Standard dairy calf management sees that calves are fed a consistent liquid diet until weaning at ∼60 d of age, which is generally provided as whole milk from the bulk tank (a composite of all lactating cows) or a commercial milk replacer product. Although these diets aim to satisfy the nutritional needs of the calf, their composition is not similar to the transient profile of hormones and nonnutritive bioactive factors in the milk the dam produces at this stage. Inclusion or exclusion of hormones in milk during this time may have substantial effects on reproductive programming via lactocrine signaling. This review proposes 4 potential lactocrine factors (IGF-1, insulin, estradiol, and progesterone) relevant to current dairy calf feeding strategies and highlights known interactions within female reproductive development, wide knowledge gaps, and opportunities for further investigation.
{"title":"From milk to maturity: The potential for lactocrine programming of heifer reproduction","authors":"Adam D. Beard, Sabine Mann","doi":"10.3168/jdsc.2025-0842","DOIUrl":"10.3168/jdsc.2025-0842","url":null,"abstract":"<div><div>Standard dairy calf management sees that calves are fed a consistent liquid diet until weaning at ∼60 d of age, which is generally provided as whole milk from the bulk tank (a composite of all lactating cows) or a commercial milk replacer product. Although these diets aim to satisfy the nutritional needs of the calf, their composition is not similar to the transient profile of hormones and nonnutritive bioactive factors in the milk the dam produces at this stage. Inclusion or exclusion of hormones in milk during this time may have substantial effects on reproductive programming via lactocrine signaling. This review proposes 4 potential lactocrine factors (IGF-1, insulin, estradiol, and progesterone) relevant to current dairy calf feeding strategies and highlights known interactions within female reproductive development, wide knowledge gaps, and opportunities for further investigation.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 89-93"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L.T. Casarotto , H.N. Jones , L. Galio , C. Henry , P. Chavatte-Palmer , G.E. Dahl
Extracellular vesicles (EV) are recognized as important mediators of cell-cell communication, capable of transferring various cargo between cells. Thus, EV are potential biomarkers of health status in heat-stressed cows. We hypothesized that heat stress during late gestation would alter the protein profile of EV at parturition in dairy cows. To test this, maternal plasma samples were collected within 2 h after parturition (n = 16–17/treatment) from cows exposed to late-gestation heat stress (HT) or an active cooling system (CL). The EV were isolated from plasma via single-step size exclusion chromatography. Preparations were checked for quality by transmission electronic microscopy and then quantified by nanoparticle tracking analysis before proteomic analysis. High-resolution MS was performed, and a two-sided, unpaired Welch's t-test was done on proteins showing at least 3 valid values in one group and at least 70% of valid values in the other group using log2 (label-free quantification intensity). The significance threshold was P ≤ 0.059, and proteins with a log2 fold change (CL/HT) above 1.2 or below 0.66 were considered significantly affected. Potential EV biomarkers from bovine plasma were detected, including several proteins significantly affected when comparing CL and HT. We noted more abundance in the CL group of laminin subunit gamma 1, α 2, and β 1; transferrin receptor protein 1; collagen IV; fibrinogen α chain, gamma-B chain, and β chain; von Willebrand factor; and SPN protein. Furthermore, in the CL group, the less abundant proteins included immunoglobulin domain lambda and heavy chains; HGF activator; protein HP-20 homolog; trafficking from endoplasmic reticulum to Golgi regulator (TFG) protein; amine oxidase 3; and collectin member 10. These findings suggest that these EV may play a role in modulating maternal metabolism and immune adaptations at the time of parturition within the maternal circulation. In addition, late-gestation heat stress alters the secretion of specific proteins that are involved in adaptations related to parturition. Further investigation is needed to better understand the functionality of EV during late gestation and the impact of heat stress on the molecules they carry.
{"title":"Characterization of extracellular vesicles at parturition in dairy cows with late-gestation heat stress","authors":"L.T. Casarotto , H.N. Jones , L. Galio , C. Henry , P. Chavatte-Palmer , G.E. Dahl","doi":"10.3168/jdsc.2025-0821","DOIUrl":"10.3168/jdsc.2025-0821","url":null,"abstract":"<div><div>Extracellular vesicles (EV) are recognized as important mediators of cell-cell communication, capable of transferring various cargo between cells. Thus, EV are potential biomarkers of health status in heat-stressed cows. We hypothesized that heat stress during late gestation would alter the protein profile of EV at parturition in dairy cows. To test this, maternal plasma samples were collected within 2 h after parturition (n = 16–17/treatment) from cows exposed to late-gestation heat stress (HT) or an active cooling system (CL). The EV were isolated from plasma via single-step size exclusion chromatography. Preparations were checked for quality by transmission electronic microscopy and then quantified by nanoparticle tracking analysis before proteomic analysis. High-resolution MS was performed, and a two-sided, unpaired Welch's t-test was done on proteins showing at least 3 valid values in one group and at least 70% of valid values in the other group using log2 (label-free quantification intensity). The significance threshold was <em>P</em> ≤ 0.059, and proteins with a log2 fold change (CL/HT) above 1.2 or below 0.66 were considered significantly affected. Potential EV biomarkers from bovine plasma were detected, including several proteins significantly affected when comparing CL and HT. We noted more abundance in the CL group of laminin subunit gamma 1, α 2, and β 1; transferrin receptor protein 1; collagen IV; fibrinogen α chain, gamma-B chain, and β chain; von Willebrand factor; and SPN protein. Furthermore, in the CL group, the less abundant proteins included immunoglobulin domain lambda and heavy chains; HGF activator; protein HP-20 homolog; trafficking from endoplasmic reticulum to Golgi regulator (TFG) protein; amine oxidase 3; and collectin member 10. These findings suggest that these EV may play a role in modulating maternal metabolism and immune adaptations at the time of parturition within the maternal circulation. In addition, late-gestation heat stress alters the secretion of specific proteins that are involved in adaptations related to parturition. Further investigation is needed to better understand the functionality of EV during late gestation and the impact of heat stress on the molecules they carry.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 101-106"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fiona Louise Guinan , Robert H. Fourdraine , Francisco Peñagaricano , Kent A. Weigel
