Dairy Herds Research Articles

Metabolomic fingerprinting of milk fever cows: Pre- and postpartum metabolite alterations.

Milk fever (MF), a metabolic disorder in dairy cows characterized by low blood calcium concentrations postpartum, is well-recognized clinically. However, comprehensive data on the alteration of metabolites associated with this condition remains sparse. Delineate serum metabolite profiles and metabolic pathways preceding, coinciding with, and after the onset of MF. Twenty-six cows, including 20 healthy cows and 6 cows initially affected by MF. Because of culling, the number of MF-affected cows decreased to 4 at MF week, +4 weeks, and +8 weeks postpartum. A nested case-control longitudinal study was conducted, with blood samples collected at -8 and -4 weeks prepartum, MF week, and +4 and +8 weeks postpartum. Serum analysis utilized direct injection/liquid chromatography/tandem mass spectrometry (DI/LC/MS/MS) techniques. Key findings included the identification of diverse metabolites such as hexose, amino acids, phosphatidylcholines, lysophosphatidylcholines, and sphingomyelin, which varied between studied groups (P < .05). The most marked metabolic alterations were observed 4 weeks prepartum. In total, 42, 56, 38, 29, and 24 metabolites distinguished the MF group at the respective time points (P < .05). Additionally, 33 metabolic pathways, including amino acid, antioxidant metabolism, fatty acid degradation, and carbohydrate processing, were impacted (P < .05). Metabolic disruptions in dairy cows begin several weeks before the clinical manifestation of MF and persist up to 8 weeks postpartum. These findings emphasize the complexity of MF, extending beyond only hypocalcemia and indicate the necessity for preemptive monitoring in dairy herd management.

Herd-Level Risk Factors Associated with Mycoplasma bovis Serostatus in Youngstock on Irish Dairy Farms

Mycoplasma bovis is a globally significant pathogen of cattle associated with a wide range of clinical syndromes, including respiratory disease, mastitis, arthritis, otitis, and reproductive failure. Since its detection in Ireland in 1994, M. bovis has become a significant contributor to morbidity and mortality in Irish cattle. This study aimed to investigate herd-level risk factors associated with M. bovis seropositivity in replacement dairy heifers, using data from 105 Irish dairy herds. Ten heifers per herd were sampled on three occasions: spring 2018, spring 2019, and autumn 2019. Seropositivity was evaluated using two thresholds: ≥1 positive heifer (Model ≥ 1POS) and ≥3 positive heifers (Model ≥ 3POS). M. bovis seropositivity varied over time, with at least one positive heifer in 50.4% (95% confidence interval (CI): 40.5–60.3) of herds in spring 2018, 35.2% (95% CI: 26.2–45.1) in spring 2019, and 45.7% (95% CI: 36.0–55.7) in autumn 2019. Herds with three or more positive heifers increased from 31.4% (95%CI: 22.7–41.2) in spring 2018 to 42.9% (95% CI: 33.2–52.9) by autumn 2019. Risk factors for M. bovis seropositivity included the purchase of cattle, which significantly raised the odds of seropositivity across multiple visit periods (Model ≥ 1POS: Odds ratio (OR) 3.84, p = 0.02; Model ≥ 3POS: OR 3.69, p = 0.02). Managing more than three land parcels, housing heifer calves separately from bull calves, and sharing airspace between calves and older animals also increased seropositivity risks. Conversely, more colostrum feeds reduced the risk of seropositivity (Model ≥ 1POS: OR 0.81, p = 0.05), while colostrum quality assessment and feeding waste milk showed a trend toward increased risk. These findings suggest the importance of robust biosecurity measures, including limiting cattle purchases, improving calf management, and enhancing colostrum feeding practices, to control the spread of M. bovis. This study provides valuable insights into the epidemiology of M. bovis in Irish dairy herds, emphasising the need for targeted biosecurity and surveillance to safeguard herd productivity.

Economic impact of staphylococcal and mammaliicoccal subclinical mastitis in dairy herds from Northeast Brazil.

