Effect of feeding glyphosate-tolerant (roundup-ready events GA21 or nk603) corn compared with reference hybrids on feedlot steer performance and carcass characteristics

Three experiments were conducted to compare the feeding value of genetically enhanced corn (Roundup Ready corn events GA21 and nk603) with nontransgenic hybrids. The four treatments included two separate reference hybrids (REF), the near-isogenic control hybrid (CON), and the genetically enhanced corn (RR), resulting in two preplanned comparisons of CON vs. RR and RR vs. the average of REF. In Exp. 1 (RR event GA21), 175 steers (BW = 427 kg) were fed in 25 pens with seven pens per corn hybrid, except CON, which contained four pens due to limited quantities of that hybrid. In Exp. 2 (RR event nk603), 196 steers (BW = 420 kg) were fed in 28 pens with seven pens per corn. In Exp. 3 (RR event nk603), 200 steers were fed in 20 pens, with a similar treatment design to Exp. 2 and five pens per corn. All experiments were conducted as completely randomized designs and utilized corn produced at University of Illinois (Exp. 1 and 2) and University of Nebraska (Exp. 3) research farms under identity-preserved protocols. In all experiments, DMI, ADG, and feed efficiency were similar (P > 0.30) between RR and REF. In Exp. 1 and Exp. 2, RR was not different (P > 0.25) than CON for growth performance. In Exp. 3, RR was not different from CON for ADG and DMI (P > 0.15) or for feed efficiency (P = 0.08). No differences were observed between RR and CON or RR and REF for carcass weight, longissimus dorsi area, and marbling scores in any of the experiments. Subtle differences were observed between RR and either CON or REF for fat depth in each experiment; however, cattle fed RR were not consistently greater and varied from either the CON or the REF (but not both contrasts) within an experiment. Based on these results, insertion of glyphosate-tolerant genes had no significant effect on nutritive quality of corn. Performance and carcass characteristics were not influenced, which suggests that Roundup Ready corn is similar to conventional, nontransgenic corn when fed to finishing feedlot cattle.     

Performance of growing-finishing pigs fed diets containing YieldGard Rootworm corn (MON 863), a nontransgenic genetically similar corn, or conventional corn hybrids

Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either YieldGard Rootworm corn (MON 863), a non-transgenic genetically similar corn (RX670), or two conventional nontransgenic corn hybrids (DK647 and RX740). A randomized complete block design with a 2 x 4 factorial arrangement of treatments (two genders and four corn hybrids) was used. Study 1 used 72 barrows and 72 gilts (progeny of Danbred sires x [Danbred x NE White line] dams grown from 22.7 to 117.0 kg BW). Pigs were housed in a modified open-front building in single-gender groups of six (six pens per dietary treatment). Study 2 used 80 barrows and 80 gilts (progeny of PIC 337 sires x C22 dams) grown from 29.5 to 114.9 kg BW. Pigs were housed in an environmentally controlled finishing building in single-gender groups of five (eight pens per dietary treatment). The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered at the end of the growth period using standard procedures, and carcass measurements were taken. There were no diet x gender interactions for growth performance or carcass measurements in either study. In both studies, overall ADG, ADFI, and G:F were not affected by corn hybrid. There was no effect of corn hybrid on carcass or LM quality measurements in Study 1. In Study 2, LM protein content was less (P< 0.05) for pigs fed RX740 compared with those fed either MON 863 or RX670; however, there was no effect of corn hybrid on other LM composition measures or on quality traits. In both studies, differences between barrows and gilts for growth and carcass traits were similar to previous research. These results suggest that the YieldGard Rootworm corn (MON 863) results in equivalent growth performance and carcass quality to nontransgenic corn hybrids in growing-finishing pigs.     

Growth performance and carcass characteristics of pigs fed short-season corn hybrids

