Relative availability of five inorganic magnesium sources in non-pregnant non-lactating Holstein cows.

Inorganic sources of Mg are commonly used in dairy cow diets, but their availability varies significantly. This study assessed the relative availability of 4 commonly used inorganic Mg sources and a novel alkalinizing proprietary mineral blend [PMB; Multesium (GLC Minerals, LLC, Green Bay, WI, USA)]. The study was a duplicated 6 × 6 Latin square, with 12 nonlactating, non-pregnant Holstein dairy cows assigned to a square based on BW and parity. Cows were fed 90% of their voluntary DMI (diet contained 0.21% Mg). Each experimental period lasted 7 d. On d 2 of each period, urinary catheters were fitted. Total urine collection started on d 3 for 48 h with samples collected and measured every 12 h. On d 4, 30 g of Mg were administered as boluses with gelatin capsules: negative control (one empty capsule), magnesium oxide (MgO), magnesium sulfate (MgSO4), calcium magnesium hydroxide [CaMg(OH)4], calcium magnesium carbonate [CaMg(CO3)2], and PMB [a blend of Ca and Mg sources that includes CaMg(CO3)2, CaMg(OH)4, and MgO]. Blood samples were collected at 0, 1, 2, 3, 12, and 24 h after treatment administration on d 4 of each treatment period. Urine and blood samples were analyzed for Mg and Ca concentration. Statistical analyses were conducted with PROC GLIMMIX including treatment, time, period, square, treatment × time, treatment × period, and time × period as fixed effects, and cow nested within square as a random effect in the model. Urinary Mg excretion for 4 of the Mg sources studied [PMB, MgO, CaMg(OH)4, and MgSO4] increased significantly, representing an increase of at least 40.8% relative to control. The supplementation of CaMg(CO3)2 did not significantly increase relative to control. There were no significant changes in blood Mg concentration with treatment; but, a significant treatment × time effect was observed. Calcium-rich sources [PMB, CaMg(OH)4, CaMg(CO3)2] had lower blood Mg concentrations at 12 or 24 h after treatment than control and CaMg(CO3)2. Based on urinary Mg excretion 24 h after treatment, 4 of the Mg sources evaluated (including PMB) showed a similar availability, however, the availability of the commercial CaMg(CO3)2 source included in our study was similar to the negative control (no-supplemented cows).

miRNA-protein-metabolite interaction network reveals the regulatory network and players of pregnancy regulation in dairy cows.

Pregnancy is a complex process involving complex molecular interaction networks, such as between miRNA-protein, protein-protein, metabolite-metabolite, and protein-metabolite interactions. Advances in technology have led to the identification of many pregnancy-associated microRNA (miRNA), protein, and metabolite fingerprints in dairy cows. An array of miRNA, protein, and metabolite fingerprints produced during the early pregnancy of dairy cows were described. We have found the in silico interaction networks between miRNA-protein, protein-protein, metabolite-metabolite, and protein-metabolite. We have manually constructed miRNA-protein-metabolite interaction networks such as bta-miR-423-3p-IGFBP2-PGF2α interactomes. This interactome is obtained by manually combining the interaction network formed between bta-miR-423-3p-IGFBP2 and the interaction network between IGFBP2-PGF2α with IGFBP2 as a common interactor with bta-miR-423-3p and PGF2α with the provided sources of evidence. The interaction between bta-miR-423-3p and IGFBP2 has many sources of evidence including a high miRanda score of 169, minimum free energy (MFE) score of -25.14, binding probability (p) of 1, and energy of -25.5. The interaction between IGFBP2 and PGF2α occurs at high confidence scores (≥0.7 or 70%). Interestingly, PGF2α is also found to interact with different metabolites, such as PGF2α-PGD2, PGF2α-thromboxane B2, PGF2α-PGE2, and PGF2α-6-keto-PGF1α at high confidence scores (≥0.7 or 70%). Furthermore, the interactions between C3-PGE2, C3-PGD2, PGE2-PGD2, PGD2-thromboxane B2, PGE2-thromboxane B2, 6-keto-PGF1α-thromboxane B2, and PGE2-6-keto-PGF1α were also obtained at high confidence scores (≥0.7 or 70%). Therefore, we propose that miRNA-protein-metabolite interactomes involving miRNA, protein, and metabolite fingerprints of early pregnancy of dairy cows such as bta-miR-423-3p, IGFBP2, PGF2α, PGD2, C3, PGE2, 6-keto-PGF1 alpha, and thromboxane B2 may form the key regulatory networks and players of pregnancy regulation in dairy cows. This is the first study involving miRNA-protein-metabolite interactomes obtained in the early pregnancy stage of dairy cows.