The ability of an animal to be minimally affected by or bounce back rapidly from a disturbance is known as resilience. With increasing variability in climate conditions, along with skilled labor shortages and disease outbreaks, the value of genetic selection of animals for increased resilience has become important. The goal of this study was to assess alternative resilience phenotypes in lactating Holstein cows. Our data set included 34,044 US Holstein cows from parities 1, 2, or 3 that experienced a single perturbation lasting at least 5 d but up to 14 d, with a severity of at least 5% for the entire duration of the perturbation. Perturbations were identified by detecting runs of poor performance at the pen level as the percentage difference between mean expected and mean observed milk production levels. After identifying the date within a detected perturbation with the lowest mean daily milk production level (nadir), we investigated 7 different resilience phenotypes for individual cows, comprising 2 distinct groups. The first consisted of 4 resilience phenotypes calculated using change in milk yield (ΔMY) over numerous days relative to the pen nadir. These phenotypes include (1) ΔMY throughout the entire event, (2) ΔMY before the nadir, (3) ΔMY near the nadir (1 d before, on the nadir, and 1 d after the nadir), and (4) ΔMY after the nadir. The second group of resilience phenotypes were calculated using a single day during the perturbation and include (5) residual on d 1 of the perturbation, (6) residual at the nadir, and (7) residual on the last day of the perturbation. Heritabilities for resilience phenotypes were estimated using a univariate model, whereas genetic correlations between resilience phenotypes and with 305-d milk yield were estimated using a bivariate model. Heritability (SE) estimates ranged from 0.004 (0.004) to 0.04 (0.009) for resilience phenotypes. Resilience traits calculated over the entire or partial perturbation period tended to show higher heritability estimates than those calculated using a residual on a single day. Genetic correlations among resilience indicators ranged from 0.21 (0.01) to 0.99 (0.01) and with 305-d milk yield ranged from −0.02 (0.45) to −0.30 (0.38), indicating potential to select for increased resilience while simultaneously increasing milk production. Overall, our findings suggest that resilience indicators based on subsets of the perturbation period or on single-day measurements tend to have low heritability. In contrast, resilience indicators calculated across several days within the perturbation period, such as ΔMY, capture greater genetic variation in resilience and are therefore more appropriate for the genetic improvement of resilience in dairy cattle.
{"title":"Genetic parameters for alternative resilience phenotypes in Holstein cows","authors":"Fiona Louise Guinan , Robert H. Fourdraine , Francisco Peñagaricano , Kent A. Weigel","doi":"10.3168/jdsc.2025-0823","DOIUrl":"10.3168/jdsc.2025-0823","url":null,"abstract":"<div><div>The ability of an animal to be minimally affected by or bounce back rapidly from a disturbance is known as resilience. With increasing variability in climate conditions, along with skilled labor shortages and disease outbreaks, the value of genetic selection of animals for increased resilience has become important. The goal of this study was to assess alternative resilience phenotypes in lactating Holstein cows. Our data set included 34,044 US Holstein cows from parities 1, 2, or 3 that experienced a single perturbation lasting at least 5 d but up to 14 d, with a severity of at least 5% for the entire duration of the perturbation. Perturbations were identified by detecting runs of poor performance at the pen level as the percentage difference between mean expected and mean observed milk production levels. After identifying the date within a detected perturbation with the lowest mean daily milk production level (nadir), we investigated 7 different resilience phenotypes for individual cows, comprising 2 distinct groups. The first consisted of 4 resilience phenotypes calculated using change in milk yield (ΔMY) over numerous days relative to the pen nadir. These phenotypes include (1) ΔMY throughout the entire event, (2) ΔMY before the nadir, (3) ΔMY near the nadir (1 d before, on the nadir, and 1 d after the nadir), and (4) ΔMY after the nadir. The second group of resilience phenotypes were calculated using a single day during the perturbation and include (5) residual on d 1 of the perturbation, (6) residual at the nadir, and (7) residual on the last day of the perturbation. Heritabilities for resilience phenotypes were estimated using a univariate model, whereas genetic correlations between resilience phenotypes and with 305-d milk yield were estimated using a bivariate model. Heritability (SE) estimates ranged from 0.004 (0.004) to 0.04 (0.009) for resilience phenotypes. Resilience traits calculated over the entire or partial perturbation period tended to show higher heritability estimates than those calculated using a residual on a single day. Genetic correlations among resilience indicators ranged from 0.21 (0.01) to 0.99 (0.01) and with 305-d milk yield ranged from −0.02 (0.45) to −0.30 (0.38), indicating potential to select for increased resilience while simultaneously increasing milk production. Overall, our findings suggest that resilience indicators based on subsets of the perturbation period or on single-day measurements tend to have low heritability. In contrast, resilience indicators calculated across several days within the perturbation period, such as ΔMY, capture greater genetic variation in resilience and are therefore more appropriate for the genetic improvement of resilience in dairy cattle.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 40-45"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carmelo Cavallo, Annalisa Amato, Luigi Liotta, Vincenzo Lopreiato
The efficiency of thermoregulation varies among breeds of cattle and can be part of the adaptive ability of local cows, such as Cinisara. This study aimed to assess the resilience to heat stress (HS) of Cinisara cows in a semi-extensive system during summer, evaluating rectal temperature (RT), milk yield (MY) and composition. The study was carried out from June to September 2024 on a commercial dairy farm located in Cinisi (Sicily, Italy) involving 15 primiparous and 20 multiparous lactating Cinisara cows. Temperature-humidity index (THI) was calculated based on temperature and humidity data registered by 3 probes every 15 min. The RT was recorded monthly (once a month) after the morning and evening milking. The MY was recorded monthly and milk samples were collected. Data were analyzed with PROC GLIMMIX and NLIN of SAS. Parity did not affect RT or milk performance response to HS. Overall, the highest RT was registered in August in both morning and afternoon, when THI was above 77 (38.51°C and 39.21°C, respectively). The nonlinear regression (NLIN) analysis revealed a strong and statistically significant relationship between the THI and RT (adjusted R2 = 0.89). A THI breakpoint of 77.65 was identified for RT, beyond which RT increased significantly and abruptly by approximately +0.12°C for each unit increase in THI above the threshold. The nonlinear regression analysis applied to MY data revealed a strong relationship between THI and milk production (adjusted R2 = 0.90). A THI breakpoint of 76.9 was identified, beyond which MY declined sharply by approximately −8.77 kg/d for each unit increase in THI above the threshold, compared with a much milder decline (−0.69 kg/d for each unit) observed below the breakpoint. This highlights the breed's notable heat tolerance and its suitability for semi-extensive dairy systems in hot climates. Further studies exploring the genetic basis of this adaptation may support conservation and enhancement strategies for native breeds in Mediterranean regions.
