Large Dairy Research Articles

Genetic diversity and molecular epidemiology of outbreaks of Klebsiella pneumoniae mastitis on two large Chinese dairy farms

Klebsiella pneumoniae is an opportunistic and environmental mastitis-causing pathogen, with potential for contagious transmission. Repetitive element sequence-based PCR was used to determine genetic diversity and explore potential transmission and reservoirs for mastitis caused by K. pneumoniae on 2 large Chinese dairy farms. A total of 1,354 samples was collected from the 2 dairy farms, including milk samples from cows with subclinical and clinical mastitis, bedding, feces, feed, teat skin, and milking liners. Environmental samples were collected from all barns and milking parlors and extramammary samples from randomly selected dairy cows on both farms. In total, 272 and 93 K. pneumoniae isolates were obtained from Farms A and B, respectively (with ~8K and 2K lactating cows, respectively). Isolation rates from clinical mastitis (CM), subclinical mastitis (SCM), and environmental or extramammary samples were 34, 23 and 37%, respectively for Farm A and 42, 3, and 34% for Farm B. The K. pneumoniae isolated from CM milk and extramammary or environmental sources had high genetic diversity (index of diversity >90%) on the 2 farms and from SCM on Farm A. However, on Farm B, 9 SCM isolates were classified as 2 genotypes, resulting in a relatively low index of diversity (Simpson's index of diversity = 0.39; 95% CI = 0.08-0.70). Genotypes of K. pneumoniae causing mastitis were commonly detected in feces, bedding, and milking liners (Farm A), or from teat skin, sawdust bedding, and feed (Farm B). Based on its high level of genetic diversity, we inferred K. pneumoniae was an opportunistic and environmental pathogen causing outbreaks of CM on these 2 large Chinese dairy farms. Nevertheless, that only a few genotypes caused SCM implied some strains had increased udder adaptability and a contagious nature or a common extramammary source. Finally, control of intramammary infections caused by K. pneumoniae on large Chinese dairy farms must consider farm-level predictors, as the 2 outbreaks had distinct potential environmental sources of infection.

A large-scale survey of Theileria orientalis infection in grazing dairy heifers in Kyushu, Japan.

The objective of the present study was to investigate the prevalence of Theileria orientalis infection and the influence of this disease on dairy grazing heifers in Kyushu by monitoring red blood cell (RBC) indexes, and to evaluate the efficacy of diminazene diaceturate treatment of T. orientalis-infected animals. A monthly epidemiological survey was conducted for Holstein heifers, which were reared from 10 to 16 months of age on a large commercial dairy farm and grazed on eight independent grasslands from April to November, 2009. During the survey, a total of 2,803 blood samples were collected from the 891 grazing heifers, in which the prevalence of T. orientalis infection was 52.4%. Compared with the heifers before infection, heifers with high parasitemia (more than 100 parasites per 104 RBC) had significantly decreased RBC indexes, such as RBC count, hemoglobin concentration, and hematocrit (P<0.05), whereas heifers with low parasitemia (less than 100 parasites per 104 RBC) had similar RBC indexes as those before infection. Treatment with diminazene diaceturate had lower efficacy in heifers with high parasitemia than those with low parasitemia (40.7% and 73.2% became negative, respectively, P<0.05). In summary, T. orientalis infection is a potentially serious problem in Kyushu, and it is important to routinely implement control programs for heifers that are grazed on grasslands in this region.

Milk Components by In-Line Fiber Optic Probe-Based FT-NIR: Commercial Scale Evaluation of a Potential Alternative Measurement Approach for Milk Payment.

