JDS communications最新文献

{"title":"Evaluating breed and seasonal effects on milk yield, composition, and cheesemaking ability of 2 Italian dairy sheep breeds","authors":"Silvia Graziani,&nbsp;Simone Callegaro,&nbsp;Claudio Cipolat-Gotet,&nbsp;Maria Chiara Fabbri,&nbsp;Giorgia Stocco,&nbsp;Lina Fernanda Pulido-Rodríguez,&nbsp;Davide Valoppi,&nbsp;Irene Tedeschi,&nbsp;Francesco Sirtori,&nbsp;Bianca Castiglioni,&nbsp;Silverio Grande,&nbsp;Christian Maltecca,&nbsp;Riccardo Bozzi,&nbsp;Stefano Biffani,&nbsp;Francesco Tiezzi","doi":"10.3168/jdsc.2025-1006","DOIUrl":"10.3168/jdsc.2025-1006","url":null,"abstract":"<div><div>This study aimed to characterize milk yield, composition, and cheesemaking traits of Comisana and Massese ewes managed under uniform conditions and to evaluate the effects of breed, season, and their interaction. Milk samples were collected from 161 ewes across 4 sampling periods, measuring productive, compositional, and cheesemaking traits. A linear mixed model was implemented, with fixed effects of breed, sampling period, stage of lactation, parity, and relevant interactions and random effects of animal and residual. Massese ewes showed higher milk yield, resulting in higher component yields and cheese output, whereas Comisana ewes showed higher protein and casein concentrations, leading to better cheesemaking ability. A significant interaction between breed and season revealed breed-specific responses to seasonal variation, with Massese exhibiting more consistent milk production and Comisana showing more pronounced seasonal fluctuations. These findings highlight the importance of considering both breed and season for optimizing milk production and cheesemaking efficiency in local Italian sheep breeds.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 541-546"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cost-benefit analysis of feeding market dairy cows prior to slaughter compared with shipping direct","authors":"M.W. Overton,&nbsp;H.M. Goetz,&nbsp;S.M. Roche,&nbsp;J. Byrne,&nbsp;T.F. Duffield","doi":"10.3168/jdsc.2026-1041","DOIUrl":"10.3168/jdsc.2026-1041","url":null,"abstract":"<div><div>Cull (market) dairy cattle often arrive at auction facilities and slaughterhouses in poor body condition, which presents welfare concerns and results in low return on carcasses at slaughter. The objective of this study was to evaluate the potential economic value of feeding market-designated dairy cows for 60 d before shipping compared with shipping directly to slaughter and determine sensitivity of this value to BCS, market price, and feed costs. A deterministic partial budget was created to estimate the costs associated with feeding market cows for 60 d, considering inputs related to initial and final BCS, management costs, and discounts applied for cull cattle at various BCS. Compared with a market cow shipped directly at a BCS of 2.0, a cow fed for 60 d to achieve a BCS of 3.0 would sell for approximately Can$664 greater. However, this benefit was partially offset by the associated costs of retaining her on the farm. Sensitivity analyses showed the greatest benefit-to-cost ratio (BCR) in feeding cows from a relatively low initial BCS when the cost of lactating cow TMR was low. Specifically, the highest BCR of 1.9 was seen when cows began with a BCS of 2.0 and the average cost of lactating cow TMR was Can$0.23/kg or Can$0.24/kg. A BCR of 1.7 was observed in cows with an initial BCS of 2.0 at market values of Can$4.00 or Can$4.50/kg. This economic model and associated sensitivity analyses show that it may be profitable, while also improving cow welfare, to dry off and feed market dairy cattle before shipping in certain circumstances, yet advisors and producers should consider the individual farm's capacity to retain market cattle beyond a typical culling management protocol.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 638-643"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal impact of metritis and systemic antibiotics on immune cell function inferred from the blood leukocyte transcriptome","authors":"Monica O. Caldeira,&nbsp;Joao G.N. Moraes,&nbsp;Scott E. Poock,&nbsp;Matthew C. Lucy","doi":"10.3168/jdsc.2026-1067","DOIUrl":"10.3168/jdsc.2026-1067","url":null,"abstract":"<div><div>Within 2 wk postpartum approximately 20% of dairy cows develop metritis, a uterine infection associated with reduced fertility and increased risk of reproductive culling. Antibiotics improve clinical cure and milk production following metritis but do not consistently increase subsequent fertility postpartum compared with untreated control cows. To better understand why antibiotic treatment improves clinical recovery but not fertility, we tracked changes over time in blood leukocyte gene expression to examine circulating immune cell function during the resolution of metritis in antibiotic-treated and untreated cows. Twenty-three primiparous Holstein cows diagnosed with metritis (n = 11) or classified as healthy controls (n = 12) between 7 and 10 d postpartum were enrolled. Cows were assigned to receive systemic ceftiofur (1.25 g/d for 3 d) or remain untreated in a 2 × 2 factorial design. Blood samples were collected at diagnosis (wk 1), and at 1 and 3 wk after treatment (wk 2 and wk 4) postpartum. The blood leukocyte RNA was isolated and sequenced, and differentially expressed genes were analyzed for functional enrichment and immune cell type. Healthy cows exhibited enrichment of B cell activation and receptor signaling pathways, whereas metritis cows showed upregulation of inflammatory and innate immune responses, including monocyte and neutrophil markers. In untreated cows (healthy versus metritis), transcriptomic differences in blood leukocytes were resolved by wk 4 postpartum. In contrast, antibiotic-treated metritis cows displayed a distinct immune trajectory. At wk 2 postpartum (1 wk after antibiotic treatment), cytotoxic T cell and natural killer cell gene expression signatures increased, differing clearly from untreated metritis cows. By wk 4, a second wave of inflammatory cell–associated differentially expressed genes emerged exclusively in antibiotic-treated metritis cows, suggesting prolonged immune cell activation. These findings demonstrate that antibiotic treatment reshapes systemic immune dynamics during recovery from metritis. The altered sequence (e.g., early cytotoxic activation followed by extended inflammation) may explain why antibiotic-induced clinical cure in metritis cows does not consistently translate into improved fertility.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 691-697"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supplementation of rumen-protected choline during warm summer days reduces body surface temperature and improves dry matter intake of Holstein dairy cows","authors":"I. Abousoliman,&nbsp;J. Schwerdtfeger,&nbsp;F. Koch,&nbsp;M.R. Schneider,&nbsp;B. Kuhla","doi":"10.3168/jdsc.2025-1000","DOIUrl":"10.3168/jdsc.2025-1000","url":null,"abstract":"<div><div>Elevated ambient temperature negatively affects dairy cows' productivity. The present study investigated the efficacy of rumen-protected choline (RPC) supplementation in alleviating the adverse effects of heat load and improving the productive performance in multiparous Holstein dairy cows at elevated ambient temperatures. Two multiparous cow groups, each enrolled since preceding calving, underwent a 2-phase experimental design consisting of a 1-wk pre-experimental period (wk −1) and a 4-wk experimental period (wk 1–4) in the same free-ranging barn. At the start of the pre-experimental period, cow groups were randomly assigned to a control group (CON, n = 9, 77 ± 26 DIM) receiving a basal diet throughout the study, whereas the RPC group (RPC, n = 9, 77 ± 8 DIM) received the same basal diet during the pre-experimental phase and was supplemented with RPC (60 g/cow per d) during the experimental phase. During the study in July 2025, the weekly mean ambient temperature ranged from 18.3°C ± 1.2°C to 20.9°C ± 1.8°C, with corresponding temperature-humidity index (THI) values between 64.1 ± 1.7 and 67.9 ± 2.6. Respiration rate was measured during the pre-experimental period (wk −1, d −6). Rectal temperature was determined using a digital thermometer and surface temperatures (muzzle, ear, eye, and neck) by aFLIR T620 infrared camera, during both the pre-experimental (wk −1, d −6) and experimental (wk 3, d 20) phases. Additionally, DMI, water intake (WI), milk yield (MY), ECM, BW, and milk composition were recorded for each cow individually in both periods. No significant differences were detected between the 2 groups during the pre-experimental phase, except for DMI, WI, BCS, and milk lactose percentage; however, pre-experimental differences were accounted for in the model. During the experimental period, RPC supplementation reduced eye temperature (RPC 34.7°C ± 0.1°C vs. CON 35.1°C ± 0.1°C) and tended to reduce ear (33.6°C ± 0.2°C vs. 34.4°C ± 0.4°C), muzzle (33.0°C ± 0.3°C vs. 33.6°C ± 0.2°C), and neck (34.3°C ± 0.2°C vs. 34.8 ± 0.2°C) temperatures. Moreover, RPC supplementation increased DMI (22.5 ± 0.47 vs. 18.6 ± 0.47 kg/d), WI (95.3 ± 1.05 vs. 71.6 ± 0.72 L/d), and BW (676 ± 3.53 vs. 657 ± 2.38 kg) relative to the CON group. Furthermore, RPC supplementation significantly increased milk fat yield (1.24 ± 0.04 vs. 1.16 ± 0.04 kg/d). Overall, the findings show that RPC supplementation may serve as an effective nutritional intervention to alleviate the negative effects of high ambient temperatures and to improve productivity in dairy cows.