Biocontrol capacity of bacteria isolated from sawdust of the dairy cattle production environment.

This research paper aimed to find endemic bacteria from the cattle production system to control the growth of mastitis pathogens. Bacteria were isolated from compost barn sawdust of two dairy cattle systems and later tested to verify their ability to control the growth of Staphylococcus aureus isolates obtained from cattle with mastitis. Bacterial isolates from these systems were tested to verify biocontrol capacity using the double-layer method. A total of 189 isolates were obtained from all samples by considering the morphology of the different bacterial colonies, with 30 isolates showing positive results for the growth control of at least one S. aureus strain and 19 isolates showing the ability to control more than one pathogen strain. The ability to control more than one pathogen and present a significant halo of inhibition in our isolates represents positive traits in the search for cattle mastitis biocontrol microorganisms. Thus, the results obtained represent the range of bacteria capable of controlling the pathogens without the use of antibiotics.

Udder Hygiene and Mastitis Indicators in Contrasting Environmental Conditions during Half-Time Confinement in Pasture-Based Dairy Systems.

This study aimed to compare the association between two types of housing, compost barns (CB) vs. outdoor soil-bedded yard (OD), and udder hygiene and mastitis indicators in Holstein dairy cows calving in autumn (n = 31) and spring (n = 27). After calving, cows were transferred to a pasture-based system with half-time confinement in one of two treatments: CB or OD. The udder hygiene score (UHS) was evaluated monthly and on days after rainfall over the entire lactation period. Individual somatic cell count (SCC) was determined throughout lactation, and the prevalence of intramammary infection (IMI) was estimated. Cows confined in OD presented higher UHS compared to cows in CB (p < 0.05) in both calving seasons. After rains, autumn-calving cows in OD were dirtier than on days without previous rain (OR = 1.85, CI 95%: 1.1-3.1; p < 0.02). However, no differences in IMI and clinical mastitis were found between OD and CB cows in either calving season.

Association between Mastitis Occurrence in Dairy Cows and Bedding Characteristics of Compost-Bedded Pack Barns.

Compost-bedded pack barns (CB) are receiving increasing attention as a housing system that can potentially improve the welfare of dairy cows. This study characterized the frequency and profile of pathogens isolated from clinical (CM) and subclinical (SCM) mastitis in dairy cows housed in CB. It evaluated the association between mastitis occurrence and bedding characteristics in CB systems. Over six months, seven dairy herds were visited monthly for milk and bedding sample collections. Milk samples from mastitis cases were submitted to microbiological identification by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF MS). Bedding samples were submitted to physical-chemical (pH, organic matter, moisture, and carbon to nitrogen ratio) and microbiological counting (total bacterial counts, coliforms, streptococci, and staphylococci) analyses. Regression analysis was used to determine the association between mastitis occurrence and CB characteristics. Our results showed that Escherichia coli and environmental streptococci were the most frequently isolated pathogens from CM cases, while Staphylococcus chromogenes and contagious pathogens (Staphylococcus aureus and Streptococcus agalactiae) were the most commonly isolated from SCM cases. Bedding moisture content was positively associated with the incidence of CM. The bedding carbon to nitrogen ratio was negatively associated with the incidence of SCM, and the bedding total bacteria counts tended to be associated with the incidence of SCM. Bedding counts of coliforms positively associated with the prevalence of SCM. Our results can support decision-makers in the dairy industry seeking strategies for bedding management and mastitis control.

Effects of Heat Stress in Dairy Cows Raised in the Confined System: A Scientometric Review.

Due to climate change, heat stress is a growing problem for the dairy industry. Based on this, annual economic losses in the dairy sector are verified mainly on a large scale. Despite several publications on thermal stress in lactating dairy cows in confinement systems, there need to be published reviews addressing this issue systematically. Our objective was to scientometrically analyze the effects of heat stress in dairy cows managed in a confinement system. Based on PRISMA guidelines, research articles were identified, screened, and summarized based on inclusion criteria for heat stress in a confinement system. Data was obtained from the Web of Science. A total of 604 scientific articles published between 2000 and April 2022 were considered. Data was then analyzed using Microsoft Excel and CiteSpace. The results pointed to a significant increase in studies on heat stress in lactating cows housed in confinement systems. The main research areas were Agriculture, Dairy Animal Science and Veterinary Sciences. The USA showed the highest concentration of studies (31.12%), followed by China (14.90%). Emerging themes included heat stress and behavior. The most influential journals were the Journal of Dairy Science and the Journal of Animal Science. The top authors were L. H. Baumgard and R. J. Collier. The leading institutions were the Chinese Academy of Agricultural Sciences, followed by the State University System of Florida and the University of Florida. The study maps the significant research domains on heat stress of lactating cows in confinement systems, discusses implications and explanations and highlights emerging trends.

