Compost Bedded Pack Research Articles

Mapping of the Thermal Microenvironment for Dairy Cows in an Open Compost-Bedded Pack Barn System with Positive-Pressure Ventilation.

Simple SummaryAdequate environmental conditions are essential to ensure the wellbeing and productivity of dairy cattle. The use of compost-bedded pack barn (CBP) systems in dairy farming certainly improves animal welfare conditions, but it is necessary to evaluate and characterize the thermal environment inside the facilities. The main objective of this study was to map the thermal environment inside a CBP system with positive-pressure ventilation. Through mapping, it was possible to identify regions with more challenging conditions for animals in terms of thermal comfort. The results achieved can be used to direct decision-making processes to create adequate environmental conditions for the hosted animals.The objective of this study was to evaluate and characterize the dependence and the spatial and temporal distribution of variables and indices of the thermal environment in an open compost-bedded pack barn system with positive-pressure ventilation (CBPPV) during the winter period. The study was conducted in a CBPPV system located in the Zona da Mata region, Minas Gerais, Brazil. The indoor environment was divided into a mesh composed of 55 equidistant points, where data on dry-bulb air temperature (tdb) and relative humidity (RH) were collected. The collected data were divided into four periods—dawn, morning, afternoon, and night—and mean values were obtained. To evaluate the thermal microenvironment, the temperature and humidity index (THI) and the specific enthalpy of air (h) were used. For spatial dependence analysis, geostatistical techniques were applied. Through the results, a strong spatial dependence was verified for all variables evaluated. Through THI and h maps, conditions of thermal comfort were found for dairy cattle. The highest values of tdb, THI, and h were recorded in the afternoon period in the northwest region of the facility (tdb = 23.2 °C, THI = 69.7, and h = 50.9 kJ∙kg of dry air−1).

CFD Study of a Tunnel-Ventilated Compost-Bedded Pack Barn Integrating an Evaporative Pad Cooling System.

Simple SummaryIt is known that improving the welfare of cows increases dairy productivity. A compost-bedded pack barn equipped with evaporative cooling pads to regulate the inside environmental conditions of dairy seems to be a synergic combination to improve substantial the welfare in dairy facilities. However, there is a lack of information about both techniques working together. A computational model of a tunnel-ventilated compost-bedded pack barn with an evaporative pad cooling system was developed to know the spatial distribution of temperature, relative humidity and velocity of the air inside the barn. These variables allowed us to compute a thermal stress index for dairy cattle to identify the geometric characteristics and operative conditions of the evaporative pad cooling that provide the best environmental conditions inside the barn according to the outside environmental conditions.Evaporative cooling is one of the most efficient techniques to reduce heat stress in cows in agricultural facilities. Additionally, compost-bedded pack barn has been shown to improve the welfare and production of cows. Two techniques were combined and analysed by developing a computational fluid dynamics (CFD) model of a tunnel-ventilated compost-bedded packed barn that integrated the heat and airflow dynamics of an evaporative pad cooling system. This allowed us to study the distribution of dry-bulb temperature, relative humidity and airflow velocity inside the barn based on the external environmental conditions, thickness of the pad, water temperature and specific manufacturer characteristics of the pad, providing optimal cooling pad location, size and operating conditions in the barn. Employing experimental data the CFD model was validated showing good agreement. The Equivalent Temperature Index for dairy Cattle (ETIC) was used to determine the level of stress of the cows considering the airflow velocity. It was found a moderate stress due to high relative humidity and low airflow velocity. From the predicted results, it was recommended to increase the airflow velocity above 3 m s when simultaneously the external dry-bulb temperature and relative humidity exceed 30 °C and 55%, respectively, simultaneously. Additionally, installation of baffles at the pad outlet to drive the airflow to the floor was suggested to improve the drying of the compost-bedded closed to the pads, where a low airflow velocity region was established.

