Study of nitrogen fluxes across conventional solid floor cubicle and compost-bedded pack housing systems in dairy cattle barns located in the Mediterranean area: Effects of seasonal variation

Understanding Compost-Bedded Pack Barn Systems in Regions with a Tropical Climate: A Review of the Current State of the Art

The main challenge in milk production has been to maintain a focus on efficient processes that enhance production outcomes while aligning with animal welfare and sustainability and being valued by society. As an alternative to improve cow welfare in production and provide better handling of the waste generated by the activity, the system called the compost-bedded pack barn (CBP) has been widely adopted in countries with temperate climates and higher milk production. This CBP has been attracting global interest, including from countries with tropical and subtropical climates, such as Brazil, where many producers have started to use it due to the response in terms of milk productivity. A CBP can be designed either in (a) an open facility with natural ventilation or a positive-pressure ventilation system or (b) totally closed facilities, equipped with negative-pressure ventilation systems and permanent thermal control. The latter system is being implemented in Brazil, despite insufficient knowledge about its efficiency. The objective of this study was, through a review, to gather and describe the most recent information on the use of open and closed CBP systems for dairy cattle housing, mainly covering how it is applied in tropical climate regions. To achieve the proposed objective, this review study included the following topics related to CBPs: (i) implementation, (ii) bedding, (iii) general construction and architectural characteristics, and (iv) ambient thermal conditioning. Knowledge gaps and directions for future research are also identified here.

Measurement of Methane and Ammonia Emissions from Compost-Bedded Pack Systems in Dairy Barns: Tilling Effect and Seasonal Variations

Dairy cattle contribute to environmental harm as a source of polluting gas emissions, mainly of enteric origin, but also from manure management, which varies among housing systems. Compost-bedded pack systems use manure as bedding material, which is composted in situ daily. As current literature referring to their impact on NH3 and CH4 emissions is scarce, this study aims to characterize the emissions of these two gases originating from three barns of this system, differentiating between two emission phases: static emission and dynamic emission. In addition, the experiment differentiated emissions between winter and summer. Dynamic emission, corresponding to the time of the day when the bed is being composted, increased over 3 and 60 times the static emission of NH3 and CH4, respectively. In terms of absolute emissions, both gases presented higher emissions during summer (1.86 to 4.08 g NH3 m-2 day-1 and 1.0 to 4.75 g CH4 m-2 day-1 for winter and summer, respectively). In this way, contaminant gases produced during the tilling process of the manure, especially during the warmer periods of the year, need to be taken into account as they work as a significant factor in emissions derived from compost-bedded pack systems.

Ammonia emissions and their key influencing factors from naturally ventilated dairy farms

Ammonia (NH₃) contributes several adverse impacts to the environment, especially the crucial role of PM_2.5 precursors. In China, approximately 13.5% of the total NH₃ emissions from agricultural activities are related to dairy cows farming. The goals of this study were to define NH₃ emissions, localize emission factors, and clarify relationships between NH₃ emissions and potential influencing factors from dairy farms. The measurements were carried out in three typical naturally ventilated dairy farms with different scales, floor materials and manure managements over four seasons. Results showed that NH₃ emission rate from all areas changed in the range of 0.01-2.96 mg min^-1 m^-2 in the three farms. NH₃ emission factors ranged from 5.21 to 38.10 kg a^-1 cow^-1 with the outdoor exercise area as the largest contributor. The variation of NH₃ emissions in the three farms was consistent and positively related to ambient temperature (R² > 0.8, p < 0.01). Strong relationships (p < 0.01) between NH₃ emissions and relative humidity were found only in outdoor exercise and sedimentation tank of Farm A and manure storage of Farm B. The NH₃ emission rates were dependent on floor material and the frequency of manure collection. However, the effect of manure collection methods on NH₃ emissions was insignificant. Results from this study provide accurate data to improve the atmospheric pollutant emission inventories, and clarify the impact of different influencing factors on NH₃ emissions from livestock farms.

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

Simple Summary

Environmental 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.

Abstract

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.