Mid-infrared (MIR) spectroscopy has traditionally been used to determine the macronutrients in bovine milk, as the basis of milk payment. Recent studies have demonstrated that NIR/FT-NIR spectroscopic systems can not only achieve MIR measurement performance, but are also generally simpler, more robust, and thus much more amenable to actual industrial process applications. The goal of this unique study was to investigate the feasibility of in-line FT-NIR spectroscopy for milk fat, protein, and total solids (TS) determination in a large industrial dairy processing facility, as an alternative basis for milk payment. Multivariant chemometric models using partial least squares (PLS) regression were built to predict the milk components. Over 1000 composite FT-NIR results gathered from the milk unloading process were compared directly to independent third-party FT-IR results. Accuracy, precision, and linearity of the method were shown by Standard Error of Prediction (SEP) and Range/SEP of individual components. The SEP for fat, protein, and TS models were 0.09, 0.11, and 0.52, respectively. Range/SEP were 25.10, 12.60, and 6.40 for fat, protein, and TS, respectively. Accuracy and precision for the three components were further evaluated by the mean differences (0.01, 0.05, and 0.51) from dairy FT-IR results and the standard deviations of the mean difference (0.09, 0.09, and 0.13). Robustness was demonstrated by evaluating milk with natural variation over 6 months and using multiple instrumentation setups. The repeatability was also evaluated. Overall, the in-line FT-NIR technology was found to have accurate, reliable, consistent performance similar to dairy FT-IR technology.

The Impact of Paratuberculosis on Milk Production, Fertility, and Culling in Large Commercial Hungarian Dairy Herds.

Paratuberculosis (PTBC) is a chronic disease caused by Mycobacterium avium subsp. paratuberculosis (MAP), which is common in dairy herds worldwide, although the scale of its impact on herd productivity is unclear. The aim of our study was to determine the differences between MAP ELISA positive vs. negative cows in terms of milk production and quality, reproductive parameters, and culling. The data of five large dairy herds that participated in the voluntary PTBC testing program in Hungary were analyzed. Cows were tested by ELISA (IDEXX Paratuberculosis Screening Ab Test, IDEXX Laboratories, Inc., Westbrook, ME, USA) using milk samples collected during official performance testing. The outcome of the initial screening test involving all milking cows in the herds was used for the classification of the cows. The 305-day milk production, reproduction and culling data of 4,341 dairy cows, and their monthly performance testing results (n = 87,818) were analyzed. Multivariate linear and logistic models, and right censored tobit model were used for the statistical analysis. Test-day and 305-day milk production of ELISA positive cows decreased by 4.6 kg [95% CI: 3.5–5.6 kg, P < 0.0001 (−13.2%)] and 1,030 kg [95% CI: 708–1,352 kg, P < 0.0001 (−9.4%)], compared to their ELISA negative herdmates, respectively. Milk ELISA positive cows had 35.8% higher [95% CI: 17.9–56.4%, P < 0.0001] somatic cell count, on average. Test positive cows conceived 23.2 days later [95% CI: 9.2–37.3 days, P = 0.0012 (+16.5%)] and their calving interval was 33.8 days longer [95% CI: 13.2–54.4 days, P = 0.0013, (+9.7%)], compared to the negative cows, on average. Milk ELISA positive cows were less likely to conceive to first insemination (odds ratio: 0.49, 95% CI: 0.31–0.75, P = 0.0013), and required 0.42 more inseminations to conceive [95% CI: 0.07–0.77, P = 0.0192 (+13.7%)], on average. Milk ELISA positive cows were culled 160.5 days earlier after testing compared to their ELISA negative herdmates (95% CI: 117.5–203.5 days, P < 0.0001). Our results suggest that MAP ELISA positive cows experience decreased milk production, milk quality, fertility, and longevity, which supports the need to control the prevalence of PTBC in dairy herds.

Intensified Use of Reproductive Technologies and Reduced Dimensions of Breeding Schemes Put Genetic Diversity at Risk in Dairy Cattle Breeds.

In the management of dairy cattle breeds, two recent trends have arisen that pose potential threats to genetic diversity: the use of reproductive technologies (RT) and a reduction in the number of bulls in breeding schemes. The expected outcome of these changes, in terms of both genetic gain and genetic diversity, is not trivial to predict. Here, we simulated 15 breeding schemes similar to those carried out in large French dairy cattle breeds; breeding schemes differed with respect to their dimensions, the intensity of RT use, and the type of RT involved. We found that intensive use of RT resulted in improved genetic gain, but deteriorated genetic diversity. Specifically, a reduction in the interval between generations through the use of ovum pick-up and in vitro fertilization (OPU-IVF) resulted in a large increase in the inbreeding rate both per year and per generation, suggesting that OPU-IVF could have severe adverse effects on genetic diversity. To achieve a given level of genetic gain, the scenarios that best maintained genetic diversity were those with a higher number of sires/bulls and a medium intensity of RT use or those with a higher number of female donors to compensate for the increased intensity of RT.