{"title":"Estimation of heat stress thresholds in lactating Sicilian Cinisara cows under naturally occurring conditions","authors":"Carmelo Cavallo, Annalisa Amato, Luigi Liotta, Vincenzo Lopreiato","doi":"10.3168/jdsc.2025-0797","DOIUrl":"10.3168/jdsc.2025-0797","url":null,"abstract":"<div><div>The efficiency of thermoregulation varies among breeds of cattle and can be part of the adaptive ability of local cows, such as Cinisara. This study aimed to assess the resilience to heat stress (HS) of Cinisara cows in a semi-extensive system during summer, evaluating rectal temperature (RT), milk yield (MY) and composition. The study was carried out from June to September 2024 on a commercial dairy farm located in Cinisi (Sicily, Italy) involving 15 primiparous and 20 multiparous lactating Cinisara cows. Temperature-humidity index (THI) was calculated based on temperature and humidity data registered by 3 probes every 15 min. The RT was recorded monthly (once a month) after the morning and evening milking. The MY was recorded monthly and milk samples were collected. Data were analyzed with PROC GLIMMIX and NLIN of SAS. Parity did not affect RT or milk performance response to HS. Overall, the highest RT was registered in August in both morning and afternoon, when THI was above 77 (38.51°C and 39.21°C, respectively). The nonlinear regression (NLIN) analysis revealed a strong and statistically significant relationship between the THI and RT (adjusted R<sup>2</sup> = 0.89). A THI breakpoint of 77.65 was identified for RT, beyond which RT increased significantly and abruptly by approximately +0.12°C for each unit increase in THI above the threshold. The nonlinear regression analysis applied to MY data revealed a strong relationship between THI and milk production (adjusted R<sup>2</sup> = 0.90). A THI breakpoint of 76.9 was identified, beyond which MY declined sharply by approximately −8.77 kg/d for each unit increase in THI above the threshold, compared with a much milder decline (−0.69 kg/d for each unit) observed below the breakpoint. This highlights the breed's notable heat tolerance and its suitability for semi-extensive dairy systems in hot climates. Further studies exploring the genetic basis of this adaptation may support conservation and enhancement strategies for native breeds in Mediterranean regions.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 94-100"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marina Madureira Ferreira, Francisco A. Leal Yepes
Blood gases, electrolytes, and metabolites assist clinicians and researchers with disease diagnosis and prognosis, and can inform treatment decisions on farms. Delays between sample collection and processing can lead to significant changes in these parameters, affecting their clinical and biological value. Therefore, the objective of this study was to evaluate the stability of selected blood gas, electrolyte, and metabolite measurements in dairy cattle whole blood samples stored at 4°C, in addition to frozen plasma samples stored at −80°C for different storage periods. Multiple blood samples were collected from Holstein lactating dairy cows (n = 10) and preweaning heifer calves (n = 16) at a commercial dairy farm in New York state at a single time point. Samples were analyzed using a blood gas analyzer for sodium (Na), potassium (K), chloride (Cl), ionized calcium (iCa), ionized magnesium (iMg), pH, bicarbonate (HCO3−), base excess (BE), anion gap (AnGap), glucose (Glu), lactate (Lac), creatinine (Creat), and BUN. One blood sample was analyzed within 30 min after collection to provide baseline values. The remaining 6 samples were stored at 4°C and analyzed after 8, 12, 24, 48, 72, and 168 h. After baseline analysis, the first sample was used to collect plasma samples. The plasma baseline was immediately analyzed, and the 2 aliquots were stored at −80°C for analysis after 2 and 4 wk. The effect of storage time on blood gases, electrolytes, and metabolites was analyzed separately for whole blood and plasma using linear mixed-effects models for each individual blood parameter. Blood concentrations of iCa, iMg, and Creat remained stable during storage at 4°C for up to 168 h. Measurements of pH, Na, K, Cl, Glu, Lac, BUN, BE, and AnGap changed over time, with greater differences observed after 48 h for Glu, BUN, and BE compared with the baseline. Although statistical differences were observed for pH and Na at 24 h, values remained within the normal range until 48 h. The K and Lac were identified as the least stable parameters and underwent significant changes after 8 h. We conclude that bovine whole blood samples can be analyzed for electrolytes, blood gases, and metabolites within 48 h postcollection without significant clinical changes, if well stored and refrigerated at 4°C, except for K and Lac. Plasma samples, however, provide stable and reliable measurements for K and Lac for up to 4 wk of storage at −80°C; the results agree with whole blood concentrations.