Distribution of staphylococcal and mammaliicoccal species from compost-bedded pack or sand-bedded freestall dairy farms

The purpose of this prospective observational study was to determine whether dairy cattle housing types were associated with staphylococcal and mammaliicoccal populations found on teat skin, bedding, and in bulk tank milk. Twenty herds (n = 10 sand-bedded freestall herds; n = 10 compost-bedded pack herds) were enrolled. Each herd was visited twice for sample collection, and at each visit, 5 niches were sampled, including bulk tank milk, composite teat skin swab samples collected before premilking teat preparation, composite teat skin swab samples collected after premilking teat preparation, unused fresh bedding, and used bedding. All samples were plated on Mannitol salt agar and Columbia blood agar and staphylococcal-like colonies were selected for further evaluation. Bacterial colonies were speciated using MALDI-TOF mass spectrometry. All species were grouped into 4 categories included host-adapted, opportunistic, environmental, and unclassified. Absolute numbers and proportions of each genus and species were calculated. Proportional data were compared between groups using Fisher's exact test. Data representing 471 staphylococcal-like organisms were analyzed. Overall, 27 different staphylococcal and mammaliicoccal species were identified. Staphylococcus chromogenes was the only species identified from all 20 farms. A total of 20 different staphylococcal-like species were identified from bulk tank milk samples with the most prevalent species being S. chromogenes, followed by Staphylococcus aureus and Mammaliicoccus sciuri. Overall, more staphylococcal and mammaliicoccal isolates were identified among used bedding than unused bedding. The increased numbers of isolates within used bedding were primarily from used sand bedding samples, with 79% (76/96) of used bedding isolates being identified from sand bedding and only 20.8% (20/96) from used compost-bedded pack samples. When comparing categories found among sample types, more unclassified species were found in used sand bedding than in used compost-bedded pack samples. This finding is possibly related to the composting temperatures resulting in reduced growth or destruction of bacterial species. The prevalence of S. aureus was high in bulk tank milk for all herds, regardless of herd type, which may represent the influence of unmeasured management factors. Overall, staphylococcal and mammaliicoccal species were highly prevalent among samples from both farm types.

Views of Consumers, Farmers and Stakeholders on Alternative Dairy Cattle Housing Systems.

Simple SummarySustainable alternative housing systems for dairy cattle depend on being accepted by key categories like farmers, stakeholders, and consumers. Alongside tie-stall and cubicle housing systems, alternative free-walk systems (compost-bedded pack and artificial floor systems) are available today. This study aimed to determine and compare the acceptance of (alternative) housing systems and attitudes to certain aspects of housing systems for dairy cattle among Slovenian consumers, farmers, and stakeholders. They were asked online about their views on the most important aspects (animals, farmers, products, environment) of housing systems as well as the acceptance of four housing systems and related issues. The results reveal differences in attitude and acceptance among the main groups of respondents. Consumers, stakeholders, and conventional farmers preferred the artificial floor system, while organic farmers preferred the compost-bedded pack housing system. Consumers and organic farmers showed below-average scores for all aspects analyzed concerning animals, products, and the environment, whereas conventional farmers and stakeholders had shown above-average scores for aspects related to animals and the environment and negative attitudes to products. The findings suggest the need to tailor information about different housing systems to specific groups.Alternative housing systems for dairy cattle have recently emerged, such as compost-bedded packs and artificial floor ones. To determine their acceptability among categories of people with a connection to animal husbandry, this study aimed to identify and compare the acceptability of (alternative) housing systems and attitudes to aspects of housing systems for dairy cattle among Slovenian consumers, farmers, and stakeholders. Farmers (N = 306), consumers (N = 508), and stakeholders (N = 40) were interviewed about their views on the main aspects (animals, farmers, products, environment) of housing systems for dairy cattle, the acceptance of four housing systems, and important housing features. The results show that consumers, stakeholders, and conventional farmers preferred housing systems with an artificial floor, while organic farmers preferred a housing system with a compost-bedded pack. Consumers and organic farmers expressed the greatest acceptance of almost every aspect of the housing system, except for a sufficient income for farmers and a low workload. Conventional farmers and stakeholders hold similar views, except for the expectation that the animals have enough space to move around, the image of the landscape, and the animals’ health and wellbeing, where stakeholders showed more acceptance than conventional farmers. The results imply that systematically planned information aimed at different target categories is needed to increase the acceptance of (alternative) housing systems for cattle.