The effects of omega-3 α-linolenic acid from flaxseed oil supplemented to high-yielding dairy cows on production, health, and fertility

Among the long-chain fatty acids (FA), the omega-3 (n-3) FA have the most potent immunomodulatory activities. In the present large-scale study, we tested the effects of supplementation of α-linolenic acid (ALA) from flaxseed commenced at the dry period on milk yield, health and fertility of dairy cows. Cows in a large commercial dairy farm were randomly divided into two groups 21 days before expected calving. During the dry period, cows in the treatment group were fed a diet that contained, on a DM basis, 40 g/kg of an extruded flaxseed supplement (EFLX; n = 276); their postpartum diet contained 50 g/kg of the same supplement. The cows were group-fed, and based on average cow's intake, the EFLX cows consumed 80 and 220 g ALA/day per cow prepartum and postpartum, respectively. The control cows received a diet with a different composition but a similar content of nutrients (CTL; n = 240). A veterinarian routinely examined the cows 7 to 10 days after calving, treated them according to the farm's routine practice, and determined their body condition score at that visit and at peak lactation. Milk yield was 4.5% greater (1.8 kg/day; P < 0.0001), and fat (P < 0.0001) and protein (P = 0.002) contents were lower in the EFLX vs. CTL group. The proportion of n-3 FA in milk was 3.9 times higher in EFLX than in CTL cows (P < 0.0001), and the omega-6 (n-6):n-3 ratio in the milk fat decreased from 13.0 in the CTL cows to 4.1 in the EFLX cows (P < 0.0001). The unsaturated FA content in milk fat was 20.1% greater in EFLX than in CTL cows (P < 0.0001). Ketosis incidence was lower in the EFLX vs. CTL group, 23.5 and 31.2%, respectively (P = 0.05), and ketosis was less severe in the former (P = 0.03). The mortality rates in EFLX and CTL cows were 0.7 and 4.6%, respectively (P = 0.005). No differences were observed in conception rates at first or second insemination, but days from first service to conception and calving to conception were 17 (P = 0.07) and 18 days (P = 0.09) less in the EFLX cows, respectively. In conclusion, supplementation of EFLX to dairy cows from the dry period increased milk yield, decreased incidence of ketosis and severe metritis, reduced mortality, and tended to enhance fertility performance. Overall, ALA supplementation improved milk quality and was beneficial to the cow's health and fertility.

Epidemiological study to investigate the incidence and prevalence of clinical mastitis, peracute mastitis, metabolic disorders and peripartum disorders, on a dairy farm in a temperate zone in Japan

BackgroundOur aim was to investigate the incidence and prevalence of clinical mastitis, peracute mastitis, metabolic disorders, and peripartum disorders, and to examine factors affecting the prevalence of each disease in cows raised on a large dairy farm in a temperate climate in Japan. The present study was performed on a large commercial dairy farm with approximately 2500 Holstein cows. Data were collected from 2014 to 2018, and involved 9663 calving records for 4256 cows.ResultsThe incidence rate on the farm was 21.9% for clinical mastitis, 10.4% for peracute mastitis, 2.9% for metabolic disorders, and 3.2% for peripartum disorders. The prevalence rates for clinical mastitis, peracute mastitis, metabolic disorders, and peripartum disorders were 28.0, 13.3, 3.7, and 4.0%, respectively. In all four diseases, the probability of time to occurrence for each disease was associated with parity and calving season (P < 0.05). Regarding metabolic disorders and peripartum disorders, the probability of occurrence decreased during the first 10 days after calving.ConclusionsOur results showed that clinical mastitis occurred most often in this temperate zone, and that metabolic disorders and peripartum disorders occurred from calving to day 10 post-calving.

