Intake estimation in dairy cows fed roughage-based diets: An approach based on chewing behaviour measurements

摘要

Chewing behaviour of 23 lactating Swiss Fleckvieh cows was analysed in order to evaluate the predictive potential for quantitative dry matter intake in a roughage-based indoor cattle feeding system. Cows were fed total mixed rations (TMR) based on silages and hay with different concentrate supplements. They were kept in a tie stall enabling individual feed intake measurements. Two measurements were conducted within one month. Chewing behaviour was recorded with RumiWatch (R) sensor collars, based on pressure tubes in the collar's noseband. Cows were equipped with collars for 96 h per measurement period. First 24 h were accounted as adaptation time; data of the subsequent 72 h were used for analysis. Data included ruminating, eating (min/day), rumination boli (n per day), chewing frequency and intensity during ruminating (chews/min and chews/bolus), and activity changes (switching between ruminating, eating and idle; n per h). The constancy of parameters within cows across measurement days was tested with linear regression models. A linear mixed-effects model was applied to estimate a regression on measured feed intake. Average feed intake per day across all measurements was 19.7 kg dry matter per cow, average eating time was 389 min/day and ruminating time was 551 min/day. For most of the chewing behaviour variables, factor 'cow' was significant, while 'day' was not, indicating a between animals variance but good consistency of the data within animal. After a stepwise backward procedure in the mixed-effects model, the remaining significant variable was 'chewing frequency' (chews per minute during rumination). Inclusion of 'animal' as a random factor resulted in an equation with conditional R-2 = 0.7. The model without random factor revealed a very low R-2. In conclusion, the random factor model allowed estimation of individual changes in feed intake within animal but not across animals. Chewing behaviour measurements proved to have a potential for the detection of relative intake alterations with roughage-based TMR diets but data were not sufficient for quantitative estimations. (C) 2016 Elsevier B.V. All rights reserved.