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 575-580"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of 2 culture-based rapid tests used by veterinary practices as a tool for selective treatment of clinical mastitis","authors":"Lien Creytens,&nbsp;Sofie Piepers,&nbsp;Sarne De Vliegher","doi":"10.3168/jdsc.2026-1011","DOIUrl":"10.3168/jdsc.2026-1011","url":null,"abstract":"<div><div>Antimicrobial resistance necessitates more judicious antimicrobial use, including in dairy production where mastitis remains the primary driver of antibiotic consumption. Selective treatment of nonsevere clinical mastitis (STCM) requires rapid differentiation between gram-positive and gram-negative pathogens, as only gram-positive infections generally benefit from antimicrobial therapy. Because conventional laboratory culture is too slow for STCM, rapid testing systems for pathogen detection in milk are used on farm (performed and analyzed by farm personnel) or on practice (performed and analyzed at the veterinary practice). This study evaluated the diagnostic performance of 2 culture-based rapid tests (MicroMast and VetoRapid) via an on-practice culture approach as part of a clinical trial, with standard laboratory bacteriology as the gold standard. The performance to distinguish (1) gram-positive from gram-negative bacteria and (2) further pathogen identification was assessed by determining sensitivity, specificity, positive predictive values, negative predictive values, accuracy, and Cohen's kappa values. Both tests (VetoRapid more than MicroMast) reliably distinguished gram-positive from gram-negative pathogens, supporting their use in STCM decision-making. However, their ability to identify specific pathogens was limited, restricting their suitability for broader udder health management decisions.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 678-683"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the genetic potential of a milk mid-infrared prediction of heat stress response in dairy cows using a temperature-humidity index–independent approach","authors":"P. Lemal,&nbsp;K. Wijnrocx,&nbsp;H. Soyeurt,&nbsp;M. Schroyen,&nbsp;N. Gengler","doi":"10.3168/jdsc.2026-1053","DOIUrl":"10.3168/jdsc.2026-1053","url":null,"abstract":"<div><div>Selection for heat tolerance remains challenging due to the difficulty of accessing reliable phenotypes at large scale. An alternative could be established using mid-infrared spectra, which are collected routinely through milk recording, and have already shown their value as proxies for a variety of phenotypes that are costly or difficult to measure. Recently, a first prediction of heat stress response in dairy cows based solely on milk mid-infrared spectra was developed. This prediction was obtained using models calibrated on surface body temperature and milk composition variations. Its potential as a detection tool was explored, but no genetic analyses has been performed. On this basis, the objectives of this study were to estimate the heritability of the predicted heat stress response, assess its genetic correlations with traits from the Walloon official genetic evaluation, and identify genomic regions associated with heat tolerance through a GWAS, all without using temperature-humidity index (THI) information. The estimated heritability (0.10) was low but sufficient to enable genetic selection and consistent with expectations for a heat stress–related trait. Also as expected, an antagonistic relationship between heat tolerance and milk production was observed, but its extent was notably reduced compared with traditional approaches. In addition, genetic correlations with other traits were neutral (fat yield) or favorable (protein yield, SCS, fertility, longevity). Concerning the GWAS, genomic regions and candidate genes previously associated with the response to heat stress were highlighted, as well as others related to energy balance maintenance. Overall, these results support the relevance of the prediction for the heat stress response as a new phenotype for heat tolerance selection that does not require any THI information. They also reinforce the importance of energy balance for dairy cows to cope with heat stress.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 614-619"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circannual pattern of milk crude protein and urea nitrogen and their relationship in Holstein cows in Swiss grassland-based dairy systems over a 30-year period","authors":"Jedidiah Yi Lin Ong,&nbsp;Usman Arshad,&nbsp;Mutian Niu","doi":"10.3168/jdsc.2026-1030","DOIUrl":"10.3168/jdsc.2026-1030","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The objectives of the study were to characterize the circannual variation in milk CP and MUN concentrations and to evaluate their relationship in Holstein cows managed under Swiss grassland-based dairy production systems. We hypothesized that milk CP and MUN exhibit distinct seasonal patterns, reflecting changes in forage quality and feeding practices, and that the strength of their association varies across seasons and production eras. A retrospective cohort study was conducted using historical milk recording data consisting of 2,313,348 cow-lactations from 897,854 unique Holstein cows across 22,830 Swiss dairy farms collected between 1994 and 2023. The dataset included primiparous (n = 817,638) and multiparous (n = 1,495,710) cow-lactations, with multiparous cows contributing a mean (±SD) lactation number of 3.04 ± 1.04. Monthly test-day records (January to December) within a 305-d lactation were used to assess temporal changes in milk CP (%) and MUN (mg/dL) and their relationship, resulting in approximately 18.3 