\u2018Milk from the purest place on earth\u2019: examining Chinese investments in the Australian dairy sector

This article explores the emerging intersections between the shift towards higher quality food consumption in China and Chinese investment in overseas farmland. Based on an ethnographic study of a Chinese company acquiring one of Australia’s largest dairy farms, the article argues that the linkage between imported Australian milk and perceptions of safety and quality has served as a powerful driver of Chinese investment in overseas farmland—a linkage that has largely been overlooked by literature on China’s role in the global land rush. Drawing on the notion of ‘quality imaginaries’, the paper shows how images of Australian farmland as natural, pure, and geographically isolated have been mobilized by the investor company to position itself as provider of fresh, premium milk in the Chinese market. While such place-based qualities constitute a prized advantage, ironically, they also present a looming risk as the investor company struggles to reconcile fresh milk’s perishability with the farm’s location at the ‘edge of the world’. Thus, the case study not only demonstrates how cultural meanings tied to food and eating shape the ways in which investors imagine land’s affordances and possibilities but also draws attention to land’s materiality as a factor that both facilitates and destabilizes investment in farmland.

Vibrations as a cause of texture defects during yogurt manufacturing – Formation of vibrations and their propagation in dairy production lines

Abstract Vibrations during the fermentation of yogurt and related milk products have recently been reported to disturb the gelation and result in quality defects such as particle formation, graininess, and syneresis. However, primary research on this topic was focused on experiments performed on a laboratory and pilot-plant scale. In this study, three large dairy factories were visited, and yogurt samples were directly taken out of various fermentation tanks, showing great differences in terms of graininess and particle content. Thereupon, vibration measurements were conducted at three industrial yogurt plants. Particularly, pumps and their influence on the vibrational excitation of the fermentation tanks were examined. The major structural and mechanical differences of these plants, such as distances between the vibration source and the tank or the types of pumps used, led to varying vibrational states at the fermentation tanks. We concluded that the vibrational excitation of each plant must be evaluated individually in order to estimate the potential for vibration-induced texture defects.

Industrial Heat Pump Integration in Non-Continuous Processes Using Thermal Energy Storages as Utility – An NLP Enhancement of the Graphical Approach

The aim of this paper is to enhance the results of the graphical approach for Heat Pump (HP) integration in non-continuous processes. A nonlinear programming (NLP) formulation is developed which optimizes temperature levels of condensation, evaporation, and storage temperature layers in order to further reduce total annual cost (TAC) and greenhouse gas (GHG) emissions. In addition, the NLP formulation requires low computation time given the practical approach. By its application on an AMMIX butter production of a large dairy factory, it is shown, that the temperature differences in the condenser and evaporator are reduced sharply which improves the COP of the HP from 2.2 to 3.4. As a result, the TAC can be reduced by an additional 16,721 NZD/y and the GHG emissions by an additional 29 tCO2/y in comparison to the graphical approach.

Epidemiological study on calf diarrhea and coccidiosis in dairy farms in Bahir Dar, North West Ethiopia

BackgroundA longitudinal prospective study was conducted from October 2017 to April 2018 on calf diarrhea and coccidiosis in dairy farms in Bahir Dar, North West Ethiopia with the objectives of determining the incidence of calf diarrhea and calf coccidiosis from diarrheic calves, assessing the major risk factors associated with calf diarrhea and coccidiosis and identifying the existing Eimeria species. A total of 237 calves, 86 calves from 52 smallholder dairy farms and 151 calves from 8 large dairy farms, were used for this study. Fresh fecal samples were collected from 86 diarrheic calves for identification of Eimeria species.ResultsOverall incidences of calf diarrhea and coccidiosis found in this study were 33.5 and 20.1%, respectively. In total, 19 potential risk factors were investigated for their association with calf diarrhea and coccidiosis from diarrheic calves using Cox regression. Age of calf (HR = 2.057, P = .002), body condition (HR = 1.802, P < .001), house condition (HR = 2.072, P = .004) and age at first colostrum feeding time (HR = 2.107, P = .002) were found significantly (P < 0.05) associated with the risk of diarrhea by multivariate Cox regression. Among the risk factors tested, age (HR = 13.36, P < .001) and sex of calves (HR = 3.500, P = .020) were found significantly (P < 0.05) associated with coccidiosis by multivariate Cox regression. A total of nine Eimeria species were identified. E. bovis (28.6%), E. zuernii (19.0%) and E. auburnensis (14.3%) were the most common Eimeria species encountered.ConclusionThe incidence of calf diarrhea and coccidiosis was high in the dairy herds in North West Ethiopia. Therefore, sound dairy calf management practices are needed to mitigate risk factors for calf diarrhea and coccidiosis with a view to reducing the incidence of calf diarrhea and coccidiosis in Ethiopian dairy farms.