Animal Health in Compost-Bedded Pack and Cubicle Dairy Barns in Six European Countries.

Simple SummaryDairy barns with compost-bedded pack housing systems are relatively new in Europe. They have housing systems that are vastly different from traditional tie-stall or cubicle housing and provide possibilities for improved animal welfare. However, it is important to investigate how actual cow health is influenced. We used readily available data from 32 dairy herds throughout Europe, half of which had compost-bedded pack housing and half cubicle housing, to investigate differences in dairy cow health. We found that herds with compost-bedded packs had poorer udder health than did herds with cubicles, while they seemed to have fewer problems with reproductive disorders. Our conclusion was that there were few, relatively minor differences between the systems. This knowledge is valuable for farmers interested in applying new housing systems for dairy cows and for consumers who want to stay informed about production conditions in dairy herds.The purpose of this study was to compare animal health in compost-bedded pack (CBP) and cubicle housing (CH) systems using data from dairy herd improvement associations. Thirty-two commercial dairy farms located in Austria, Germany, Italy, The Netherlands, Slovenia, and Sweden were included in the study. A matching design (pairing CBP and CH within country) according to herd selection criteria was used. We explored the following health indicators: somatic cell counts (SCC), high SCC, new high SCC, ketosis risk, prolonged calving intervals, dystocia, and stillbirth. Traits for culling and culling-related issues, such as length of life and length of productive life, were also included. We used multivariable (mixed) linear and logistic regression models to evaluate differences between the systems. Udder health, as measured by SCC, was inferior in CBP, although the geometric means were low in both systems. The incidence of stillbirths was higher in CBP, while prolonged calving intervals were fewer, indicating that there were fewer reproductive disorders. There were no differences in longevity between the systems, although CBP had lower proportions of first calvers. Overall, we conclude that there were few and minor differences in health and longevity between the CBP and CH systems in the European context.

Spatial analysis of microclimatic variables in compost-bedded pack barn with evaporative tunnel cooling.

In this study, we aimed to assess the spatial variability of microclimate inside a closed compost-bedded pack barn (CBP) with a negative ventilation system during summer and winter. The research was carried out in a CBP located in the Zona da Mata region, Minas Gerais, Brazil. For each of the stations analyzed, the following environmental mean variables observed inside a CBP were measured: air dry-bulb temperature (tdb), air relative humidity (RH), and windspeed, Temperature-Humidity index, and specific enthalpy. The kriging maps showed that the most critical housing conditions in the thermal environment were found, mainly, from the central part of the CBP, close to the exhaust fans. The analyses also pointed out that the system presented temperature gradients along the length, up to 3°C. During the summer afternoon, the entire region of the CBP was in a discomfort situation (tdb>26°C; RH>75%). During the winter, the measured environmental data remained within the comfort zone throughout the facility. However, probably due to the lack of thermal insulation of the material used to close the sides of the CBP, it did not allow spatial thermal uniformity for both seasons. It was also inefficient to keep the animals within the comfort zone for lactating cattle during the critical summer period.

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

Simple SummaryManagement and housing conditions have been reported to significantly affect the health and welfare of livestock species. Therefore, the adoption of novel, alternative housing systems (such as the compost-bedded pack barn, developed in the USA) requires extensive research to assess the implications for animal welfare. From a general point of view, animal welfare is typically assessed by means of animal-based (such as blood biochemical markers) and resource-based (such as management practices) indicators. Based on such considerations, the present study evaluated the fluctuation of circulating cortisol and beta-endorphins in dairy cows housed in a conventional freestall barn (FB) and in the alternative compost-bedded pack barn (CB). The results obtained suggest that the CB housing system did not elicit significant changes in either blood cortisol or beta-endorphins.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.