million test-day observations. Mean (±SD) CP concentrations were 3.29% ±  0.34% for primiparous and 3.32% ± 0.36% for multiparous cows, and MUN concentrations were 10.8 ± 3.72 mg/dL and 10.5 ± 3.81 mg/dL, respectively. The study period was stratified into 2 eras: EraA (1994–2008) and EraB (2009–2023). Generalized linear mixed-effects models were fitted to assess temporal variation in milk CP and MUN and included fixed effects of test-day month (January to December), parity (primiparous vs. multiparous), era (EraA vs. EraB), their 2- and 3-way interactions, a natural cubic spline for DIM, and the interaction between parity and DIM, and random effects of farms and cow. To evaluate the relationship between milk CP and MUN, the model included fixed effects of linear and quadratic covariates of CP, parity, era, their 2- and 3-way interactions, a natural cubic spline for DIM and its interaction with parity, and random effects of farm nested within monthly test-day record and cow. A 3-way interaction between month, parity, and era was associated with milk CP and MUN concentrations, indicating that seasonal patterns differed between eras and that the magnitude and timing of these changes varied between primiparous and multiparous cows. Milk CP declined from winter to summer in both eras (EraA: primiparous 3.29–3.12, multiparous 3.34–3.18; EraB: primiparous 3.30–3.09, multiparous 3.36–3.12). In contrast, MUN concentrations increased from winter to late summer in both eras (EraA: primiparous 10.0–12.5, multiparous 9.82–12.2; EraB: primiparous 10.0–12.0, multiparous 9.71–11.8). A 3-way interaction between milk CP, parity, and era was observed for MUN, with MUN decreasing nonlinearly as CP increased from 2.40% to 4.20%, and steeper declines at lower CP. Across the milk CP range, multiparous cows generally exhibited slightly lower MUN than primiparous cows, with smaller parity differences in EraB. Overall, milk CP and MUN concentrations e","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 590-595"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Co-incubation of Bacillus spp. alleviated the growth and gas production of potentially harmful bacteria in different in vitro methodologies","authors":"Lena Capern,&nbsp;Nina Milora,&nbsp;Emily George,&nbsp;Audrey Segura,&nbsp;Raphaele Gresse,&nbsp;Oscar Queiroz,&nbsp;Giuseppe Copani,&nbsp;Bruno I. Cappellozza","doi":"10.3168/jdsc.2025-0896","DOIUrl":"10.3168/jdsc.2025-0896","url":null,"abstract":"<div><div>A series of experiments evaluated the effects of a <em>Bacillus</em>-based direct-fed microbial (DFM) on the growth of potentially harmful bacteria. Experiment 1 evaluated the effects of co-incubating <em>Bacillus licheniformis</em> 809 or <em>Bacillus subtilis</em> 810 with <em>C. perfringens</em> type A on in vitro gas production and <em>Clostridium</em> counts. This methodology was performed using the in vitro gas production Ankom RF system bottle. Bottles were incubated with <em>C. perfringens</em> type A (CPF) or with the addition of individual DFM strains (<em>B. licheniformis</em> 809 [BL] or <em>B. subtilis</em> 810 [BS]). Gas production of the different treatments was recorded for 24 h, and then enumeration of the strains was performed. A treatment × hour interaction was observed, as CPF grew faster than either BL or BS from 7 to 24 h, whereas BS grew faster than BL at 7 h. Adding BL or BS reduced gas production versus CPF from 18 to 24 h (treatment × hour interaction). Moreover, the co-incubation of BL or BS with <em>C. perfringens</em> type A significantly reduced the counts of these potentially harmful bacteria by 63% and 69%, respectively. Experiment 2 was performed by using an agar-diffusion assay to evaluate <em>C. perfringens</em> types A, B, C, D, and E; <em>Fusobacterium necrophorum</em>; <em>Trueperella pyogenes</em>; and <em>L. monocytogenes</em>. After incubation, the zone of decreased growth was measured. The <em>Bacillus</em>-based DFM addition resulted in efficacy against <em>C. perfringens</em> that ranged from 10.5 mm (type C) to 15.5 mm (types A and E). Moreover, for <em>T. pyogenes</em> and <em>F. necrophorum</em>, the clearance zone was in the order of 11.5 and 8.7 mm, respectively. Three strains of <em>L. monocytogenes</em> were assessed following 4 h of incubation with BL and BS, and zones between 10.5 and 11.5 mm were reported. In summary, this series of in vitro experiments demonstrated the inhibitory activity of BL and BS against selected potentially harmful bacteria of interest for livestock.