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Allowing dairy cattle to access pasture or outdoor areas is known to be beneficial for cows' welfare and is considered important by the general public. However, in confinement-based operations with high-yielding cows, pasture access may be difficult to implement, especially for lactating animals. Providing pasture access to heifers and dry cows seems a more feasible option for most farms. The objective of this study was to investigate the effects of providing high-yielding dairy cows with free-choice pasture access during the dry period on their health, behavior, and milk production. Over the study period, a total of 78 Holstein cows were assigned to 1 of 2 treatments during the dry period (51 ± 8 d): housing with free-choice access to the pasture (PAST) or housing continuously without any access to the outdoors (CTRL). After calving, all cows from both treatments were mixed and housed continuously. To assess the effects of the treatment on cows' performance, all animals enrolled were monitored both before calving and during the first 100 d in milk of the following lactation. The behavior of all cows involved was monitored continuously during the whole observation period using collar-based sensors. All cows were inspected monthly to assess lameness, hock lesions, cleanliness, and body condition score. During the period after calving (0–100 d in milk), milk production and composition were also monitored. Results showed that free-choice pasture access affected cows' feeding behavior. Before calving, the animals in PAST spent more time feeding than in CTRL and, interestingly, this difference tended to persist for several weeks after calving. During the dry period, cows in PAST were cleaner than in CTRL but no differences in locomotion and body condition score were found between the 2 groups. Free-choice pasture access during the dry period also affected milk production during the following lactation. The cows that spent the dry period in PAST produced more milk than CTRL counterparts, particularly for the animals that calved during summer. In the current study we have found that providing free-choice pasture access during the dry period can positively affect the performance of dairy cattle and represents a desirable practice in confinement-based dairy production systems. [ABSTRACT FROM AUTHOR]

Manure management is a crucial aspect warranting attention since a significant proportion of anthropogenic NH 3 emissions are derived from it. In dairy cattle, only 20 to 30% of the dietary N is retained in milk, while a relevant amount is excreted in urine and faeces. A substantial proportion (60 to 80%) of the urine-N of high-producing dairy cows exists as urea, which is rapidly converted to NH 4 + by the urease enzyme, and volatilizes into the atmosphere as NH 3. While extensive literature studied the effects of technical solutions for cattle housing and waste storage, environmental parameters and manure treatments on NH 3 emission, limited information exists on its quantification under controlled conditions from isolated and mixed excreta. The aim of the study was to evaluate the NH 3 emission reduction potential from maintaining urine and faeces separate in dairy farming systems. NH 3 emissions from urine (U) and faeces (F) alone, as well as their mixture (M) were monitored under different environmental conditions (10 °C and 20 °C) and different exposure periods (24 and 72 h). The M samples had significantly higher NH 3 emissions (about 100 times higher) than U and F, both in cold and warm conditions and at all exposure periods. Significantly higher NH 3 emissions were measured from U, compared to F, after 48/72 h of exposure, probably linked to the higher pH and water content found in U. Separating urine and faeces (before contact) has the potential to reduce NH 3 emissions by about 99% during the first 24–72 h of air exposure in dairy cow management systems. This potential approach should also be coupled with accurate urine management, under conditions that prevent environmental urease contamination. Such strategy could also be an effective solution to improve on-farm N reuse and to reduce the adoption of chemical fertilizers. [Display omitted] • NH 3 emissions from dairy cattle excreta were monitored using a dynamic chamber. • Faeces, urine and the mix of them were monitored at different exposure period. • NH 3 emissions from the mix are almost 100 times higher than faeces and urine alone. • Separation of dairy cattle excreta is an effective strategy to cut NH 3 emissions. • Warm conditions promote NH 3 emissions. [ABSTRACT FROM AUTHOR]

The bedding material used in barns for dairy cows has a significant effect on animal welfare and performance. Bedding influences the duration in which animals remain lying down and, consequently, the processes of rumination and milk production. It is crucial to have a complete understanding of the properties of bedding materials and the effects of alternative bedding materials on dairy cattle. This paper aims to evaluate the physical, chemical, and biological properties of various alternative and conventional bedding materials for dairy cattle for use in compost bedded pack or freestall barn systems. We analyzed 50 samples of 17 bedding materials produced in 3 European countries. We analyzed physical properties including the water holding capacity, porosity, moisture content, bulk density, dry bulk density, and particle size. Chemical analyses were performed to determine the total N, total organic C, and C:N ratio. In the biological analyses, the Escherichia coli count, total bacteria count, coliform count, and Klebsiella spp. count were assessed. The results demonstrated how the physical properties of the bedding materials may influence the chemical and biological properties. All of the materials presented adequate chemical properties to be used as bedding material. The physical properties of the bedding materials differed widely among the materials except for the dry bulk density, which presented no difference. Moreover, the contamination of each studied microorganism was observed for each bedding material to determine which material had the lowest level of contamination. Posidonia oceanica, Miscanthus grass, and spelt husks could be considered as a potential alternative material for use as bedding material for dairy cows in both systems (i.e., composted bedded pack and freestall). This experiment illustrated the importance of performing thorough physical, chemical, and biological analyses before implementing a material as bedding for dairy cattle. [ABSTRACT FROM AUTHOR]

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. • The use of geostatistics made possible to assess the quality of the CBP bed. • The high cow stocking density had an impact on the worsening of the moisture content and internal temperature in the bed. • Dairy cows showed a good hygiene and locomotion scores in the CBP. • In the closed CBP system average milk production was slightly lower during the summer in comparison with winter. • The use of infrared thermography made possible to evaluate the surface temperatures of in cows and bed in closed CBP. [ABSTRACT FROM AUTHOR]