Microscopic differential cell count and specific mastitis pathogens in cow milk from compost-bedded pack barns and cubicle barns

Compost bedded pack barns (compost) as a new free walk housing system favorably influence udder health due to improved animal welfare and lying comfort. On the other hand, unfavorable effects on udder health are possible, due to the open bedded pack and the associated larger bacterial content in moisture. For in-depth farming system comparisons, the present study aimed to evaluate the specific cell fractions and mastitis pathogens in milk from cows kept in compost and in conventional cubical barns (cubicle). For milk sample collection we used a repeated measurement data structure of 2,198 udder quarters from 537 Holstein cows kept in six herds (3 in compost and 3 in cubicle). Differential cell counting was conducted including lymphocytes, macrophages and polymorphonuclear leukocytes (PMN). Specific mastitis pathogens comprised major and minor pathogens. Mixed models were applied to infer environmental and cow associated effects on cell fractions and on prevalences for pathogen infections, with specific focus on system × lactation stage, system × milk yield and system × somatic cell count effects. The interaction between system and lactation stage showed significant differences (P < 0.01) between the systems. A significantly smaller number of bacteriologically positive quarters and lower prevalences for minor pathogens were detected in compost compared to cubicle. Least squares means for pathogen prevalences indicated a quite constant proportion of bacteriologically negative udder quarters across milk yield levels in compost, but a slight increase with increasing milk yield in cubicle. Cell fraction responses in both systems differed in relation to the overall bacteriological infection status and farming system particularities. In conclusion, different cell fractions and specific mastitis pathogens should be considered as an indicator for udder health in different production systems, taking into account cow associated factors (lactation stage, milk yield).

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±7.2kg day-1, and during summer, it was 26.9±6.7kg day-1.

268 Growth Performance of Weaned Angus Bulls Housed in a Compost-bedded Pack Barn

Abstract Compost-bedded pack barns (CBP) are commonly utilized in dairy cattle operations across the United States. Their popularity is the result of improved animal welfare and reduced costs. The crossover of CBP into the beef cattle industry is new and the benefits and downfalls are not yet explored. Through a grant from NRCS, a CBP was built at the Morehead State University Derrickson Agricultural Complex in 2019–2020. In fall of 2020, the pack was established by mixing manure and sawdust shavings to start the aerobic composting process. The objective of our study was to determine the performance of growing bulls utilizing a CBP compared to a fully outdoor pasture housing system and measure the pack development. Growth data from 2 consecutive years of growing bulls were utilized, with calves born in 2019 being used as a control (CON) group and calves born in 2020 being used as the CBP group. Adjusted weaning and yearling weights reported to the American Angus Association were utilized to measure growth performance. Heifers born in both years were also evaluated as an outside standardization mechanism to eliminate genetic bias. Temperature measurements, surface and internal, were collected 3 times weekly to measure pack establishment. Weaning weights for CON and CBP bulls were similar (P = 0.45), though interestingly the corresponding heifer calves weaned with CBP bulls were heavier (P &amp;lt; 0.01) than those weaned with the CON bulls. Bulls housed in the CBP were significantly heavier (P &amp;lt; 0.01) as yearlings compared to the CON bulls (496 kg vs. 425 kg, respectively). Temperature differed (P &amp;lt; 0.02) between day, side of the barn, and measurement location. Our results suggest that utilizing a compost bedded pack barn during the winter growing phase may be beneficial to the producer by increasing growth potential of weaned calves.

Identification of Thermophilic Aerobic Sporeformers in Bedding Material of Compost-Bedded Dairy Cows Using Microbial and Molecular Methods.