This study aimed to assess the impact of S. aureus as well as Non-aureus Staphylococci and Mammaliicocci (NASM) subclinical mastitis-causing in the economic return in dairy herds. Data were gathered from the databases of five dairy herds located in the Agreste region of Pernambuco state, Northeastern Brazil, over a period of three consecutive months. A total of 155 mammary quarters from 155 healthy cows were categorized into the healthy group. Meanwhile, 257 mammary quarters from 187 cows that tested positive for either S. aureus or NASM were categorized into the infected group. The effect of mammary quarter infection in economic return was estimated using milk payment criteria on milk samples from healthy vs. infected cows based on a linear mixed model. Milk yield and milk price influenced the economic return, and both varied according to factors like herd, parity, stage of lactation, period of analysis, and the type of pathogen causing subclinical mastitis. There was a reduction in the average economic return caused by NASM infection (by 0.41 to 0.65 US$/cow/day) and S. aureus infection (by 0.25 to 0.36 US$/cow/day), when considering the effect of the pathogen over time for 1 and ≥ 2 infected quarters. Although no significant differences were observed in economic return between healthy cows and those infected with NASM or S. aureus, it is important to collect data on these pathogens for a more precise assessment of the economic impact of subclinical mastitis and for developing enhanced approaches for prevention and control.

From One Heath to One Sustainability: The Role of Contagious Mastitis Pathogens in Decreasing the Dairy Herd Sustainability.

Economic, social, and environmental sustainability are the results of efforts aiming to improve all aspects of milk production, respecting animal welfare and improving herd health. An epidemiological study was designed to assess the role of contagious pathogens (S. aureus and S. agalactiae) in a cohort of 120 dairy herds located in the southern regions of Italy. Milk quality was assessed using certified methods, and the prevalence of mastitis pathogens in bulk tank milk was determined using quantitative polymerase chain reaction. Welfare scores were assessed using a scoring card that has more than 100 items, including animal-based measurements. Statistical analyses were performed using general lineal model and logistic regression procedures. The results showed that S. aureus had a significant negative effect on the amount of milk nutrients delivered to the dairy plant, and on the level of welfare, whereas the presence of S. agalactiae did not show any significant association. The major risk factors associated with the presence of S. aureus were also identified to help prioritize control programs. These results support the "One Sustainability" approach, implying that an increase in animal productivity is related to the improvement of animal health and welfare and potentially leading to the mitigation of greenhouse gas emissions.

Gene Enrichment and Pathway Analysis for Ketosis Resistance in Dairy Cattle: A GWAS-Based Approach

Ketosis in dairy cattle is a common metabolic disorder that arises during the transition period from late gestation to early lactation. It is primarily caused by an imbalance between energy intake and expenditure, leading to an excessive accumulation of ketone bodies. This condition can significantly affect cattle health and productivity. Recent advances in genomic research, especially genome-wide association studies (GWAS), offer an opportunity to explore the genetic factors that contribute to ketosis resistance. The aim of this study is to comprehensively review and analyze existing GWAS data using gene enrichment analysis to identify potential functional candidate gene pathways associated with ketosis resistance in dairy cattle. In this study, data obtained from seven different studies were examined and 640 non-repetitive genes were obtained after filtering. Using Enrichr, an online tool for gene annotation, pathway analysis was performed with human homologs of the identified genes. Our findings highlight the acylglycerol homeostasis pathway, the regulation of triglyceride metabolism, and the role of chylomicrons in maintaining metabolic balance during ketosis. Additionally, immune response pathways were found to be linked to the genes associated with ketosis, offering insights into the intricate interplay between metabolic and immune pathways in ketosis. This study emphasizes the importance of understanding genetic factors in developing breeding strategies aimed at enhancing metabolic health and productivity in dairy cattle. Future research should focus on validating these candidate genes and exploring their mechanistic roles to facilitate targeted interventions and improve resistance to ketosis in dairy herds.

