No abstract

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 ...

Feed is an important end use of barley (Hordeum vulgare L.). Recent research has identified high starch content, low acid‐detergent fiber (ADF), low ruminal dry‐matter digestibility (DMD), and large particle size after dry rolling as desirable barley feed‐quality characteristics for beef cattle. Knowledge about the variation available may help barley breeders develop strategies for feed‐quality improvement. Our objective was to estimate the variation in feed‐quality characteristics in barley around the world. The spring barley core subcollection from the USDA‐ARS National Small Grains Collection was planted in 1995. Ruminal DMD of 1480 accessions was evaluated. Seventy‐three accessions, selected on variation in DMD, were planted in two field replications in 1996 and 1997. These 73 accessions were evaluated for starch, DMD, ADF, and particle size after dry rolling. The range in DMD was 82 to 621 g kg−1, with a mean of 398 g kg−1 (SD = 75 g kg−1). The ranges for other traits of the 73 selected accessions were 387 to 593 g kg−1 (starch); 15 to 96 g kg−1 (ADF); 187 to 510 g kg−1 (DMD); and 1118 to 1572 μm (particle size). Six‐row types had greater ADF and particle size (P < 0.001), lower starch, and DMD (P < 0.001), compared with 2‐row types. Starch was higher (P < 0.01), and ADF and DMD were lower (P < 0.01), for hulless than for hulled accessions. Substantial variation in the spring barley core collection for feed quality‐related characters could be exploited to develop barley cultivars for feed quality.

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.

No abstract

We conducted two experiments to determine the effects of monensin addition on digestion of high-concentrate diets based on corn or barley and to identify any interactions between grain source and monensin addition. A replicated in vitro experiment with a 2 x 4 factorial arrangement was used to evaluate monensin addition (0 or 72 mg/kg in vitro substrate) and grain source (corn, Gunhilde barley [GUN], Harrington barley [HAR], or Medallion barley [MED]). Triplicate tubes for each treatment were incubated for 0, 3, 6, 9, 12, 18, 24, and 30 h. Rate and extent of IVDMD were determined. Four ruminally and abomasally cannulated steers were used in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to test the effects of monensin addition (0 vs 270 mg x steer(-1) x d(-1)) and grain source (70% corn vs 80% Medallion barley). Diets were balanced to be isocaloric and isonitrogenous. An interaction (P < .10) was found between monensin addition and grain source for IVDMD during 3 through 9 h of incubation. Monensin increased the IVDMD of GUN and MED, but it decreased the IVDMD of HAR. Corn IVDMD was not affected by monensin addition. Steers fed Medallion barley had greater (P < .05) microbial protein synthesis, rate of in situ DM and starch disappearance, ruminal and postruminal digestion of starch, ruminal total VFA concentrations, and total tract digestion of DM, OM, and starch compared with steers fed corn. Monensin addition decreased (P < .10) ruminal digestion of feed N and ruminal proportions of acetate and butyrate and increased (P < .001) the ruminal proportion of propionate. No monensin x grain source interactions were observed for the variables measured in vivo.

Two ruminally cannulated Holstein heifers were used to evaluate effects of three forage species and two particle sizes in a 3 x 2 factorial arrangement on in situ fiber disappearance and carboxymethylcellulase activity (CMCase). A second objective was to compare CMCase and 15N as relative bacterial colonization markers. At time zero, 15N-enriched ammonium sulfate was dosed into the rumen. Residues in nylon bags incubated for 3, 6, 9, 12, 18, 24, 30, 36, 42, 48, 60, and 72 h were analyzed for NDF, ADF, CMCase, and 15N. Rates of NDF and ADF disappearance were faster (P < .05) for red clover (RC) than for gamagrass (GG) or orchardgrass (OG) and for forages ground to pass a 2-mm screen (P < .05) than for those ground to pass a 5-mm screen. Cumulative area under the curve (AUC) of CMCase activity was related to both NDF disappearance (r2 = .93) and 15N AUC (r2 = .99), indicating that CMCase can be used to estimate relative colonization of cellulolytic particle-associated bacteria (PAB). During the first 18 h of incubation, RC had greater (P < .05) CMCase and 15N enrichment of in situ residues than did OG or GG. The RC residues also had a greater (P < .05) ratio of CMCase activity:15N enrichment; this was presumed to indicate that, during this time, RC supported a greater total PAB population and had a greater proportion of cellulolytic PAB than did either GG or OG. Differences in the colonization rate of forage particles by cellulolytic PAB relative to total PAB may account for differences in rate of fiber digestion.