Epsilon Archive for Student Projects

Abstract

This study was conducted at VikingGenetics' bull breeding station in Falkenberg, Sweden. The bulls waiting for the results of their progeny testing at this station are either kept in group housing or individual housing. Since both of these housing systems have advantages and disadvantages, it was in the interest of VikingGenetics to know which of these housing systems is the best. The aim of this study was to investigate the welfare of the bulls in these two housing systems through behavioural observations and the use of activity monitors. In the preparations for the study 16 bulls, 8 in each housing system, were chosen. These bulls were from 34-60 months of age and of the breeds Swedish Holstein and Swedish Red.

The behaviour of the bulls was recorded using focal animal sampling with instantaneous recording at three minute intervals of general behaviours and continuous recording of social and abnormal behaviours. Each bull was observed one hour per week during three weeks. Activity monitors (IceTags 2.004, IceRobotics) were placed on each bulls hind leg and were left there during the whole behavioural observation period. The behavioural data and activity data were analyzed using Wilcoxon rank sum test. The results showed a significantly higher level of activity and number of steps per 24 hours in the group housed bulls. There were no significant differences in the general behaviours, or social and abnormal behaviours performed, except for the behaviour “pushing”, which was significantly more performed in group housing than individual housing. "Pushing" is when one animal places its cheek against another individual and pushes. Few aggressive interactions and no abnormal behaviours were recorded during the study.

Since the reason for the higher activity level in group housing is unknown. It is, from this, difficult to draw conclusions about the welfare of the bulls in the two housing systems. The higher activity in group housing could indicate that the bulls can get outlet for their motivation to be locomotive. However, it could also be a result of the animals moving around to avoid other individuals.

The individual pens were equipped with social gates, through which the bulls could place their heads and necks. These enabled the individually housed bulls to have social interactions, although limited. One advantage with individual housing is that it is more difficult for the bulls to injure each other, while some of the disadvantages are the restriction in social interactions and the smaller area to move around upon. Some of the advantages with group housing are that the bulls can have more social interactions and the total area is larger. Some disadvantages with group housing are the higher risk of injuries and that subordinates might be chased or displaced from resources.

Hence, answering the question of which housing system is the best is not a simple task and the advantages and disadvantages must be weighted against each other.