{"title":"Effect of storage time on the stability of selected blood gases, electrolytes, and metabolite concentrations in dairy cattle whole blood and plasma","authors":"Marina Madureira Ferreira, Francisco A. Leal Yepes","doi":"10.3168/jdsc.2025-0908","DOIUrl":"10.3168/jdsc.2025-0908","url":null,"abstract":"<div><div>Blood gases, electrolytes, and metabolites assist clinicians and researchers with disease diagnosis and prognosis, and can inform treatment decisions on farms. Delays between sample collection and processing can lead to significant changes in these parameters, affecting their clinical and biological value. Therefore, the objective of this study was to evaluate the stability of selected blood gas, electrolyte, and metabolite measurements in dairy cattle whole blood samples stored at 4°C, in addition to frozen plasma samples stored at −80°C for different storage periods. Multiple blood samples were collected from Holstein lactating dairy cows (n = 10) and preweaning heifer calves (n = 16) at a commercial dairy farm in New York state at a single time point. Samples were analyzed using a blood gas analyzer for sodium (Na), potassium (K), chloride (Cl), ionized calcium (iCa), ionized magnesium (iMg), pH, bicarbonate (HCO<sub>3</sub><sup>−</sup>), base excess (BE), anion gap (AnGap), glucose (Glu), lactate (Lac), creatinine (Creat), and BUN. One blood sample was analyzed within 30 min after collection to provide baseline values. The remaining 6 samples were stored at 4°C and analyzed after 8, 12, 24, 48, 72, and 168 h. After baseline analysis, the first sample was used to collect plasma samples. The plasma baseline was immediately analyzed, and the 2 aliquots were stored at −80°C for analysis after 2 and 4 wk. The effect of storage time on blood gases, electrolytes, and metabolites was analyzed separately for whole blood and plasma using linear mixed-effects models for each individual blood parameter. Blood concentrations of iCa, iMg, and Creat remained stable during storage at 4°C for up to 168 h. Measurements of pH, Na, K, Cl, Glu, Lac, BUN, BE, and AnGap changed over time, with greater differences observed after 48 h for Glu, BUN, and BE compared with the baseline. Although statistical differences were observed for pH and Na at 24 h, values remained within the normal range until 48 h. The K and Lac were identified as the least stable parameters and underwent significant changes after 8 h. We conclude that bovine whole blood samples can be analyzed for electrolytes, blood gases, and metabolites within 48 h postcollection without significant clinical changes, if well stored and refrigerated at 4°C, except for K and Lac. Plasma samples, however, provide stable and reliable measurements for K and Lac for up to 4 wk of storage at −80°C; the results agree with whole blood concentrations.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 83-88"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Highly pathogenic avian influenza (HPAI) H5N1 (clade 2.3.4.4b) has spilled over into dairy cattle populations in the United States. A year after the initial outbreak, many uncertainties remain about the virus' epidemiology. The objective of this observational study was to examine cow-level factors that may influence cow's susceptibility to manifest clinical signs during an HPAI H5N1 outbreak using on-farm herd records. The study was conducted on a commercial dairy farm in Colorado that housed only mid-to-late lactation cows and experienced the peak of its outbreak in late May 2024. Herd records were used to identify clinical cases. The study population comprised 3,281 cows that were housed across 7 freestalls and 5 open-lot pens. Pens were classified as comparable if they housed cows with similar individual-level characteristics, as determined using a network-based clustering approach based on ANOVA and chi-squared tests. Univariate associations between case status and potential risk factors were evaluated in the full study population using t-tests and chi-squared tests. The association between clinical disease and pregnancy was assessed using a 1:1 matched subset of pregnant and nonpregnant cows (n = 196), matched on parity, lactation stage, milk yield, and pen ID, and analyzed using conditional logistic regression. Other potential risk factors of clinical disease were evaluated in a subset of pregnant cows from comparable pens (n = 1,546) using mixed-effects logistic regression. The overall proportion of clinical cases reported was 14.0% (n = 458). Unadjusted analysis showed significant differences in pregnancy (6% in nonpregnant cows vs. 15% in pregnant cows) and parity (9% in first-parity cows, 16% in second- and third-parity cows, and 18% in cows with ≥4 parities). Across all 12 pens, the proportion of clinical cases ranged from 7% to 27%, and when restricted to comparable pens (n = 5), the variation was similar (11% to 24%). The matched odds ratio (OR), using nonpregnant cows as the reference group, was 4.9 (95% CI: 1.6–14.9), indicating higher odds of being a case among pregnant cows. Among pregnant cows, the OR for multiparous cows versus primiparous cows was 2.1 (95% CI: 1.5–2.8). The findings suggest that pregnancy and parity are 2 cow-level factors that contribute to HPAI H5N1 clinical disease. Expanding the number of herds studied is critical for a better understanding of these risk factors.
