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- Author or Editor: Abram H. Babcock x
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Abstract
ObjectiveβTo evaluate associations between economic and performance outcomes with the number of treatments after an initial diagnosis of bovine respiratory disease (BRD) in commercial feedlot cattle.
Animalsβ212,867 cattle arriving in a Midwestern feedlot between 2001 and 2006.
ProceduresβAn economic model was created to estimate net returns. Generalized linear mixed models were used to determine associations between the frequency of BRD treatments and other demographic variables with economic and performance outcomes.
ResultsβNet returns decreased with increasing number of treatments for BRD. However, the magnitude depended on the season during which cattle arrived at the feedlot, with significantly higher returns for cattle arriving during fall and summer than for cattle arriving during winter and spring. For fall arrivals, there were higher mean net returns for cattle that were never treated ($39.41) than for cattle treated once ($29.49), twice ($16.56), or β₯ 3 times (β$33.00). For summer arrivals, there were higher least squares mean net returns for cattle that were never treated ($31.83) than for cattle treated once ($20.22), twice ($6.37), or β₯ 3 times ($β42.56). Carcass traits pertaining to weight and quality grade were deemed responsible for differences in net returns among cattle receiving different numbers of treatments after an initial diagnosis of BRD.
Conclusions and Clinical RelevanceβDifferences in economic net returns and performance outcomes for feedlot cattle were determined on the basis of number of treatments after an initial diagnosis of BRD; the analysis accounted for the season of arrival, sex, and weight class.
Abstract
ObjectiveβTo determine the accuracy of accelerometers for measuring behavior changes in calves and to determine differences in beef calf behavior from before to after castration.
Animalsβ3 healthy Holstein calves and 12 healthy beef calves.
Proceduresβ2-dimensional accelerometers were placed on 3 calves, and data were logged simultaneous to video recording of animal behavior. Resulting data were used to generate and validate predictive models to classify posture (standing or lying) and type of activity (standing in place, walking, eating, getting up, lying awake, or lying sleeping). The algorithms developed were used to conduct a prospective trial to compare calf behavior in the first 24 hours after castration (n = 6) with behavior of noncastrated control calves (6) and with presurgical readings from the same castrated calves.
ResultsβOn the basis of the analysis of the 2-dimensional accelerometer signal, posture was classified with a high degree of accuracy (98.3%) and the specific activity was estimated with a reasonably low misclassification rate (23.5%). Use of the system to compare behavior after castration revealed that castrated calves spent a significantly larger amount of time standing (82.2%), compared with presurgical readings (46.2%).
Conclusions and Clinical Relevanceβ2-dimensional accelerometers provided accurate classification of posture and reasonable classification of activity. Applying the system in a castration trial illustrated the usefulness of accelerometers for measuring behavioral changes in individual calves.