Effect of recombinant bovine granulocyte colony-stimulating factor treatment during the peripartum period on postpartum diseases, reproductive performance, and milk production in Holstein cattle.

To boost the immune function around parturition, recombinant bovine granulocyte colony-stimulating factor (rbG-CSF) has been used to increase the number of neutrophils. Therefore, the aim of this study was to quantify the effect of rbG-CSF administration on the incidence of postpartum pathologies, reproductive performance, and milk production during the first three months of lactation. A total of 199 Holstein cows from one herd were included and were randomly allocated into two groups: Control (n = 103) and rbG-CSF (n = 96). Cows in the rbG-CSF group received 2 doses of a rbG-CSF injectable formulation, one 7 days before the expected date of calving and the other within 24 h after calving. For 6 weeks following calving, animals were examined weekly to assess the presence of postpartum pathologies. Milk production, protein and fat content, and somatic cell count were determined monthly by the regional dairy herd improvement association. Data about the reproductive performance were collected from on-farm software. To analyse the effect of treatment on the incidence of postpartum pathologies, Pearson's χ2 test and multivariable logistic regressions were performed. The effect on reproductive performance was analysed using Cox proportional hazard regression analysis for days open, binary logistic regression for first service conception rate and Oneway ANOVA test for the number of artificial inseminations. The effects of treatment on milk yield and milk composition were checked using GLM repeated measures analysis. No statistically significant differences were observed between treatment groups for any of the parameters evaluated. Only parity had a significant effect on days open and milk production (p < 0.05). In conclusion, in the present study no evidence was found that rbG-CSF could have an effect on the reproductive and productive parameters evaluated.

An investigation of antioxidative and anti-inflammatory effects of Taraxacum coreanum (white dandelion) in lactating Holstein dairy cows.

Objective: The aim of this investigation was to examine the impact of Taraxacum coreanum (known as dandelion) (TC) and TC mixtures with milk thistle (MT) or Aspergillus oryzae (AO) as feed additives on the immune response, milk quality, and milk production in Holstein cows over 6 weeks of administration. Materials and Methods: Thirty-two healthy Holstein dairy cows were provided 30 kg of total mixed ration (TMR) with no TC, 90 gm TC, 54 gm TC + 36 gm MT, or 54 gm TC + 36 gm AO 40% groups. The feed additives were supplied daily in two equal portions (per 45 gm) by topdressing the TMR for 6 weeks. Milk and blood samples were collected weekly. Results: In the TC-treated cows (TC, TC + MT, and TC + AO groups), significantly lower peripheral blood white blood cell (WBC) counts at 6 weeks and milk somatic cell counts (SCCs) at 4-6 weeks of administration were observed. Concentrations of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) were notably elevated in cows treated with TC for 4-6 weeks, while levels of proinflammatory cytokines concentrations of tumor necrosis factor-alpha (TNF-α) and chemokine (IL-8) were significantly reduced in TC-treated cows after 3-6 weeks of administration. Conclusion: These results suggested that TC or a TC mixture with other medicinal herbs supplementations enhanced the serum antioxidative activities and, consequently, might suppress the adverse immune response due to lower serum TNF-α and IL-8 release supported by lower WBC and SCC counts.

Quantification of the Environmental Impact of Feeding Yeast Probiotic Saccharomyces cerevisiae Actisaf Sc 47 in Dairy Cow: A Life Cycle Assessment Approach.

Today, one of the major challenges of dairy farmers is to reduce their environmental footprint to establish more effective, efficient, and sustainable production systems. Feed additives such as yeast probiotics could potentially allow them to achieve these objectives through the improvement of milk production, feed efficiency, and ration valorization, hence mitigating the environmental impacts of milk production. In this study, the life cycle assessment (LCA) principle was performed to estimate the environmental impact of the production and supplementation of a commercial yeast probiotic (Actisaf Sc 47) in three trials performed in three different countries that are representative for around 50% of the milk production in Europe: France (French trial), United Kingdom (UK trial), and Germany (German trial). For each trial, two groups of animals were compared: control, without Actisaf Sc 47 supplementation, used as baseline; and experimental, with Actisaf Sc 47 supplementation at 5 or 10 g/cow/day. Different impact categories were analyzed for each group to calculate the impact of producing 1 kg of fat- and protein-corrected milk. An initial analysis was done only during the period of Actisaf Sc 47 supplementation and showed than the supplementation with Actisaf Sc 47 reduced, on average by 5%, the carbon footprint during the three trials. A second analysis was done via the extrapolation of all the data of each trial to an annual farm level, including the lactation period (305 days), dry period (60 days), and the period with and without Actisaf Sc 47 supplementation. Reported at a farm annual scale, the average reduction allowed by Actisaf Sc 47 supplementation was 2.9, 2.05, 2.47, 1.67, 2.28, 2.18, 2.14, and 2.28% of the carbon footprint, land use, water use, resource use, acidification, freshwater eutrophication, marine eutrophication, and terrestrial eutrophication, respectively. On average, the production of 1 kg of fat- and protein-corrected milk by using Actisaf Sc 47 was shown to improve environmental impacts compared to control. Regarding Actisaf Sc 47 production, the LCA showed that the production of 1 kg of Actisaf Sc 47 emitted 2.1 kg CO2 eq with a negligible contribution to total the carbon footprint of milk ranging from 0.005 to 0.016%. The use of Actisaf Sc 47 in dairy cows could then result in different positive outcomes: improving performance and efficiency while reducing the global carbon footprint.

