Large variability in feeding behavior among crossbred growing cattle

Abstract

The purpose of this study was to define an extensive suite of feeding behavior traits in growing crossbred cattle and to investigate their phenotypic inter-relationships as well as relationships with other performance and efficiency traits. Time-series feeding behavior data, as well feed intake and live-weight records, were available for 624 growing crossbred cattle, of which 445 were steers and 179 were heifers. Feeding behavior repeatability estimates were calculated using linear mixed models. Additionally, partial Spearman correlations were estimated among 14 feeding behavior traits, as well as between feeding behavior with both performance and feed efficiency traits, using residuals retained from linear mixed models. The marginal contribution of several feeding behavior traits to the variability in metabolizable energy intake (MEI) was also determined. Repeatability estimates of 0.57, 0.36, and 0.48 were calculated for the number of feed events per day, the total time spent feeding per day and feeding rate, respectively. Cattle that ate more frequently each day ate at a faster rate and consumed less energy in each visit to the feed bunk. More efficient cattle fed less often per day and fed for a shorter duration per day; they also had a slower feeding rate and fed for longer in each visit to the feed bunk. Moreover, heavier cattle fed for a longer duration per day, had a faster feeding rate, but fed less often per day; heavier animals also fed first in the pen after fresh feed was offered. The number of feed events per day and feeding time per day together explained an additional 13.4 percentage points of the variability in MEI above that already explained by all of growth rate, live-weight, and backfat depth. The results from the present study suggest that several repeatable time-series related feeding behavior traits, that are less resource intensive to measure, may have a role as useful predictor traits of important but relatively difficult to record traits, such as feed intake and efficiency.

Genetic variability in the feeding behavior of crossbred growing cattle and associations with performance and feed efficiency

“…Furthermore, as feed intake data are expensive to collect in cattle, also of interest was the use of easier-to-measure time-related feeding behavior traits in genetic evaluations in order to improve the precision of genetic merit for feed intake. The respective phenotypic correlations among and between feeding behavior and both performance and feed efficiency have been reported previously by Kelly et al (2020) for a subset of the cattle included in the current study and are therefore not discussed further.…”

“…Furthermore, additional steps were taken to remove potentially erroneous time-related feeding behavior data, which are described in detail by Kelly et al (2020) but are mentioned briefly here. Feed events greater than 60 min in duration and/or feed events with a dry matter intake per minute >5 kg/min were considered errors and all feed intake and feeding behavior data from an animal in the test-day that these erroneous feed events occurred were removed ( Kelly et al 2020 ). Subsequently, animals with fewer than 45 test-day records within the test period were removed ( Kelly et al 2020 ).…”

“…Feed events greater than 60 min in duration and/or feed events with a dry matter intake per minute >5 kg/min were considered errors and all feed intake and feeding behavior data from an animal in the test-day that these erroneous feed events occurred were removed ( Kelly et al 2020 ). Subsequently, animals with fewer than 45 test-day records within the test period were removed ( Kelly et al 2020 ). Finally, 118 cattle without a known sire were also removed.…”

“…Time series feeding behavior data from automatic feed stations were available from steers and heifers that were tested for feed intake from the year 2015 onwards. The derivation and definitions of all of the feeding behavior traits used in the present study have been described previously by Kelly et al (2020) . Each feeding behavior trait described herein was averaged across valid test days, such that a single average value per animal was generated.…”

“…In order to derive the meal feeding behavior traits, individual feed events were clustered into meals for each animal, as described by Kelly et al (2020) ; meals were assumed to include short time intervals between feed events within meals and short intervals within meals where cattle interrupted a feed event to go to the water trough, whereas longer time intervals separated consecutive meals ( Yeates et al, 2001 ). Following the methods proposed by Tolkamp and Kyriazakis (1999) and Yeates et al (2001) , the time intervals, in seconds, between feed events for all steers and heifers were log-transformed, pooled, and a mixture of a Gaussian distribution and two Weibull distributions were fitted to the overall frequency distribution of the pooled log-transformed time intervals using PROC FMM (SAS v9.4, SAS Institute Inc., Cary, NC).…”