Influence of Dietary Manipulation on the Blood Biochemical Profile and Growth Performance of Crossbred Dairy Heifer

This study aimed to assess the influence of dietary manipulation with commonly available concentrate sources on the nutritional status and growth performance of crossbred dairy heifer. Concentrates that were used alternatively in three feed preparation were (Wheat bran, rice polish and maize powder). Twelve crossbred dairy heifers (50% Holstein Friesian blood (HF) (age around 12-13 months; body weight (173-196) kg were chosen from the existing dairy herd of Bangladesh Agricultural University (BAU) Dairy Farm, Department of Dairy Science, BAU. Latin square design was used to conduct the study. The feeding experiment was lasted for a duration of 100 days (10 days for adjustment period and rest 90 days for main trial that was divided into 3 periods). Blood analysis, growth performance measurement, feed efficiency calculation and feed cost analysis were performed at 15 days interval. Among the twelve blood biochemical parameters no significant (p&lt;0.05) variation was found except the result of total cholesterol which was found highest in rice polish fed group (170.1 mg/dL). Body weight gain per 15 days was significantly higher (9.08 kg/15d) and dry matter intake per kg of body weight gain (9.56kg DMI/kg BWG) was significantly lower when heifers were supplied feed preparation containing wheat bran. Rest other body growth parameters didn’t show any significant difference when feed with three feed preparations.

B-001 Serum 25-hydroxyvitamin D and C-3 epimer concentrations throughout gestation in a bovine dairy herd

Abstract Background Serum 25-hydroxyvitamin D (25(OH)D) serves as an indicator of vitamin D status in most animal species. The recent identification of its C-3 epimer, 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3) remains diagnostically confounding. The appearance of this epimer in blood serum has been reported for both pregnant women and infants; however, because of its recent discovery, its physiologic role, biochemical regulation, and overall biologic importance have yet to be fully elucidated. Given its prevalence in pregnant women, it was hypothesized that 3-epi-25(OH)D3 may serve as a novel predictive biomarker of pregnancy in animals. Methods In the current study, we validated an LC-MS/MS method to measure the mono-hydroxyvitamin D metabolites 25-hydroxyvitamin D2 (25(OH)D2), 25-hydroxyvitamin D3 (25(OH)D3), and 3-epi-25(OH)D3, in bovine serum. Serum was collected from dairy cows at six stages of pregnancy (n=60 (10 per group), pre-breeding heifers, 30-40 days pregnant, 70-90 days, 120-180 days, 210-260 days, and 30-45 days post-calving). The 25(OH)D metabolites were extracted from serum by supported liquid extraction (SLE) and the eluate was derivatized with 2-Nitrosopyridine. Derivatized samples were introduced to the LC-MS/MS, ionized by electrospray ionization in positive-ion mode, and detected and quantified by multiple-reaction monitoring. Results The LC-MS/MS method was linear in the concentration range of 0.25 ng/mL to 100 ng/mL with an r2 &amp;gt; 0.99 for each analyte. 3-epi-25(OH)D3 and total serum 25(OH)D concentrations were calculated for each stage of pregnancy. Pre-bred heifers had serum 25(OH)D concentrations ranging from 65 - 85 ng/mL with trends toward non-significant increases with mean values approaching 100 ng/mL during pregnancy. Interestingly, 3-epi-25(OH)D3 remained near baseline (1.3 - 1.9 ng/mL) for the first 90 days and elevated 3- to 4-fold thereafter. Conclusions This study confirms that epimerization of 25(OH)D3 is a conserved biochemical process across species. While not predictive of pregnancy itself, the increase in circulating 3-epi-25(OH)D3 concentrations was consistent with mid- to late-gestational increases in estrogen concentration observed for dairy cattle. Future studies will explore the potential link between increases in gestational estrogen and epimerization.

Risk factors for introduction of BVDV in the context of a mandatory control program in Dutch dairy herds.