When Implementing the Presynch-11/Ovsynch Reproductive Management Program, the Fertility of Lactating Dairy Cows Improved When They Received Timed Artificial Insemination Compared with the Inclusion of Estrus Detection.

Artificial insemination 12 h following observed standing estrus is a standard estimate of the fertility levels of cattle. The main objective of this study was to determine if controlling ovarian development with a fertility program could alter the fertility of lactating dairy cows. Lactating dairy cows (n = 1356) 60-66 days in milk (DIM) were randomly assigned to receive timed AI following Presynch-11/Ovsynch (Presynch-11) or a combination of estrus detection and timed AI using the Presynch-11/Ovsynch program (Estrus + TAI). Cows in standing estrus, following the first two cloprostenol sodium (CLO) injections, in the Estrus + TAI group were artificially inseminated using the AM/PM rule. Cows in this group that were not observed in standing estrus received Ovsynch and TAI beginning 11 d after the second CLO injection. Cows in the Presynch-11 group received two injections of 500 µg CLO 14 d apart but were not observed for estrus. The first GnRH (100 µg) of Ovsynch was administered 11 d following the second CLO injection. All cows in the Presynch-11-Ovsynch group received TAI following Ovsynch. Cows in this treatment were then assigned randomly to receive either CLO or dinoprost 7 d following the first GnRH of Ovsynch. The final GnRH of Ovsynch was administered 56 h later and TAI 16 h after the final GnRH. Pregnancies/AI (P/AI) were greater (p < 0.001) for the Presynch-11 group compared with the Estrus + TAI group (45 vs. 31%). Primiparous cows had greater fertility following observed standing estrus compared with multiparous cows. Days in milk at the first AI were greater (p < 0.01) in the Presynch-11 group vs. the Estrus + TAI group (98 vs. 80) but less variable (p < 0.01). The range of DIM at the first AI was 95 to 101 in the Presynch-11 group and 60 to 101 in the Estrus + TAI group. Within the Presynch-11 group, there were no differences in the rate of luteolysis or P/AI for the prostaglandin type at the final PGF2α of Ovsynch. Multiparous cows treated with Presynch-11 had >60% chance of pregnancy compared with multiparous cows receiving AI following standing estrus. In summary, lactating dairy cows receiving timed AI following the Presynch-11/Ovsynch program had improved fertility compared with a group of cows that received AI following standing estrus or, if not observed in estrus, timed AI. This comparison indicated that controlling ovarian development with GnRH and PGF2α positively impacted the fertility of lactating dairy cows.

A new dataset for video-based cow behavior recognition.

A new video based multi behavior dataset for cows, CBVD-5, is introduced in this paper. The dataset includes five cow behaviors: standing, lying down, foraging,rumination and drinking. The dataset comprises 107 cows from the entire barn, maintaining an 80% stocking density. Monitoring occurred over 96 h for these 20-month-old cows, considering varying light conditions and nighttime data to ensure standardization and inclusivity.The dataset consists of ranch monitoring footage collected by seven cameras, including 687 video segment samples and 206,100 image samples, covering five daily behaviors of cows. The data collection process entailed the deployment of cameras, hard drives, software, and servers for storage. Data annotation was conducted using the VIA web tool, leveraging the video expertise of pertinent professionals. The annotation coordinates and category labels of each individual cow in the image, as well as the generated configuration file, are also saved in the dataset. With this dataset,we propose a slowfast cow multi behavior recognition model based on video sequences as the baseline evaluation model. The experimental results show that the model can effectively learn corresponding category labels from the behavior type data of the dataset, with an error rate of 21.28% on the test set. In addition to cow behavior recognition, the dataset can also be used for cow target detection, and so on.The CBVD-5 dataset significantly influences dairy cow behavior recognition, advancing research, enriching data resources, standardizing datasets, enhancing dairy cow health and welfare monitoring, and fostering agricultural intelligence development. Additionally, it serves educational and training needs, supporting research and practical applications in related fields. The dataset will be made freely available to researchers world-wide.