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 601-607"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of bedding treatments to inhibit Klebsiella pneumoniae growth in wood shavings and sand","authors":"Gabriella Harb,&nbsp;Samuel Rowe,&nbsp;Ruth N. Zadoks","doi":"10.3168/jdsc.2026-1027","DOIUrl":"10.3168/jdsc.2026-1027","url":null,"abstract":"<div><div>Mastitis caused by <em>Klebsiella</em> spp. leads to significant milk losses and increased rates of culling and mortality in affected cows on dairy farms. Control of environmental bacterial loads in bedding is critical to prevent intramammary infections caused by <em>Klebsiella</em> spp. However, little is known about how commercially available disinfectants and bedding conditioners perform against this pathogen. To determine the efficacy of a bedding conditioner and a surface disinfectant against <em>Klebsiella pneumoniae</em> in wood shavings and sand, a controlled laboratory study using bedding experimentally inoculated with bacteria and randomized allocation of bedding samples to treatments was conducted using a 2 × 3 factorial design. Bedding material (wood shavings, sand) and treatment (control, conditioner, disinfectant) were fixed factors, and <em>Escherichia coli</em> was used as the control species. Bacterial recovery from inoculated bedding samples was quantified, and the effect of treatment on bacterial counts was estimated using linear mixed models. Counts of <em>E. coli</em> were reduced in wood shavings treated with bedding conditioner. This is consistent with previously reported effects of the conditioner and supports the validity of the bedding inoculation model, but counts were not reduced in sand. In contrast, the conditioner significantly reduced <em>K. pneumoniae</em> counts in sand only. The disinfectant significantly decreased <em>E. coli</em> and <em>K. pneumoniae</em> counts in sand but increased <em>K. pneumoniae</em> counts in wood shavings. Overall, treatment effects were dependent on bacterial species and bedding material, indicating that their performance cannot be generalized across substrates or pathogen groups. Field studies incorporating on-farm bedding conditions are required to validate these laboratory findings and account for variability in responses among bacterial species of concern in mastitis management.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 644-651"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dairy sire mating recommendations to limit extremes and target intermediate optima","authors":"D.P. Berry","doi":"10.3168/jdsc.2026-1037","DOIUrl":"10.3168/jdsc.2026-1037","url":null,"abstract":"<div><div>Traditional genetic selection using total merit indexes operates under the simple assumption that higher is better. Some traits, however, are subject to preferred upper or lower thresholds and some may have intermediate optima. Therefore, mating recommender systems should consider these herd-specific breeding goals. Mating recommendations in this study were performed at a herd level for dairy cattle using a constrained optimization approach based on simulated estimates of genetic merit for 9 traits or subindexes. A total of 10,000 herds, each with 200 females, were simulated. The top 100 sires from a simulated population were chosen to represent the pool of candidate sires. Within each herd separately, candidate female–male pairings were evaluated on a mate utility function that combined parental average genetic merit for the 9 traits or subindexes. The utility function penalized matings expected to generate progeny exceeding predefined thresholds (milk yield was used as an example trait) or deviating from an intermediate optimum (cow liveweight was used as an example trait), thereby reflecting both avoidance of genetic extremes and targeting of biologically and system-relevant optima. Imposing a linear penalty on the parental average genetic merit for a trait exceeding a given threshold reduced, considerably, the number of recommended matings that had a parental average genetic merit exceeding that threshold. For the vast majority of herds, no mating that exceeded that parental average genetic merit threshold was recommended but it was unavoidable in some herds because of the presence of females with extreme genetic merit for the trait and the absence of sires capable of delivering the desired parental average genetic merit. Including the threshold penalty had minimal effect on the mean total merit index of the recommended matings. Preselection of candidate dams before mating recommendations, although slightly reducing the proportion of progeny exceeding the threshold, resulted in a lower mean total merit index of the recommended matings. Penalizing matings that generated parental averages deviating from an intermediate optimum resulted in recommended matings that, although lower in genetic merit for the total merit index, were more homogeneous in parental average for the trait in question. Although preselecting dams for mating consideration did not alter the proportion of matings deviating from the optimum, it resulted in a lower mean total merit of the matings. Although the specific conclusions of the present study are dependent on the simulated population, the overarching finding is that developing a utility function that penalizes matings exceeding defined thresholds or deviating from desired optima can support mating recommendations aligned with herd-specific breeding goals that are nonlinear in nature.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 5","pages":"Pages 620-625"},"PeriodicalIF":2.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}