Oudshoorn, Frank W.3; S. Nadimi, Esmaeil5; Jørgensen, Rasmus Nyholm6
1 Institute of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, SDU2 Faculty of Engineering, SDU3 unknown4 The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, SDU5 The Maersk Mc-Kinney Moller Institute, Faculty of Engineering, SDU6 Institute of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, SDU
Objective of the experiment was to investigate if bite frequency could be measured by registering head movements in the field. Background for this research question was the found variation of bite frequency measured on different initial grass length (Oudshoorn & Nadimi, 2008) as also documented bite frequency variation related to grass length and grass quality (Pulido & Leaver 2001; Barrett et al. 2003). . Head movements and bite frequency were registered in spring and autumn in 2009, with 2x10 cows grazing two weeks in two stocking densities. Head movements were measured by activity sensors placed on the head of the cows, bite frequency was registered manually by noting the rip off sound during a specified time bout. Sward registrations comprised grass length measurement by rising plate meter , grass quality by laboratory analysis of hand harvested grass simulating the cows grazing and grass offer and grass growth during the trial by interval harvesting using a Haldrup grass harvester. Cows biting frequency for the same paddock, the same day were found to be cow specific and correlation with milk yield level and barn feed intake was investigated. Barrett, P.D., McGilloway, D.A., Laidlaw, A.S. & Mayne, C.S., 2003. The effect of sward structure as influenced by ryegrass genotype on bite dimensions and short-term intake rate by dairy cows. Grass and Forage Science 58, 2-11. Oudshoorn, F.W., Nadimi, F.W., 2007. Intelligent grazing systems using wireless sensor networks. ECPLF 2007 Skiathos, Greece. p 111-116 Pulido, R.G. & Leaver, J.D., 2001. Quantifying the influence of sward height, concentrate level and initial milk yield on the milk production and grazing behaviour of continuously stocked dairy cows. Grass and Forage Science 56, 57-67.