Journal of Dairy Science最新文献

{"title":"INTERPRETIVE SUMMARIES, MAY 2025","authors":"","doi":"10.1016/S0022-0302(25)00310-8","DOIUrl":"10.1016/S0022-0302(25)00310-8","url":null,"abstract":"","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages viii-xv"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of monopropylene glycol on milk production, uterine health, and reproductive performance in cows diagnosed with hyperketonemia on 3 pasture-based dairy farms","authors":"S.J. Hendriks ,&nbsp;J.R. Roche ,&nbsp;J.A.A. McArt ,&nbsp;T.M. Grala ,&nbsp;S-A. Turner ,&nbsp;C.R. Burke ,&nbsp;B. Kuhn-Sherlock ,&nbsp;C.V.C. Phyn","doi":"10.3168/jds.2024-25208","DOIUrl":"10.3168/jds.2024-25208","url":null,"abstract":"<div><div>In housed systems, administration of oral monopropylene glycol (MPG) in postpartum cows increases the likelihood that cows resolve hyperketonemia (HYK), reduces the incidence of clinical ketosis, and improves milk production, uterine health, and reproductive performance. The objective of our study was to investigate the efficacy of MPG as a treatment for hyperketonemia (blood BHB 1.2 to 2.9 mmol/L) and its effects on milk production, uterine health, and reproductive performance in 3 seasonal-calving, pasture-based dairy herds in New Zealand. Cows were tested a maximum of 15 times for HYK (3 times weekly on Monday, Wednesday, and Friday; mean ± SD; 14.9 ± 0.4 tests) from 1 to 35 DIM using a handheld meter. In total, 749 (76.4%) of 980 cows sampled were diagnosed with HYK (blood BHB ≥1.2 to 2.9 mmol/L) or severe HYK (blood BHB ≥3.0 mmol/L) at least once during the first 35 DIM. Cows that never tested above 1.2 mmol/L were classified as non-HYK (n = 231) and were excluded from the study. Cows with HYK that were randomly allocated to the control group (n = 362) were left untreated, whereas those allocated to the MPG treatment group (n = 387) were orally drenched with 300 mL of MPG (equivalent dose 310 g) every time the BHB test was ≥1.2 to 2.9 mmol/L during the first 35 DIM (mean ± SD treatment bouts per cow: 2.0 ± 1.2 bouts). The MPG treatment was repeated once daily until blood BHB was &lt;1.2 mmol/L at subsequent tests. Data from the survival analysis indicated that MPG reduced the time to resolve HYK (blood BHB &lt;1.2 mmol/L) and delayed time to onset of severe HYK. The MPG-treated cows were 52% more likely (hazard ratio [HR] = 1.52, 95% CI: 1.30–1.76) to resolve HYK and 69% less likely (HR = 0.31, 95% CI: 0.17–0.58) to develop severe HYK compared with control cows. However, repeated measures analysis indicated that MPG-treated cows had marginally lower ECM yield in the first 15 wk in milk (24.7 ± 0.24 kg/d) compared with control cows (25.1 ± 0.24 kg/d). Logistic regression was used to determine the effect of MPG on uterine health and reproductive performance. The prevalence of purulent vaginal discharge endometritis (score ≥3) was lower in MPG (n = 9/350) compared with control cows (n = 19/301). There were no overall effects of treatment on risk of submission to artificial insemination (AI) within 21 d of breeding start, confirmed pregnancy to first AI, pregnant within 42 d of breeding start, or the entire seasonally defined breeding period. Treating HYK with MPG improved the likelihood of a cow resolving HYK and reduced the incidence of severe HYK; however, there were minimal benefits for improving uterine health and reproductive performance and a biologically small difference in milk production in cows diagnosed with HYK based on a threshold of 1.2 mmol/L and treated with MPG.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5271-5286"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circulating progesterone concentrations and pregnancy outcomes in high-producing lactating dairy cows treated with human chorionic gonadotropin on day 2 of the estrus cycle","authors":"I. Cuevas-Gómez ,&nbsp;L. Molina ,&nbsp;J.F. Sánchez-Madueño ,&nbsp;I. Sánchez-Madueño ,&nbsp;P. Lonergan ,&nbsp;D. Rizos ,&nbsp;C.C. Pérez-Marín ,&nbsp;J.M. Sánchez","doi":"10.3168/jds.2024-26000","DOIUrl":"10.3168/jds.2024-26000","url":null,"abstract":"<div><div>Suboptimal concentrations of circulating progesterone (P4) in the early postovulatory period have been associated with low fertility observed in high-producing lactating dairy cows. The administration of human chorionic gonadotropin (hCG) increases P4 in cattle by stimulating its endogenous production by the corpus luteum (CL) and creating an accessory CL if administered at an appropriate stage of the cycle. The aim of this study was to evaluate the effect of a single administration of hCG on d 2 of the estrus cycle on circulating P4 concentrations and pregnancy per artificial insemination (P/AI) in high-producing lactating dairy cows in confinement systems. To that end, 796 lactating Holstein-Friesian dairy cows from 15 farms were enrolled on this study. The mean ± SD parity and