Simple SummaryCompost-bedded pack barns (CBP) reflect a novel dairy cattle housing system with favourable effects on animal health and animal behavior but can promote the growth of thermophilic aerobic sporeformers (TAS) in the composting lying surface. In our study, we determined a medium–high mean TAS concentration across all bedding samples of four different CBP groups. Six different TAS species were identified based on their 16S rRNA-gene sequence, with Bacillus licheniformis being the predominant species. Season, the moisture content of the bedding material and the relative humidity above the bedding material had significant influences on the amount of TAS in the bedding material of the CBP. In addition, the moisture content and the relative humidity above the bedding material significantly influenced the concentration of TAS species each. Other characteristics such as the bedding temperature, the bedded area/cow and the usage time of the bedding material had slight effects on the TAS species occurrence. Due to the negative effect of TAS on milk product quality, considering all identified farm characteristics to optimise TAS contents will contribute to sustainable CBP farming.Compost-bedded pack barns (CBP) are of increasing interest in dairy farming due to their positive effect on animal welfare. The temperature and the moisture content of the bedding material characterising the composting process can promote the growth of thermophilic aerobic sporeformers (TAS). Therefore, the aim of this study was to determine CBP bedding material characteristics, such as moisture content and temperature, and to determine TAS species. The dilution, the heat inactivation of all non-TAS species and the incubation of 13 bedding samples from four CBP groups resulted in a mean TAS amount over all samples of 4.11 log10 cfu/g bedding material. Based on the subsequent sequencing of parts of the 16S rRNA-gene of 99 TAS colonies, the TAS species Aneurinibacillus thermoaerophilus, Bacillus licheniformis, Geobacillus thermodenitrificans, Laceyella sacchari, Thermoactinomyces vulgaris and Ureibacillus thermosphaericus were identified. The moisture content of the bedding material, the relative humidity above the bedding material and the sampling season significantly affected the amount of TAS. The moisture content or relative humidity above the bedding material significantly influenced the concentration of Ureibacillus thermophaericus or Laceyella sacchari. Consequently, an optimal CBP management including a dry lying surface and an optimal composting process will contribute to a moderate microbial, especially TAS amount, and TAS species distribution.

Behaviour, Hygiene, and Lameness of Dairy Cows in a Compost Barn During Cold Seasons in a Subtropical Climate

AbstractThis study aimed to assess the thermal environment, behaviour, hygiene, and lameness in dairy cows with different numbers of lactations housed in a compost-bedded pack barn system in a humid subtropical climate during autumn and winter. Between April and July 2016, behavioural and microclimatic environment assessments were conducted in a compost barn system, and hygiene and lameness assessments were performed. Crossbred cows in lactation (n = 10) were divided into two groups according to the number of lactations: primiparous and multiparous. Air temperature, relative humidity, and air ventilation speed were measured at 09:00, 12:00, and 15:00. The cows’ hygiene and lameness were evaluated using subjective scores ranging from 1 to 4 and 1 to 5, respectively. The daytime behaviour assessment was performed as sampling 0/1, using the focal method. Primiparous cows showed a greater probability of walking (P&lt;0.05) than multiparous cows between 09:20 and 11:20, and at 15:20, and increased the water intake at 14:00. Regarding the eating behaviour and the effect of time of day within each group (P&lt;0.05), the cows ate more in the morning’s early hours. The cows’ hygiene scores were 1 or 2, and most cows presented scores of 1 or 2 for lameness. Our research has shown that microclimatic variables may influence the walking behaviour and water intake of primiparous cows during the hottest periods of the day, even during cold weather, in a humid subtropical climate. The dairy cows showed low hygiene and lameness scores, which indicates that the compost bar positively influenced cleanliness and locomotion comfort.