Association between non-esterified fatty acids and calcium concentrations at calving with early lactation clinical diseases, fertility and culling in grazing dairy cows in Uruguay.

This study describes the association of non-esterified fatty acids (NEFA) and calcium concentrations at calving with early lactation disease, reproductive performance and culling in 646 dairy cows from 13 commercial grazing dairy herds in Uruguay. During one year, health events were recorded from calving to 30 days in milk (DIM). The first author visited each farm every 20 days. During each visit, body condition score (BCS) was recorded (scale 1-5), defining BCS < 3 as suboptimal and BCS > 3 as optimal, and a blood sample was taken from cows between 0 and 4 DIM for metabolite determination. To evaluate the association between health events (i.e., retained placenta-metritis and clinical mastitis) and risk factors (parity, BCS, high NEFA (> 0.6 mmol/L) and subclinical hypocalcemia (SCH) (< 2.10 mM)) data were analysed using multivariable logistic regression models. To evaluate the association of health events and risk factors with reproductive performance and culling, data were analysed using Cox proportional hazard regression models. A risk factor and an outcome of interest were assumed to be associated at P < 0.05 and a tendency to be associated was defined at P < 0.10. Overall, 47 % (n = 303) of the cows showed elevated NEFA concentration and 77 % (n = 499) had SCH. In addition, 21.5 % (n = 139) of the cows recorded at least one clinical disease. Cumulative incidence was 17 % (n = 109) for clinical mastitis, 4.2 % (n = 27) for retained placenta (RP)-metritis and 1.4 % (n = 7) for lameness. Clinical mastitis was associated with parity, with lower odds in primiparous (PP) cows (OR = 0.42, P < 0.01). Cows in an optimal BCS also tended to have lower odds (OR = 0.66, P = 0.07). Moreover, high NEFA and SCH cows had higher odds of CM (OR = 4.5, P = 0.01 and OR = 1.75, P = 0.04, respectively). Retained placenta-metritis tended to be associated with high NEFA concentration (OR = 2.2, P = 0.06). Primiparous cows with suboptimal BCS showed an increased first insemination rate (HR = 2.34; P < 0.01). The risk of culling was lower in PP cows (HR = 0.19; P < 0.01) and in cows with optimal BCS and low NEFA concentration (HR = 0.38; P = 0.03). Our data show that metabolic challenge (defined as peripartum suboptimal BCS, high NEFA or SCH) is associated with increased odds of clinical mastitis and RP-metritis, decreased probability of insemination and increased hazard of culling. Under grazing conditions, we suggest that farm management to improve the metabolic adaptation to lactation represents an opportunity to enhance cow performance in terms of health, fertility and longevity.

Analysis of the relationship between energy balance and properties of rumen fermentation of primiparous dairy cows during the perinatal period.

Short-chain fatty acids (SCFAs) produced in the rumen are key factors affecting dairy cows' energy balance (EB). This study aimed to quantitatively evaluate the effects of SCFAs production on EB in dairy cows. Primiparous dairy cows were divided into high non-esterified fatty acid (NEFA; group H) and low NEFA (group L) groups based on their blood NEFA levels at week 3 postpartum, which served as an indicator of EB. The amounts of SCFAs produced in the rumen, including acetate, propionate, and butyrate (SCFAsP), were calculated using the predicted rumen volume. Because there were no differences between the groups in SCFAsP/dry matter intake, whereas 4% fat-corrected milk (FCM)/SCFAsP was significantly higher in group H, it was suggested that more body fat was mobilized for milk production in group H. However, group L, which showed better EB, had propionate dominant and lower FCM/SCFAsP and milk energy/SCFAs energy at 3 and 7 weeks postpartum, indicating that group L had a better energy supply for milk production. These results suggest that SCFAsP produced by rumen fermentation and the composition of SCFAs in the rumen affect milk production and EB.

Effects of cashew nutshell liquid on milk production and methane emission of dairy cows in a farm condition.

This study aimed to clarify the efficacy of cashew nutshell liquid (CNSL) in methane emissions, milk production, and rumen fermentation of lactating cows in practical conditions. Ten Holstein lactating cows were used in a free-stall barn with a milking robot. Two treatments were arranged as control (no CNSL additive, n = 5) or CNSL addition (10 g/day of CNSL, n = 5) for 21 days after the 7-day preliminary period. A sniffer method was applied to predict daily methane production and methane conversion factor (MCF). In vitro, rumen gas production was also tested using the rumen fluid of individual cows. Daily dry matter intake (DMI), eating time, milk production, and methane production were not affected by the CNSL addition. However, methane production per DMI and MCF were lower (p ≤ 0.01) for the CNSL cows than those for the control cows. Ruminal total volatile fatty acid (VFA) concentration and acetate proportion tended to be lower (p < 0.15) for CNSL cows. A tendency to decrease (p < 0.10) in methane was also observed in the in vitro incubation with the rumen fluid obtained from the CNSL cows compared with those from the control cows. These results suggest that adding CNSL to diets could reduce the methane yield of cows in practical conditions.