DIM at enrollment were 2.3 ± 1.4 and 86.7 ± 17.8, respectively. After a voluntary waiting period (50–60 d after calving), cows underwent fixed-time artificial insemination (FTAI) following a routine protocol for synchronization of ovulation (Double Ovsynch, G6G, or 7-d Ovsynch + P4). Cows on each farm were blocked on parity, DIM, BCS, and synchronization protocol and were randomly assigned to receive either 3,000 IU of hCG (n = 420) or an equivalent volume of saline solution (control; n = 376) on d 2 after estimated estrus (∼16 h before FTAI = d 0). Blood samples were collected from a subset of cows from both treatments (control n = 65 and hCG n = 65) on d 0, 7, and 14 of the estrus cycle to measure serum P4 concentrations. Pregnancy per artificial insemination on d 30 after FTAI was affected by hCG treatment and parity. Moreover, there was a tendency for an interaction between treatment and parity. Overall, treatment with hCG on d 2 of the estrus cycle increased P/AI (45.2% vs. control 38.8%). In first- or second-lactation cows, P/AI was similar between hCG-treated and control cows (47.1% vs. control 45.9%). Conversely, cows in third or greater lactation treated with hCG had greater P/AI (42.1% vs. control 27.3%). The overall incidence of pregnancy loss between d 30 and d 70 was 14.7% and was not affected by treatment. Cows treated with hCG had higher P4 concentrations on d 7 and 14 compared with control cows (3.4 ± 0.66 vs. 3.0 ± 0.58 ng/mL and 6.6 ± 1.28 vs. 5.3 ± 1.02 ng/mL, respectively). Moreover, an interaction between treatment and parity revealed that P4 concentrations were higher in hCG-treated cows in third or greater lactation compared with control cows in the same parity group on d 7 and 14, while no differences were observed in first- or second-lactation cows. In conclusion, administration of hCG on d 2 of the estrus cycle increased fertility in high-producing dairy cows in third or greater lactation, in association with an early increase of circulating P4.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5448-5461"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of A1 and A2 β-casein in cow milk by high-performance liquid chromatography tandem mass spectrometry","authors":"Fengen Wang ,&nbsp;Min Ding ,&nbsp;Ruiju Li ,&nbsp;Kun Wang ,&nbsp;Xiuxin Zhao ,&nbsp;Xia Li ,&nbsp;Zengmei Li ,&nbsp;Shiming Guo ,&nbsp;Ligang Deng ,&nbsp;Jianbin Li","doi":"10.3168/jds.2024-26179","DOIUrl":"10.3168/jds.2024-26179","url":null,"abstract":"<div><div>A2 β-CN milk has gained widespread acceptance due to its nutritional benefits. To verify the authenticity and detect adulteration and contamination in A2 milk, we developed an HPLC-MS/MS method for determining the characteristic peptides of A1 and A2 β-CN in cow milk. The method demonstrated good specificity, sensitivity, and linearity for both A1 and A2 characteristic peptides, with limit of detection of 0.01 and 0.03 mg/L, limit of quantitation of 0.03 and 0.1 mg/L, and determination coefficients of 0.9994 and 0.9992, respectively. Whereas accuracy and precision were reasonable, the recoveries varied (69.4%–151%) across concentration levels (0.04, 0.2, and 1.0 g/kg), with higher recoveries for both peptides at low concentrations and lower recoveries for A2 peptide at medium and high concentrations, influenced by factors such as adsorption and ionization efficiency. We optimized the tryptic hydrolysis conditions, selecting a trypsin-to-casein ratio of 1:25 and a hydrolysis time of 6 h at 37°C. However, the hydrolysis of A1 and A2 β-CN was incomplete and asynchronous, exhibiting parabolic relationships with their respective concentrations, with hydrolysis degrees of 12.3% for A1 β-CN and 9.6% for A2 β-CN in pure powders. We finally established a regression model to calculate the actual proportion of A1 and A2 β-CN, with the detection limits of 5% for both β-CN. In the quantitation range of this model, A1 β-CN accounting for 10% to 80% or A2 β-CN accounting for 20% to 90%, the measured value of A1/A2 or A2/A1 was a power function relationship with the theoretical value. This method effectively verifies the authenticity of A1 and A2 milk, providing a reliable tool for detecting adulteration and contamination.