An experiment was conducted to determine growth performance, carcass characteristics, and fat quality of growing-finishing pigs fed diets based on short-season corn hybrids. Twenty-four individually housed, Cotswold, growing pigs with an initial BW of 41.4 (SD = 1.4) kg were blocked by BW and sex and randomly allotted from within block to 1 of 3 diets to give 8 replicate pigs per diet. Experimental diets consisted of a control based on barley and 2 diets based on corn as the main energy sources. A 3-phase feeding program for 20 to 50 kg (phase I), 50 to 80 kg (phase II), and 80 to 110 kg (phase III) of BW was used. Diets for each phase contained approximately 3.5 Mcal/kg of DE, with total lysine of 0.95, 0.75, and 0.64% in phase I, II, and III diets, respectively. Average daily gain, ADFI, and G:F were monitored weekly during each phase. Pigs were slaughtered after reaching a minimum BW of 100 kg to determine carcass characteristics. There were no effects of diet on ADG, ADFI, and G:F (0.45 +/- 0.02, 0.34 +/- 0.02, and 0.31 +/- 0.02 for phase I, II, and III, respectively). Carcass length, dressing percent, LM area, loin depth, backfat thickness, belly firmness, and L*, b*, and a* fat color were not different across dietary treatments. Pigs fed one corn variety had no differences in fatty acid profile with barley-fed pigs, whereas those fed the other variety of corn had a greater (P < 0.05) concentration of PUFA in their backfat. The results indicate that growth performance, carcass characteristics, and fat quality of pigs fed diets based on short-season corn hybrids and those fed the barley-based diet were not different.     

Effects of different grazing and feeding periods on performance and carcass traits of beef steers

Over three consecutive years, 180 (60/yr) fall-born steer calves were weaned in May (average initial BW = 238 kg, SD = 36.2 kg) and allocated to one of three groups: 1) calf-fed steers that entered the feedlot at weaning; 2) short yearlings that grazed irrigated pasture for another 4 mo and entered the feedlot in September; and 3) long yearlings that grazed with short yearlings during the summer, remained on annual California foothills range through the fall, winter, and spring, and entered the feedlot the following May. All steers were fed until the average group backfat (BF), determined by ultrasound, reached 11 to 12 mm. On pasture, short- and long-yearling steers gained weight in the summer; long yearlings then slightly lost weight in the fall and winter, and then gained weight again the following spring. Average days in the feedlot were 188, 158, and 94 (P < 0.10) for calves, short yearlings, and long yearlings, respectively. Feedlot DMI increased with age (and weight) at feedlot entry, with no difference among groups in gain:feed ratio. The gain of BF was nil on pasture, even when animals were gaining weight, and then increased rapidly when animals were placed on a high-energy diet. Final body weights were heaviest (P < 0.10) in long yearlings, followed by short yearlings and then calves, indicating that a prolonged growing period increases the apparent mature size of the animal. Moreover, total carcass fat contents and percentage of Choice or above were all lower (P < 0.10) in cattle that were older at feedlot entry (i.e., long yearlings) compared with the other groups. In conclusion, increasing the backgrounding period decreased time and total concentrate requirements in the feedlot of Angus-Hereford steers. Older cattle reached 10 mm of BF at heavier weights. Grazing animals gained weight without increasing BF; however, BF increased rapidly in the feedlot. Prolonged grazing may decrease quality grade, either by impairing the ability of the animal to deposit intramuscular fat or by decreasing the time during which dietary energy supply is adequate for intramuscular fat deposition to occur.     

Effects of treating corn silage with alpha-amylase and(or) sorbic acid on beef cattle growth and carcass characteristics

The effects on beef cattle growth performance and carcass characteristics of feeding silages produced by altered fermentations were determined. Alpha-amylase was added at 0 or .05% (wet basis) and sorbic acid was added at 0 or .10% (wet basis) to chopped whole corn plants before ensiling in a 2 x 2 factorial arrangement of treatments. For three successive years, 40 beef heifers (224 kg) were fed these silages for 80 d, finished on corn-and-cob meal (107 d) and slaughtered when backfat thickness over the 13th rib reached 12 mm. Silages treated with alpha-amylase had a slightly higher percentage of N-free extract (P less than .10). Silages treated with sorbic acid had lower percentages of ADFN (P less than .10). During the silage-feeding phase, heifers fed silages treated with alpha-amylase gained more (P less than .01) daily than heifers fed the other two silages (.84 vs .78 kg) and they were more efficient (P less than .01) in weight gain per unit of dry feed consumed (.149 vs .139 kg). During the finishing phase, heifers that previously had been fed the alpha-amylase-treated silage continued to have higher (P less than .05) ADG (.93 vs .87 kg), although all were fed the same diet during this period. Added sorbic acid had no effect on ADG in either period. The percentage of kidney fat in heifers on the alpha-amylase treatments was increased (P less than .02, 2.2 vs 2.0). The biological mechanisms associated with the beneficial results of alpha-amylase addition are not understood yet.     

