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1.
A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high: 3,537, medium: 3,369, and low: 3,317 kcal/kg of ME) to determine the effects of feeding ractopamine and various dietary energy levels on the fatty acid profile of 4 carcass fat depots (jowl, belly, subcutaneous loin, and intramuscular) and the predictive relationships of calculated iodine value (IV) between these 4 fat depots. Carcasses were sampled for fat tissues at the anterior tip of the jowl, posterior to the sternum on the belly edge, three-quarters the distance around the LM (subcutaneous fat; SC), and within the LM (intramuscular fat; IMF). Feeding ractopamine diets reduced (P < 0.05) total SFA in SC and IMF and increased (P = 0.04) total MUFA in SC. Also, feeding ractopamine diets increased (P < 0.01) the IV of IMF. Total MUFA of belly fat was reduced (P < 0.05) when the low-energy diet was fed compared with the high-energy diet. Jowl fat total MUFA was reduced (P < 0.05) and total PUFA was increased (P < 0.05) when the medium-energy diet was fed compared with the high- and low-energy diets. Iodine values, independent of treatment, were 60.97, 64.51, 55.59, and 58.26 for belly, jowl, IMF, and SC fat depots, respectively. The IV correlations within fat depots were not consistent across dietary treatments because of the effect of treatments on carcass fatty acid characteristics. Feeding ractopamine diets shifted the fatty acid profile from SFA to MUFA in the SC depot. Feeding ractopamine diets did not change belly fat profiles, thus avoiding the potential negative effect of softening belly fat, which is detrimental to processing value. The IV of one fat depot may not be a good indication of IV of other fat depots because of weak correlation coefficients and the apparent influence of dietary treatment.  相似文献   

2.
Two hundred sixteen crossbred barrows and gilts (84.3 kg BW) were used to test the effects of dietary energy density and lysine:energy ratio (Lys:ME) on the performance, carcass characteristics, and pork quality of finishing pigs fed 10 ppm ractopamine. Pigs were blocked by BW and gender, allotted to 36 pens (six pigs per pen), and pens were assigned randomly within blocks to dietary treatments (as-fed basis) arranged in a 2 x 3 factorial design, with two levels of energy (3.30 or 3.48 Mcal/kg) and three Lys:ME (1.7, 2.4, or 3.1 g lysine/Mcal) levels. Pigs were fed experimental diets for 28 d, and weights and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Upon completion of the feeding trial, pigs were slaughtered and carcass data were collected before fabrication. During carcass fabrication, hams were analyzed for lean composition using a ham electrical conductivity (TOBEC) unit, and loins were collected, vacuum-packaged, and boxed for pork quality data collection. Energy density had no (P > 0.22) effect on ADG or ADFI across the entire 28-d feeding trial; however, pigs fed 3.48 Mcal of ME were more (P < 0.02) efficient than pigs fed 3.30 Mcal of ME. In addition, ADG and G:F increased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. Carcasses of pigs fed 3.48 Mcal of ME were fatter at the last lumbar vertebrae (P < 0.08) and 10th rib (P < 0.04), resulting in a lower (P < 0.03) predicted fat-free lean yield (FFLY). Conversely, 10th-rib fat thickness decreased linearly (P = 0.02), and LM depth (P < 0.01) and area (P < 0.01) increased linearly, with increasing Lys:ME. Moreover, FFLY (P < 0.01) and actual ham lean yield (P < 0.01) increased as Lys:ME increased in the diet. Dietary energy density had no (P > 0.19) effect on pork quality, and Lys:ME did not (P > 0.20) affect muscle pH, drip loss, color, and firmness scores. Marbling scores, as well as LM lipid content, decreased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. There was a linear (P < 0.01) increase in shear force of cooked LM chops as Lys:ME increased in the finishing diet. Results indicate that 3.30 Mcal of ME/kg (as-fed basis) is sufficient for optimal performance and carcass leanness in pigs fed ractopamine. The Lys:ME for optimal performance and carcass composition seems higher than that currently used in the swine industry; however, feeding very high Lys:ME (> 3.0 g/Mcal, as-fed basis) to ractopamine-fed pigs may result in decreased marbling and cooked pork tenderness.  相似文献   

3.
An experiment using 264 crossbred barrows was conducted to examine the interaction between space allocation and dietary ractopamine addition on pig performance and carcass characteristics using a 2 x 2 factorial arrangement of treatments. Treatments were 0.55 (19 pigs per pen) or 0.74 (14 pigs per pen) m2/pig from start (29.7 +/- 0.1 kg BW) to slaughter (108 kg BW) in a fully slatted facility and 0 or 10 ppm (as-fed basis) ractopamine for 28 d before slaughter. There were few treatment interactions. Pigs given 0.55 m2/pig had a lower ADG (P = 0.010), ADFI (P = 0.088), 10th-rib backfat depth on d 86 (P = 0.010), and carcass loin muscle depth (P = 0.011) than pigs given 0.74 m2/pig. There was no difference in feed conversion (P = 0.210) as a result of space allocation. Pigs fed diets containing 10 ppm ractopamine had decreased (P = 0.004) ADFI and improved (P = 0.001) feed conversion efficiencies for the 28-d feeding period, along with greater loin depth (P = 0.005) and carcass lean percent (P = 0.001). The improvements in 28-d carcass lean growth associated with feeding 10 ppm ractopamine resulted in an improvement in overall daily fat-free lean gain (P = 0.046). Under these experimental conditions, the response to dietary ractopamine was similar for crowded and uncrowded pigs.  相似文献   