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5361-5371"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perspective: Impacts of dairy forage management on soil carbon change and net zero accounting","authors":"Joshua D. Gamble,&nbsp;Jonathan Alexander","doi":"10.3168/jds.2024-25796","DOIUrl":"10.3168/jds.2024-25796","url":null,"abstract":"<div><div>The US dairy industry has pledged to achieve net zero GHG emissions by 2050, but reliance on corn (<em>Zea mays</em> L.) silage as a primary forage source undermines progress toward this goal. Soils managed for corn silage production are a substantial source of carbon (C) emissions to the atmosphere, with soil C losses ranging from 3.7 to 7.0 Mg C ha⁻¹ yr⁻¹ (13.5 to 25.6 Mg CO₂ ha⁻¹ yr⁻¹) reported in the literature. However, biogenic emissions from soil C loss are not typically represented within C footprints or life cycle inventories. Using an example dairy farm, we demonstrate that including emissions associated with soil C losses under dairy forage production can increase the C footprint of milk nearly 2-fold. We suggest that this approach represents a more accurate estimate of the emissions impact of milk production, and that gains in the GHG efficiency of milk have come, in part, at the expense of soil C, where forage rotations are predominated by silage corn. The C balance of forage production systems can likely be improved with advanced manure management technologies and application strategies that return more manurial C to the soil while minimizing N and P loading. However, we argue that more extensive changes to forage cropping systems will also be required. Expanding the role of perennials and winter annual crops in forage rotations; breeding forages with greater yield, persistence, and deeper more extensive root systems; and additional creative solutions to retain more plant-derived C in soils are necessary to balance soil C budgets and achieve net zero emissions targets.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4479-4484"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diverse spore-forming bacterial populations in US organic raw milk are driven by climate region","authors":"Renee T. Lee,&nbsp;Rachel L. Weachock,&nbsp;Zoe D. Wasserlauf-Pepper,&nbsp;Martin Wiedmann,&nbsp;Nicole H. Martin","doi":"10.3168/jds.2024-26045","DOIUrl":"10.3168/jds.2024-26045","url":null,"abstract":"<div><div>Spore-forming bacteria pose significant challenges to the dairy industry, as they are present at high levels in the natural environment and can cause finished product spoilage. To improve organic raw milk quality and minimize spoilage caused by spore-forming bacteria, we used a farm-to-table approach, by assessing the levels and diversity of various spore types through longitudinal studies of United States (US) organic dairy supplies, including (1) raw milk from 100 organic dairy farms, (2) raw milk intended for organic cheese production from 5 processing plants, (3) pasteurized milk from 5 processing plants, and (iv) dairy powders from 2 processing plants. Based on a total of 4,194 isolates characterized by either <em>rpoB</em> or 16S rRNA gene sequencing, <em>Bacillus</em> spp. dominated the aerobic spore-formers isolated from farm raw milk, pasteurized milk, and powders. Nonmetric multidimensional scaling revealed that aerobic spore-former populations in organic farm raw milk differ significantly between climate zones at genus, species, and allelic type levels. The anaerobic/facultative anaerobic spore-formers isolated from farm and cheese raw milk samples represented the orders <em>Clostridiales</em> and <em>Bacillales</em>. Evaluation of the gas produced by anaerobic/facultative anaerobic spore-forming bacteria isolates showed that gas production varied significantly between <em>Clostridiales</em> clades, and 1 <em>Bacillales</em> clade produced gas amounts that were not significantly different from most <em>Clostridiales</em> clades. Overall, our data indicate (1) a substantial diversity of aerobic and anaerobic spore-formers in US organic dairy supplies with predominant genera and species similar between organic and conventional dairy supplies as previously described; (2) both anaerobic and facultative anaerobic spore-formers found in organic raw milk produce gas; and (3) climate may affect aerobic spore-former diversity in farm raw milk.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4674-4692"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining high-pressure processing and low storage temperature to extend the functionality shelf life of low-moisture, part-skim mozzarella cheese","authors":"L.A. Jiménez-Maroto ,&nbsp;S. Govindasamy-Lucey ,&nbsp;J.J. Jaeggi ,&nbsp;M.E. Johnson ,&nbsp;J.A. Lucey","doi":"10.3168/jds.2024-26112","DOIUrl":"10.3168/jds.2024-26112","url":null,"abstract":"<div><div>High-pressure processing (HPP) and low-temperature storage (0°C) were explored as alternatives to freezing for extending the performance shelf life of low-moisture, part-skim (LMPS) mozzarella intended for export. Batches (n = 5) of reduced Na LMPS mozzarella were manufactured using camel chymosin as a lower proteolytic type of rennet. Cheeses were stored for 2 wk at 4°C, divided into control (non-HPP) and HPP (600 MPa for 3 min) groups, and stored at 3 different temperatures (4, 0, and −18°C) for 365 d. Analyses were performed at 0, 90, 150, 210, 270, and 365 d of storage. Frozen and 0°C samples (∼2.3 kg) were thawed/tempered at 4°C for 1 wk before analysis. Urea PAGE and quantification of the pH 4.6 soluble N over time were used to