellosis control requires synergizing epidemiological interventions and market management, with dynamic, differentiated cross-sectoral strategies accounting for both epidemiological and market drivers.
Mastitis remains one of the most important causes of economic loss in dairy farms. However, few studies have quantified the herd-level costs of both clinical (CM) and subclinical (SM) mastitis. The objectives of this study were to estimate the annual economic impact of CM and SM in dairy farms located in Northwest Spain, to disaggregate costs into their principal direct and indirect components, and to assess the relative contribution of both presentations of mastitis to total economic losses. A retrospective observational herd-level economic analysis was conducted using production, health, reproductive, and economic data collected during 2023 from 63 commercial dairy farms enrolled in a milk recording and quality control program. A deterministic economic model integrating farm-specific data with coefficients derived from the literature was used to estimate direct and indirect costs. Parameter uncertainty was evaluated through a Monte Carlo simulation with 10,000 iterations and a dominance analysis. Average mastitis total cost was €31,643.48 per farm per year (€261.23/cow). Subclinical mastitis accounted for €18,480.56 (58.4%) and CM for €13,162.99 (41.6%). In the deterministic analysis, milk production losses were the largest contributor to both CM (€3679.60 ± 5954.92) and SM (€15,643.70 ± 14,797.20) costs. However, under uncertainty, culling-related costs were the most frequent primary driver of total economic losses (72.2% of simulations), followed by increased days open (21.9%) and milk-related losses (5.9%). Mastitis represents a substantial economic burden in Atlantic dairy systems. Although milk losses are consistently important, culling and reproductive inefficiency may dominate total costs under plausible biological and economic conditions.
A fully automated 2-dimensional imaging system that uses machine learning to produce real-time mobility scores has been developed and previously externally validated using human mobility scores and foot lesion records as ground truth. This randomized controlled trial evaluated the effect of integrating this system into an early detection and prompt treatment lameness management protocol on a large dairy farm in the UK A total of 419 multiparous cows ≤30 d-in-milk (DIM) were randomly allocated to either a control (CON) group (n = 208), managed under the farm's standard protocol or an intervention (AUTO) group (n = 211). The CON protocol consisted of routine trims at early (approximately 80 DIM) and mid-lactation (approximately 180 DIM), and examination of cows identified as lame by farm staff. In addition to the CON protocol, weekly automated scores were obtained for AUTO cows. Any AUTO cow exceeding the pre-defined threshold (≥50, on a scale of 0 to 100) or those with a ≥20 points increase in absolute scores during the last 2 weeks were scheduled for examination and treatment. Lameness scores from monthly human mobility scoring sessions were compared between groups using Fisher's exact tests or Chi-squared tests, with relative risks (RR) and odds ratios (OR) calculated. Trimming events, foot lesion prevalence and severity, and number of hoof block applications required were compared between groups using Poisson regressions and Chi-squared tests. The effect on weekly average milk yield was assessed with linear mixed effects models. Culling hazard was assessed using Cox proportional hazards regression (COXPHR). Time to 1st artificial insemination (AI) and time to conception by 150 DIM were assessed with COXPHR, whereas odds for pregnancy to the 1st AI were assessed with binary logistic regression. Cows in the AUTO group had a lower proportion of cows that developed severe lameness (2.0% vs. 7.9%, RR = 0.25; 95% CI: 0.09-0.66; OR = 0.24; 95% CI: 0.08-0.69) and chronic lameness (3.9% vs. 9.8%, RR = 0.40; 95% CI: 0.18-0.91; OR = 0.38; 95% CI: 0.16-0.88) compared with CON cows. Cows in the AUTO group underwent 2.67 trimming events per cow compared with 1.83 in the CON group during the study period (as estimated marginal means). At the 180 DIM routine trim, the AUTO group had a higher proportion of lesion-free cows (22.4% vs. 12.0%) and a lower proportion of cows with moderate lesions (16.0% vs. 25.3%). The small subset of second-parity cows in the AUTO group had higher odds of conception to 1st AI (OR = 7.6; 95% CI: 1.6-36.7) and a greater hazard of conception by 150 DIM (HR = 3.1; 95% CI: 1.3-7.3) compared with their CON counterparts. No differences were detected for weekly average milk yield or culling risk. Our findings indicate that automated mobility monitoring can improve lameness control programs by reducing severe and chronic lameness and improving mid-lactation foot health in cows.