Effects of feeding high-oil corn to beef steers on carcass characteristics and meat quality

To assess the effects of feeding high-oil corn on carcass characteristics and meat quality, 60 yearling steers were fed high concentrate diets containing either control corn (82% of diet), high-oil corn (82% of diet), or high-oil corn at a concentration that was isocaloric with the control diet (74% of diet). After being fed for 84 d, steers were slaughtered. At 72 h postmortem, carcass data were collected and rib sections from five steers grading U.S. Choice and five steers grading U.S. Select from each treatment were collected, vacuum packaged, and aged for 14 d. Three steaks (2.54 cm thick) were removed from each rib for Warner-Bratzler shear force measurement, sensory appraisal, and fatty acid composition analyses. Data were analyzed with treatment as the main effect for the carcass data and treatment, quality grade, and two-way interaction in the model for the longissimus data. The two-way interaction was nonsignificant (P > 0.05) for all variables tested. No differences were detected (P > 0.05) in carcass measurements except for marbling scores and quality grades, both of which were greater (P < 0.05) for carcasses from steers fed the high-oil corn. Overall, 78% of steers fed the high-oil corn graded U.S. Choice compared with 47% for the control and 67% for isocaloric group. Shear force and sensory properties of the longissimus were not different (P > 0.05) among treatments. Steaks from U.S. Choice carcasses rated higher (P < 0.05) for tenderness and tended to rate higher (P < 0.10) for juiciness. Feeding the isocaloric and high-oil diets increased (P < 0.05) linoleic acid, arachidonic acid, and the total PUFA content of lipid extracted from the longissimus. Saturated fatty acid percentage was lowest (P < 0.05) for high-oil corn and highest (P < 0.05) for control, with isocaloric being intermediate. Feeding high-oil corn increased (P < 0.05) pentadecyclic acid, margaric acid, and total odd-chain fatty acid content. Feeding high-oil corn in finishing beef cattle diets enhanced intramuscular lipid deposition and increased unsaturation of fatty acids of the longissimus.     

不同饲养水平对瑶山鸡生产性能和胴体品质的影响

文章旨在研究不同饲养水平对瑶山鸡生产性能和胴体特征的影响.试验将400只平均体重一致的1日龄瑶山鸡随机分为2组,每组4个重复,每个重复50只.2组分别饲喂代谢能水平为3155 Kcal/kg、粗蛋白质水平为225 g/kg的高能高蛋白日粮和代谢能水平为2965 Kcal/kg、粗蛋白质水平为195 g/kg的低能低蛋白...     

Effects of wet corn gluten feed and roughage levels on performance, carcass characteristics, and feeding behavior of feedlot cattle

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.     

Effects of feeding strategy and age on live animal performance, carcass characteristics, and economics of short-term feeding programs for culled beef cows

To evaluate production and economic effects of feeding management strategy and age on intensively managed culled beef cows, a study was conducted using 125 cows of British breeding blocked by age (Young = 3 and 4 yr olds; LowMid = 5 and 6 yr olds; HighMid = 7 and 8 yr olds; and Aged = 9 yr and older) and assigned to one of three steam-flaked corn based feeding strategies. Treatments were as follows: Conservative (CSV), 30% roughage throughout; Standard (STD), decrease roughage from 30 to 10% over 20 d; and Aggressive (AGR), decrease roughage from 30 to 10% over 10 d. There were four pens per treatment in a randomized complete block design. Cows were fed for a total of 54 d, and BW was measured on d 0, 14, 28, 42, and 54. Half the cows from each pen were randomly selected and slaughtered at a commercial abattoir, and carcass data were collected. Average daily gain, daily DMI, and G:F during each weigh period and across the entire feeding period were calculated. Over the 54-d feeding period, strategies that employed more energy-dense diets numerically increased ADG (1.28, 1.63, and 1.55 +/- 0.14 kg/d for CSV, STD, and AGR; P = 0.26) and decreased DMI (11.91, 10.74, and 10.89 +/- 0.27 kg/d for CSV, STD, and AGR; P = 0.05), such that G:F was lower for CSV than for STD or AGR (0.105, 0.150, and 0.141 +/- 0.010; P = 0.05). Carcass weight was least for the CSV strategy (298 kg) and greatest for STD (328 kg); AGR resulted in intermediate carcass weight (317 +/- 6 kg; P = 0.04). Total cost of gain was over 30% greater for CSV strategy than for STD or AGR strategies (P < 0.01). In many cases, block effects (age) had a greater effect on responses than treatments. Average daily gain, DMI, and G:F decreased linearly with age (P < 0.01). Hot carcass weight, dressing percent, and fat thickness decreased linearly with age (P < 0.03); yield grade decreased and carcass maturity attributes increased linearly with age (P < 0.02). Performance and intake differences resulted in linear increases in total cost of gain (P < 0.01) and breakeven price (P = 0.03) with increasing age. These data indicate advantages to more aggressive feeding management strategies for culled beef cows, although maximal intake may be achieved with higher-roughage diets. Despite management effects, an increase in market price above purchase price may be required for intensive feeding of culled beef cows to be a profitable enterprise.     