monitor primary proteolysis. Body and rheological properties were monitored using texture profile analysis (TPA) and dynamic low-amplitude oscillatory rheology. Changes in flavor, body, shred properties, and pizza performance were evaluated using quantitative descriptive analysis with 12 trained panelists using a 15-point scale. High-pressure processing treatment caused ∼5 log cfu/mL reduction in starter counts, partial solubilization of the insoluble Ca, and a small pH increase (from ∼5.2 to 5.3). The rate of primary proteolysis was reduced by HPP and low-temperature storage. High-pressure processing treatment reduced initial cheese hardness, but no further significant decrease was observed over storage time, whereas the hardness of non-HPP samples decreased over the 365 d of storage, apart from the frozen samples. In pizza applications, blister quantity development and loss of strand thickness were limited by storage at −18°C. Freezing LMPS mozzarella to −18°C gave the least changes in proteolysis and pizza performance over the 365 d of study, storage of cheese at 0°C slowed the loss of hardness and the deterioration of pizza performance attributes. The combination of HPP and 0°C storage of cheese resulted in little change in blistering quantity of pizza during the 365 d of study, whereas cheese stored at 0°C had blisters covering much of the pizza after this extended storage time. Combining HPP with low-temperature storage is a promising alternative approach to freezing for the extension of the functionality shelf life of LMPS mozzarella.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4589-4603"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Daily rhythms of glucose, insulin, and nonesterified fatty acid responses to an intravenous glucose tolerance test in dairy cows","authors":"Anay D. Ravelo ,&nbsp;Cesar Matamoros ,&nbsp;Kevin J. Harvatine ,&nbsp;Isaac J. Salfer","doi":"10.3168/jds.2024-26146","DOIUrl":"10.3168/jds.2024-26146","url":null,"abstract":"<div><div>In nonruminant species, glucose tolerance and insulin sensitivity are known to be regulated by circadian rhythms, which are repeating ∼24-h cycles that govern many aspects of behavior, physiology, and metabolism. However, it is unknown if these rhythms exist in dairy cows. Our objective was to determine the fit of a daily rhythm of glucose, insulin, and nonesterified fatty acid (NEFA) clearance rates independent of daily patterns of nutrient intake. To accomplish our objective, 12 multiparous lactating Holstein cows were enrolled in a within-subject design conducted over 2 experimental periods (n = 6/period). Within each period, cows were subjected to intravenous glucose tolerance tests (IVGTT) at 4 timepoints, representing different times of the day (0300, 0900, 1500, and 2100 h). The 0900 and 2100 h IVGTT were performed 36 h apart, followed by a 7-d washout, and then the 1500 and 0300 h IVGTT were performed 36 h apart. Cows were fed 12 times/d at 2-h intervals beginning 24 h before the first IVGTT in each set until the second IVGTT in each set to stabilize feed intake across the day, with 1 time/d feeding occurring during the washout period. For each IVGTT, 250 g of glucose was infused as a 50% (wt/vol) <span>d</span>-glucose solution via a jugular catheter and blood was collected at −15, −5, immediately before, 0, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min relative to infusion. A linear mixed model with the fixed effects of cosine and sine and random effect of cow within period was used for the outcomes of clearance rate, half-life, baseline concentration, time to baseline concentration, and area under the curve (AUC) for glucose, insulin, and NEFA. A zero-amplitude test was used to determine the fit of a 24-h cosine function and cosinor rhythmometry was used to determine the amplitude and acrophase of the 24-h rhythm. Insulin concentrations at baseline followed a diurnal rhythm. Glucose and insulin clearance rate, half-life, and AUC also followed a diurnal rhythm. Glucose and insulin clearance rates peaked at 1247 h and 0944 h, respectively. No circadian rhythm was detected for plasma NEFA concentrations. Results suggest that insulin-stimulated glucose uptake is controlled differently throughout the day by circadian rhythms.