title: Application of overall dynamic body acceleration as a proxy for estimating the energy expenditure of grazing farm animals: relationship with heart rate.
abstract: Estimating the energy expenditure of farm animals at pasture is important for efficient animal management. In recent years, an alternative technique for estimating energy expenditure by measuring body acceleration has been widely performed in wildlife and human studies, but the availability of the technique in farm animals has not yet been examined. In the present study, we tested the potential use of an acceleration index, overall dynamic body acceleration (ODBA), as a new proxy for estimating the energy expenditure of grazing farm animals (cattle, goats and sheep) at pasture with the simultaneous evaluation of a conventional proxy, heart rate. Body accelerations in three axes and heart rate for cows (n = 8, two breeds), goats (n = 6) and sheep (n = 5) were recorded, and the effect of ODBA calculated from the body accelerations on heart rate was analyzed. In addition, the effects of the two other activity indices, the number of steps and vectorial dynamic body acceleration (VeDBA), on heart rate were also investigated. The results of the comparison among three activity indices indicated that ODBA was the best predictor for heart rate. Although the relationship between ODBA and heart rate was different between the groups of species and breeds and between individuals (P<0.01), the difference could be explained by different body weights; a common equation could be established by correcting the body weights (M: kg): heart rate (beats/min) = 147.263∙M-0.141 + 889.640∙M-0.179∙ODBA (g). Combining this equation with the previously reported energy expenditure per heartbeat, we estimated the energy expenditure of the tested animals, and the results indicated that ODBA is a good proxy for estimating the energy expenditure of grazing farm animals across species and breeds. The utility and simplicity of the procedure with acceleration loggers could make the accelerometry technique a worthwhile option in field research and commercial farm use.
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Miwa
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Kazato
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Nakagawa
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Maeno
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Anzai
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kumagai
authors.affiliation: Animal Science Laboratory, Department of Biological Resources Management, School of Environmental Science, The University of Shiga Prefecture, 522 8533 Shiga, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Okano
authors.affiliation: Laboratory of Animal Nutrition and Feeding, Department of Animal Science, School of Agriculture, Tokai University, 869 1404 Kumamoto, Japan.
authors.forename: Hisaya
authors.initials: H
authors.lastname: Tobioka
authors.affiliation: Laboratory of Animal Husbandry Resources, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, 606 8502 Kyoto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hirooka
mesh_terms: D000054:Acceleration; D000818:Animals; D002417:Cattle; D004435:Eating / Q000502:physiology*; D004734:Energy Metabolism; D006041:Goats / Q000378:metabolism* / Q000502:physiology; D006339:Heart Rate; D012756:Sheep / Q000378:metabolism* / Q000502:physiology