4.
The objective of this research was to use recent ractopamine research data to develop an updated mathematical model to describe the daily compositional growth of pigs fed ractopamine. Mean increases of 18.2, 23.1, and 25.0% for daily protein accretion were assumed for 5, 10, and 20 ppm of ractopamine for an overall gain of 40 kg of BW gain during the feeding period. The relative effect of ractopamine described the rapid increase and subsequent decrease in the effect of ractopamine as a function of BW gain or days on test and ractopamine concentration (RC, ppm). The reduction in ME intake produced by ractopamine was described as 0.036 x (RC/20)(0.7) multiplied by the ME intake for the first 20 kg of BW gain, and then increasing to 0.078 x (RC/20)(0.7) at 40 kg of BW gain feeding period. The ratio of fat-free muscle gain to protein accretion increased by 14 to 16% with the feeding of ractopamine, depending on the dietary lysine/essential AA levels. The ratio of carcass fat gain to empty body lipid gain was increased when lysine and essential AA requirements were met. Daily protein accretion and fat-free lean growth were described as functions of dietary lysine/essential AA intakes. The percentage of lysine in protein accretion increased with the feeding of ractopamine from 6.80 to 7.15%, depending on ractopamine concentration. Equations predicting carcass measurements, such as fat and longissimus muscle depths from carcass weight and composition, were modified to incorporate prediction biases produced by ractopamine. For the four concentrations of ractopamine (0, 5, 10, and 20 ppm, respectively) during a 78 to 110 kg of BW feeding period, the model predicted performance levels for ADG (1.03, 1.15, 1.16, and 1.16 kg/d), gain:feed (kg of ADG/kg of ADFI; 0.360, 0.401, 0.412, and 0.425), dressing percentage (75.1, 76.0, 76.3, and 76.4), percentage fat-free lean (48.7, 51.0, 51.5, and 52.2), longissimus muscle area (38.8,41.8,42.5, and 43.5 cm2), 10th-rib fat depth (22.1, 19.8, 19.3, and 18.7 mm), and fat-free lean gain (321, 446, 467, and 495 g/d), comparable to recent research data. The model allows the effect of ractopamine to be added to farm specific pig growth curves. It can be used to evaluate ways to optimize the use of ractopamine, including duration of ractopamine feeding, concentration of ractopamine, and dietary lysine concentration.  相似文献   

5.
One hundred ninety-six crossbred barrows of high lean gain potential (21.2 kg BW) were used in an experiment to determine the effect of dietary feather meal (FM) on barrow performance, specifically, the effects of the ingredient on ADG and carcass leanness. Additionally, 28 gilts (26.8 kg BW) were used to compare gender differences on the corn-soybean meal control diets. Treatments were control barrows and control gilts fed corn-soybean meal diets, and barrows fed according to a 2 x 3 factorial arrangement of FM levels (10 or 20%, as-fed basis) and starting weights on the diets (36, 60, or 86 kg BW). All barrow diets were formulated to contain the same apparent digestible lysine and ME. Control barrows ate more feed (2.61 vs. 2.39 kg/d; as-fed), grew faster (0.911 vs. 0.827 kg/d), had greater backfat depth at slaughter (15.6 vs. 11.6 mm), and had lower carcass lean content (P < 0.001), with no difference in daily lean gain (P = 0.848) compared with gilts. There was a linear (P = 0.010) decrease in ADG for barrows fed increasing amounts of FM from 36 kg BW to slaughter, with no effect of FM additions on ADG when initiated at 60 or 86 kg BW. There was a quadratic reduction (P = 0.008) in ADFI and estimated digestible lysine intake with increasing FM for the 36 to 60 kg BW period for barrows fed FM starting at 36 kg BW. There was a linear (P = 0.006) decrease in ADFI for the 60 to 86 kg BW period with increasing FM for barrows started on FM at 60 kg BW. There was no effect of experimental diets or starting weight on barrow 10th-rib backfat depth at slaughter. These results suggest that diets containing 10 and 20% FM were effective in decreasing overall ADG and ADFI by barrows when feeding of FM was initiated at 36 kg BW; however, backfat at slaughter was still greater than for control gilts.  相似文献   

6.
A total of 120 pigs (60 barrows and 60 gilts; TR4 × PIC 1050; 54.4 kg initial BW) were used in an 83-d study to evaluate the effects of added fat in corn- and sorghum-based diets on growth performance, carcass characteristics, and carcass fat quality. Treatments were arranged in a 2 × 3 factorial with grain source (corn or sorghum) and added fat (0, 2.5, or 5% choice white grease; CWG) as factors. There were 2 pigs (1 barrow and 1 gilt) per pen and 10 replicate pens per treatment. Pigs and feeders were weighed on d 14, 22, 39, 53, 67, and 83 to calculate ADG, ADFI, and G:F. At the end of the trial, pigs were slaughtered and jowl fat and backfat samples were collected and analyzed for fatty acid profile. No interactions were observed for growth performance. Pigs fed sorghum-based diets had greater (P < 0.01) ADG than pigs fed corn-based diets. Adding CWG improved (linear, P < 0.01) ADG. Pigs fed corn-based diets tended to have greater (P < 0.09) carcass yield, 10th-rib backfat, and percentage lean than pigs fed sorghum-based diets. Adding CWG increased (linear, P = 0.02) 10th-rib backfat, tended to increase (linear, P = 0.08) HCW, and tended to decrease (linear, P = 0.07) percentage lean. There was no grain source × fat level interaction for iodine value (IV) in backfat, but an interaction (P = 0.03) was observed for IV in jowl fat. Adding CWG increased (P < 0.01) IV in jowl fat for pigs fed sorghum- and corn-based diets; however, the greatest increase was between 0 and 2.5% CWG in sorghum-based diets and between 2.5 and 5% CWG in corn-based diets. Pigs fed corn-based diets had less (P = 0.01) C18:1 cis-9 and MUFA but greater (P = 0.01) C18:2n-6, PUFA, and backfat IV than pigs fed sorghum-based diets. Increasing CWG in the diet increased (linear, P = 0.01) backfat IV. Of the 2 fat depots, backfat generally had a reduced IV than jowl fat. In summary, feeding sorghum-based diets reduced carcass fat IV and unsaturated fats compared with corn-based diets. As expected, adding CWG increased carcass fat IV regardless of the cereal grain in the diet.  相似文献   