The study investigated how three types of commercial starter diets, formulated for ostrich (OS), turkey (TS), and chicken (CS), along with hatching time and manual assistance, affected the early growth and survival of ostrich (Struthio camelus) chicks during the first 4 weeks of rearing. A total of 75 chicks were individually marked and randomly assigned to one of the three diet groups. From day 5, chicks received a 55% starter feed and 45% alfalfa hay mix ad libitum. Weekly body weight and daily mortality were recorded. Based on hatching circumstances, chicks were categorized as unassisted on day 40 (D40), assisted on day 41 (D41), or assisted on day 42 (D42). We applied univariate analysis of variance (GLM) for weekly weight and weight gain analysis, and we investigated the correlations between hatching group and hatching weight, and hatching group and 4-week growth intensity with Pearson's bivariate correlation in SPSS 22.0. We performed Kaplan-Meier procedure and Cox regression in SPSS 22.0 to analyse the effect of hatching and feeding groups on the relative culling risk of chicks. Results showed that the starter diet strongly influenced both growth and survival. Starter feed with 11.4 MJ/kg metabolizable energy, 25.91% crude protein, and 3.89% crude fiber content showed the best effects both on growth intensity (341.41 g in weekly average) and survival (85%) during the 4-week experimental period. Chicks fed with starter feed with similar energy (11.1 MJ/kg) and similarly low (5.08%) crude fibre, however, remarkably lower crude protein (17.9%) content performed moderately well (239.79 g in weekly average with 76% survival). In contrast, starter feed with low metabolizable energy of 8 MJ/kg, relatively low (17.77%) crude protein, but extremely high crude fibre (13.00%) content resulted in poor growth (193.34 g in weekly average) and extremely high mortality (> 80%), with only 16% surviving. Hatching groups also exhibited significant differences in chick mortality, with D40 showing the lowest culling risk. These findings highlight that early nutrition is critical, and starter diets with higher metabolizable energy and protein and lower crude fiber markedly improve survival and productivity in ostrich chick rearing.
Based on herdbook data from over 2.44 million Swiss dairy cows with approximately 7.33 million lactations (01 January 1999 - 31 August 2020), culling risk factors were analyzed using Weibull proportional hazard models. Time-dependent fixed effects included fat-protein production level compared to herdmates, number of inseminations, calving interval, calving ease, lactation cell count, herd size, herd size changes, calving season, and production zone. Time-independent fixed effects comprised age at first calving, farm changes between first and last lactation, and the origin of replacement heifers, while herd-year-season was included as random effect. All traits significantly affected culling risk. Together, the investigated traits improved model fit substantially, with Maddala's R² values ranging between 0.20 and 0.40 for productive lifespan (PL). However, most individual trait effects were small in magnitude despite statistical significance. The number of inseminations accounted for the largest proportion of PL variation across all breeds, followed, in most breeds, by the cow's fat-protein yield relative to her herdmates. The importance of other traits varied by breed. Linear composite traits explained only a small proportion of PL variation (1.2 to 3.7 %), with a good udder score improving longevity. Cows with a high final linear score had longer PL, though its explanatory power was low (0.7 to 2.5 %), and few cows were scored at the extremes. The findings highlight the critical role of fertility management for longevity and the economic importance of productivity for cow survival, while emphasizing that longevity is influenced by many factors with generally small individual contributions.