Animal-based welfare indicators for dairy cows and their validity and practicality: a systematic review of the existing literature.

Animal welfare is of increasing importance, with consumers preferring animal products made with ethical practices due to growing awareness. This shift highlights the need for reliable methods to evaluate welfare. This systematic review aims to assess the validity of current animal-based welfare indicators for dairy cows to aid farmers and agricultural professionals in evaluating and improving welfare amidst the lack of a clear legislative definition. The literature search spanned five databases: CAB Direct, PubMed, Scopus, Google Scholar and Livivo, covering publications in English and German from 2011 to 2021. Specific search terms were employed, and abstracts were screened for relevance. Publications were categorized based on exclusion criteria, with a final verification process conducted by three independent scientists. Research highlights correlations between welfare measures, farm characteristics and innovative indicators like hair cortisol concentration. Farming systems and housing methods significantly affect welfare, with pasture-based systems generally resulting in reduced lameness and improved behavior. Proper housing design and management practices are important, as they influence indicators like lameness and cleanliness. Heart rate variability and heart rate monitoring provide insights into dairy cow stress levels during milking and other stressors, making them valuable for welfare assessment. Biomarker research emphasizes the need to balance productivity and health in breeding strategies, as high milk production alone does not indicate good welfare. Behavioral studies and the human-animal relationship are key to understanding welfare. Precision Livestock Farming offers real-time assessment capabilities, although validation is needed. Stress physiology is complex, and while cortisol measurement methods are promising, further research is necessary. Assessment tools like the Animal Needs Index and routine herd data analysis are valuable for identifying welfare concerns. Key findings highlight the WQ® protocol's effectiveness and versatility, the challenge of its time demands, and the DCF protocol's promise for more practical and efficient welfare assessments. Commercial animal welfare audits should prioritize easily observable indicators and herd records due to logistical constraints in measuring biomarkers or heart rate variability. This focus on easily accessible indicators, such as body condition score, lameness, claw health, cleanliness, and somatic cell count allows effective welfare assessments, enabling prompt action to enhance wellbeing.

Magnitude of change in prepartum feed intake: estimations using multiple classes of predictors and associations with transition metabolism, health, and milk production.

The objectives of this study were to identify factors associated with the relative change in prepartum dry matter intake (RCDMI) of 273 cows fed individually, evaluate the performance of linear models to estimate RCDMI using different classes of predictors, and characterize the implications of RCDMI to transition metabolism, health, and subsequent milk production. Two periods of interest were established. Period 1 comprised d -21 to -12 relative to calving, when DMI was stable. Period 2 comprised d -4 to -1, when average DMI was distinctly declined. The RCDMI from period 1 to 2 was calculated as a percentage value, which ranged from -75 to 15% and averaged -18.1% (±15.0). Season, parity, body fatness, body weight, milk production in the previous lactation and at dry-off, and length of dry period were associated with RCDMI and explained 11% of the variation in all cows, and 19% when only parous cows were considered. Performance of linear models to predict RCDMI was improved when data on rumination and physical activities and target blood metabolites were added. The adjusted R2 increased to values between 0.45 and 0.55, and selected models performed consistently in cross-validation analyses. To evaluate the implications of RCDMI, cows were ranked within parity according to RCDMI and classified into terciles as large decline (LD), moderate decline (MD), or small decline (SD). By design, DMI did not differ between tercile groups in period 1 (13.3 ± 0.2 kg/d), but differed substantially in period 2 (LD = 8.8; MD = 11.2; SD = 12.7 ± 0.2 kg/d), creating important differences in RCDMI among groups (LD = -33.8; MD = -16.2; SD = -3.4% ± 0.8%). At enrollment, cows in the LD and MD groups were heavier (LD = 788; MD = 775; SD = 750 ± 7 kg), and the proportion of cows with BCS >3.5 was higher in LD (LD = 63; MD = 47; SD = 38%). An interaction of group and time was observed for postpartum DMI, which started lower in LD than in SD cows, but equaled by the end of transition, and inverted at wk 13 and 14 after calving. Yields of energy-corrected milk were greater in LD than in SD cows, and both groups did not differ from MD (LD = 41.0; MD = 40.3; SD = 39.0 ± 0.5 kg/d). LD cows had decreased energy balance and greater concentrations of nonesterified fatty acids, ß-hydroxybutyrate, and aspartate aminotransferase in serum, and greater glutathione peroxidase activity in plasma than SD cows. Larger declines in prepartum DMI were also associated with increased risk for postpartum disease, although the associations were only weak to moderate. In conclusion, a large decline in prepartum DMI was associated with important adjustments in the energy metabolism and antioxidants activities, and greater milk production in the subsequent lactation. These findings indicate that feed intake decline close to parturition is likely a normal response to physiological adaptations at the onset of lactation when cows are fed at libitum.