7.
Two experiments were conducted to evaluate the effects of adding combinations of wheat middlings (midds), distillers dried grains with solubles (DDGS), and choice white grease (CWG) to growing-finishing pig diets on growth, carcass traits, and carcass fat quality. In Exp. 1, 288 pigs (average initial BW = 46.6 kg) were used in an 84-d experiment with pens of pigs randomly allotted to 1 of 4 treatments with 8 pigs per pen and 9 pens per treatment. Treatments included a corn-soybean meal-based control, the control with 30% DDGS, the DDGS diet with 10% midds, or the DDGS diet with 20% midds. Diets were fed in 4 phases and formulated to constant standardized ileal digestible (SID) Lys:ME ratios within each phase. Overall (d 0 to 84), pigs fed diets containing increasing midds had decreased (linear, P ≤ 0.02) ADG and G:F, but ADFI was not affected. Feeding 30% DDGS did not influence growth. For carcass traits, increasing midds decreased (linear, P < 0.01) carcass yield and HCW but also decreased (quadratic, P = 0.02) backfat depth and increased (quadratic, P < 0.01) fat-free lean index (FFLI). Feeding 30% DDGS decreased (P = 0.03) carcass yield and backfat depth (P < 0.01) but increased FFLI (P = 0.02) and jowl fat iodine value (P < 0.01). In Exp. 2, 288 pigs (initial BW = 42.3 kg) were used in an 87-d experiment with pens of pigs randomly allotted to 1 of 6 dietary treatments with 8 pigs per pen and 6 pens per treatment. Treatments were arranged in a 2 × 3 factorial with 2 amounts of midds (0 or 20%) and 3 amounts of CWG (0, 2.5, or 5.0%). All diets contained 15% DDGS. Diets were fed in 4 phases and formulated to constant SID Lys:ME ratios in each phase. No CWG × midds interactions were observed. Overall (d 0 to 87), feeding 20% midds decreased (P < 0.01) ADG and G:F. Pigs increasing CWG had improved ADG (quadratic, P = 0.03) and G:F (linear, P < 0.01). Dietary midds or CWG did not affect ADFI. For carcass traits, feeding 20% midds decreased (P < 0.05) carcass yield, HCW, backfat depth, and loin depth but increased (P < 0.01) jowl fat iodine value. Pigs fed CWG had decreased (linear, P < 0.05) FFLI and increased (linear, P < 0.01) jowl fat iodine value. In conclusion, feeding midds reduced pig growth performance, carcass yield, and increased jowl fat iodine value. Although increasing diet energy with CWG can help mitigate negative effects on live performance, CWG did not eliminate negative impacts of midds on carcass yield, HCW, and jowl fat iodine value.  相似文献   

8.
This study was conducted to determine the effects of dietary crude glycerol and dried distillers grains with solubles (DDGS) on growing-finishing pig performance, carcass characteristics, and carcass fat quality. We hypothesized that because dietary crude glycerol has been observed to increase carcass SFA, it might ameliorate the negative effects of DDGS on fat quality. The 97-d study was conducted at a commercial swine research facility in southwestern Minnesota with 1,160 barrows (initial BW = 31.0 ± 1.1 kg). Pigs were blocked by initial BW, and pens were randomly allotted to 1 of 6 dietary treatments with 7 replications per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of crude glycerol (0, 2.5, or 5%) and DDGS (0 or 20%). All corn-soybean meal-based diets contained 3% added fat (choice white grease). There were no glycerol × DDGS interactions for any response criteria evaluated. Increasing dietary glycerol did not affect finishing pig growth performance. Adding 20% DDGS to the diet did not affect ADG; however, finishing pigs fed diets with added DDGS had greater (2.47 vs. 2.41 kg/d; P = 0.02) ADFI and poorer (0.39 vs. 0.40; P = 0.01) G:F than pigs not fed DDGS. Feeding increasing dietary glycerol or 20% DDGS did not affect carcass characteristics. For carcass fat quality, feeding 20% DDGS resulted in decreased (P < 0.01) palmitic and oleic acids, total SFA and total MUFA, and increased (P < 0.01) linoleic, total PUFA, total unsaturated fatty acids, and iodine value in jowl fat, belly fat, and backfat. Increasing dietary crude glycerol increased myristic acid (linear, P < 0.05) and MUFA (quadratic, P < 0.05) in jowl fat and increased (quadratic, P < 0.05) oleic acid and MUFA in backfat. In conclusion, feeding 20% DDGS to finishing pigs increased ADFI, reduced G:F, and increased carcass fat iodine value, whereas feeding crude glycerol did not influence growth performance, carcass characteristics, and had a minor influence on fatty acids of carcass fat. Both of these biofuel coproducts can be used in combination without affecting finishing pig performance or carcass traits; however, feeding crude glycerol did not fully mitigate the increased unsaturation of carcass fat observed when feeding DDGS.  相似文献   