中草药对山羊生长性能和胴体特征的影响

文章旨在研究在山羊日粮中添加中草药对其生长性能和胴体特征的影响.试验将平均体重为(19.22±0.08)kg的45头山羊随机分为3组,每组3个重复,每个重复5头羊.对照组饲喂基础日粮,两个处理组分别用10％的穿心莲茎叶和全珠穿心莲替代苜蓿草,试验共进行14周.结果:饲喂全珠穿心莲的山羊末重、屠体重、采食量和日增重分别较...     

自然放牧与放牧补饲育肥对肉羊育肥性能和屠宰性能的影响

试验研究了自然放牧(NG)与放牧补饲(GS)育肥对呼伦贝尔羊(HL)和呼杜杂交1代(HZ)羔羊育肥性能及屠宰性能的影响。采用2×2完全随机试验设计,选择4月龄断奶后HL和HZ公羔各60只,共120只,分为4组,每组30只。因素1为育肥方式,分为NG与GS;因素2为品种,分为HI和HZ。育肥期均为60 d。结果表明,与NG组相比,GS能显著增加羔羊的体重、日增重、宰前活重、胴体重、屠宰率、净肉重、净肉率与大网膜脂重,提高屠宰性能(P<0.05);在整个育肥阶段,HZ羔羊体重均显著高于HI羔羊(P<0.05),且HZ羔羊屠宰性能优于呼伦贝尔羔羊。与NG相比,GS可显著提高羔羊的育肥性能和屠宰性能;同种育肥方式下,HZ羔羊体重增加极显著大于HL羔羊,且屠宰性能较优。     

Effects of feeding cattle manure on growth performance and carcass characteristics of large white pigs

Summary Thirty-six weaner Large White piglets were randomly assigned to 3 replicates of 3 treatments to determine the effects of feeding 0, 10 or 20% of cattle manure in partial replacement of ground maize in the diet. The trial lasted 15 weeks. Feed efficiency was not significantly affected. However, pigs fed on the control diet consumed significantly more feed than pigs on the experimental diets containing cattle manure, and although their higher daily weight gain was not statistically significant, at the end of the trial they were significantly heavier (P<0·05) than those fed the diet containing 20% cattle manure. Carcasses from pigs fed on the diets containing cattle manure were leaner than pigs fed on the control diet.

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Efectos De La Inclusion De Estiercol De Vaca En La Dieta De Cerdos De Engorde Sobre El Crecimiento Y La Caracteristicas De La Canal

Resumen Un total de 36 cerdos recién destetados de raza Large White fueros distribuídos al azar en 3 réplicas de 3 tratamientos que tuvieron como objetivo determinar los efectos de incluir en la dieta 0, 10 o 20% de estiércol de vaca en sustitución parcial de maiz. El ensayo duró 15 semanas. La eficiencia alimentaria no se vió afectada de forma significative. Sin embargo, los cerdos alimentados con la dieta control consumieron más alimento que los animales que recibieron dietas con estiercol de vaca. Además, si bien el creciemiento diario de los animales control no fue significativamente distinto, al final del ensayo su peso vivo fue significativamente superior (p<0·05) al de los animales que recibieron una dieta con un 20% de estiercol de vaca. Las canales de los cerdos que recibieron dietas con estiercol tuvieron un porcentaje de grasa inferior al de las canales de los animales control.