Dairy cows' longevity integrates multiple functional traits and influences dairy production sustainability. This study assessed the impact of productive lifespan on lifetime productivity in Swiss low-input and organic dairy farms, compared the predictability of longevity and lifetime production using first- versus second-lactation data, and evaluated whether lactation curve parameters (LCP) derived from test-day records improve predictions. Herdbook data of culled cows were analyzed using mixed-effects models to predict length of productive lifespan (LPL; days from first calving to culling), number of lactations until culling (MaxLN), lifetime milk production (LTP; kg energy-corrected milk, ECM), and average daily milk yield during productive lifespan (DMY_LPL; kg ECM). Records from first and second lactation were used in three datasets: a large dataset (n = 10,031 cows, 384 farms), a dataset with insemination records (n = 6,011 cows in first and 5,662 in second lactation, 372 farms), and a dataset with LCP (n = 6,048 cows in first and 6,735 in second lactation, 384 farms). Models based on second-lactation data with insemination records performed best for LPL and LTP, whereas MaxLN was best predicted using first-lactation data with insemination records. Predictability remained low for LPL (0.7%) and MaxLN (0.8%), and moderate for LTP (10.0%). Models including LCP best predicted DMY_LPL (64.9%). Predictive performance improved with additional factors, including somatic cell count, breed, calving interval, age at first calving, lactation persistency, milk yield traits, fat-to-protein ratio, and alpine pasturing. Based on second-lactation data, lifetime milk yield traits were reasonably predictable, whereas longevity prediction remained challenging.
Occlusion culling is a cornerstone of real-time rendering, particularly in mobile games where limited GPU bandwidth demands highly efficient scene management. At the heart of occlusion culling lies the use of simplified proxy geometry-called occluders-that approximate scene geometry for rapid visibility testing. However, producing high-quality occluders that are low in polygon count, conservative in coverage, and tightly aligned with the original geometry remains a manual and labor-intensive process. In this paper, we present a fast and fully automated two-stage approach for robust occluder generation tailored to real-world game assets. Our method begins with a novel strategy for inward offset mesh computation, followed by a conservative simplification step leveraging a new variant of Quadric Error Metrics (QEM). This approach effectively handles noisy and topologically complex inputs, generating production-ready occluders in seconds. Extensive experiments on a wide range of asset types demonstrate that our technique achieves aggressive triangle reduction while preserving critical occlusion fidelity. By offering a practical and scalable solution, our method bridges the gap between academic research and demanding needs for game development.
Improving dairy cattle performance in a sustainable way should imply developing breeding programmes able to enhance both productive and functional traits without increasing the environmental footprint. Although several studies investigated cow longevity, a fully integrated international framework that coherently links biological understanding, genomic and genetic evaluation systems, and management strategies is needed. This review addresses this issue by examining peer-reviewed articles focusing on trait biology, phenotyping, genetic and genomic evaluations, or management strategies influencing longevity. Intensive selection for production traits has historically reduced cow resilience and longevity. In the U.S., genomic evaluations for livability were introduced in 2016 and included in the Net Merit index in 2017, while productive life (incorporated in the index since 1994) has shown notable genetic gains, particularly since the adoption of genomic selection. Genotyping has markedly increased the accuracy of identifying sires whose daughters remain longer in the herd, despite the low heritability of longevity traits. Nevertheless, the average productive life may be around 3-4 years, and management decisions continue to shorten cows' productive life, with many culling occurring without evident health or reproductive issues. Extending productive life would provide a better welfare for the animals and a reduced environmental footprint.
