Epsilon Archive for Student Projects

Abstract

In some systems dairy cows are gathered in a waiting area (WA) prior to milking, to ensure that all cows pass through the milking unit. However, cows of low social rank might have to stand in the WA for a considerable amount of time before entering the milking unit. They may also be exposed to aggressive behaviours by cows of higher rank, which would be detrimental to their health and welfare. One of the factors which could influence the time that the cows spend in the WA and the amount of aggressive behaviours is the shape of the WA. The aim of this study was to investigate how the shape of the WA and the number of cows released towards it simultaneously affect the time that the cows spend in the WA and the frequency of aggressive behaviours. Additionally the time that the staff spent herding the cows in the different shapes of the WA was investigated. For this study 175 lactating Swedish Red and Swedish Holstein cows were used, of which 109 cows were included in all treatments. The cows were kept in 3 groups in a loose housing system with cubicles and were all milked twice daily in a DeLaval Automatic Milking Rotary (AMRTM). However, only the evening milking sessions were included in the study. The experiment was divided into 6 different treatments: S50, S100, R50, R10, D50 and D10. The treatments were a combination of the shapes of the WA and a various number of cows approaching the WA at the same time. The 3 different shapes investigated were the large WA (S treatments), a reduced WA (R treatments) and a curved single file race instead of a WA (D treatments). The cows were released towards the AMR in 3 different ways; 1 group every 50 minutes (50), 10 cows every 10 minutes (10) and 2 groups simultaneously (100). The time that the cows spent in the WA was recorded for 5 to 7 days per treatment using data from a selection gate by the entrance to the WA and from the AMR system. The behaviour of the cows in the WA was recorded using video cameras and data on the frequency of aggressive behaviour was collected from 2 milking sessions per treatment. Data on the time that the staff spent herding the cows in the WA was collected from 2 milking sessions per treatment. The maximum time that the cows spent in the WA differed considerably among treatments, and ranged from 52 min in D50 to 2 h 59 min in R50. There was a significant difference between treatments (p < 0.0001) regarding the time that the cows spent in the WA. The cows spent more time in the large WA than in the reduced and more time in the reduced WA than in the single file race. There was a significant effect of treatment (p < 0.01) on the behaviours ‘pushing’ and ‘pushbutt’ (which was the frequency of ‘pushing’ and ‘butting’ combined). Regarding the behaviour ‘butting’, there was a tendency for an effect of treatment, while no significant effect of treatment was found for ‘head to head pushing’. The amount of ‘pushbutt’ was significantly (p < 0.05) higher in the reduced WA (R50 and R10) compared to all other treatments. This could have been an effect of low ranking cows being unable to avoid interactions with cows of higher rank due to the limited space in the WA. However, due to the limited number of observations and a number of factors affecting the cows’ behaviour, it is difficult to draw any conclusion on which shape of the WA would be preferable regarding the amount of aggressive interactions. The amount of time spent herding the cows was highest in both S treatments (49 min and 40 min in S50 and S100 respectively), while the least amount of herding time was spent in the D treatments (13 min and 10 min in D50 and D10 respectively). The maximum times and mean times spent in the WA and the herding times were shorter in the single file race compared to the other treatments. These results suggest that constructing a single file race in front of the AMR, instead of a WA, could have the potential to improve the welfare of low ranking cows around milking and minimize the negative effects of social dominance.