Development of Predictive Equations for Thermal Conductivity of Compost Bedding

Among animal facilities, compost-bedded pack (CBP) barns have attracted a lot of attention from milk producers and the scientific community. Systematic investigation of the main thermal properties utilizing sawdust in CBP barns is of environmental and economic relevance. In this paper, the aim was to (a) develop predictive equations for the thermal conductivity (k) of compost bedding as a function of moisture content (MC), the degree of compaction (DCo), and particle size (PS); and (b) investigate the links between k and depth within bedding material. Samples of compost bedding materials were collected from 42 commercial CBP barns distributed throughout Kentucky (USA). From these predictive equations, it was possible to understand how the MC, DCo, and PS of the bedding materials may influence the behavior of k. These results are very useful for solving obstacles to simulate and predict the variable outcomes of the compost bedding materials process in CBP barns, allowing for its optimization, consequently reducing the time and energy spent on their optimization and allowing for simulation and assessment of compost bedding process modifications. The results of the current study may have important implications in the design and management of bedded pack barns.

Thermophilic composting of the pack can reduce nitrogen loss from compost-bedded dairy barns

Volatile nitrogen (N) loss from dairy barns is a concern. In compost-bedded pack barns, where the cattle rest on an organic pack, controlled thermophilic composting of that pack could promote microbial conversion of inorganic N (excreted by the cattle on the pack) into organic form, resulting in a reduction of pack inorganic N concentration and of volatile N loss from the barn. We tested this hypothesis during an 8-month period, including winter, on a commercial farm in the Netherlands where a specific composting method had been developed for a woodchip-bedded pack. A conversion of excreted inorganic N into organic form was assessed by repeated pack analysis; volatile N loss from the barn by calculation of its accumulating N mass balance. Our results show that volatile N loss from the barn was closely related to pack C:N ratio (P < 0.001; R 2 adj. = 83 %) and was negative during the first two months of composting. The negative loss was likely the result of NH 3 -absorption and/or N 2 -fixation by microorganisms from ambient air, two phenomena reported in literature. The critical pack C:N ratio, at which volatile N loss from the barn was zero, was 35, in line with critical ratios found in other studies. We conclude that controlled thermophilic composting of a woodchip-bedded pack, at a relatively high C:N ratio, has potential to minimise volatile N loss from compost-bedded dairy barns. • Pack composting resulted in low volatile nitrogen loss from a dairy barn. • Level of nitrogen loss was closely related to pack C:N ratio. • The critical pack C:N ratio of 35 was in line with ratios found in other studies. • Above this critical ratio, nitrogen from ambient air was probably fixed into the pack.

Identification and antimicrobial susceptibility of milk pathogen isolated from dairy production systems

Livestock has been recognized as a reservoir of antibiotic-resistant bacteria. Prevalence of resistance has been associated with herd size and intensification of animal production systems. Brazil is one of the emergent hotspots of bacterial resistance, which is also associated with animal husbandry. This study aimed to evaluate the resistance profile of pathogens that cause subclinical mastitis and the relationship between resistance status at farm level and different production systems. Milk samples from cows diagnosed with subclinical mastitis were collected from farms that adopt different husbandry systems with different production intensities, i.e., agroecological, low input, high input, Free-Stall and Compost-bedded pack barn. Etiological agents were isolated and microbiologically identified, and antibiotic susceptibility testing was conducted, using the disk diffusion method. The main isolated agents were Streptococcus spp. (n = 54, 30.5 %) and coagulase-positive Staphylococcus (CPS) (n = 54; 30.5 %). The recovered isolates displayed high antibiotic resistance against Sulfamethazine (80.2 %), Gentamicin (29.37 %), Penicillin (29.37 %), Oxacillin (28.82 %) and Ampicillin (26 %). Multidrug resistance was found for all agents and in all farming systems (39.54 %). Neither production systems (p = 0.26) nor farming systems (p = 0.24) significantly affected the resistance rates of samples. Therefore, intensive production systems may not be a root cause of increased rates of antimicrobial resistance in the milk production chain, suggesting that other environmental factors should be investigated. It is noteworthy that high levels of multidrug resistance were even found in bacteria earlier considered as minor pathogens. This development can be taken as a warning that environmental bacteria are potential transmitters of resistance genes to the environment.

