Onderwerp scriptie

The effects of pasture management on grazing behaviour and production in dairy cows - Linlin Bi

The research objective was to examine whether grass conditions can affect grazing and social behaviors of dairy cattle during grazing. The second objective was to investigate the correlation between cows’ sociality and their social interactions. Thirdly, the effects of sociality on milk production were investigated. Behavioral observation was conducted during grazing and 2 h after provision of the silage when housed.

The research objective was to examine whether grass conditions can affect grazing and social behaviors of dairy cattle during grazing. The second objective was to investigate the correlation between cows’ sociality and their social interactions. Thirdly, the effects of sociality on milk production were also investigated. Three groups of cows (n = 15/group) were strip-grazed on rye grass pastures, which were allocated to 3 treatments according to a 3X3 Latin square with three 8-day grazing periods. The whole experiment lasted 24 days. The three treatments were 1) graze on untreated paddock, 2) graze on paddock topped after a grazing session, 3) graze on paddock mowed after a grazing session. Grazing session (GS) was from 8:30 am to 14: 30 am. Three groups of cows were housed together at night in a free stall system. Cows only had access to the automatic milking machine when housed. Silage was provided once per day around 16:00 am. The daily DM intake was about 18 kg per cow. Behavioral observation was conducted during grazing and 2 h after provision of the silage when housed. Sociality, time budget, the distance to nearest neighbor (NN) and behavior synchronization were measured during GS. Direct neighbor (DN), the incidences of agonistic interactions and allogrooming were recorded during indoor observations.

The results showed that restricted grazing intensified the grazing behavior of dairy cows. On average, grazing, lying and rumination accounted for 67%, 19% and 13% of the time on pasture. Secondly, cows spent more time on grazing when grazed on the mowed and the topped paddocks, indicating the ability to adapt their grazing time budget in response to the paddock conditions. Furthermore, pasture topping and mowing had positive effects on the synchronization of grazing behaviors of cows, probably due to the improved homogeneity of vegetation conditions on the paddocks. However, paddock treatments did not affect the cows’ sociality. This study did not find any significant correlation between sociality and social interactions in dairy cows. Last but not least, the average daily milk yield was 22L. Although not statistically significant, milk yield was negatively correlated with sociality.


Student: L Bi

Supervisor: dr ir K van Reenen

30 Ects