9.
British × Continental heifers (n = 3,382; initial BW = 307 kg) were serially slaughtered to determine if increasing days on the finishing diet (DOF) mitigates negative consequences of zilpaterol HCl (ZH) on quality grade and tenderness of beef. A 2 × 3 factorial arrangement of treatments in a completely randomized block design (36 pens; 6 pens/treatment) was used. Zilpaterol HCl (8.33 mg/kg DM) was fed 0 and 20 to 22 d before slaughter plus a 3 to 5 d withdrawal to heifers spending 127, 148, and 167 DOF. Feedlot and carcass performance data were analyzed with pen as the experimental unit. Three hundred sixty carcasses (60 carcasses/treatment) were randomly subsampled, and strip loin steaks were aged for 7, 14, and 21 d for assessment of Warner-Bratzler shear force (WBSF) and slice shear force (SSF) with carcass serving as the experimental unit for analysis. No relevant ZH × DOF interactions were detected (P > 0.05). Feeding ZH during the treatment period increased ADG by 9.5%, G:F by 12.5%, carcass ADG by 33.6%, carcass G:F by 35.9%, carcass ADG:live ADG by 15.6%, HCW by 3.2% (345 vs. 356 kg), dressing percent by 1.5%, and LM area by 6.5% and decreased 12th-rib fat by 5.2% and yield grade (YG) by 0.27 units (P < 0.01). Feeding ZH tended to decrease marbling score (437 vs. 442 units; P = 0.10) and increased WBSF at 7 (4.25 vs. 3.47 kg; P < 0.01), 14 (3.57 vs. 3.05 kg; P < 0.01), and 21 d (3.50 vs. 3.03 kg; P < 0.01). Feeding ZH decreased empty body fat percentage (EBF; 29.7% vs. 30.3%; P < 0.01) and increased 28% EBF adjusted final BW (473.4 vs. 449.8 kg; P < 0.01). Analysis of interactive means indicated that the ZH × 148 DOF group had a similar percentage of USDA Prime, Premium Choice, Low Choice, and YG 1, 2, 3, 4, and 5 carcasses (P > 0.10) and decreased percentage of Select (30.4 vs. 36.6%; P = 0.03) and Standard (0.2 vs. 0.9%; P = 0.05) carcasses compared with the control × 127 DOF group. As a result of ZH shifting body composition, extending the DOF of beef heifers is an effective feeding strategy to equalize carcass grade distributions. This can be accomplished along with sustaining the ZH mediated advantages in feedlot and carcass weight gain.  相似文献   

10.
The objective of this experiment was to determine if growth, carcass composition, and myofiber characteristics of lambs were affected by heterozygosity for a myostatin mutation (g+6723G>A) when offered differing allowances of feed administered with or without ractopamine. Heterozygote [MSTN A/G (n = 40)] and homozygote wildtype [MSTN G/G (n = 39)] castrate male lambs were individually fed ad libitum (HI; 1.8 × estimated ME(m)) or a restricted allowance (LO; 1.1 × estimated ME(m)) of a diet (191 g of CP/kg of DM and 12 MJ of ME/kg of DM), supplemented with (0.4 mg/kg of BW) or without the β-adrenergic agonist ractopamine (RAC or NO RAC) for 47 d. The lambs were scanned by computed tomography at the beginning and completion of the feeding experiment to calculate composition of lean, fat, and bone in the carcass component of the body. The MSTN A/G HI intake lambs had significantly greater total daily carcass growth (P = 0.045) and loin eye depth (P = 0.022) and tended to have a greater daily growth of lean (P = 0.09) in the carcass, compared with MSTN G/G HI intake lambs. Conversely, MSTN A/G LO intake lambs tended to have less daily lean deposition (P = 0.09), significantly less total daily carcass growth (P = 0.045), and had a greater percentage of type IIX myofibers (P < 0.01) and total myofiber area (relative area) of type IIX myofibers (P = 0.013). The inclusion of RAC increased final BW (P = 0.03) and ADG (P = 0.02), percentage of type IIC (P < 0.001) and IIA (P = 0.012) myofibers, cross-sectional area of types I (P = 0.04) and IIAX (P = 0.04) fibers, and the relative area of type IIC (P = 0.003) and IIA (P = 0.01) myofibers in the LM. The experiment demonstrated that including RAC in the diet of lambs increased final BW and ADG, but not HCW, and increased proportion of type IIC and IIA myofibers and cross-sectional area of type I and IIAX myofibers. Our data suggest that RAC and the heterozygous myostatin mutation act together to increase growth of muscle on a high plane of nutrition. The experiment also demonstrated that poor nutritional background of lambs heterozygous for the myostatin mutation may negatively influence their growth rates and myofiber characteristics.  相似文献   