Annual Nitrogen Balance from Dairy Barns, Comparison between Cubicle and Compost-Bedded Pack Housing Systems in the Northeast of Spain.

Simple SummaryEnvironmental concerns related to livestock production have driven the importance of developing manure-management alternatives to mitigate N emissions. Hence, we carried out measurements of N loss in two different dairy housing systems (compost-bedded pack vs. cubicles), each system with a very distinct manure-management procedure. Since each system performs different manure-management practices, it may be important to compare their efficiency in terms of N recovery from manure in both systems. In contemplation of annual temperature variation, measurements of N recovery after manure management were carried out during warm and cold seasons of the year. Significantly higher volatilization rates were found in compost-bedded pack system with respect to cubicles system, therefore, N left in manure was lower in compost-bedded pack barns.The aim of this study was to determine N recovery and irreversible losses (i.e., through NH3-N volatilization) from manure in two different housing systems throughout a year using an N mass balance approach. Dietary, milk, and manure N were monitored together with outside temperatures in six dairy barns during six months, comprising two different seasons. Three barns were designed as conventional free stalls (cubicle, CUB) and the other three barns as compost-bedded packs (CB). All the barns were located in the Ebro’s valley, in the northeast of Spain. Mass N balance was performed simultaneously in the six barns, during two three-month periods (Season I and II) and sampling at a 15-day interval. Results of ANOVA analysis showed that annual N retained in manure (kg/head per year) from cows housed in CUB barns was significantly higher than in manure from cows housed in CB (133.5 vs. 70.9, p < 0.001), while the opposite was observed for N losses (26.9 vs. 84.8, for CUB and CB barn, respectively; p < 0.005). The annual mean proportion of irreversible N loss from manure in relation to N intake was much lower in barns using conventional free-stall cubicles than the mean ratio registered in bedded pack systems barns.

Genome-Wide Associations for Microscopic Differential Somatic Cell Count and Specific Mastitis Pathogens in Holstein Cows in Compost-Bedded Pack and Cubicle Farming Systems.

Simple SummaryNew free walk housing systems such as compost-bedded pack barns might positively influence animal welfare. However, udder health can be negatively affected due to the microbial environment in the pack. Udder health depends on many factors, such as the environment, the feed, the pathogen species, and the genetic mechanisms of the cow’s immune system. For a more precise evaluation of udder health, we examined novel traits including specific mastitis pathogens and differential somatic cell fractions in milk. In order to identify possible candidate genes for udder health, a genome-wide association study, including single-nucleotide polymorphisms (SNP) by housing system interactions (compost-bedded pack barn and conventional cubicle barn), was performed. We identified two potential candidate genes for the interaction effect in relation to udder health. The identified potential candidate gene HEMK1 (HemK methyltransferase family member 1) is involved in immune system development, and CHL1 (cell adhesion molecule L1 like) has an immunosuppressive effect during stress conditions. The results suggest housing system-specific breeding strategies in order to improve udder health in compost-bedded pack and conventional cubicle barns.The aim of the present study was to detect significant SNP (single-nucleotide polymorphism) effects and to annotate potential candidate genes for novel udder health traits in two different farming systems. We focused on specific mastitis pathogens and differential somatic cell fractions from 2198 udder quarters of 537 genotyped Holstein Friesian cows. The farming systems comprised compost-bedded pack and conventional cubicle barns. We developed a computer algorithm for genome-wide association studies allowing the estimation of main SNP effects plus consideration of SNPs by farming system interactions. With regard to the main effect, 35 significant SNPs were detected on 14 different chromosomes for the cell fractions and the pathogens. Six SNPs were significant for the interaction effect with the farming system for most of the udder health traits. We inferred two possible candidate genes based on significant SNP interactions. HEMK1 plays a role in the development of the immune system, depending on environmental stressors. CHL1 is regulated in relation to stress level and influences immune system mechanisms. The significant interactions indicate that gene activity can fluctuate depending on environmental stressors. Phenotypically, the prevalence of mastitis indicators differed between systems, with a notably lower prevalence of minor bacterial indicators in compost systems.