Compost Dairy Barn Layout and Management Recommendations in Kentucky: A Descriptive Study.

This study was conducted to describe the building layout and dimensions, characterize the bedding material, and observe the management practices in 42 compost-bedded pack (CBP) barns in Kentucky (USA). The average herd size found in the study was 90 cows and the breeds consisted of Jersey (6.8%), Holstein (72.7%), and mixed (20.5%). The average CBP barn dimensions were 49.1 m (length) by 21.9 m (width). Many of these barns had feed alleys and driveways; overshot ridges with frequent orientation from NE to SW; and green sawdust, kiln-dried sawdust, or a mixture of both as the most common bedding materials. The bed-turning process was performed mechanically at depths of less than 0.25 m, and the loading of fresh material was performed every one to five weeks, varying by season, weather conditions, barn size, and cow density. The average bedding moisture content was found to be 59.0% (wet bulb-w.b.) and ranged from 36.2 to 71.8%. Coliforms were not present in barns that had a higher compost temperature, and the E. coli, Bacillus, and Streptococcus counts were higher in the barns that had a lower moisture content. In conclusion, it was observed that heterogeneous management was used among the barns and that the producers were satisfied with the compost barn system.

Spatial distribution of bed variables, animal welfare indicators, and milk production in a closed compost-bedded pack barn with a negative tunnel ventilation system.

This research aimed to characterize, evaluate and compare the spatial distribution of the leading bed variables, animal welfare indicators, and milk production in a closed compost-bedded pack barn (CBP) with a negative tunnel ventilation system, for summer and winter periods. The study was carried out in a CBP located in the Zona da Mata region, Minas Gerais, Brazil. The geostatistical modeling technique evaluated the variables of temperature, moisture content, and pH (on the surface and depth of 0.20m) across the length of the bed. Bed samples were characterized for carbon (C), nitrogen (N), and C:N ratio. Cows housed in the CBP were assessed for locomotion and hygiene scores and average milk production. To evaluate the thermoregulation of the cows, the respiratory rate (RR) and surface temperature (ST) were measured. Geostatistical analysis showed spatial dependence and the non-uniformity of the spatial distribution of bed variables. The worst levels of bed temperature and moisture were found in the regions close to the evaporative cooling plate, surrounding the feeding alley, and in the region with the highest cow stocking. The C:N ratio, obtained in both climatic seasons of the year, remained outside the recommended range for ideal composting. During the summer and winter, the bed variables' values suggest that the material was below levels for optimal composting; however, the aerated inner layer was biologically active. The high animal density significantly impacted the worsening of the bed moisture content and internal temperature. In general, dairy cows showed adequate hygiene (score of 1 and 2) and locomotion (score of 0 and 1) scores for the two climatic seasons evaluated, indicating good welfare conditions. In relation to RR and ST, the summer period presented less favorable environmental conditions. During winter, the average milk production was 28.1 ± 7.2 kg day-1, and during summer, it was 26.9 ± 6.7 kg day-1.

Effects of Compost-Bedded Pack Barn on Circulating Cortisol and Beta-Endorphins in Dairy Cows: A Case Study.

The up-to-date literature suggests that the compost-bedded pack barn housing system is capable of remarkably improving productive and reproductive performance, as well as health status and welfare, in dairy cattle. However, there is currently limited knowledge available on the endocrine and biochemical changes in animals housed in such alternative systems. Therefore, this study aimed to measure blood cortisol (COR) and beta-endorphins (BE) in 22 two-year-old primiparae Fleckvieh cows, who were randomly allotted to the following two different housing systems: CB (n = 11) and FB (n = 11). Blood samples were collected at the beginning of the experiment (T0) and every two months thereafter (T1, T2, and T3). The COR and BE were measured through an immunoenzymatic kit. With the only exception being T0, no differences were observed over time between the two groups, neither for COR nor for BE. However, the blood cortisol levels of the CB cows decreased over time, while a T1 peak was identified in the FB group. On the contrary, both the housing systems displayed numerically higher BE at T3 than at the other experimental times. Therefore, the overall data suggest that the compost-bedded pack barn did not significantly affect the studied parameters. Accordingly, cow welfare should be assessed using a wider panel of animal-based indicators.

