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ABSTRACT: Two experiments were conducted to determine the effects of DMI restriction on diet digestion, ruminal fermentation, ME intake, and P retention by beef steers. In Exp. 1, twelve Angus x steers (average initial BW = 450 +/- 18 kg) were assigned randomly to 1 of 3 diets that were formulated to promote a 1.6-kg ADG at intake levels corresponding approximately to 100% (ad libitum, AL), 90% (IR90), or 80% (IR80) of ad libitum DMI. In Exp. 2, twelve crossbred steers (average initial BW = 445 +/- 56 kg) fitted with ruminal cannulae were randomly assigned to 1 of 2 diets that were formulated to promote a 1.6-kg ADG at AL or IR80. All diets delivered similar total NE, MP, Ca, and P per day. During both experiments, fecal DM output by IR80 was less (P </= 0.03) than that of AL; IR90 was similar (P = 0.51) to AL during Exp. 1. Digestion of DM by IR80 cattle was greater (P </= 0.03) than that of AL during both experiments; IR90 was similar (P = 0.31) to AL during Exp. 1. Metabolizable energy intake was similar (P >/= 0.20) among treatments during both experiments, whereas P retention was similar (P >/= 0.46) among treatments during Exp. 1. Total VFA and the molar proportion of acetate of AL were greater (P </= 0.03) than that of IR80 during Exp. 2; however, IR80 had a greater (P = 0.03) molar proportion of propionate. Under the conditions of these studies, restricting DMI while holding NE, ruminally degradable protein, and MP intakes constant decreased fecal DM output and changed ruminal fermentation patterns in finishing steers. Improvements in performance associated with programmed-feeding regimens of the type studied here do not appear to be related to changes in diet digestion or ME intake.
Journal of Animal Science 12/2007; 85(12):3383-90. · 2.10 Impact Factor
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ABSTRACT: One hundred forty spring-born Angus x Gelbvieh and purebred Angus steers were selected for study as early weaned (EW; average age at weaning = 90 +/- 30 d) or traditionally weaned (TW; average age at weaning = 174 +/- 37 d) steers that were non-implanted or implanted (Synovex-S, Fort Dodge Animal Health, Overland Park, KS). Initially, steers were sorted by age, sire, and farm, and then allotted randomly in a 2 x 2 factorial arrangement of treatments of EW implanted (EWI), EW nonimplanted (EWN), TW implanted (TWI), or TW nonimplanted (TWN). Ultrasound measurements (US) of LM area (LMA), 12th rib fat thickness (US-BF), and marbling (US-M) were collected every 28 d during the time that steers were on feed. At 202 d of age, EW calves had larger US-LMA, US-BF, and BW than TW calves (37.9 vs. 32.3 cm2, 0.38 vs. 0.26 cm, and 271.6 vs. 218.9 kg, respectively; P < 0.001). At slaughter, EW calves had heavier HCW (290.4 vs. 279.7 kg, respectively; P < 0.05) and greater USDA marbling scores (51.25 vs. 46.26, respectively; P < 0.05) than TW calves; more EW steers graded USDA Choice or greater (P = 0.05). However, no differences were detected in BW (P = 0.15), LMA (P = 0.39), BF (P = 0.45), or liver abscess scores (P = 0.41). Twenty-four implanted steers were selected from the original group of 140 and sorted into two slaughter groups of 12. Twelve implanted steers from each weaning group, matched in slaughter BW but differing in age, were subsampled at slaughter to assess the effect of weaning age and chronological age on muscle tenderness. Younger animals had lower Warner-Bratzler shear force values (P < 0.001) than older calves after 14 d of postmortem aging; however, no differences were found in tenderness after 21 d of aging. Furthermore, there was greater variance (P < 0.001) in Warner-Bratzler shear force values among younger, EW steers vs. older, TW steers. These data provide evidence that early weaning of beef calves may be used as a tool to more effectively manage the cow-calf production system without compromising the quality of the offspring.
Journal of Animal Science 01/2006; 83(12):2752-61. · 2.10 Impact Factor
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ABSTRACT: Two studies were conducted to deter-mine the effects of restricting DMI on growth performance and carcass merit of finishing steers. In Trial 1, 84 Angus cross steers (BW = 313 ± 7 kg) were ran-domly assigned to one of three treatment diets that were designed to achieve a 1.6 kg/d ADG at three intake levels: ad libi-tum, 90% of ad libitum DMI (LF90), or 80% of ad libitum DMI (LF80). In Trial 2, 84 Angus cross steers (BW = 327 ± 20 kg) were randomly assigned to one of two treatment diets that were designed to achieve an ADG of 1.6 kg/d at two in-take levels: ad libitum or LF80. All diets delivered similar total NE, metabolizable protein, and P per day. Daily feed deliv-ery (0800 h) for each treatment was de-termined based on a rolling 5-d average of DMI by steers fed ad libitum. No steers were treated for digestive disorders in either trial, and liver abscess scores 1 Thanks are extended to Phillip Brooks, Pat-rick McCarty, and David Kemp at the Uni-versity of Missouri and Steve Morgan and Gregg Davis at Tyson Fresh Meats (Empo-ria, KS) for their help in conducting this re-search. 2 To whom correspondence should be ad-dressed: olsonkc@missouri.edu were similar between treatments (Trial 1, P=0.65; Trial 2, P=0.73). Actual average DMI during Trial 1 were 2.45% BW for ad libitum steers, 2.26% BW for LF90 (92% of ad libitum intake), and 1.99% BW for LF80 (81% of ad libitum in-take). During Trial 2, actual average DMI was 2.43% BW for ad libitum steers and 1.94% BW for LF80. Steer ADG was greater (P≤0.04) for LF80 than for ad libitum feeding during both trials. Similarly, growth efficiency [gain to feed ratio; G:F] by LF80 steers was greater (P<0.01) than that of ad libitum steers during both trials. During Trial 1, hot carcass weights of LF80 steers were greater (P=0.01) than those for ad libi-tum steers or for LF90 steers. Marbling scores of ad libitum steers and for LF80 steers were greater (P<0.05) than those for LF90 steers. Yield grade tended to be more favorable (P=0.11) in ad libitum steers and for LF90 steers compared with LF80 steers. Hot carcass weights, marbling scores, and yield grades were similar between treatments in Trial 2. Growth performance was greater than that predicted by NRC models when fin-ishing steers were fed a diet formulated to promote 1.6 kg/d ADG but limited to approximately 80% of ad libitum DMI.