11.
An experiment was conducted to determine the efficacy of dietary betaine, CLA, or both as growth promotants and carcass modifiers in growing Iberian pigs. Twenty gilts (20 kg of BW) were individually penned and fed barley- and soybean meal-based diets (12% CP, 0.81% Lys, and 14.8 MJ of ME/kg of DM) containing either no added betaine or CLA (control), 0.5% betaine, 1% CLA, or 0.5% betaine + 1% CLA, at 95% of ad libitum energy intake. An additional group of 5 pigs was slaughtered at the beginning of the experiment to obtain the initial body composition. At 30 kg of BW, a balance experiment was conducted. At 50 kg of BW, pigs were slaughtered and viscera was removed and weighed. Betaine or CLA alone did not affect growth performance. However, betaine + CLA increased ADG (601 vs. 558 g, P = 0.03) and gain relative to ME intake (25.4 vs. 22.2 g/MJ, P = 0.03) compared with control pigs. Digestibility of nutrients and metabolizability of energy did not differ among diets (P = 0.46 to 0.75). Carcass protein, water, and lean deposition (g/d) increased (19.8, 24.2, and 23.4%, respectively, P < 0.01) in pigs fed betaine + CLA compared with control pigs. Similarly, protein deposition relative to ME intake increased by 28% in betaine + CLA-supplemented pigs (P < 0.05). Fat and mineral deposition did not differ among treatments. Carcass protein, water, and lean content (g/kg of carcass) of pigs fed betaine + CLA-supplemented diets tended to increase (P = 0.07 to 0.09) and carcass fat content tended to decrease (P = 0.09). Similarly, estimated composition of carcass gain was affected, such that water and lean content tended to increase (P = 0.06 to 0.08), whereas fat tended to decrease (P = 0.08) in pigs fed betaine + CLA-supplemented diets. Longissimus muscle area was not altered by treatments (P = 0.49). The liver of pigs fed betaine + CLA diets had increased weight (19%, P < 0.05) compared with control pigs. Overall, dietary supplementation of betaine + CLA increased ADG, protein, water, and lean deposition in growing Iberian gilts. There appears to be a synergistic action when betaine and CLA are used together.  相似文献   

12.
An experiment was conducted to determine the relationship between feeding ractopamine and different amounts of MP on growth and carcass characteristics of feedlot heifers. Seventy-two crossbred heifers (475 kg of initial BW) were fed individually a diet based on steam-flaked corn for ad libitum intake for 29 d. Heifers were implanted with 140 mg of trenbolone acetate and 14 mg of estradiol-17beta 60 d before the experiment. Treatments were arranged as a 2 x 3 factorial and included 0 or 200 mg of ractopamine-HCl (23 ppm)/ d, and urea, solvent soybean meal, or expeller soybean meal (ESBM) as the predominant protein supplement. The amounts of MP supplied by the urea, solvent soybean meal, and ESBM diets were 688, 761, and 808 g/ d, respectively, calculated according to level 1 of the NRC model. Body weights were obtained 1 d before ractopamine feeding and at slaughter. Blood samples were obtained 1 d before starting the experiment and 13 d later. Ractopamine improved ADG, efficiency of gain, carcass-adjusted ADG, and carcass-adjusted efficiency of gain (P < 0.01). For ADG, heifers demonstrated a ractopamine x protein source interaction (P < 0.05); heifers not fed ractopamine had greater ADG when fed ESBM than when fed urea, whereas for heifers fed ractopamine there were no differences (P > or = 0.10) among protein supplements. This interaction was not observed for carcass-adjusted ADG (P = 0.60). Final live weights (P = 0.02) and carcass weights (P = 0.01) were greater with ractopamine feeding. Carcass marbling scores and yield grades were not affected by ractopamine or protein source (P > or = 0.39). Plasma total alpha-amino N and glucose concentrations decreased more from pretreatment concentrations when heifers were fed ractopamine (P < 0.05). Feeding ractopamine to heifers for 28 d before slaughter improved ADG and efficiency of gain without any large effects on carcass characteristics. The MP supply does not need to be increased from that provided by finishing diets based on steam-flaked corn with urea as the primary N supplement to allow the maximal response to ractopamine by finishing heifers.  相似文献   

13.
Forty-eight barrows and forty-eight gilts (PIC 337 sires x PIC C22 dams) were evaluated to determine the effects of feeding ractopamine hydrochloride (RAC) and different cereal grains on the carcass and fat quality in late finishing pigs. The study was carried out using four replicates with 24 animals in each replicate (four pigs per pen, six pens per replicate, two replicates per slaughter date, 12 pens per slaughter date). Treatments for the experiment included corn, wheat, and barley (early finisher period); and corn, corn + RAC, wheat, wheat + RAC, barley, and barley + RAC for the late finisher period. Ractopamine was fed at the level of 10 mg/kg (as-fed basis) of feed. Pigs were allotted to early finisher period treatments at approximately 45 kg BW. Pigs were then given late finisher period treatments at approximately 80 kg BW and fed for 28 d. The dietary digestible lysine level for all diets was maintained at 2.7 g/Mcal of ME. Pigs fed the wheat and corn diets during the late finisher period had a greater (P <0.05) G:F than those fed the barley diets. Pigs fed diets with RAC had lower (P <0.05) leaf fat weights, 10th-rib fat, last-rib fat, and belly firmness and had improved (P <0.05) dressing percents and loin muscle areas compared with those not receiving RAC. Pigs fed the wheat diets had a greater (P <0.05) dressing percent than those receiving the barley diets, but pigs fed the barley diets had a higher (P <0.05) Minolta L* for fat color than pigs fed wheat. Pigs fed diets containing RAC produced pork that was less tender (P <0.05) compared with pigs that did not receive RAC. Linoleic acid percent values were higher (P <0.05) for pigs fed diets with RAC than in those that did not. Feeding RAC improved G:F and lowered feed intake of pigs during the late finisher period (P <0.05). Feeding diets equal in lysine (2.7 g/Mcal of ME) but varying in ME, whether based on corn, wheat, or barley with or without RAC, had little to no effect on carcass, meat, or fat quality attributes.  相似文献   