JA:2021-31. Does the Use of a Nasal Lavage Intervention Improve Pulmonary Function for Dairy Workers?

ABSTRACT Purpose: Dairy workers are at the frontline of exposure to bioaerosols, which typically contain bacteria and associated pro-inflammatory constituents (e.g., endotoxin). As such, dairy workers are at an increased risk for respiratory illness, most likely mediated through a strong proinflammatory response. Very few studies have systematically evaluated control strategies to reduce exposure and improve health. Given the challenges and limitations of implementing engineering controls, we propose the use of a low-cost and low-burden intervention. Hypertonic saline (HTS) was recently shown to attenuate inflammation in trauma patients. Here, we conducted an intervention to administer HTS in a nasal lavage to determine if the inflammatory response was mitigated and if the airway function improved among dairy workers. Methods: Ten participants were recruited from a large herd dairy and randomly assigned to treatment (n = 5) and control groups (n = 5). Each participant received normotonic saline (308 mOsm) nasal lavage (NL) before their shift over 5 consecutive days. After each shift, the treatment group received HTS, while the control group received normotonic saline. All samples were analyzed for 10 different cytokines using a multiplex assay. Spirometry was performed pre- and post-shift to examine forced expiratory volume in one second, forced vital capacity and the subsequent ratio, and peak expiratory flow rate (PEFR). Personal breathing zone samples for inhalable bioaerosols were collected across the work shift; mass concentrations and endotoxin abundance were determined by gravimetry and a fluorescent assay, respectively. Statistical analyses and models were performed using SAS. Results/Findings: Differences in pro-inflammatory cytokines were observed. There was an interaction effect on IL-10 between treatment, day, and time of day, indicating promotion of anti-inflammatory effect. The treatment group experienced an increase in PEFR change (0.76 L, p = 0.12) near statistical significance; no statistically significant differences were observed in the other spirometry measures. Both groups of dairy workers in this study experienced less of a decline in cross-shift pulmonary function when compared to other studies. Practical Application: The HTS nasal lavage is designed as a low-cost intervention that can be self-administered before and after every shift across other agricultural operations. This study was limited by small sample size and warrants further investigation.

Effects of employer management on employee recruitment, satisfaction, engagement, and retention on large US dairy farms

Lack of employee engagement and satisfaction and high turnover rate of employees are major problems on some US dairy farms. Farm adoption of human resource management (HRM) practices varies widely. Using feedback from 168 employees from 12 large dairy farms, our objectives were to understand employee perceptions of HRM strengths and weaknesses and their influence on (1) employee satisfaction, (2) retention of employees, (3) willingness of employees to recommend the farm as a place to work, and (4) level of employee engagement on the farm. Employees who rated their employers higher for almost any management-related question (MRQ) were more satisfied in their jobs and more likely to recommend their place of work to other potential employees. Employees reported a higher intention to stay on the farm when employers scored higher on MRQs connected to employer-employee relationships. Employees who rated "Relationships" (a component consisting of 5 MRQs) higher were more likely to have a higher rate of satisfaction, were more likely to intend to stay at their job, and were more likely to recommend their place of work to others. No single management question was positively related to employee engagement (as measured by employees having and sharing ideas to improve the business); however, ethnicity, gender, job role, duration of employment, and employee's self-appraisal of their desire to learn and commitment to the farm were each associated with engagement. Female employees were less likely to provide ideas to their employers (compared with male employees), as were Spanish-speaking employees (compared with English-speaking employees). Differences between Spanish- and English-speaking employees were also present in measures such as intention to stay (shorter) and willingness to recommend the farm as a place to work (higher). Employees who rated themselves higher on their desire to learn and commitment to the farm were more likely to provide ideas to their employers, as were longer-term employees. In conclusion, we inferred that dairy farm management can improve employee retention and engagement through improved use of HRM practices.