Bovine Viral Diarrhea Virus (BVDV) is a common viral disease in cattle, causing economic losses in naive herds where the virus is introduced. In the Netherlands, a BVDV control program has been in place since 1998, evolving from voluntary to mandatory participation for dairy herds since April 2018. Participation in the BVDV control program is not mandatory for non-dairy farms. The aim of this study was to determine risk factors for new introduction of BVDV into certified BVDV-free herds in the context of a national BVDV control program in dairy herds. In this retrospective case-control study, survey data were collected from 149 dairy farms that lost their BVDV-free status (case herds) and 148 matched dairy farms that maintained their BVDV-free status (control herds) between 2018 and 2021. The survey captured information about potential risk factors and herd characteristics in the 2 years leading up to the loss of BVDV-free status (case herds, virus detection in at least one animal or when seroconversion was detected) or remaining BVDV-free (control herds). Descriptive statistics and logistic regression with a backward selection and elimination procedure were used to identify potential risk factors associated with losing BVDV-free status. Risk factors were quantified as an Odds Ratio (OR) with the associated 95% confidence interval (CI). The risk factor with the highest OR for losing BVDV-free status was purchasing cattle from herds without BVDV-free status (OR 1.25, CI 1.10-1.41), followed by the farmer having another profession that resulted in contact with other cattle (OR 1.25, CI 1.06-1.47), housing young calves and adult cows in the same barn (OR 1.22, CI 1.08-1.38), having a permanent employee on the farm (OR 1.17, CI 1.04-1.31), having a group calving pen (OR 1.16, CI 1.03-1.32), escaped cattle from other farms that mingled with own cattle (OR 1.16, CI 1.01-1.33), and nearest distance to a non-dairy farm (OR 1.15, CI 1.03-1.28). Although the BVDV status of most dairy herds can be checked in an open register, approximately half of the farmers indicated that they purchased cattle from BVDV-free herds while they were actually purchasing from non-BVDV-free farms. Farmers should be stimulated to actively check the true BVDV status of the herd from which cattle are purchased to further reduce the risk of introduction. In addition, indirect contact with cattle from other farms through either the farmer or other on-farm staff should be avoided. It is strongly advised to work in these situations with proper biosecurity measures such as changing boots and coveralls. The results can be used to improve BVDV control programs to further decrease the prevalence.

A longitudinal study of the dynamics of Mycoplasma bovis antibody status in primiparous cows and bulk tank milk in Swedish dairy herds

Mycoplasma (M.) bovis is an important pathogen causing pneumonia, mastitis, and arthritis in cattle all over the world entailing reduced animal welfare and economic losses. In this longitudinal study, we investigated the presence of M. bovis antibodies in bulk tank milk (BTM) and in milk from primiparous (PP) cows at 4 sampling occasions over 2 years. Herd characteristics associated with a positive antibody test result in PP cows were investigated. The participating dairy herds (n = 149) were situated in southern Sweden, samples were collected and analyzed with ID Screen antibody ELISA. Information on herd characteristics was retrieved from the national Dairy Herd Improvement database. To identify herd characteristics associated with the presence of antibodies in PP cows, mixed linear regression with herd and sample as random factors were used. The apparent herd-level prevalence of M. bovis infection based on antibodies in BTM was 17% but with the addition of PP cows the prevalence increased to 28%. The results showed that larger herds and introduction of cattle was associated with higher antibody levels in PP cows. In conclusion, this study showed a clear difference in the apparent prevalence of M. bovis infection based on antibodies in BTM or in PP cows, the no. of positive herds were almost doubled when including PP cows. This motivates repeated sampling of a few PP cows to find newly infected herds in an early stage. Finally, the results showed that introduction of cattle influences the level of M. bovis antibodies. This is important in the control and prevention of further spread of the infection. It is essential for free herds to know their M. bovis status and antibody testing is highly recommended if introducing cattle.

Exploring Longitudinal Associations between Farmer Health and Wellbeing, and Dairy Herd Subclinical Mastitis Prevalence and Productivity: The HUNT Study, Norway