Reference limits for blood gas analysis performed from coccygeal vessels of multiparous Holstein dairy cows: Effects of stage of lactation and season of sampling.

Blood gas analysis is a great support to the diagnostic process of critically ill patients. Its correct application to the medicine of dairy cows depends on the availability of specific reference intervals that are still difficult to find in the literature. They may vary according to the type of blood sampled, animals' age and production stage, and climatic conditions. This study aimed at calculating the reference limits for some blood gas parameters in the blood collected from the coccygeal vessels of multiparous Holstein dairy cows. This site of sampling implies the risk of withdrawing blood of unknown origin (venous, arterial, or mixed), but has a high practical interest for the easy and quick performance and the minimal animal restraint required. Data from 379 cows were used, and reference limits were produced for pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3), total carbon dioxide concentration (tCO2), oxygen saturation (sO2), hemoglobin (Hb), hematocrit (Hct), base excess (BE), glucose, Na, K, and ionized calcium (iCa). The effects of stage of lactation (5 to 60 vs. > 60 DIM) and season of sampling (cold vs. hot) were investigated, and specific reference limits were produced for each variable and each level of the factors whenever a significant effect was detected. The pH, sO2, K, and iCa were not influenced by season or stage of lactation. All the other blood gas parameters were significantly affected by season of sampling, and Hb, Hct, glucose, and Na were also affected by stage of lactation. Reference limits provided in this study are specific to the site of sampling (coccygeal vessels) and the animal category considered. Further studies are needed to produce reference intervals for other blood gas parameters, cow categories, and blood types.

Performance of dairy cows offered silages produced from grass swards harvested on either three or five occasions during the growing season.

The nutritive value of grass silage can be improved by harvesting herbage at a less mature growth stage, which in practice usually involves more frequent harvests. This study examined the performance of dairy cows offered grass silages produced from perennial ryegrass (Lolium perenne) based swards harvested at 2 different frequencies during the growing season (3-harvest (3H) vs. 5-harvest (5H)). Thirty-four mid-lactation (av. 147 d in milk) dairy cows (30 multiparous, 4 primiparous) were offered either 3H or 5H silages in a continuous design (21 wk) experiment. Within each treatment cows were offered silage from each harvest (in harvest number order) for a pre-determined number of days in proportion to herbage DM yield at each harvest. Silages were offered ad libitum while a common concentrate was offered to all cows at 12.0 kg per cow/d over the first 15 wk of the study, 8.0 kg per cow/d during wk 16 -19 and 6.0 kg cow/d during wk 20 - 21. Total yield of herbage harvested over the season from within 3H and 5H were 12.6 and 11.2 t DM/ha, respectively. Across all harvests the mean ME and CP concentration of silages were 10.9 MJ/kg DM and 131 g/kg DM for 3H, and 11.5 MJ/kg DM and 152 g/kg DM for 5H. Silage DMI was greater for cows offered 5H silages compared with 3H silages (14.1 vs. 11.7 kg/d, respectively). Cows offered 5H silages had a greater daily milk yield (33.5 vs. 31.9 kg) and ECM yield (37.4 vs. 35.6 kg) compared with cows offered 3H silages. Treatment had no effect on milk fat or protein concentration. Cows offered 5H silages produced milk with greater concentrations of CLA and n-3 fatty acids. Treatment had no effect on mean BW or BCS, or on efficiency metrics such as milk yield or ECM yield per kg of DMI. Molar proportions of VFA in ruminal fluid differed between the treatments, with cows offered 3H silages having higher proportion of total butyrate (15.9 vs. 14.4% of total VFA) and lower total valerate (3.2 vs. 3.7% of total VFA) compared with those offered 5H. The acetate: propionate and acetate plus butyrate: propionate ratios were unaffected by treatment. In conclusion, increasing herbage harvesting frequency from 3 to 5 times per year improved the nutritional value of the resulting silages, and this led to higher silage DMI, milk yield and ECM yield. However, overall production efficiency (ECM/DMI) was unaffected by treatment.

Prevalence of Antibiotic-Resistant Escherichia coli Isolated from Beef Cattle and Dairy Cows in a Livestock Farm in Yamagata, Japan.