Typologie des systèmes d’élevage camelins du sud du Maroc

Bien que disposant d’un appui des autorités nationales dans le cadre du Plan Maroc Vert, l’élevage camelin au Maroc est encore assez mal connu. La présente étude a eu pour objectif de disposer d’une description des types d’élevages camelins dans une portion vaste du sud du pays, caractérisée par sa grande concentration des élevages camelins. Pour ce faire, dans le cadre d’une enquête sanitaire, 168 éleveurs chameliers appartenant à neuf provinces du sud du Maroc ont été interviewés sur leur système de production. Les 168 troupeaux camelins ont représenté 11 426 dromadaires soit environ 10 % de la population cameline de cette zone. Au final, un tableau comprenant 168 élevages camelins décrits par 20 variables actives (taille et structure du troupeau, organisation de la gestion et pouvoir de décision, ampleur de la mobilité, commercialisation, pratiques de complémentation alimentaire et de prévention sanitaire) et deux variables illustratives (statut de l’enquêté et région d’origine) a été soumis à une analyse multivariée (analyse des correspondances multiples et classification automatique). L’analyse a permis d’identifier quatre types d’éleveurs : a) ceux possédant de grands troupeaux laitiers traditionnels, b) les citadins possédant des petits troupeaux, c) les éleveurs pluriactifs opportunistes, et d) les éleveurs parfois pluriactifs, faiblement intégrés au marché et sous-traitant leur activité d’élevage. Cette typologie paraît être très liée à la région d’origine des éleveurs indiquant une certaine spécificité régionale.

APPLICATION OF SMART GRID TECHNOLOGY ON A LARGE DAIRY FARM

Currently, the improved performance of renewable energy sources triggered their increased application. In most cases, however, they are combined with a centralized power supply. Therefore, power production from multiple sources and power consumption requires efficient coordination. A solution may be Smart Grid Technology. It allows improving efficiency, reliability, and stability of electricity generation and distribution under certain economic benefits. The study objective was to assess the practicability of establishing a smart grid on large-scale dairy farms with above 1000 cow stock. The study was based on the electricity consumption data obtained on the modern dairy farms in the Leningrad Region, Russia, associated with the electricity inputs, the energy distribution scheme on a dairy farm and the use of transformer substations. The conceptual scheme of the smart grid for a dairy farm was developed. The factors for assessing the local electricity generation resources were considered including a proposed comprehensive environmental indicator, which takes into account the volume of pollutants produced and the degree of their negative impact on the environment. The study verified the principal possibility and feasibility of establishing a smart grid for large dairy farms.