The health and wellbeing of farmers is one aspect of the sustainability of agriculture, as is the health and productivity of livestock. Previous research suggests a possible association between the 2, but the complexity of the relationships between farmers and their livestock can hamper research efforts. This observational study utilizes high quality existing survey and register data from a cohort of Norwegian dairy enterprises to explore possible longitudinal associations between farmer health and wellbeing (general health, chronic disease or condition, chronic pain, anxiety or depression symptoms, or poor life satisfaction) and changes in dairy herd udder health (estimated by the proportion of milk tests with a high somatic cell count (SCC%)) or milk yield (kilograms per cow-year equivalent). We found evidence of a general trend toward increased SCC% with poor farmer health or wellbeing. If the farmer had poor self-reported general health, the odds ratio (OR) for a one-year increase in SCC% at the enterprise was 1.51 (95% CI: 0.76,2.99, OR 1.80 (0.71, 4.51) after adjustment for possible effect modifiers) compared with those with good health, and for poor life satisfaction the OR was 1.50 (0.71,3.15) (2.61 (0.92,7.39) after adjustment). We also find evidence that enterprises where a farmer was experiencing poor health or wellbeing tended to have lower odds of a decrease in milk yield than other enterprises. The OR for a one-year decrease in milk yield with any chronic disease or condition was 0.42 (0.24,0.76), and with symptoms of anxiety or depression the OR was 0.56 (0.23,1.34). Potential confounders and effect modifiers are discussed and explored. These results suggest that further longitudinal research to unravel the relationships between farmer health and wellbeing, and livestock health and productivity is needed.

Association between perinatal mortality and the management of cows before and at calving in large dairy herds

Stillbirths account for a relevant proportion of total calf mortality on dairy farms. In addition, the stillbirth rate is an important criterion for assessing animal welfare. The aim of this study was to determine the relationship between the stillbirth rate and aspects concerning the management of cows ante partum and during the calving period in larger dairy herds. In 97 dairy farms with an average herd size of 550 cattle (≥24 months old), data concerning farm management and animal health were collected as part of a farm inspection using a questionnaire. The stillbirth rate of the respective farms was determined based on the farm's own data on the milk yield test and analyzed for possible correlations with farm management using a multivariable factor analysis. A higher stillbirth rate was found on farms with particularly lean and overconditioned transit cows in the herd. A positive association to the stillbirth rate was also found for farms using a special birth monitoring system for heifers and those with more than 20% assisted calvings. There was no association with herd size. Regardless of herd size, factors that are related to the stillbirth rate may be determined by analyzing the farm management. The body condition of the cows is a key parameter. The introduction of special birth monitoring for heifers can probably be interpreted as a reaction to increased stillbirths in the herd. Conditioning cows before calving is an important field of action for herd managers in order to avoid stillbirths. The cows should not approach the calving period in an overly lean or over-conditioned state. When in such state, however, it is advisable for these cows to be monitored more closely in order to allow for professional assistance at the pertinent time period. Integration of body condition scoring of cows at dry-off, calving and the end of the high-yielding period, assessment of calving conditions and training of staff involved in obstetrics into veterinary herd management is warranted.

First detection and impact of bovine herpesvirus type 4 on dairy cattle reproduction in Thailand

Background and Aim: Postpartum reproductive tract infections pose significant challenges to dairy farms, leading to economic losses due to reduced fertility associated with uterine inflammation. In veterinary practice, numerous research groups have explored the underlying causes of subfertility in cows, including surveying endemic viral infections related to endometritis in local areas. This study investigated bovine herpesvirus 4 (BoHV-4) infection in Thai dairy herds and assessed its impact on endometritis and subsequent reproductive outcomes. Materials and Methods: The present study analyzed BoHV-4 DNA in various samples, including milk, blood, and endometrial tissue, from 44 Holstein-Friesian cows 21–47 days postpartum across five dairy herds in Central Thailand. BoHV-4 glycoprotein B and thymidine kinase DNA sequences were detected using the polymerase chain reaction (PCR) and nested PCR, with sequence comparisons made to GenBank data for phylogenetic analysis. The endometritis status was diagnosed through vaginal mucus examination and endometrial cytology, with reproductive performance monitored up to the subsequent calving. Results: BoHV-4 DNA was identified in blood and endometrial tissues (15.91%) but not in milk samples. Phylogenetic analysis revealed that the local BoHV-4 strains are similar to those identified in Brazil and Japan. Notably, the presence of BoHV-4 was correlated with reduced postpartum reproductive performance, particularly extending the interval from calving to the first service. Conclusion: Our findings underscore the importance of integrating BoHV-4 genomic surveys and uterine health assessments to refine reproductive management strategies within the dairy industry. Keywords: bovine herpesvirus-4, dairy cattle, endometritis, phylogenetic analysis, reproductive performance, Thailand.