Production, economic viability and risks associated with switching dairy cows from drylots to compost bedded pack systems.

The use of compost bedded pack systems (CBS) has increased over the past 5 years in tropical countries, and studies associating production traits with economical outcomes of this system are warranted. Our objectives were to evaluate productive traits, economic outcomes and the risks of losses of dairy farms that switched from a drylot system (DLS) to a CBS and to compare these with similar farms that did not change their system. We collected data from 18 farms over 36 consecutive months (August 2014 to July 2017). All farms started the study as DLS, and six farms switched to CBS in the second year. The other 12 farms kept their DLS during the 36 months of evaluation. Annual technical and economic indexes per farm were collected and calculated. Additionally, a risk analysis was performed based on a 10-year historical series of milk prices. The results were analysed using a regression model including year and herd as categorical variables (fixed), system and herd size as quantitative variables (fixed), and system × herd as a random variable. Furthermore, a non-metric multidimensional scaling plot was used to evaluate producers' profiles in each year. Milk fat, milk total solids, and somatic cell count did not change when farms switched from DLS to CBS, and averaged 3.80%, 12.04%, and 256 500 cells/ml, respectively. However, milk protein (%) decreased in CBS farms. The majority of milk production variables were not affected. Nevertheless, farms that switched to CBS increased milk production per cow by 13.3% compared with DLS farms. Total operation costs (296 076.83 $/year) were not affected by the system, and neither were the costs of concentrates, roughage, labour or medicines. Net margin per litre (0.09 $/l), operating profit (14.95%), assets per litre (398.68 $/l per day) and return on assets (10.27%) did not change when farms switched from DLS to CBS. Net margin ($/l and $/cow) and asset turnover rate increased in CBS farms. Risk analysis indicated that the risk was reduced by 38% in CBS farms. Furthermore, our analysis showed that producers who switched to CBS had similar technical and economic indexes in the first year before switching their system. In conclusion, this study demonstrates that CBS systems might be promising for producers in tropical countries who are looking for a more productive and less risky system. We did not observe improvements in animal health as previously reported in the literature.

Effects of winter housing systems on production, economics, body weight, body condition score, and bedding cultures for organic dairy cows.

Certified-organic dairy cows (n = 268) were used to evaluate the effect of 2 winter (December to April) housing systems on milk production, somatic cell score (SCS), body weight, body condition score (BCS), and economics across 3 winter seasons (2013, 2014, and 2015). Bedding cultures from the housing systems were also evaluated. Cows were randomly assigned to 2 treatments (2 replicates per group): (1) outdoor (straw pack, n = 140) or (2) indoor (3-sided compost bedded pack barn, n = 128). Cows calved during 2 seasons (spring or fall) at the University of Minnesota West Central Research and Outreach Center, Morris, Minnesota, organic dairy. Milk, fat, and protein production and SCS were recorded from monthly milk recording. Body weight and BCS were recorded biweekly as cows exited the milking parlor. Bedding cultures from the housing systems were collected biweekly. Costs for key inputs and the price received for milk production were recorded for the study period and averaged for use in the profitability analysis. Energy-corrected milk and SCS were not different for the outdoor (15.1 kg/d, 2.64) and indoor (15.7 kg/d, 2.57) housing systems, respectively. In addition, cows in the outdoor and indoor housing systems were not different for body weight (528 vs. 534 kg) and BCS (3.22 vs. 3.23), respectively. Daily dry matter intake was 19.1 kg/d for the outdoor cows and 19.6 kg/d for indoor cows. The total bacteria count from bedding samples tended to be lower in the outdoor (13.0 log10 cfu/mL) compared with the indoor (14.9 log10 cfu/mL) system. Milk revenue and feed cost were not different for the 2 housing systems. Labor and bedding costs were lower and net return was higher for the outdoor housing system. The outdoor straw pack system had a $1.42/cow per day net return advantage over the indoor compost bedded pack barn. In summary, lactating cows housed outdoors on straw-bedded packs did not differ for production or SCS, or for body weight, BCS, or dry matter intake, but had greater profitability than cows housed in an indoor compost bedded pack barn.