Ninety-three crossbred steer calves (BW+/-SD=385+/-50 kg) were used (n=48 steers in yr 1, n=45 steers in yr 2) to examine the relationship among carcass traits, lean, bone, and fat proportions, visceral tissue weights, and pancreatic digestive enzyme activity with DMI, ADG, G:F, and residual feed intake. Calves were progeny from crossbred dams predominantly of Angus and Simmental breeding and were sired by Angus, Simmental, crossbred (predominantly of Angus and Simmental breeding), Charolais, or Piedmontese bulls. Steers were fed a high-moisture corn-based diet for an average of 112 d. Partial correlation analysis accounting for year, pen within year, week of slaughter within year, and sire breed was conducted. Gain:feed was negatively correlated (P 0.10) between performance measures and the pancreatic proportional content of alpha-amylase and trypsin activity (units/kg of BW). These data indicate that carcass fatness traits and changes in the proportional weight of total viscera may be negatively associated with G:F and that visceral fat weight proportion and trim and kidney fat weight proportion may be important factors influencing this relationship.

. 2007. Corn or soybean hull incorporation into haylage-based backgrounding beef cattle diets: Effect on growth and efficiency during the backgrounding and finishing periods. Can. J. Anim. Sci. 87: 615-621. This experiment was conducted to evaluate the effects of corn or soybean hull incorporation into haylage-based diets on backgrounding calf performance and subsequent feedlot performance. Crossbred steers [n = 48, initial body weight (BW) = 303 ± 3.4 kg] were individually fed dietary treatments consisting of: (1) haylage [17.5% crude protein, dry matter (DM) basis; control], (2) haylage + 20% (DM basis) cracked corn, and (3) haylage + 20% (DM basis) soybean hulls during a 112-d backgrounding period. After the backgrounding period, all steers were adapted to a common high moisture corn-based finishing diet and fed until an ultrasound estimated backfat thickness of 7 mm was obtained. During the backgrounding period, steers fed cracked corn or soybean hulls had greater (P < 0.01) average daily gain, dry matter intake and gain:feed and lower (P = 0.05) plasma urea N as compared with controls. However, when finished on a common high-concentrate diet, steers previously fed cracked corn had greater (P < 0.08) average daily gain, final body weight, and longissimus muscle area than those fed soybean hulls, suggesting that source of supplemental energy during the backgrounding period may influence subsequent feedlot performance. Anim. Sci. 87: 615-621. L'expérience devait préciser les conséquences de l'incorporation de maïs ou de pellicules de soja à la ration à base d'ensilage mi-fané sur la performance des veaux de semi-finition et sur leur rendement ultérieur en parc d'engraissement. Des bouvillons hybrides (n = 48, poids corporel initial = 303 ± 3,4 kg) ont chacun reçu une ration consistant en 1) ensilage mi-fané (17,5 % de protéines brutes, selon la matière sèche; témoin), 2) ensilage mi-fané plus 20 % (matière sèche) de maïs concassé et 3) ensilage mi-fané plus 20 % (matière sèche) de pellicules de soja lors d'une période de semi-finition de 112 jours. Ensuite, les auteurs ont habitué les bouvillons à une ration de finition très humide à base de maïs jusqu'à ce que la couche de gras dorsal atteigne 7 mm d'épaisseur, selon la sonde aux ultrasons. Pendant la période de semi-finition, les animaux nourris au maïs concassé ou aux pellicules de soja ont enregistré de meilleurs résultats (P < 0,01) pour le gain quotidien moyen, l'absorption de la matière sèche et le ratio gain:aliment, mais les résultats étaient inférieurs (P = 0,05) à ceux des témoins pour la concentration de N uréique dans le sang. Quoi qu'il en soit, quand ils reçoivent la même ration de finition, riche en concentré, les bouvillons antérieurement nourris de maïs concassé se caractérisent par un gain quotidien moyen, un poids final et une superficie du longissimus supérieurs (P < 0,08) à ceux des bouvillons engraissés avec des pellicules de soja, signe que la source d'énergie supplémentaire durant la période de semi-finition pourrait influer sur le ren...

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