{"title":"Insights into cow-level risk factors for highly pathogenic avian influenza H5N1 clinical disease in lactating Holsteins from a single outbreak in Colorado: An observational study","authors":"A. Rico , B. Nicks , A. Lago , N. Silva-del-Rio","doi":"10.3168/jdsc.2025-0799","DOIUrl":"10.3168/jdsc.2025-0799","url":null,"abstract":"<div><div>Highly pathogenic avian influenza (HPAI) H5N1 (clade 2.3.4.4b) has spilled over into dairy cattle populations in the United States. A year after the initial outbreak, many uncertainties remain about the virus' epidemiology. The objective of this observational study was to examine cow-level factors that may influence cow's susceptibility to manifest clinical signs during an HPAI H5N1 outbreak using on-farm herd records. The study was conducted on a commercial dairy farm in Colorado that housed only mid-to-late lactation cows and experienced the peak of its outbreak in late May 2024. Herd records were used to identify clinical cases. The study population comprised 3,281 cows that were housed across 7 freestalls and 5 open-lot pens. Pens were classified as comparable if they housed cows with similar individual-level characteristics, as determined using a network-based clustering approach based on ANOVA and chi-squared tests. Univariate associations between case status and potential risk factors were evaluated in the full study population using <em>t</em>-tests and chi-squared tests. The association between clinical disease and pregnancy was assessed using a 1:1 matched subset of pregnant and nonpregnant cows (n = 196), matched on parity, lactation stage, milk yield, and pen ID, and analyzed using conditional logistic regression. Other potential risk factors of clinical disease were evaluated in a subset of pregnant cows from comparable pens (n = 1,546) using mixed-effects logistic regression. The overall proportion of clinical cases reported was 14.0% (n = 458). Unadjusted analysis showed significant differences in pregnancy (6% in nonpregnant cows vs. 15% in pregnant cows) and parity (9% in first-parity cows, 16% in second- and third-parity cows, and 18% in cows with ≥4 parities). Across all 12 pens, the proportion of clinical cases ranged from 7% to 27%, and when restricted to comparable pens (n = 5), the variation was similar (11% to 24%). The matched odds ratio (OR), using nonpregnant cows as the reference group, was 4.9 (95% CI: 1.6–14.9), indicating higher odds of being a case among pregnant cows. Among pregnant cows, the OR for multiparous cows versus primiparous cows was 2.1 (95% CI: 1.5–2.8). The findings suggest that pregnancy and parity are 2 cow-level factors that contribute to HPAI H5N1 clinical disease. Expanding the number of herds studied is critical for a better understanding of these risk factors.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 66-71"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yannick Le Cozler , Laurent Delattre , Thibault Luginbuhl , Maxime Dumesny
The use of 3-dimensional (3D) imaging technology to monitor dairy cows enables the acquisition of morphological, surface, and volume data, which can then be employed to estimate BW or BCS. Accurate tracking of morphological changes in these animals could lead to better management of the gestation and parturition periods, which are especially critical for primiparous cows. Indeed, BCS values that are too low or too high are associated with reproductive disorders and early culling after calving. To assess the potential utility of precise and continuous recordings in gestating animals, we studied BW and morphological changes in 13 gestating Holstein heifers from 3 mo of gestation until the start of lactation. Body condition score was estimated using both 3D imaging technology (BCS3d) and manual scores determined by trained technicians (BCSm). From mid-April (start of experiment) until the end of August (start of calving season) in 2021, average BW increased from 515 (±SD, 40.5) kg to 604 (±49.4) kg, whereas average BCS3d decreased slightly, from 2.50 (±0.19) to 2.32 (±0.30). A similar decrease was noted for BCSm, from 2.63 (±0.19) to 2.11 (±0.24). Linear regression between the 2 estimates of BCS indicated that the technicians usually gave a higher BCS value than the imaging device (BCS3d = 0.97 × BCSm; R2 = 0.58). Because of the small number of observations and the fact that the experiment ended after the first calving, we are not able to draw any conclusions about the long-term effects of changes in BCS during gestation on the overall longevity of cows. Nevertheless, using our system, it was possible to detect small changes in BCS during the first gestation of nulliparous cows. Such information could be employed to adapt the diet of heifers to avoid inadequate, insufficient, or excessive fatness at parturition, thus potentially ameliorating calving difficulties (dystocia) and poor starts to lactation. The precise evolution of BCS in the pregnant heifer is of great interest, and the next step will be to examine larger groups of animals to shed more light on the potential value of this technology.