14.
Fifty-eight purebred castrated male Iberian (IB) piglets (initial BW 9.9 ± 0.1 kg) were used in an experiment to determine the effect of dietary protein content (PC) and feeding level (FL) on the rates of BW gain, whole body protein deposition (PD), and energy utilization between 10 and 25 kg of BW using the serial slaughter method. Treatments followed a 4 × 2 factorial arrangement with 4 PC (201, 176, 149, and 123 g of CP/kg of DM) and 2 FL (0.95 and 0.70 × ad libitum) and 6 or 7 piglets per combination of treatments. All diets were formulated to have an optimal AA pattern. Six piglets were slaughtered at the start of the trial to estimate initial body composition. The experimental pigs were individually housed in an environmentally controlled room (27 ± 2°C) until they reached 25 kg of BW, when they were slaughtered and analyzed for body composition. Positive linear effects of dietary PC on ADG, G:F, and gain:ME intake were observed (P < 0.001). Piglets fed at the highest FL showed greater ADG, G:F, and gain:ME intake (P < 0.001). An average increase was estimated to be 38.0 g of gain/MJ of ME intake. Protein deposition increased linearly from 35.6 to 50.9 g/d with increasing dietary PC (P < 0.001). A daily increase was estimated to be 0.35 g of PD/g of CP intake. Although the maximal genetic potential for PD of the IB piglet was not attained, a maximal value of 59.9 g/d for whole-body PD was achieved when the diet provided 201 g of CP/kg of DM and was fed at 0.95 × ad libitum. Piglets on the highest FL deposited on average 39% more body protein (P < 0.001) than restricted piglets. An average value of 4.39 g increase in PD/MJ of ME intake was obtained for diets containing 201 and 176 g of CP/kg of DM. Maintenance energy requirements and net efficiency of utilization of ME for growth, calculated by linear regression of ME intake on body retained energy, were 427 kJ/kg of BW(0.75)·d(-1) and 0.552, respectively. The corresponding partial efficiencies of utilization of ME for protein and fat deposition were 0.378 and 0.672, respectively, considerably less than the accepted values for conventional pig breeds. Practical diets of the young IB piglet should contain at least 201 g of ideal CP/kg of DM.  相似文献   

15.
A study with 3 experiments was conducted to determine the AA digestibility and energy concentration of deoiled (solvent-extracted) corn distillers dried grains with solubles (dDGS) and to evaluate its effect on nursery pig growth performance, finishing pig growth performance, and carcass traits. In Exp. 1, a total of 5 growing barrows (initial BW = 30.8 kg) were fitted with a T-cannula in the distal ileum and allotted to 1 of 2 treatments: 1) a diet with dDGS as the sole protein source, or 2) a N-free diet for determining basal endogenous AA losses in a crossover design at 68.0 kg of BW. Apparent and standardized (SID) ileal digestibility of AA and energy concentration of dDGS were determined. In Exp. 2, a total of 210 pigs (initial BW = 9.9 kg) were used in a 28-d experiment to evaluate the effect of dDGS on nursery pig performance. Pigs were allotted to 5 dietary treatments (0, 5, 10, 20, or 30% dDGS) formulated to contain equal ME (increased added fat with increasing dDGS) and SID Lys concentrations based on the values obtained from Exp. 1. In Exp. 3, a total of 1,215 pigs (initial BW = 29.6 kg) were used in a 99-d experiment to determine the effect of dDGS on growth and carcass characteristics of finishing pigs. Pigs were allotted to dietary treatments similar to those used in Exp. 2 and were fed in 4 phases. The analyzed chemical composition of dDGS in Exp. 1 was 35.6% CP, 5.29% ash, 4.6% fat, 18.4% ADF, and 39.5% NDF on a DM basis. Apparent ileal digestibility values of Lys, Met, and Thr in dDGS were 47.2, 79.4, and 64.1%, respectively, and SID values were 50.4, 80.4, and 68.9%, respectively. The determined GE and DE and the calculated ME and NE values of dDGS were 5,098, 3,100, 2,858, and 2,045 kcal/kg of DM, respectively. In Exp. 2, nursery pig ADG, ADFI, and G:F were similar among treatments. In Exp. 3, increasing dDGS reduced (linear; P < 0.01) ADG and ADFI but tended to improve (linear; P = 0.07) G:F. Carcass weight and yield were reduced (linear; P < 0.01), loin depth tended to decrease (linear; P = 0.09), and carcass fat iodine values increased (linear; P < 0.01) as dDGS increased. No difference was observed in backfat, percentage of lean, or fat-free lean index among treatments. In conclusion, dDGS had greater CP and AA but less energy content than traditional distillers dried grains with solubles. In addition, when dietary fat was added to diets to offset the reduced ME content, feeding up to 30% dDGS did not affect the growth performance of nursery pigs but did negatively affect the ADG, ADFI, and carcass fat quality of finishing pigs.  相似文献   

