Grete Helen Meisfjord Jørgensen

Air quality in Norwegian horse stables at low outdoor temperatures

Abstract Many horse stables have mechanical‐fan ventilation systems but still try to regulate ventilation manually by closing doors and windows on a cold winter night. The aim of this study was to investigate the variation in air quality in Norwegian horse stables with different ventilation systems on days with low outdoor air temperatures. A total of 19 insulated, mechanically ventilated stables with horses kept inside during the night were included in the study. Almost all fans were operated during the night (n = 18), but inlets for fresh air were highly variable in design and management leading to potential for ineffectiveness of ventilation functions. In four of the stables, there were no specific air inlet systems, and in five stables, the exit door was used as the only air inlet. The air exchange rate was sufficient in all the stables with an automated temperature thermostat for ventilation control. Mean level of carbon dioxide (CO2) was 1,800 ppm and in one stable CO2 exceeded 3,000 ppm. Mean inside ammonia (NH3) was 1.3 ppm, and only in one stable the level of NH3 exceeded 5 ppm. The total dust concentration was 0.69 ± 0.19 mg/m3, and in two stables, the dust concentration exceeded 1.0 mg/m3. Total and respirable dust levels were higher in stables with ventilation rate below recommended level. Half of the stables visited had a lower calculated air exchanges rate than recommended, and the majority of the stables regulated the ventilation manually by closing doors and inlets during night. This indicates a general lack of knowledge among the stable managers of climatic demand in horses and how to operate mechanical ventilation. Still, the majority of the stables maintained acceptable air quality, with NH3 and dust levels within recommended levels, although most stables had elevated humidity. HighlightsIn the majority of the stables, the ventilation was also regulated manually by closing doors and windows during night.This indicates a general lack of knowledge among the stable managers of climatic demand in horses and how to operate mechanical ventilation.Half of the stables visited had a lower calculated air exchanges rate than recommended.Still, the majority of the stables maintained good air quality with ammonia and dust levels within recommended levels.

The use of outdoor yards by sheep during winter.

In order to investigate the effect of roof cover and location of feed on sheep’s use of an outdoor yard under different weather conditions, we conducted a 2 x 2 factorial experiment with roof covering of outdoor yard (yes or no) and location of feed (indoors or outdoors) in four different combinations. The experiment was performed from November 2009 to March 2010, and twenty adult ewes of the Norwegian White breed were randomly allotted to 4 groups with 5 animals. Groups were rotated between treatment pens on a weekly basis and twenty-four hour video recordings were performed once a week. General behaviours (standing, feeding, resting) and location of animals (indoors or outdoors) were scored for each individual using instantaneous sampling. Weather factors affected resting behavior, but did not affect the proportion of time sheep spent in the outdoor yards, feeding or standing/walking. More sheep were resting in the outdoor yard in pens with a roof covering the yard (24.2 ± 1.4%) compared to in yards that did not have a roof cover (15.5 ± 1.2%; P<0.01). Locating the feed outdoors increased the time spent resting indoors (47.4 ± 1.5% vs. 31.6 ± 1.5%; P<0.0001), indicating that if a dry and comfortable resting area is offered indoors, the feed should be located in the outdoor yard. Utilizing an outdoor yard as part of the total area may be a cost effective way of meeting new space regulations for sheep production.

Effect of Reduced Feeding Space for Dairy Goats on Feed Intake and Social Interactions

The aim of this experiment was to examine how type of roughage and restricted feeding space affected feeding time, feed intake, and the level of aggressive competition in groups of dairy goats. In a 3 x 2 factorial experiment with number of goats per feeding place (1, 2, 3) and type of roughage (silage or hay) as main treatments, we tested a total of 48 adult goats divided into 8 groups. Roughage was given ad libitum and all groups were exposed to all treatments. From 24-hour video recordings at the end of each experimental period (one week), we scored activity and behaviours such as feeding, queuing, standing/walking, and lying using instantaneous sampling with 10-minute intervals. All incidents of social interactions were scored continuously for six hours between 09:00 and 15:00 hours. The goats spent significantly less time feeding and more time queuing in front of the feed barrier as the number of goats per feeding place increased. The number of displacements at the feed barrier and aggressive interactions increased with an increasing number of goats per feeding place, and the aggression level was higher when offered hay than silage. Some individuals reduced their time spent feeding by more than 80% when increasing the number of goats per feeding place from 1 to 3. Low-ranked goats spent significantly less time feeding and more time queuing than goats in medium- and high-rank categories.