{"title":"Monitoring changes in body reserves in gestating dairy heifers with 3-dimensional imaging technology: A potential tool to prevent early culling?","authors":"Yannick Le Cozler , Laurent Delattre , Thibault Luginbuhl , Maxime Dumesny","doi":"10.3168/jdsc.2025-0830","DOIUrl":"10.3168/jdsc.2025-0830","url":null,"abstract":"<div><div>The use of 3-dimensional (3D) imaging technology to monitor dairy cows enables the acquisition of morphological, surface, and volume data, which can then be employed to estimate BW or BCS. Accurate tracking of morphological changes in these animals could lead to better management of the gestation and parturition periods, which are especially critical for primiparous cows. Indeed, BCS values that are too low or too high are associated with reproductive disorders and early culling after calving. To assess the potential utility of precise and continuous recordings in gestating animals, we studied BW and morphological changes in 13 gestating Holstein heifers from 3 mo of gestation until the start of lactation. Body condition score was estimated using both 3D imaging technology (BCS3d) and manual scores determined by trained technicians (BCSm). From mid-April (start of experiment) until the end of August (start of calving season) in 2021, average BW increased from 515 (±SD, 40.5) kg to 604 (±49.4) kg, whereas average BCS3d decreased slightly, from 2.50 (±0.19) to 2.32 (±0.30). A similar decrease was noted for BCSm, from 2.63 (±0.19) to 2.11 (±0.24). Linear regression between the 2 estimates of BCS indicated that the technicians usually gave a higher BCS value than the imaging device (BCS3d = 0.97 × BCSm; R<sup>2</sup> = 0.58). Because of the small number of observations and the fact that the experiment ended after the first calving, we are not able to draw any conclusions about the long-term effects of changes in BCS during gestation on the overall longevity of cows. Nevertheless, using our system, it was possible to detect small changes in BCS during the first gestation of nulliparous cows. Such information could be employed to adapt the diet of heifers to avoid inadequate, insufficient, or excessive fatness at parturition, thus potentially ameliorating calving difficulties (dystocia) and poor starts to lactation. The precise evolution of BCS in the pregnant heifer is of great interest, and the next step will be to examine larger groups of animals to shed more light on the potential value of this technology.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 23-28"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Duplessis , A.L. Kerwin , D.H. Kleinschmit , M.T. Socha , T.R. Overton
Folates are required in one-carbon metabolism and DNA methylation. During the transition period, these roles are particularly important for the final stages of fetal development and the onset of lactation. The objective of this retrospective study was to assess plasma folate concentration when a portion of dietary inorganic chloride trace minerals (ITM) and cobalt (Co) carbonate was replaced by AA complexes of trace minerals (AATM) and Co glucoheptonate during the transition period. Relationships between serum folate concentration and health biomarkers were also evaluated. With dietary trace mineral concentrations being the same between treatments, a total of 36 Holstein multiparous cows were randomly assigned based on their parity number and previous 305-d mature equivalent milk production to either (1) an ITM blend consisting of zinc (75 mg/kg DM), manganese (65 mg/kg), and copper (10 mg/kg) as hydroxychlorides, and cobalt (1 mg/kg) as carbonate (ITM) or (2) partial replacement of ITM with AATM of Zn (40 mg/kg), Mn (20 mg/kg), Cu (3.5 mg/kg), and Co glucoheptonate (1 mg/kg; AATM, Availa-Dairy, Zinpro Corp.) from 1 wk after dry-off through 8 wk of lactation. Milk yields were recorded at each milking. Blood samples were taken at wk −8 (before treatment administration), −1, 1, 2, and 8 relative to parturition for serum folate analysis. Serum folate concentration from wk −1 to 8 relative to parturition averaged 8.39 (SE: 0.44) ng/mL and was not affected by treatments. Regardless of treatments, serum folate concentration significantly decreased from wk −8 to −1, plateaued from wk −1 to 2 relative to parturition, and then significantly increased through wk 8 of lactation. Milk yield, DMI, serum alanine aminotransferase, and alkaline phosphatase concentrations were positively correlated with serum folate concentration, whereas serum BHB concentration tended to be negatively correlated with serum folate concentration. In conclusion, in the current study, the source of the trace mineral supplement fed during the dry period and early lactation did not have an impact on serum folate concentrations.
{"title":"Effect of supplying a portion of trace mineral amino acid complexes on serum folate concentration from the dry period to early lactation","authors":"M. Duplessis , A.L. Kerwin , D.H. Kleinschmit , M.T. Socha , T.R. Overton","doi":"10.3168/jdsc.2025-0833","DOIUrl":"10.3168/jdsc.2025-0833","url":null,"abstract":"<div><div>Folates are required in one-carbon metabolism and DNA methylation. During the transition period, these roles are particularly important for the final stages of fetal development and the onset of lactation. The objective of this retrospective study was to assess plasma folate concentration when a portion of dietary inorganic chloride trace minerals (ITM) and cobalt (Co) carbonate was replaced by AA complexes of trace minerals (AATM) and Co glucoheptonate during the transition period. Relationships between serum folate concentration and health biomarkers were also evaluated. With dietary trace mineral concentrations being the same between treatments, a total of 36 Holstein multiparous cows were randomly assigned based on their parity number and previous 305-d mature equivalent milk production to either (1) an ITM blend consisting of zinc (75 mg/kg DM), manganese (65 mg/kg), and copper (10 mg/kg) as hydroxychlorides, and cobalt (1 mg/kg) as carbonate (ITM) or (2) partial replacement of ITM with AATM of Zn (40 mg/kg), Mn (20 mg/kg), Cu (3.5 mg/kg), and Co glucoheptonate (1 mg/kg; AATM, Availa-Dairy, Zinpro Corp.) from 1 wk after dry-off through 8 wk of lactation. Milk yields were recorded at each milking. Blood samples were taken at wk −8 (before treatment administration), −1, 1, 2, and 8 relative to parturition for serum folate analysis. Serum folate concentration from wk −1 to 8 relative to parturition averaged 8.39 (SE: 0.44) ng/mL and was not affected by treatments. Regardless of treatments, serum folate concentration significantly decreased from wk −8 to −1, plateaued from wk −1 to 2 relative to parturition, and then significantly increased through wk 8 of lactation. Milk yield, DMI, serum alanine aminotransferase, and alkaline phosphatase concentrations were positively correlated with serum folate concentration, whereas serum BHB concentration tended to be negatively correlated with serum folate concentration. In conclusion, in the current study, the source of the trace mineral supplement fed during the dry period and early lactation did not have an impact on serum folate concentrations.