16.
Two experiments were conducted to determine the effect of phytase on energy availability in pigs. In Exp. 1, barrows (initial and final BW of 26 and 52 kg) were allotted to four treatments in a 2 x 2 factorial arrangement. Corn-soybean meal (C-SBM) diets were fed at two energy levels (2.9 and 3.2 x maintenance [M]) with and without the addition of 500 phytase units/kg of diet. The diets contained 115% of the requirement for Ca, available P (aP), and total lysine, and Ca and aP were decreased by 0.10% in diets with added phytase. Pigs were penned individually and fed daily at 0600 and 1700, and water was available constantly. Eight pigs were killed and ground to determine initial body composition. At the end of Exp. 1, all 48 pigs were killed for determination of carcass traits and protein and fat content by total-body electrical conductivity (TOBEC) analysis. Six pigs per treatment were ground for chemical composition. In Exp. 2, 64 barrows and gilts (initial and final BW of 23 and 47 kg) were allotted to two treatments (C-SBM with 10% defatted rice bran or that diet with reduced Ca and aP and 500 phytase units/kg of diet), with five replicate pens of barrows and three replicate pens of gilts (four pigs per pen). In Exp. 1, ADG was increased (P < 0.01) in pigs fed at 3.2 x M. Based on chemical analyses, fat deposition, kilograms of fat, retained energy (RE) in the carcass and in the carcass + viscera, fat deposition in the organs, and kilograms of protein in the carcass were increased (P < 0.10) in pigs fed the diets at 3.2 vs. 2.9 x M. Based on TOBEC analysis, fat deposition, percentage of fat increase, and RE were increased (P < 0.09) in pigs fed at 3.2 x M. Plasma urea N concentrations were increased in pigs fed at 3.2 x M with no added phytase but were not affected when phytase was added to the diet (phytase x energy, P < 0.06). Fasting plasma glucose measured on d 28, ultrasound longissimus muscle area (LMA), and 10th-rib fat depth were increased (P < 0.08) in pigs fed phytase, but many other response variables were numerically affected by phytase addition. In Exp. 2, phytase had no effect (P > 0.10) on ADG, ADFI, gain:feed, LMA, or 10th-rib fat depth. These results suggest that phytase had small, mostly nonsignificant effects on energy availability in diets for growing pigs; however, given that phytase increased most of the response variables measured, further research on its possible effects on energy availability seems warranted.  相似文献   

17.
Three experiments were conducted to determine effects of restricting intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in grain over a period of 20 to 22 d on overall cattle performance, carcass characteristics, digestibility, digesta kinetics, and ruminal metabolism. In Exp. 1, 84 Angus x Hereford yearling steers (initial BW = 418 +/- 29.0 kg) were fed for 70 d. Restricting intake during adaptation had no effect (P > 0.10) on overall ADG:DMI, but decreased (P < 0.05) DMI compared with ad libitum access to adaptation diets, which resulted from differences during the initial 28 d of the experiment. In Exp. 2, 150 mixed crossbred steer calves (initial BW = 289 +/- 22.9 kg) were fed for an average of 173 d. Restricting intake decreased (P < 0.01) overall daily gain (1.51 vs 1.65 kg/d) and DMI (8.68 vs 9.15 kg/d) compared with ad libitum fed steers; however, ADG:DMI was not influenced (P > 0.10) by adaptation method. Experiment three used eight ruminally and duodenally fistulated steers (initial BW = 336 +/- 20 kg) in a completely random design. Total tract digestibility, digesta kinetics and ruminal metabolism were determined. Restricting intake reduced (P < 0.10) daily DMI variation from d 1 through 7, 8 through 14, and 22 through 28 compared with ad libitum feeding of three adaptation diets. Restricted steers had reduced (adaptation method x period interaction, P < 0.05) intakes and fecal excretions of ADF and greater OM digestibilities on d 4 through 7, 11 through 14, and 18 through 21. Digesta kinetics and ruminal metabolism were generally not affected (P > 0.10) by adaptation method. Our results suggest that restricted-feeding of the final diet as a means of dietary adaptation can be used in finishing cattle with few problems from acidosis or related intake variation. In light-weight steers (Exp. 2), disruptions in intake during the adaptation period might have resulted in restriction for an extended period, which decreased (P < 0.01) hot carcass weight compared with calves fed ad libitum. Effects of limit feeding during the initial 28 d of the feeding period on site and extent of digestion, digesta kinetics, and ruminal metabolism were minimal, supporting few differences in performance across the finishing period for yearling cattle.  相似文献   

18.
Two studies were conducted to assess the energy content of low-solubles distillers dried grains (LS-DDG) and their effects on growth performance, carcass characteristics, and pork fat quality in grow-finish pigs. In Exp. 1, 24 barrows (Yorkshire-Landrace × Duroc; 80 to 90 d of age) in 2 successive periods were assigned to 1 of 6 dietary treatments. In individual metabolism stalls, pigs were fed a corn-soybean meal diet (control); control replaced by 30, 40, or 50% LS-DDG; or control replaced by 30 or 40% distillers dried grains with solubles (DDGS) at 3% of their initial BW for 12 d. All diets contained 0.25% CrO(2). During the 5-d collection period, feces and urine were collected from each pig. Feed, feces, and urine were analyzed for DM, GE, and N concentrations, and feed and feces were analyzed for Cr content. The ME content of LS-DDG (2,959 ± 100 kcal/kg of DM) was similar to that determined for DDGS (2,964 ± 81 kcal/kg of DM). In Exp. 2, 216 Yorkshire-Landrace × Duroc pigs were blocked by initial BW (18.8 ± 0.76 kg) and assigned to 1 of 24 pens (9 pigs/pen). Pens within block were allotted to 1 of 3 dietary treatments (8 pens/treatment) in a 4-phase feeding program: a corn-soybean meal control (control), control containing 20% LS-DDG, or control containing 20% DDGS. Treatment had no effect on final BW, ADG, ADFI, or HCW. Pigs fed LS-DDG had similar G:F (0.367) compared with pigs fed DDGS (0.370), but tended (P = 0.09) to have decreased G:F compared with pigs fed the control (0.380; pooled SEM = 0.004). Dressing percent was less (P < 0.01) for pigs fed LS-DDG (72.8%) and DDGS (72.8%) compared with the control (73.8%; pooled SEM = 0.22). Pigs fed LS-DDG (54.8%) had greater (P = 0.02) carcass lean compared with pigs fed DDGS (53.4%), but were similar to pigs fed control (54.1%; pooled SEM = 0.33). Bellies from pigs fed DDGS (12.9°) were softer (P < 0.01) than those from pigs fed control (17.7°; pooled SEM = 1.07) as determined by the belly flop angle test. Feeding LS-DDG (14.1°) tended (P < 0.10) to create softer bellies compared with control-fed pigs. The PUFA content of belly fat was reduced (P < 0.01) by LS-DDG (14.0%) compared with DDGS (15.4%), but was increased (P < 0.05) compared with pigs fed the control (9.4%; pooled SEM = 0.34). In conclusion, LS-DDG and DDGS had similar ME values and inclusion of 20% LS-DDG in diets for growing-finishing pigs supports ADG and ADFI similar to that of diets containing 20% DDGS, and may reduce negative effects on pork fat compared with DDGS.  相似文献   