Spatio-Thermal Variability and Behaviour as Bio-Thermal Indicators of Heat Stress in Dairy Cows in a Compost Barn: A Case Study.

Simple SummaryThe thermal distribution inside a compost-bedded pack barn and the behavioural aspects plays an important role in terms of welfare and sustainability for dairy cows. Through a spatial variability assessment of thermal conditions in a compost barn, we found different regions with comfortable or stressful conditions based on air and bed temperature, as well as wind speed. Regarding the behaviour of cows with different number of lactations, we observed a higher probability of water intake in primiparous cows and increased walking behaviour in multiparous cows during the hottest periods. We suggest that special attention must be given to environmental control in a compost barn, mainly during hot seasons, to avoid different hot spots inside the facility. Additionally, with unbalanced environmental resources, the hierarchy of multiparous over primiparous cows might predominate the alleviation of the herd’s thermal stress.The spatial variability and behavioural aspects of compost-bedded pack barns remain unknown in subtropical regions. In this study, we investigated whether spatial variability occurs in the thermal environment of a compost barn and how the behaviour of dairy cows with different numbers of lactations differs in this system. The spatial sampling design comprised a grid of 108 locations inside the facility. At each location, we measured air temperature, relative humidity, wind speed, and bed temperature at 9:00, 12:00, and 15:00. We performed 24-h behavioural observations. Regarding spatial variability, the north face showed high air temperature values, and the distribution of relative humidity varied from the north to the south face. Kriging maps revealed a high bedding temperature trend, indicating heterogeneous ventilation management. Primiparous cows visited the water trough during the hottest hours of the day, whereas multiparous cows displayed a higher probability of walking during these periods. In conclusion, we observed a heterogeneous management of ventilation through the spatial distribution of the thermal environment inside the compost-bedded pack barn, with multiparous cows exhibiting dominance over primiparous cows seeking environmental resources.

Agronomic Characteristics of the Compost-Bedded Pack Made with Forest Biomass or Sawdust

To ascertain the agronomic value of the material resulting from the compost-bedded pack (CBP) in dairy barns, a cross-over experiment was designed with eight dry non-pregnant Holstein cows. The study was performed in two 11-week periods. Bedding materials used were: (1) CBP with sawdust (S) and (2) CBP with forest biomass (FB). Samples were taken from the raw bedding materials and from the CBP across the experiment. We conducted an additional study preparing two piles, one of each CBP material, to accomplish a composting process of 3 months, where samples were also taken. Granulometry and some chemical composition characteristics of FB made it a suitable bedding material to be used as CBP, but its high moisture content limited the ability to absorb liquid manure. Both the degree of stability of the organic matter and the temperature evolution of CBP suggest that a real composting process did not occur. Finally, the composting process of the piles did not lead to any relevant change in CBP materials. From the agronomic point of view, S and FB present potentially valuable characteristics as regards organic amendment in the soil, thanks to their high organic matter content and low nutrient content.

3D CFD Analysis of Natural Ventilation in Reduced Scale Model of Compost Bedded Pack Barn for Dairy Cows

Compost bedded pack (CBP) barns have been receiving increased attention as an alternative housing system for dairy cattle. To create a satisfactory environment within CBP barns that promotes a good composting process, an adequate air movement and minimal temperature fluctuations throughout the building are required. Therefore, a study based on compost barn structure model employing techniques of dimensional analysis for naturally ventilated buildings was developed. Three-dimensional computational fluid dynamic (CFD) simulations of compost barns with different ridge designs and wind direction, along with the visual demonstration of the impact on airflow through structure were performed. The results showed that the barn ventilation CFD model and simulations were in good agreement with the experimental measurements, predicting the airflow through the CBP barns structure for alternative roof ridge types adequately. The results also indicate that the best roof configuration in the winter was the open ridge with chimney for a west to east wind direction.