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 29-33"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<div><div>Cross-sucking is an abnormal oral behavior that is a potential barrier to the adoption of social housing of calves. The objective of this randomized control trial was to assess whether providing pelleted timothy hay to pair-housed dairy calves could affect the duration, frequency, and latency to start cross-sucking behavior surrounding the daily milk feedings for the first 21 d after pairing. We enrolled 24 calves (n = 12 pairs; 6 pairs negative control [CON], 6 pairs timothy hay pellets [Hay]) at pairing at 5 ± 3 d of age. Calves were fed 7.4 L/d of milk replacer by bottle in 2 equal feedings and access to water by bucket from birth and had access to calf starter grain by bucket and by bottle ad libitum after pairing. Orts were recorded daily by scale for hay and calf starter intake. Calves were video recorded for 21 consecutive days after pairing. Two trained observers (ĸ = 0.80) watched cross-sucking events twice daily for the hour before and 2 h after each milk feeding for cross-sucking behavior using BORIS software. A cross-sucking bout was defined as one calf suckling on the navel, udder area, or between the back legs of the receiving calf and ended when the cross-sucker broke contact with the defined areas of the receiving calf for ≥10 s. The cross-sucking bouts were summarized into the daily frequency for each pair, and the duration of the bouts was summed into the daily duration by pair. The latency to first cross-suck was the first day on which a cross-sucking bout was observed within a pair. Data were non-normally distributed (Shapiro–Wilk criteria <0.95) and were common log-transformed with a 1.0 correction factor for model fit. We used mixed linear regression models to evaluate the association of Hay with the cross-sucking duration, cross-sucking frequency, day, and the Hay × day interaction, repeating by day, and using pair as the subject. Latency to begin cross-sucking was assessed using Pearson's chi-squared test. The back-transformed geometric means minus the correction factor and 95% CI of the back-transformed data are reported. We observed that Hay and the Hay × day interaction were not associated with the duration or frequency of daily cross-sucking bouts surrounding milk feeding. The geometric mean daily duration of cross-sucking surrounding milk feeding for CON was 54.7 (95% CI: 49.3 to 60.5 s) and for Hay was 59.4 (95% CI: 53.3 to 65.5 s). The geometric mean daily frequency of cross-sucking bouts surrounding milk feeding for CON was 7.8 (95% CI: 7.5 to 8.1 bouts) and for Hay was 8.1 (95% CI: 7.7 to 8.4 bouts). The latency to cross-suck was not associated with the provision of the Hay pellets and occurred by a maximum of 2 d after pairing (95% CI: 0.81 to 2.52 d). However, the average pelleted hay DMI throughout the study was negligible (Hay 89.41 ± 99.89 g/d; mean ± SD), reaching 220.51 ± 108.81 g/d on d 21. Our results suggest that offering timothy hay to pair-housed calves was not associated with cross-suckin
{"title":"The effects of feeding pelleted timothy hay to ameliorate the duration, frequency, and latency to start cross-sucking behavior in paired dairy calves","authors":"G.D. Plaugher, M.C. Cantor","doi":"10.3168/jdsc.2025-0789","DOIUrl":"10.3168/jdsc.2025-0789","url":null,"abstract":"<div><div>Cross-sucking is an abnormal oral behavior that is a potential barrier to the adoption of social housing of calves. The objective of this randomized control trial was to assess whether providing pelleted timothy hay to pair-housed dairy calves could affect the duration, frequency, and latency to start cross-sucking behavior surrounding the daily milk feedings for the first 21 d after pairing. We enrolled 24 calves (n = 12 pairs; 6 pairs negative control [CON], 6 pairs timothy hay pellets [Hay]) at pairing at 5 ± 3 d of age. Calves were fed 7.4 L/d of milk replacer by bottle in 2 equal feedings and access to water by bucket from birth and had access to calf starter grain by bucket and by bottle ad libitum after pairing. Orts were recorded daily by scale for hay and calf starter intake. Calves were video recorded for 21 consecutive days after pairing. Two trained observers (ĸ = 0.80) watched cross-sucking events twice daily for the hour before and 2 h after each milk feeding for cross-sucking behavior using BORIS software. A cross-sucking bout was defined as one calf suckling on the navel, udder area, or between the back legs of the receiving calf and ended when the cross-sucker broke contact with the defined areas of the receiving calf for ≥10 s. The cross-sucking bouts were summarized into the daily frequency for each pair, and the duration of the bouts was summed into the daily duration by pair. The latency to first cross-suck was the first day on which a cross-sucking bout was observed within a pair. Data were non-normally distributed (Shapiro–Wilk criteria <0.95) and were common log-transformed with a 1.0 correction factor for model fit. We used mixed linear regression models to evaluate the association of Hay with the cross-sucking duration, cross-sucking frequency, day, and the Hay × day interaction, repeating by day, and using pair as the subject. Latency to begin cross-sucking was assessed using Pearson's chi-squared test. The back-transformed geometric means minus the correction factor and 95% CI of the back-transformed data are reported. We observed that Hay and the Hay × day interaction were not associated with the duration or frequency of daily cross-sucking bouts surrounding milk feeding. The geometric mean daily duration of cross-sucking surrounding milk feeding for CON was 54.7 (95% CI: 49.3 to 60.5 s) and for Hay was 59.4 (95% CI: 53.3 to 65.5 s). The geometric mean daily frequency of cross-sucking bouts surrounding milk feeding for CON was 7.8 (95% CI: 7.5 to 8.1 bouts) and for Hay was 8.1 (95% CI: 7.7 to 8.4 bouts). The latency to cross-suck was not associated with the provision of the Hay pellets and occurred by a maximum of 2 d after pairing (95% CI: 0.81 to 2.52 d). However, the average pelleted hay DMI throughout the study was negligible (Hay 89.41 ± 99.89 g/d; mean ± SD), reaching 220.51 ± 108.81 g/d on d 21. Our results suggest that offering timothy hay to pair-housed calves was not associated with cross-suckin","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 61-65"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Onan-Martinez , M.A.T. de Bari , H. Olmo , J. Lance , I.M. Toledo , J.M. Tricarico , G.E. Dahl
Methane is a major GHG produced by cattle. Strategies to reduce enteric methane include supplementation with monensin, which has shown variable outcomes. Therefore, we hypothesized that monensin (Rumensin, Elanco, Greenfield, IN) would reduce enteric CH4 yield and intensity in lactating dairy cows (∼207 DIM). Twenty cows were enrolled in a 2 4-wk period crossover completely randomized design with repeated measures including 2 treatments: control (CON, n = 10/period) and monensin (MON, n = 10/period). Monensin treatment consisted of 300 mg of monensin in 34 g/cow of dried distillers grains (DDG) whereas CON was DDG alone, both top-dressed daily on the TMR. Cows were milked 3 times/d and housed in a sand-bedded freestall barn with Calan gates to collect individual DMI. A GreenFeed system was used to measure enteric gas output. Daily milk yield and DMI were measured from each cow during the study. Additionally, fat, protein and lactose percentages were measured weekly in milk. Average (±SEM) DMI (MON = 25.4 ± 0.3, CON = 25.4 ± 0.3, kg/d) and ECM (MON = 35.8 ± 1.09, CON = 36.4 ± 1.09; kg/d) were similar between treatments. Conversely, daily CH4 was significantly reduced with monensin (MON = 207.1 ± 13.1, CON = 257.2 ± 13.1 g/d). Methane yield showed a significant decline with treatment (MON = 8.1 ± 0.4, CON = 9.9 ± 0.4 g/kg DMI). Last, methane intensity relative to ECM tended to decline with monensin (MON = 5.7 ± 0.3, CON = 6.5 ± 0.3 g/kg of ECM). The results suggest that monensin reduces daily enteric CH4 emissions and yield in dairy cattle, providing evidence to support its use to reduce CH4 emissions from cattle.