Heat load increases the risk of clinical mastitis in dairy cattle

The study was aimed at assessing heat load-related risk of clinical mastitis (CM) in dairy cows. Records of CM for the years 2014 and 2015 were obtained from a large conventional dairy farm milking about 1,200 Holstein cows in central Italy. A case of CM was defined by the presence of clinical signs and veterinary confirmation. Quarter milk samples were collected and bacteriological investigated for each CM. Etiological agents were identified and classified as environmental or contagious pathogens. Hourly weather data from the nearest weather station were used to calculate heat load index (HLI). Upper and lower thresholds of HLI, at which the animal accumulates or dissipates heat, were settled and used to measure heat load balance through the accumulated heat load (AHL) model. Zero and positive values of AHL indicate periods of thermo-neutral and heat accumulation, respectively. Each case of CM was associated with HLI-AHL values recorded 5 d before the event. The risk of CM was evaluated using a case-crossover design. A conditional logistic regression model was used to calculate the odds ratio and 95% confidence intervals of CM recorded in thermo-neutral (AHL = 0) or heat load (AHL > 0) days, pooled or stratified for pathogen type (environmental or contagious). Classes of AHL as low (<6.5), medium (6.6-34.9), and high (>35) were included in the model. Other variables included in the model were milk yield as liters (<20, 20-30, and >30), days in milk (<60, 60-150, and >150), and parity (1, 2-3, and >3). A total of 1,086 CM cases were identified from 677 cows. Escherichia coli, Streptococcus spp., and Streptococcus uberis were the environmental pathogens isolated with the highest frequency; Staphylococcus aureus prevailed within contagious species. The analysis of pooled data indicated a significant effect of heat load on the occurrence of CM in the contagious pathogen stratum. Higher milk yield, middle and late stage of lactation, and older parity increased the risk of CM under heat load conditions. However, the association between pathogen type and these factors was not clear because the model provided significant odds ratios within all pathogen categories. The present study provided the first evidence of an association between HLI and CM in dairy cattle and suggested the ability of the AHL model to assess the risk of mastitis associated with heat load.

The prevalence of pathogens causing bovine mastitis and their associated risk factors in 15 large dairy farms in China: An observational study

The primary objective of this study was to determine the distribution of major pathogens causing mastitis and analyze the association of the main pathogens with the type of milk {milk samples collected from cows with mastitis of different severities, which consisted of subclinical mastitis (Lanzhou Mastitis Test weak positive, positive, and strong positive) and clinical mastitis}, region, season, bedding material, parity and lactation stage on large dairy farms. Fifteen large dairy farms in twelve major milk-producing provinces of China were enrolled in the study for approximately one year; 1,153 mastitis milk samples were collected and processed. The most frequently isolated pathogens were Staphylococcus spp. (39.03 %), Streptococcus spp. (11.01 %), Bacillus spp. (8.24 %), Aerococcus viridans (6.76 %), and Acinetobacter spp. (3.38 %), and most of these pathogens were environmental bacteria (67.53 %). Contagious pathogens (Staphylococcus aureus and Streptococcus agalactiae) were more prevalent in milk samples from bovine clinical mastitis cases than in milk samples from bovine subclinical mastitis cases. The percentages of Staphylococcus spp. and Bacillus spp. might be higher in northeastern farms than in farms located in other regions. A higher percentage of Staphylococcus spp. was observed in summer, while a lower proportion of Streptococcus spp. was detected in fall. Streptococcus agalactiae and Streptococcus uberis were more frequently isolated in farms using sand bedding, whereas Staphylococcus aureus, Staphylococcus haemolyticus and Bacillus licheniformis were more prevalent in farms using organic bedding. No obvious associations were found between the main mastitis pathogens and parity or lactation stage. Based on these findings, the dominant pathogens, types of milk, regions, seasons and bedding materials should be considered when designing mastitis prevention and control programs at large Chinese dairy farms.

Assessment on reproductive performance of crossbred dairy cows selected as recipient for embryo transfer in urban set up bishoftu, Central Ethiopia

The reproductive status of a recipient cow is among the factors that influence the success of embryo transfer in bovine. The study was carried out on a total of 276 cows from 25 dairy farms classified as large (>20 cows), medium (10-20 cows) and small scale (1-10 cows) dairy production system. Data were collected through personal interviews of owners, from an individual animal record and gynecological evaluation of animals. Accordingly, the overall mean (±SD) of AFC, CI, LL, DMY, and NSPC were 30.07±2.17 months, 13.33±2.84 months, 9.08±1.10 months, 14.33±4.59 liters/day and 1.59±1.02, respectively. Milk yield and body condition did not have a significant effect on NSPC (P > 0.05) whereas parity significantly influenced NSPC, with cows in parity 3 showing the lowest NSPC (p<0.05).