Herd-level occurrence and risk factors associated with respiratory and enteric pathogens from dairy calves in Ontario: A cross-sectional study

This cross-sectional herd-level study aimed to determine the occurrence of and risk factors for pathogens associated with neonatal calf diarrhea and bovine respiratory disease on Ontario dairy farms. From April to August 2022, a convenience sample of 100 dairy farms were visited once. A questionnaire covering farm biosecurity, calving and colostrum management, preweaning nutrition, and housing was administered on-farm. At each farm visit, approximately 5 calves between 2 and 35 d old were randomly selected for fecal sampling. Furthermore, approximately 5 calves between 21 to 122 d old were randomly selected for nasopharyngeal sampling. In total, 363 fecal samples (from 83 dairy farms) and 390 nasopharyngeal swab samples (from 80 dairy farms) were collected. Fecal samples were analyzed individually using a multiplex PCR to identify bacterial and parasitic enteric pathogens. Nasopharyngeal swabs were analyzed as one pooled sample per farm using bacterial culture and real-time PCR. The most common enteric pathogens detected at herd-level were Cryptosporidium parvum (67.4%) and Escherichia coli K99+ (13.2%). The most common respiratory pathogens detected at herd-level were Pasteurella multocida (62.5%), bovine coronavirus (42.5%), and Mycoplasma bovis (21.2%). Multivariable logistic models were built to explore associations between the most common pathogens and herd-level predictors selected from the questionnaire. Herd positivity for C. parvum was positively associated with having more than 61 preweaned calves per year and feeding mainly whole milk to calves. The presence of M. bovis was positively associated with herds that combined manual and automatic milk-feeding systems, and the presence of bovine coronavirus was positively associated with having more than 98 preweaned calves during the year. Univariable Poisson regression models were built to explore the association between the most common pathogens and preweaning calf mortality. Herds that were positive for C. parvum, M. bovis, or bovine coronavirus had a greater risk of preweaning calf mortality. These results provide insights for future research on pathogens associated with NCD and BRD and offer guidance for veterinarians and dairy farmers in implementing disease control measures in dairy calf herds.

Hot topic: Avian influenza subtype H5N1 in US dairy—A preliminary dairy foods perspective

In February and March of 2024, an unusual illness began affecting dairy herds primarily in Texas and neighboring states. The causative agent of this illness was ultimately confirmed in late March 2024 to be a strain of highly pathogenic avian influenza H5N1 belonging to clade 2.3.4.4b. In the months following the emergence of this viral disease in cattle, infections have spread to at least 191 herds in 13 states at the time of this writing in August 2024, primarily through cattle and human movement. Surprisingly, early examination of raw milk samples from clinically affected animals indicated that the virus had an affinity for the mammary tissue, and viral shedding into raw milk occurred at high levels, exceeding 108 log10 50% tissue culture infectious dose (TCID50) in some cases. These high viral loads coupled with evidence that farm cats who consumed raw milk from clinically ill animals were infected and exhibited high mortality rates, raised concerns about the safety of the US milk supply for human consumption. To date, 4 cow-associated human infections have been reported, all from farm employees with direct contact with infected animals. Several parameters ultimately affect the theoretical public health risk from consumption of dairy products manufactured from a milk supply containing H5N1, namely (1) initial viral load, (2) persistence of H5N1 in raw milk, (3) viral inactivation through processing practices including pasteurization, and (4) human susceptibility and infectious dose. In the short period since the emergence of this disease in dairy cattle in the United States, research has begun to answer these critical questions, although our knowledge is still quite limited at this time. Here we review the literature available from the current H5N1 outbreak in US dairy cattle, as well as selected relevant literature from previous research in other animal agriculture sectors, that affect our current understanding of the parameters associated with the food safety risk of this disease in the US dairy supply chain.

Short communication: Dairy Victory™ Platform: A Novel Benchmarking Platform to Empower Economic Decisions on Dairy Farms.