甲烷是牛产生的一种主要温室气体。减少肠道甲烷的策略包括补充莫能菌素，这显示出不同的结果。因此，我们假设莫能菌素（rumenin, Elanco, Greenfield， IN）会降低泌乳奶牛肠道CH4的产量和强度（~ 207 DIM）。选取20头奶牛，采用24周交叉完全随机设计，重复试验包括2个处理：对照组（CON, n = 10/周期）和莫能菌素组（MON, n = 10/周期）。莫能菌素处理为每头奶牛34 g干酒糟（DDG）中添加300 mg莫能菌素，对照组只添加DDG，两组均在TMR上每天进行顶饲。奶牛挤奶3次/d，饲养在沙床独立式牛舍内，并设置卡兰门，收集个体DMI。使用GreenFeed系统测量肠道气体输出。研究期间测量了每头奶牛的日产奶量和DMI。此外，每周测量牛奶中脂肪、蛋白质和乳糖的百分比。处理间平均（±SEM） DMI （MON = 25.4±0.3,CON = 25.4±0.3,kg/d）和ECM （MON = 35.8±1.09,CON = 36.4±1.09,kg/d）相似。相反，莫能菌素组日CH4显著降低（MON = 207.1±13.1 g/d, CON = 257.2±13.1 g/d）。甲烷产率随处理显著下降（MON = 8.1±0.4 g/kg DMI, CON = 9.9±0.4 g/kg DMI）。最后，随着莫能菌素的增加（MON = 5.7±0.3 g/kg ECM, CON = 6.5±0.3 g/kg ECM），相对于ECM的甲烷强度呈下降趋势。结果表明，莫能菌素可减少奶牛每日肠道CH4排放和产量，为其用于减少奶牛CH4排放提供了证据。
{"title":"Monensin reduces enteric methane emissions in late-lactation Holstein cows fed high-concentrate diets","authors":"D. Onan-Martinez , M.A.T. de Bari , H. Olmo , J. Lance , I.M. Toledo , J.M. Tricarico , G.E. Dahl","doi":"10.3168/jdsc.2025-0865","DOIUrl":"10.3168/jdsc.2025-0865","url":null,"abstract":"<div><div>Methane is a major GHG produced by cattle. Strategies to reduce enteric methane include supplementation with monensin, which has shown variable outcomes. Therefore, we hypothesized that monensin (Rumensin, Elanco, Greenfield, IN) would reduce enteric CH<sub>4</sub> yield and intensity in lactating dairy cows (∼207 DIM). Twenty cows were enrolled in a 2 4-wk period crossover completely randomized design with repeated measures including 2 treatments: control (CON, n = 10/period) and monensin (MON, n = 10/period). Monensin treatment consisted of 300 mg of monensin in 34 g/cow of dried distillers grains (DDG) whereas CON was DDG alone, both top-dressed daily on the TMR. Cows were milked 3 times/d and housed in a sand-bedded freestall barn with Calan gates to collect individual DMI. A GreenFeed system was used to measure enteric gas output. Daily milk yield and DMI were measured from each cow during the study. Additionally, fat, protein and lactose percentages were measured weekly in milk. Average (±SEM) DMI (MON = 25.4 ± 0.3, CON = 25.4 ± 0.3, kg/d) and ECM (MON = 35.8 ± 1.09, CON = 36.4 ± 1.09; kg/d) were similar between treatments. Conversely, daily CH<sub>4</sub> was significantly reduced with monensin (MON = 207.1 ± 13.1, CON = 257.2 ± 13.1 g/d). Methane yield showed a significant decline with treatment (MON = 8.1 ± 0.4, CON = 9.9 ± 0.4 g/kg DMI). Last, methane intensity relative to ECM tended to decline with monensin (MON = 5.7 ± 0.3, CON = 6.5 ± 0.3 g/kg of ECM). The results suggest that monensin reduces daily enteric CH<sub>4</sub> emissions and yield in dairy cattle, providing evidence to support its use to reduce CH<sub>4</sub> emissions from cattle.</div></div>","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"7 1","pages":"Pages 34-39"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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