Reducing bovine leukemia virus prevalence on a large midwestern dairy farm by using lymphocyte counts, ELISA antibody testing, and proviral load

Cattle infected with BLV have disrupted immune systems, associated with reduced milk production, shortened lifespan, and predisposition to lymphoma. The objective of this exploratory case study was to develop a disease control testing and management protocol to reduce the prevalence of bovine leukemia virus (BLV) within a large commercial dairy herd. Three diagnostic tests were available: lymphocyte count (LC), ELISA for BLV antibodies, and proviral load (PVL) as determined by quantitative polymerase chain reaction (qPCR). Both testing and management protocols evolved over time as the BLV prevalence decreased and we learned how to reduce labor and unnecessary or redundant diagnostic testing. Test results were used to inform culling and pen assignments for cows most likely to transmit BLV or develop disease. Significant decreases in the percentage of cows with LC≥10.0x103/μL (4.22% to 1.04%) and PVL&gt;0.5 were observed for all lactations during the 4 quarters of intervention. By October 30, 2020, 6 of ~3,000 cows remained with a detectable PVL. Additionally, it was found that LC and PVL were associated with clinical lameness, but not with clinical mastitis.

Foreign experience in the development of dairy cattle and directions of its use in domestic practice

The article analyzes the support for the US market, where the government has allocated almost $ 22.2 billion for the development of dairy cattle. direct and indirect subsidies to the country's dairy sector (35.02 c/l), which is equivalent to 73% of farmers' milk sales, showed relatively high domestic support, export subsidies, conservation programs, risk management programs, disaster relief programs, loan programs, crop insurance, livestock support. Surveys to support the Indian market, which ranks second in the world in raw milk production (9.5%), have shown that almost 80% of small-scale farmers are small-scale farmers. Milk collection is carried out by 130 thousand dairy cooperatives. NABARD (National Bank for Agriculture and Rural Development) under DEDS, provides for subsidies of up to 25% of costs. China is investing heavily in the construction of large dairy farms and livestock complexes with up to 100,000 cows. The Australian market produces 9.3 million tonnes of milk, of which 36% is exported and is the world's fourth exporter of dairy products (6% of the world market). Australia's dairy cattle are characterized by a small amount of direct government support. During 2015-2016, agriculture received financial and commercial assistance over $ 147 million. US in the form of payments to farms. It has been established that price forecasting plays an important role in regulating the milk market in Australia, on the basis of which the profile Ministry, taking into account world prices, generates milk price indices. Analysis of milk production in Switzerland has shown that it remains highly subsidized. In 2013, state support for milk producers amounted to CHF 1.8 billion, incl. direct subsidies are estimated at 1.5 billion Swiss francs, which is 61 thousand Swiss francs per dairy farm, or 0.41 Swiss francs per 1 liter of milk. The state support system for dairy cattle in Canada has been found to include the following instruments: import tariffs that restrict dairy imports; minimum guaranteed prices for raw milk that are set at the maximum amount of milk sold to the dairies within the quota; a system of direct payments to farmers for milk production within the quota. The amount of direct payments per 1 liter of milk is set annually by the government. In order to support Canadian producers in technological modernization aimed at improving the efficiency of milk production, a dairy farm investment program (DFIP) is implemented with state support of $ 250 million. USA According to the Organization for Economic Co-operation and Development (OECD) in Iceland, Japan, Norway and Switzerland, the level of support for dairy producers exceeds on average 70% of the gross income of farmers, in Canada, the EU, Hungary, Korea and the USA the amount of support is 40-55%. An analysis of the support for the development of dairy cattle in the EU countries showed that the following instruments are allocated for these purposes: production restrictions (milk production quotas); government interventions and storage; Establishment of product sales regulations / regulations; the dairy package (including regulating contractual relations in the dairy sector); foreign trade (import regulations, export subsidies); government subsidies. It is found that the main factor that increases the profitability of dairy production in developed countries is the improvement of quality and differentiation of the range. Major factors contributing to the successful development of dairy cattle are increased government support and economical use of resources. Also used are a set of financial incentives, including reducing the tax burden. Key words: Livestock, milk market, domestic support, development programs, cooperation, financial incentives, subsidies, import tariffs, quotas.