Antimicrobials are used on livestock farms to treat and prevent infectious animal diseases and to promote the growth of livestock. We monitored the prevalence of antibiotic-resistant Escherichia coli (AR-EC) isolates from beef cattle (BC) and dairy cows (DCs) on a livestock farm in Yamagata, Japan. Fecal samples from 5 male BC and 10 male DCs were collected monthly from October 2022 to November 2023. In total, 152 and 884 E. coli isolates were obtained from the BC and DC fecal samples, respectively. Notably, 26 (17.1%) and 29 (3.3%) E. coli isolates in the BC and DC groups, respectively, were resistant to at least one antibiotic. The resistance rates to tetracycline, ampicillin, gentamicin, and chloramphenicol of the isolates were significantly higher than those to the other antimicrobials. The tetracycline resistance genes tetA (70.6%) in DCs and tetB (28%) in BC were identified, along with the blaTEM gene in ampicillin-resistant isolates (BC: 84.2%, DCs: 42.8%). Despite significant variations in the monthly detection rates of AR-EC isolated from BC and DCs throughout the sampling period, the judicious use of antimicrobials reduced the occurrence of AR-EC in both BC and DCs, thereby minimizing their release into the environment.

Identification of Predictive Biomarkers of Lameness in Transition Dairy Cows.

The aim of this study was to identify with a high level of confidence metabolites previously identified as predictors of lameness and understand their biological relevance by carrying out pathway analyses. For the dairy cattle sector, lameness is a major challenge with a large impact on animal welfare and farm economics. Understanding metabolic alterations during the transition period associated with lameness before the appearance of clinical signs may allow its early detection and risk prevention. The annotation with high confidence of metabolite predictors of lameness and the understanding of interactions between metabolism and immunity are crucial for a better understanding of this condition. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with authentic standards to increase confidence in the putative annotations of metabolites previously determined as predictive for lameness in transition dairy cows, it was possible to identify cresol, valproic acid, and gluconolactone as L1, L2, and L1, respectively which are the highest levels of confidence in identification. The metabolite set enrichment analysis of biological pathways in which predictors of lameness are involved identified six significant pathways (p < 0.05). In comparison, over-representation analysis and topology analysis identified two significant pathways (p < 0.05). Overall, our LC-MS/MS analysis proved to be adequate to confidently identify metabolites in urine samples previously found to be predictive of lameness, and understand their potential biological relevance, despite the challenges of metabolite identification and pathway analysis when performing untargeted metabolomics. This approach shows potential as a reliable method to identify biomarkers that can be used in the future to predict the risk of lameness before calving. Validation with a larger cohort is required to assess the generalization of these findings.

Feeding nanoparticles of copper oxide coated with lysine with or without added antagonists affects the copper status but not performance of Holstein dairy cows.

The apparent absorption of copper (Cu) in ruminants is low, with between 0.01 and 0.07 g/g absorbed from sources such as copper oxide (CuO) under typical feeding conditions, resulting in high levels of excretion. Improving the bioavailability of Cu could reduce the supplemental amount required to maintain Cu status and reduce excretion, particularly in the presence of dietary antagonists such as sulfur (S) and molybdenum (Mo). The objective of our study was to determine the Cu status of cows when fed nanoparticle CuO coated with Lys compared with conventional CuO when fed without or in combination with antagonists to Cu absorption (S and Mo) in the diet of dairy cows. Fifty-six multiparous Holstein-Friesian cows that were 48 d ± 17.4 (mean ± SD) post calving and yielding 40.6 ± 6.9 kg milk/d were used in a 2 × 2 factorial design. The 4 treatment groups were; CuO (O-), CuO with added antagonists (O+), nano CuO with a lysine coating (N-), and nano CuO with a Lys coating with added antagonists (N+), fed for 16 wks. We formulated the diets to contain approximately 17 mg Cu/kg dry matter (DM) and diets with antagonists contained an additional 1 g S/kg DM and 6 mg Mo/kg DM, with Lys added to O- and O+ to provide the same daily supply as N- and N+. Blood samples were collected at wk 0, 2, 4, 6, 10 and 16, and liver biopsy samples at wk 0 and 16. We found no effect of dietary treatment on DM intake, milk yield, live weight or body condition score, with mean values of 23.3 kg/d, 40.1 kg/d, 646 kg and 2.68, but milk SCC was higher in cows fed conventional compared with non CuO, or with added antagonist. We also found no effect of treatment on blood activity of gamma glutamyl transferase, superoxide dismutase or ceruloplasmin, hematology profile, or plasma Cu and iron concentration. We found that plasma Mo concentration was increased from 0.36 µmol/L in cows fed O- or N- to 0.80 µmol/L in those receiving O+ or N+. Additional dietary antagonists also decreased the concentration of Cu in the liver of cows fed conventional CuO (C+) over the study period by 1.3 mg/kg DM/d, but in cows fed dietary antagonists and nano CuO coated with Lys (N+), liver Cu concentration was increased by 1.1 mg/kg DM/d. Our study is the first to demonstrate that reducing the particle size of CuO into the nano scale with a lysine coating improves the bioavailability of CuO in the presence of dietary antagonists in dairy cattle, and we did not observe any negative effects on performance or health.

