The effectiveness of supplementation programs is affected by the ability to reduce intake variation and to meet target supplement consumption. A review was made of factors affecting variation in individual animal consumption of supplement by grazing cattle and sheep, including supplement type and feeding method, animal dominance and social interactions, and forage availability. The effects of palatability were not included. The proportion of animals not consuming supplement is increased by limited trough space, small supplement allowance, self-fed supplements, neophobia to feed or feed delivery devices, and group feeding situations. Variation in individual animal supplement intake is increased by excessive trough space, limited supplement allowance, self-fed supplements, feed and feed delivery equipment neophobia, and individual feeding of supplements. Factors influencing the percentage of animals consuming the target amount of supplement need to be more clearly identified. There seems to be an optimum level of feeding competition that reduces intake variation and improves the proportion of animals consuming adequate amounts of supplement, but this optimum varies with the feeding situation.

. 2001. Application of feeding behaviour to predict morbidity of newly received calves in a commercial feedlot. Can. J. Anim. Sci. 81: 315-320. The objective of this study was to use feeding behavior of newly received steers (average initial weight 191 kg) to detect morbidity in animals in a commercial feedlot. Two separate 32 d feeding trials were conducted in Wellton, Arizona, in July and November 1996. Radio frequency technology was used to record the total time spent within 50 cm of the feedbunk (animal presence every 5.25 s times 5.25 s) in 3 h intervals from 0600 to 2400 on a daily basis for 103 and 122 male calves in trial 1 and 2, respectively. Statistical procedures based on the cumulative sums (CUSUM) of the 3 h feeding intervals were used to detect morbid animals, compared with detection of animals deemed morbid by experienced pen riders. In trial 1, the CUSUM procedure detected animal morbidity 4.5 d earlier (P < 0.001) than the feedlot personnel. In trial 2, the CUSUM procedure detected animal morbidity 3.7 d earlier (P < 0.001) than feedlot pen riders. Overall accuracy, positive predictive value and sensitivity of the CUSUM prediction method were 87, 91, and 90%, respectively. Combined trial data suggest that feeding behavior during the first 30 d cattle are in a receiving pen, as collected with radio frequency technology and analyzed with CUSUM charts, may be used to detect animal morbidity approximately 4.1 d earlier (P < 0.001) than conventional methods typically employed in commercial feedlots.Key words: Feeding behavior, morbidity, quality control, feedlots Quimby, W. F., Sowell, B. F., Bowman, J. G. P., Branine, M. E., Hubbert, M. E. et Sherwood, H. W. 2001. Identification des jeunes veaux morbides grâce aux habitudes alimentaires dans un élevage commercial. Can. J. Anim. Sci. 81: 315-320. L'étude portait sur les habitudes alimentaires de jeunes bouvillons (191 kg à l'arrivée) et sur la manière dont on pourrait s'en servir pour déceler les animaux morbides dans un élevage commercial. Les auteurs ont effectué deux essais de 32 jours à Wellton (Arizona), en juillet et en novembre 1996. Un dispositif radioélectrique a servi à établir combien de temps les animaux passaient à moins de 50 cm des mangeoires (présence de l'animal pendant 5,25 s toutes les 5,25 s), par période de 3 h, de 6 h à 24 h tous les jours. Le premier essai portait sur 103 veaux mâles et le second sur 122. On a ensuite recouru à des méthodes statistiques reposant sur la somme cumulative (CUSUM) des intervalles de 3 h pour identifier les sujets morbides, comparativement à ceux repérés par des zootechniciens chevronnés. Lors du premier essai, la méthode CUSUM a permis d'identifier la morbidité des animaux 4,5 jours (P < 0,001) plus tôt que le personnel responsable du parc d'engraissement. Au deuxième essai, la même technique a permis l'identification des animaux morbides 3,7 jours (P < 0,001) avant les préposés. La précision globale, la valeur prédictive positive et la sensibilité de la méthode CUSUM s'établissent respectivement ...

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Our objective was to determine whether there were differences in feeding and watering behavior of newly received healthy and morbid feedlot steers. Two separate 32-d feeding trials were conducted in Wellton, Arizona, in July and November 1996. Radio frequency technology was used to record individual animal behaviors from 108 (average weight 139 kg) and 143 (average weight 160 kg) steers in each respective trial. Steers that were subsequently identified as morbid were present at the feed bunk in greater percentages than reported in previous studies. In Trial 1, healthy steers spent more (P < .001) time at the feed bunk and had more (P < .009) feeding bouts than morbid steers. In Trial 2, healthy steers did not spend more time at the feed bunk, but they had more (P < .02) daily feeding bouts than morbid steers. There were no differences in daily time spent at the water trough by healthy or morbid steers in either trial. The greatest proportion of feeding and watering behavior occurred during the daylight hours in response to feed delivery. The pattern of time spent at the feed bunk throughout the 32-d feeding period was similar for healthy and subsequently morbid steers, but healthy steers had more feeding bouts per day.

Twenty fine-wool, ruminally cannulated lambs (average weight 45-9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivo apparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivo DMD in lambs fed PH was greater (P < 005) than DMD calculated from IVNDF, IVADF and ADL. In lambs fed LH and LS, in vivo DMD did not differ (P > 005) from marker estimates. In vivo DMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P < 005) the ADL estimate. No differences (P > 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P > 005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P < 0-05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P < 005) for DLF compared with YLF for all diets except LS.