In the face of diminishing economic margins, dairy farmers globally are compelled to maintain economic competitiveness. Benchmarking emerges as a strategic tool to establish new, achievable improvement objectives that balance ambition with practicality. This typically requires integrating diverse data sources such as feed, milk production, diet, and market prices. However, many farms lack essential, cow-level data like daily milk output and milk income over feed cost (IOFC), which hampers economic performance visibility and informed decision-making. To address this challenge, we introduce “Dairy Victory™ platform (DVP)” a novel cloud-based benchmarking platform designed to simplify complex analyses. The DVP uniquely calculates zootechnical and economic key performance indicators (KPIs) at the cow and herd levels and benchmarks these against a dynamically selected cohort of farms, facilitating comparisons across various farm sizes, and milk production levels. The primary objective of this paper is to demonstrate the utility of DVP as a decision-making tool in supporting farmers and consultants with both operational and strategic decisions. It emphasizes leveraging benchmarking information to enhance decision-making processes, thereby highlighting the significant value that DVP brings to farmers, consultants, and dairy farm stakeholders. Our study analyzed data from 712 farms from December 2023, focusing on several KPIs, such as milk production, milk quality, feed efficiency, and IOFC using Dairy Herd Improvement (DHI) records. This approach showcases DV's ability to utilize minimal data inputs for detailed analysis, leveraging peer performance to set desirable and/or achievable goals. We present a case study demonstrating how the DVP platform can guide dairy farms using anonymized peer data. This approach enables users to potentially improve their IOFC by up to 35%. Our findings highlight DVP's potential as a powerful tool for generating insightful analyses, simulations, and recommendations, primarily from test-day data, but also integrated with market and estimated data. This supports more strategic decision-making in dairy management, including automatic goal-setting based on peer performance.

Hot topic: Epidemiological and clinical aspects of highly pathogenic avian influenza H5N1 in dairy cattle

On March 24, 2024, the US Department of Agriculture (USDA) confirmed the first case of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b in dairy cattle. Following this initial detection, the virus was found to have spread to other species, including humans. Since then, at least 192 dairy herds across 13 states have tested positive for the virus. The emergence of HPAI H5N1 in dairy cattle poses a serious threat to the dairy industry, requiring an approach that integrates human, animal, and environmental health. Enhancing biosecurity, improving surveillance, and advancing research are critical to managing this challenge. Swift adaptation is needed to protect both public health and dairy production. Through this work, we discuss the epidemiological and clinical aspects of HPAI H5N1 in cattle by reviewing the spatiotemporal situation of the disease across the United States, the clinical signs and testing leading to a confirmed case, and the surveillance and control measures implemented at the national and state levels. Further, considering pathogenesis and risk factors, we discuss surveillance and control measures to implement within herds, and note areas where research is needed to understand how to control this emerging disease.

Effects of solute carrier family 27 member 1 (SLC27A1) genotypes on fat content and major fatty acids in colostrum and milk from Murrah and “Murrah × Carabao” crossbred buffaloes

This study analyzed the effect of Solute carrier family 27 member 1 (SLC27A1) genotypes on fat content and major fatty acids (lauric acid C12:0, myristic acid C14:0, palmitic acid C16:0, stearic acid C18:0, and oleic acid C18:1n-9) in milk and colostrum of 46 Murrah and “Murrah × Carabao” crossbred buffaloes at the Philippine Carabao Center - University of the Philippines Los Baños dairy herd. The SLC27A1 genotypes (CC and CT) were determined by the polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) method using DNA extracted from hair follicles. This study found polymorphism in the SLC27A1 gene that were consistent with Hardy Weinberg’s law of equilibrium (HWE), with a polymorphic information content (PIC) and heterozygosity (H) estimate of 0.2915 and 0.3542, respectively, for Murrah; and 0.3219 and 0.4032, respectively for “Murrah × Carabao” crossbreeds. In Murrah buffaloes, the CT genotype was significantly associated (P&lt;0.05) with higher colostrum yield and milk fat content, compared to CC. In “Murrah × Carabao” crossbreds, CT was associated with higher C12:0, C14:0, and C16:0, but lower C18:1n-9 in colostrum; and lower C16:0 in milk compared to CC. This study showed polymorphisms in SLC27A1 genotypes and their significant effects on colostrum yield and milk fat content in Murrah buffaloes and some major fatty acids in colostrum and milk from “Murrah × Carabao” crosses.