Free fatty acids induce bile acids overproduction and oxidative damage of bovine hepatocytes via inhibiting FXR/SHP signaling.

Hepatic oxidative injury induced by free fatty acids (FFA) and metabolic disorders of bile acids (BA) increase the risk of metabolic diseases in dairy cows during perinatal period. However, the effects of FFA on BA metabolism remained poorly understood. In present study, high concentrations of FFA caused cell impairment, oxidative stress and BA overproduction. FFA treatment increased the expression of BA synthesis-related genes [cholesterol 7a-hydroxylase (CYP7A1), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 7, sterol 12α-hydroxylase, sterol 27-hydroxylase and oxysterol 7α-hydroxylase], whereas reduced BA exportation gene (ATP binding cassette subfamily C member 1) and inhibited farnesoid X receptor/small heterodimer partner (FXR/SHP) pathway in bovine hepatocytes. Knockdown of nuclear receptor subfamily 1 group H member 4 (NR1H4) worsened FFA-caused oxidative damage and BA production, whereas overexpression NR1H4 ameliorated FFA-induced BA production and cell oxidative damage. Besides, reducing BA synthesis through knockdown of CYP7A1 can alleviate oxidative stress and hepatocytes impairment caused by FFA. In summary, these data demonstrated that regulation of FXR/SHP-mediated BA metabolism may be a promising target in improving hepatic oxidative injury of dairy cows during high levels of FFA challenges.

Rumen microbiota succession throughout the perinatal period and its association with postpartum production traits in dairy cows: A review.

The transition period for dairy cows usually refers to the 3 weeks pre-calving to the 3 weeks post-calving. During this period, dairy cows undergo metabolic and physiological adaptations because of their susceptibility to metabolic and infectious diseases. Poor feeding management under these circumstances may adversely affect the health and subsequent production performance of the cows. Owing to long-term adaptation and evolution, the rumen has become a unique ecosystem inhabited by a complex microbial community closely associated with its natural host. Dietary components are metabolized by the rumen microbiota, and volatile fatty acids and microbial protein products can be used as precursor substances for synthesizing meat and milk components. The successful transition of perinatal dairy cows includes changes in diet, physiology, and the rumen microbiota. Rumen microbial profiles have been confirmed to be heritable and repairable; however, adverse circumstances affect rumen microbial composition, host digestion and metabolism, as well as postpartum production traits of dairy cows for a certain period. Preliminary evidence indicates a close relationship between the rumen microbiota and animal performance. Therefore, changes in rumen microbes during the transition period and the intrinsic links between the microbiota and host postpartum phenotypic traits need to be better understood to optimize production performance in ruminants.

Heat stress affects mammary metabolism by influencing the plasma flow to the glands.

BACKGROUND: Environmental heat stress (HS) can have detrimental effects on milk production by compromising the mammary function. Mammary plasma flow (MPF) plays a crucial role in nutrient supply and uptake in the mammary gland. In this experiment, we investigated the physiological and metabolic changes in high-yielding cows exposed to different degrees of HS: no HS with thermal-humidity index (THI) below 68 (No-HS), mild HS (Mild-HS, 68 ≤ THI ≤ 79), and moderate HS (Mod-HS, 79 < THI ≤ 88) in their natural environment. Our study focused on the changes in blood oxygen supply and mammary glucose uptake and utilization. RESULTS: Compared with No-HS, the MPF of dairy cows was greater (P < 0.01) under Mild-HS, but was lower (P < 0.01) in cows under Mod-HS. Oxygen supply and consumption exhibited similar changes to the MPF under different HS, with no difference in ratio of oxygen consumption to supply (P = 0.46). The mammary arterio-vein differences in glucose concentration were lower (P < 0.05) under Mild- and Mod-HS than under no HS. Glucose supply and flow were significantly increased (P < 0.01) under Mild-HS but significantly decreased (P < 0.01) under Mod-HS compared to No-HS. Glucose uptake (P < 0.01) and clearance rates (P < 0.01) were significantly reduced under Mod-HS compared to those under No-HS and Mild-HS. Under Mild-HS, there was a significant decrease (P < 0.01) in the ratio of lactose yield to mammary glucose supply compared to that under No-HS and Mod-HS, with no difference (P = 0.53) in the ratio of lactose yield to uptaken glucose among different HS situations. CONCLUSIONS: Degrees of HS exert different influences on mammary metabolism, mainly by altering MPF in dairy cows. The output from this study may help us to develop strategies to mitigate the impact of different degrees of HS on milk production.