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Effets De l'Alimentation En Fumier Bovin Sur La Croissance Et Les Caracteristiques De La Carcasse Chez Les Porcs Large White

Résumé 36 porcelets sevrés de l'espèce Large White furent répartis sur 3 traitements (avec 3 replicats chacun) pour déterminer les effects for l'alimentation avec, 0, 10 ou 20% en fumier bovin en replacement partiel du maïs dans leur nourriture. L'expérience dura 15 semaines. L'efficacité de la nourriture ne fut pas affectée, de façon significative. Cependant, les porcs nourris par l'alimention de contrôle, consoemmèrent plus de nourriture que ceux, alimentés expérimentalement avec le fumier bovin, et bien que les gains journaliers furent plus élevés mais non de façon significative, les porcs de contrôle furent de façon significative plus lourds (P<0, 05) que ceux nourris avec 20% de fumier bovin. Les carcasses de porc nourrit avec du fumier bovin furent plus maigres que ceux issus du groupe de contrôle.

     

ORIGINAL ARTICLE: Effects of long‐term feeding of genetically modified corn (event MON810) on the performance of lactating dairy cows

A long‐term study over 25 months was conducted to evaluate the effects of genetically modified corn on performance of lactating dairy cows. Thirty‐six dairy cows were assigned to two feeding groups and fed with diets based on whole‐crop silage, kernels and whole‐crop cobs from Bt‐corn (Bt‐MON810) or its isogenic not genetically modified counterpart (CON) as main components. The study included two consecutive lactations. There were no differences in the chemical composition and estimated net energy content of Bt‐MON810 and CON corn components and diets. CON feed samples were negative for the presence of Cry1Ab protein, while in Bt‐MON810 feed samples the Cry1Ab protein was detected. Cows fed Bt‐MON810 corn had a daily Cry1Ab protein intake of 6.0 mg in the first lactation and 6.1 mg in the second lactation of the trial. Dry matter intake (DMI) was 18.8 and 20.7 kg/cow per day in the first and the second lactation of the trial, with no treatment differences. Similarly, milk yield (23.8 and 29.0 kg/cow per day in the first and the second lactation of the trial) was not affected by dietary treatment. There were no consistent effects of feeding MON810 or its isogenic CON on milk composition or body condition. Thus, the present long‐term study demonstrated the compositional and nutritional equivalence of Bt‐MON810 and its isogenic CON.     

Effects of liquid feeding of corn condensed distiller's solubles and whole stillage on growth performance,carcass characteristics,and sensory traits of pigs

Background: The immense growth in global bioethanol production has greatly increased the supply of by-products such as whole stillage and condensed distiller's solubles, which could be potentially used for animal feeding. The objective of this study was to investigate effects of liquid feeding high levels of corn condensed distiller's solubles(CCDS) and whole stillage(CWS) on growth performance, carcass characteristics, belly firmness and meat sensory traits of pigs.Methods: A total of 256 pigs were blocked by sex and initial BW(13.5 ± 2.5 kg), and pens of pigs(8 pigs/pen) were randomly allocated to 1 of 4 dietary treatments(8 pens/treatment): 1) corn-soybean meal based diet as control, 2) 25%CWS + 5% CCDS, 3) 19.5% CWS + 10.5% CCDS, and 4) 19.5, 26, and 32.5% CWS + 10.5, 14, and 17.5% CCDS in phases 1(28 d), 2(38 d), and 3(60 d), respectively. Inclusion levels of CCDS and CWS for Treatments 1, 2, and 3 were fixed during all the three phases of the experiment. Inclusion levels of CWS and CCDS were on 88% dry matter basis. The liquid feeding system delivered feed from the mixing tank to feed troughs by high-pressure air, had sensors inside feed troughs, and recorded daily feed intake on the basis of a reference feed intake curve. The pigs were fed 5 to 10 times per day with increasing frequency during the experiment.Results: Control pigs had greater(P 0.05) average daily gain(0.91 vs. 0.84, 0.85, 0.85 kg/d) and gain to feed ratio(0.37 vs. 0.33, 0.34, 0.34) than pigs in the other three treatments during the overall period. Compared with the control, the other three groups had(P 0.05) or tended to have(P 0.10) lower carcass weight and backfat depth due to lighter(P 0.05) slaughter body weight, but similar(P 0.10) dressing percentage, loin muscle depth, and lean percentage were observed among the four treatments. Inclusion of CWS and CCDS reduced(P 0.05) or tended to reduce(P 0.10) belly firmness but did not influence(P 0.10) the overall like,flavor, tenderness and juiciness of loin chops when compared with the control group.Conclusion: In conclusion, our results indicate that including 30–50% of a mixture of whole stillage and condensed distiller's solubles in the growing-finishing diets may reduce growth performance, carcass weight and belly firmness, but does not affect pork sensory traits.     