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5462-5474"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic performance of the Enferplex bovine tuberculosis antibody test using bulk tank milk samples from dairy cattle","authors":"Alastair Hayton ,&nbsp;Amanda O'Brien ,&nbsp;Andy Adler ,&nbsp;Keith Cutler ,&nbsp;John Clarke ,&nbsp;Darren J. Shaw ,&nbsp;Neil J. Watt ,&nbsp;Gordon D. Harkiss","doi":"10.3168/jds.2024-25539","DOIUrl":"10.3168/jds.2024-25539","url":null,"abstract":"<div><div>Bovine tuberculosis, caused mainly by <em>Mycobacterium bovis</em>, is a major disease of cattle worldwide associated with significant economic losses and is usually diagnosed using periodic tuberculin skin tests, IFNγ release assay, or at postmortem. Recently, we developed a multiplex test for detecting antibodies to <em>Mycobacterium bovis</em> in cattle that has high sensitivity and specificity using serum or individual milk samples. Here, we assessed the performance of the test using bulk tank milk samples from skin test–positive and bovine tuberculosis–free cattle herds. In nonanamnestic bulk tank milk samples, the sensitivity relative to the comparative cervical skin test was 77.2% and the specificity was 99.8% using the high sensitivity setting of the antibody test. A kappa value of 0.85 was found, indicating almost perfect agreement between the test results and comparative cervical skin test status of the herds. Likelihood ratio analysis gave a positive likelihood ratio of 53.1 and a negative likelihood ratio of 0.030, indicating that the test provides good diagnostic evidence of the infection being either present or absent, respectively. Bulk tank milk samples from herds with inconclusive reactors to the comparative cervical skin test but had no reactors gave a test positivity of 73.7%, indicating that antibody-positive animals were present in the herd after removal of the reactors. Variances in herd prevalence did not result in statistically significant differences in test positivity, and the test was able to detect a herd prevalence of 0.1% of comparative cervical skin test reactors in 80% of low prevalence herds. The test showed good repeatability and reproducibility, giving complete concordance in results from 3 independent laboratories. The results show that the bulk milk antibody test could be used as a nonanamnestic surveillance tool for detecting and monitoring bovine tuberculosis in dairy cattle herds.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5296-5312"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the accuracy of models using routinely collected herd data for prediction of on-farm lameness prevalence","authors":"Conor Barry ,&nbsp;Esben Østergaard Eriksen ,&nbsp;Kristian Ellingsen-Dalskau ,&nbsp;Christoph Winckler ,&nbsp;Nicholas J. Bell ,&nbsp;Camilla Kielland","doi":"10.3168/jds.2024-25830","DOIUrl":"10.3168/jds.2024-25830","url":null,"abstract":"<div><div>Lameness is a major welfare and production concern for the dairy sector worldwide. Quantifying the lameness challenge is essential for herd health management. The Claw Health Indicator (CHI), developed by a Norwegian dairy company, is calculated on a monthly basis using data routinely collected in the Norwegian Dairy Herd Recording System. The CHI was hypothesized to reflect the lameness prevalence on farm. Our cross-sectional study evaluated the accuracy of predictions made about the lameness prevalence on farm by the CHI. We also developed an alternative model for predicting the lameness prevalence using additional variables of routinely collected herd data (RHD) and evaluated its accuracy. We used data from 149 Norwegian freestall dairy herds. A univariable β regression model was built with the total proportion of lame and severely lame cows as the dependent variable and the CHI score for each herd as the independent variable. A second model, a multivariable β regression model with the same dependent variable, was built using selected variables of RHD. The accuracy of both models was assessed in terms of their concordance r and prediction errors. A higher CHI score was indicative, as hypothesized, of a lower lameness prevalence and vice versa. Moving from the lowest CHI score in our sample to the highest was equivalent to a reduction of ∼6% in the prevalence of lameness. There was, however, substantial variation in the total proportion of lame cows seen in herds with the same CHI score. The CHI model was highly inaccurate when predicting the lameness prevalence on farm, with a concordance r of 0.05. The alternative RHD model, which included 6 independent variables of RHD, was more accurate than the CHI model but still inaccurate with a concordance correlation coefficient of 0.31. Both the CHI and the alternative RHD models were unsuitable for accurately predicting the prevalence of lameness on farm. Whereas their constituent parts were reflective of claw health at the herd level, they failed to reflect the complex, multifactorial nature of lameness in dairy herds. The CHI may still be useful for claw health management, as a tool for identifying potential issues on farm, and motivating producer engagement but further investigation is required. The RHD variables in the alternative model are simpler and more widely available than the CHI, facilitating replication and further development in other countries or groups of dairy herds outside of Norway.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5313-5328"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}