19.
Energy density in growing diets may affect carcass quality of cattle; however, few reports have described the impact of energy source. The objectives of this research were to determine effects of source [dried distillers grains with solubles (DDGS) vs. corn] and amount (limit-fed to gain 0.9 vs. 1.4 kg of BW/d) of energy during the growing phase on feedlot performance and marbling. Angus-cross steers (144 head) were blocked by BW (average initial BW = 252 ± 36 kg), allotted within each block to 8 pens (6 steers/pen, 24 pens total), and randomly assigned to 1 of 4 feeding systems in a 2 × 2 factorial arrangement of treatments: 1) 65% DDGS fed to gain 0.9 kg of BW/d, 2) 65% DDGS fed to gain 1.4 kg of BW/d, 3) 65% corn fed to gain 0.9 kg of BW/d, and 4) 65% corn fed to gain 1.4 kg of BW/d. Fecal grab samples were collected on d 52 of the growing phase to determine digestibility of DM, ADF, NDF, ether extract (EE), and CP. After the 98-d growing phase, all steers were fed the same finishing diet. Steers were slaughtered by pen when average BW within the pen was 544, 522, and 499 kg for the large, medium, and small BW blocks, respectively. Average daily gain and DMI differed (P<0.01) by design during the growing phase. Compared with the corn-based diets, digestibilities of DM, NDF, and EE were decreased (P<0.02) when DDGS-based diets were fed during the growing phase, whereas the digestibility of N was increased (P<0.01). The ADG was greatest (P=0.02) during the finishing phase for steers fed to gain 0.9 kg of BW/d initially, but source of energy during the growing phase did not affect (P=0.24) finishing phase ADG. Steers fed to gain 0.9 kg of BW/d during the growing phase also had less backfat (P=0.08), decreased USDA yield grades (P=0.03), and greater LM area (P<0.01) than steers fed to gain 1.4 kg of BW/d. There was an interaction between energy source and amount for marbling scores (P=0.02). Steers fed corn-based diets to gain 0.9 kg of BW/d during the growing phase had the most marbling, whereas those fed to gain 0.9 kg of BW/d on DDGS had the least marbling; the remaining feeding systems were intermediate. Overall ADG and DMI were affected (P < 0.06) by both source and amount of energy fed during the growing phase. Feeding the DDGS-based diet to achieve greater ADG during the growing phase increased marbling, whereas feeding the corn-based diet to increase ADG during the growing phase decreased marbling.  相似文献   

20.
Two experiments were conducted to evaluate the effects of feeding different levels of wet corn gluten feed (WCGF) and dietary roughage on performance, carcass characteristics, and feeding behavior of feedlot cattle fed diets based on steam-flaked corn (SFC). In Exp. 1, crossbred steers (n = 200; BW = 314 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based diet containing 9% roughage (CON) and 3 SFC-based diets containing 40% WCGF, with either 9, 4.5, or 0% roughage. A linear (P = 0.04) increase in final BW and DMI (P < 0.01) was observed in diets containing WCGF as dietary roughage increased. Steers fed WCGF and higher levels of roughage had greater (P = 0.01) ADG than steers fed lower levels of roughage. Steers fed the CON diet had lower (P = 0.04) daily DMI and greater (P = 0.03) G:F than those fed WCGF. Most carcass characteristics of steers fed CON did not differ (P > 0.10) from those of steers fed WCGF. Based on feed disappearance and visual scan data, consumption rate did not differ (P > 0.10) among treatments; however, feeding intensity (animals present at the bunk after feeding) was greater for steers fed CON (P < 0.01) than for steers fed WCGF. In Exp. 2, yearling crossbred steers (n = 1,983; BW = 339 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based control diet that contained 9% roughage (CON) and 3 SFC-based diets containing either 20% WCGF and 9% roughage or 40% WCGF with 9 or 4.5% roughage. Steers fed the CON diet tended to have lower final BW (P = 0.14), ADG (P = 0.01), and DMI (P < 0.01) than steers fed diets containing WCGF. Steers fed the 20% WCGF diet had greater (P = 0.08) G:F than steers fed the 40% WCGF diets. With 40% WCGF, increasing roughage from 4.5 to 9% decreased (P < 0.01) G:F and increased (P = 0.06) DMI. Gain efficiency was improved (P < 0.01) for steers fed CON vs. those fed diets containing WCGF, whereas HCW (P = 0.02) and dressing percentage (P < 0.01) were greater for steers fed WCGF. Percentage of cattle grading USDA Choice was greater (P = 0.02) for cattle fed WCGF. Results suggest that replacing SFC with up to 40% WCGF increased ADG and decreased G:F when 4.5 to 9.0% roughage was supplied. More CON steers were present at the feed bunk during the first hour after feeding than WCGF steers, suggesting that including WCGF at 40% of the diet affected feeding behavior.  相似文献   

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