In the whole laying cycle, the late laying phase is the longest segment, and it directly determines total egg production and influences the timing of culling. To investigate the mechanisms underlying the decline in egg-laying performance during this phase, our study selected Wenchang chickens as the research subjects, which are characterized by low egg-laying rates and high phenotypic variation. We investigated egg-laying patterns in 872 Wenchang chickens during the late laying phase and performed mechanistic studies on three high egg-laying (laying rates > 76.0 %) hens and three low egg-laying hens (laying rates < 50.0 %). RNA-seq and ATAC-seq analyses were conducted on ovarian stroma tissues from these hens. RNA-seq analysis identified 800 differentially expressed genes with thresholds of p < 0.05 and |log₂FC| ≥ 1, including 317 upregulated and 483 downregulated genes, which were enriched in biological processes such as immune response, negative regulation of endopeptidase activity, tight junction, and neuroactive ligand-receptor interaction. ATAC-seq revealed 1,065 and 428 candidate differentially accessible regions in the two groups, respectively, with 9.8 % and 5.8 % of these regions located in promoter regions. Integrated analysis identified three key genes potentially influencing the laying performance in the late phase, including MICA, MHCIA6 and MHCIY. These genes all belong to the non-classical MHC-Ⅰ family and are implicated in immune regulation. Additionally, four transcription factors (HOXB6, GATA3, TFAP2A, and WT1) were predicted to regulate these key genes. Collectively, our findings suggest that an imbalance in ovarian immune homeostasis during the late laying phase may be a significant driver of the decline in egg production. This study not only provides mechanistic insights into the maintenance of high egg-laying performance but also offers potential molecular targets for genetic improvement in Wenchang chickens and advances the understanding of reproductive regulation in poultry.
Construct a seasonal dynamic model that captures the transmission characteristics of brucellosis in Gansu, Guangdong and Sichuan provinces of China, in order to fit and predict the epidemic trends of new human brucellosis, and further formulate scientific and targeted prevention and control strategies. Based on the number of new human brucellosis cases reported by the Centers for Disease Control and Prevention in Gansu, Guangdong and Sichuan provinces from 2021 to 2024, a seasonal SEIV dynamic model of brucellosis transmission between sheep/cattle and humans was constructed, with parameters estimated by using the nonlinear least squares method and the Markov Chain Monte Carlo method. The model fitted the epidemic trends of new human brucellosis and estimated the basic reproduction number R0. Through parameter sensitivity analysis, effective prevention and control measures can be proposed. The established seasonal SEIV dynamic model can well fit the number of new human brucellosis cases and cumulative new human brucellosis cases in Gansu, Guangdong and Sichuan provinces, respectively. The calculated mean absolute percentage error (MAPE) values were approximately 20% and 6%, respectively, indicating a good agreement between the fitted and actual values. It is projected that Gansu and Sichuan provinces will reach peak values of 146,310 and 157,903 cases in July and May 2038, respectively, followed by a gradual declines toward a stable state. The epidemic in Guangdong province will reach a relatively stable, sustained prevalence by 2038. The estimated basic reproduction number R0 for brucellosis transmission in Gansu, Guangdong and Sichuan provinces were 2.2510 (95%CI: 2.2160 - 2.2859), 2.7937 (95%CI: 2.7592 - 2.8283) and 2.9499 (95%CI: 2.9007 - 2.9992), respectively. These findings indicate that brucellosis will continue to spread under the current prevention and control measures. Finally, sensitivity analyses of the number of new human brucellosis cases and R0 were conducted based on specific parameters, it is demonstrated that increasing the culling rate of infected sheep/cattle, raising the vaccination rate of susceptible sheep/cattle, and reducing the immune loss rate of vaccinated sheep/cattle can effectively suppress the spread of brucellosis. The constructed seasonal SEIV dynamic model can accurately simulates the epidemic trends of new human brucellosis cases in Gansu, Guangdong and Sichuan provinces, quantitatively proposes effective prevention and control measures, and lay a theoretical foundation for combating the spread of brucellosis.