Updated method of estimating heat load for grazing dairy cattle

ABSTRACT Understanding heat stress in dairy cows is important for ensuring their welfare and productivity. While the Temperature Humidity Index is commonly used to determine heat stress conditions it does not consider outdoor factors (e.g. wind speed and solar radiation). To address this, the Grazing Heat Load Index (GHLI) which predicts respiration rate, an indicator of heat stress, was previously developed using data from the Waikato region in New Zealand. This study updated the GHLI using a weather data and animal heat stress indicators (e.g. respiration rate and drooling), collected from dairy herds in the Northland, Waikato, Canterbury, and Southland regions. A mixed-effects linear model, which included air temperature, solar radiation and wind speed as inputs was developed using data from these diverse locations. The updated model slightly outperformed the previous model on a validation dataset when predicting respiration rate. While air temperature remained the primary driver of respiration rate, solar radiation was an exacerbating factor, whereas wind exerted a mitigating effect. Challenges persist in characterising heat stress in conditions such as high wind speed. Non-linear modelling techniques could enhance the predictive capability of the GHLI model, thereby refining heat stress assessment in pasture-based dairy systems nationwide.

Comparing the Performance of Automatic Milking Systems through Dynamic Testing Also Helps to Identify Potential Risk Factors for Mastitis.

Automatic milking systems (AMSs) are revolutionizing the dairy industry by boosting herd efficiency, primarily through an increased milk yield per cow and reduced labor costs. The performance of milking machines, whether traditional or automated, can be evaluated using advanced vacuum meters through dynamic testing. This process involves scrutinizing the system and milking routine to identify critical points, utilizing the VaDia™ logger (BioControl AS, Rakkestad, Norway). Vacuum recordings were downloaded and analyzed using the VaDia Suite™ software under the guidance of a milking specialist. Access to data from AMSs across various manufacturers and herds facilitated a retrospective study aimed at describing and comparing key milk emission parameters for different AMS brands while identifying potential mastitis risk factors. Using the proper statistical procedures of SPSS 29.1 (IBM Corp., Armonk, NY, USA), researchers analyzed data from 4878 individual quarter milkings from cows in 48 dairy herds. Results indicated a significant variability in milking parameters associated with quarter milk yield and AMS brand. Notably, despite AMSs standardizing teat preparation and stimulation, this study revealed a surprisingly high frequency of two major mastitis risk factors-bimodality and irregular vacuum fluctuations-occurring more frequently than in conventional milking systems. This study, one of the few comparing different AMS brands and their performance, highlights the crucial role of dynamic testing in evaluating AMS performance under real-world conditions.

An agroecological approach to preparation and use of a milk protein production baseline.

Commercial dairy production occurs in a complex management environment, but increasingly, the dairy manager is expected to provide detailed reporting of productivity and environmental outcomes, for which conventional research methods double-blind crossover or case:control trials are inappropriate. This paper demonstrates the development of a milk protein production monitoring tool using a temporal (baseline) control in longitudinal, census-type investigations of modulation of system performance in response to factor change. It utilises farm-derived current and historical data, and contrasts seasonal responses with those achieved on neighbouring farms in a 2×2 contingency table. The approach is then shown to be useful in assessing the effect of two approaches to moderating milk urea concentration. Firstly, milk urea content can be monitored as it falls due to reduced feed protein content, and this fall can be arrested when milk protein content starts to decline relative to the value expected for the herd at any lactation stage. Secondly, by providing a dietary intervention aimed at increasing the availability of metabolic energy in the last month before calving, udder development can be augmented, leading to greater protein secretion capacity, meaning greater utilisation of circulating amino acids, and thus more limited substrate for urea synthesis. Thus, the changing impact of differing nutrition practices on dairy herd nitrogen excretion to environment can be followed with daily precision. In principle this approach can provide useful insights into a wide range of practical management interventions.