The Professional Animal Scientist. 01/2005; 21:332-338.
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ABSTRACT: The objective of this study was to evaluate the influence of lipoic acid (LA) on beef LM steak bloom time, as well-as to characterize bloom time in the CIE L*, a*, and b* color space over a 93-min period. Thirty-two Simmental steers were supplemented with LA for 21 d immediately before slaughter at levels of 0, 8, 16, or 24 mg of LA/kg BW (eight steers per treatment). Lipoic acid was mixed with liquid paraffin, allowed to solidify, prilled, and top-dressed over a standard finishing diet. Steers were slaughtered at the University of Missouri abattoir in four groups of eight (two steers per treatment) over a 2-wk period. After a 24-h chill at 4 degrees C, the right LM was removed from each carcass. One 2.54cm steak was removed from the anterior portion of the LM, and its color characteristics (CIE L*, a*, and b*) were measured immediately with a standardized spectrocolorimeter. Color measurements were taken every 3 min thereafter for a total of 93-min. Hue angle (true red) and chroma (color saturation) were calculated from the color measurements. Addition of LA to the diet had no effect on bloom time (P = 0.67). When treatment means were analyzed, the addition of 24 mg of LA/kg BW to the diet resulted in higher (lighter) L* values (P < 0.05) compared with other treatments, whereas the addition of 16 mg of LA/kg BW to the diet caused lower hue angles (more true red; P < 0.05) when compared with other treatments. Addition of LA to the diet did not affect a* (P = 0.13) and b* (P = 0.18) values or chroma (P = 0.62). In the absence of treatment effects, bloom times for all treatments were pooled, and L* values did not change (P > 0.05) during the 93-min bloom time; however, a* and chroma values increased for 9 min and plateaued after 12 min (P < 0.01). Similarly, b* values increased (P < 0.01) for the first 6 min, and after 9 min, no further increase in yellowness was detected. Bloom time had little effect on hue angle, which stabilized after 3 min. Supplementing steers with the antioxidant LA for 21 d had no effect on the bloom time of beef LM; however, higher levels of supplemental LA affected L* values and hue angles of beef.
Journal of Animal Science 11/2004; 82(10):3034-7. · 2.10 Impact Factor
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ABSTRACT: The objective of this study was to evaluate short-duration supplementation of alpha-lipoic acid (ALA) and creatine monohydrate (CMH) to improve fresh pork quality. Forty-eight commercial hybrid barrows were blocked by BW and randomly allotted to one of four treatments: 1) no CMH or ALA; 2) supplementation of 24 g of CMH(-1) x pig(-1) x d(-1); 3) supplementation of 600 mg ALA(-1) x pig(-1) x d(-1); or 4) combined CMH and ALA supplements. Twelve pigs per treatment were individually penned with ad libitum access to water and a finishing diet. Treatments were hand-fed to individual pigs daily (divided into three equal doses) for 5 d before slaughter at 113 kg BW in two separate groups of 24 pigs each. Intramuscular pH was recorded at 45 min postmortem and again at 24 h in the ham semimembranosus (SM) and the longissimus muscle (LM) between the 10th and 11th rib. A Meatcheck (SFK Technology, Peosta, IA) conductivity probe was inserted in the same anatomical locations as pH measurement, providing an index value (PY) from 0 to 100 (a higher index value indicates more intact muscle cells and higher water-holding capacity). Color (L, a, b values) measurements were obtained at 24 h postmortem on the ham gluteus medius (GM), SM, and LM. Two 2.54-cm-thick loin chops were removed from the loin for determination of Warner-Bratzler shear force and glycolytic potential. The intact SM and the posterior portion of the boneless loin were vacuum-packaged and stored for 7 d to determine purge loss. Creatine-supplemented pigs had a higher (P = 0.03) PY value in the SM (66.67) at 45 min postmortem than either ALA, singularly (63.50), or in the combined CMH/ALA (62.27) treatments. (A higher PY index indicates superior water-holding capacity.) Lipoic acid supplementation resulted in the highest pH at 45 min (P = 0.029). These results justify further evaluation of the potential positive influence of supplementing alpha-lipoic acid to improve pork quality.
Journal of Animal Science 11/2003; 81(10):2469-74. · 2.10 Impact Factor