This study aimed to evaluate the economic and environmental impacts of clinical cure failure of metritis in dairy herds using a dynamic Markov chain model. Metritis incidence was set at 25% of postpartum cows, with 3 scenarios simulated over a 10-yr horizon: Base (no metritis), Cured (all metritis cases cured), and Not Cured (no cases cured). Herd size was constrained to 900-1,000 milking cows, and all metritis cases were treated with ceftiofur crystalline-free acid. Outputs from year 10 (steady-state herd) were used for comparison. Total herd population was greatest in the Not Cured scenario, driven by a higher proportion of heifers retained for replacement. Although the number of lactating and dry cows remained similar across scenarios (constrained by our model), milk yield declined from 42 kg/d (Base) to 40 kg/d (Cured) and 37 kg/d (Not Cured). Heifer pregnancy rate did not differ among scenarios, whereas cow 22-d pregnancy rate decreased from 25% (Base) to 22% (Cured) and 20% (Not Cured). Cow culling was highest in the Not Cured scenario. Milk revenue and income over feed cost declined with increasing disease severity, whereas operating, reproductive, and replacement costs increased. Overall farm profit decreased from $1.30 million ($1,225/cow) in the Base scenario to $1.16 million ($1,067/cow) in the Cured and $0.92 million ($838/cow) in the Not Cured scenario. Methane, nitrogen, and phosphorus excretion per liter of milk increased progressively from the Base to the Not Cured scenario. The estimated cost per case of metritis increased from $460 in the Cured scenario to $1,403 when cure failed. These results demonstrate that clinical cure failure of metritis substantially reduces herd productivity, profitability, and environmental efficiency, emphasizing the importance of metritis prevention and successful clinical resolution.
Uterine infections (metritis and endometritis) are a leading cause of culling and reproductive failure in transition dairy cows, and antibiotic-resistant Gram-negative pathogens limit conventional therapy. This randomized, controlled, multi-farm field trial evaluated whether four intravaginal infusions of a host-adapted lactic acid bacteria (LAB) cocktail (Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, P. acidilactici FUA3140; 108-109 cfu/dose) at -3, -2, +3, and +4 weeks relative to calving reduce periparturient disease and improve milk production. A total of 526 pregnant cows (426 Holstein, 100 Jersey) from four commercial Alberta farms (automatic-milking, parlor, and certified-organic systems) were block-randomized within farm and parity to TRT1 (saline; n = 175), TRT2 (saline + skim milk; n = 176), or TRT3 (LAB cocktail in saline + skim milk; n = 175). Uterine infection incidence was assessed by Metricheck™ mucus scoring and transrectal ultrasonography at +3 and +4 weeks postpartum. Across the principal peripartum infectious outcomes, TRT3 showed a consistent protective effect: uterine infection incidence was lowest in TRT3 (18.8% vs. 25.1% in pooled controls; OR = 0.69; 95% CI, 0.44-1.09; an approximately 25% relative reduction; exact p = 0.12), and this metritis signal was additionally supported by a repeated-measures mixed model accounting for farm, parity, and week (p = 0.0175), although the Bonferroni-adjusted pairwise contrasts were tendencies (adjusted p ≈ 0.12), and the effect did not differ by parity (treatment × lactation interaction, p = 0.97). Subclinical mastitis was numerically lower in TRT3 than in pooled controls (5.3% vs. 8.9%; OR = 0.57; 95% CI, 0.27-1.24; exact p = 0.16), whereas retained placenta, milk fever, displaced abomasum, and lameness showed no clear cow-level treatment effect in the cow-level exact analyses. Milk yield increased significantly in multiparous cows, which produced 4.6 L/day more milk than TRT1 and 3.22 L/day more than TRT2 over the first 50 days in milk (p < 0.01 for both contrasts; treatment × parity interaction, p = 0.01). No effect was seen on milk composition, uterine involution, or reproductive performance. The trial supports intravaginal LAB as a candidate antibiotic-free prophylactic whose response depends on farm- and cow-level contexts and whose mechanisms require confirmation through microbiological and metabolic measurements.