Effects of feeding whole cottonseed and cottonseed products on performance and carcass characteristics of finishing beef cattle

Three experiments were conducted to determine the effects of whole cottonseed or cottonseed products on performance and carcass characteristics of beef cattle. In Exp. 1, 120 beef steers (initial BW = 381 +/- 31.7 kg) were fed steam-flaked corn-based finishing diets with 10% (DM basis) basal roughage, and whole cottonseed or individual cottonseed components (cottonseed hulls, meal, and oil). Over the entire feeding period, ADG did not differ (P = 0.95), but DMI increased (P = 0.07) and G:F decreased (P = 0.06) for steers fed the cottonseed diets compared with the control diet. Dressing percent (P = 0.02) and marbling scores (P = 0.02) of carcasses from steers fed the cottonseed diets were less than for steers fed the control diet. In Exp. 2, 150 beef steers (initial BW = 364 +/- 9.9 kg) were used to determine the effects of whole cottonseed or pelleted cottonseed (PCS) on performance and carcass characteristics. Cattle were fed steam-flaked corn-based finishing diets in which whole cottonseed or PCS replaced all of the dietary roughage, supplemental fat, and supplemental natural protein of the control diet. Over the entire feeding period, steers fed the cottonseed diets had lower (P = 0.04) DMI and greater (P < 0.01) G:F than steers fed the control diet. Carcass characteristics did not differ (P = 0.16 to 0.96) among dietary treatments. In Exp. 3, 150 beef heifers (initial BW = 331 +/- 17.1 kg) were used to determine the effects of PCS or delinted, whole cottonseed (DLCS) on performance and carcass characteristics. Heifers were fed rolled corn-based finishing diets in which cottonseed replaced the dietary roughage, supplemental fat, and all or part of the supplemental natural protein of the control diet. Over the entire feeding period, ADG, DMI, and G:F of heifers fed the control diet did not differ (P = 0.19 to 0.80) from those of the cottonseed diets; however, heifers fed the diets containing PCS had greater ADG (P = 0.03) and G:F (P = 0.09) than heifers fed diets containing DLCS. Carcass characteristics of heifers fed the control diet did not differ (P > or = 0.28) from those fed the cottonseed diets. Heifers fed the diets containing PCS had greater (P < or = 0.03) HCW, dressing percent, and LM area than those fed DLCS. Based on our results, whole cottonseed, or products derived from processing whole cottonseed, can replace feedstuffs commonly used in beef cattle finishing diets with no adverse effects on animal performance or carcass characteristics.     

Effects of dried full-fat corn germ and vitamin E on growth performance and carcass characteristics of finishing cattle

Two experiments were conducted to evaluate dried full-fat corn germ (GERM) as a supplemental fat source in cattle finishing diets. In Exp. 1, 24 pens totaling 358 crossbred beef steers with an initial BW of 319 kg were allowed ad libitum access to diets containing dry-rolled corn, 35% wet corn gluten feed, and 0, 5, 10, or 15% GERM on a DM basis. Increasing GERM decreased (linear; P < 0.02) DMI and increased (quadratic; P < 0.02) ADG. Steers fed 10% GERM had the greatest ADG (quadratic; P < 0.02) and G:F (quadratic; P < 0.05). The addition of GERM increased (linear; P < 0.05) fat thickness, KPH, and the percentage of USDA Yield Grade 4 carcasses (quadratic; P < 0.03), with steers fed 15% GERM having the greatest percentage of USDA Yield Grade 4 carcasses. In Exp. 2, 48 pens totaling 888 crossbred beef heifers with an initial BW of 380 kg were allowed ad libitum access to diets containing steam-flaked corn, 35% wet corn gluten feed, and either no added fat (control), 4% tallow (TALLOW), or 10 or 15% GERM on a DM basis, with or without 224 IU of added vitamin E/kg of diet DM. No fat x vitamin E (P > or = 0.08) interactions were detected. Fat addition, regardless of source, decreased (P < 0.01) DMI, marbling score, and the number of carcasses grading USDA Choice. Among heifers fed finishing diets containing TALLOW or 10% GERM, supplemental fat source did not affect DMI (P = 0.76), ADG (P = 0.54), G:F (P = 0.62), or carcass characteristics (P > or = 0.06). Increasing GERM decreased DMI (linear; P < 0.01) and ADG (quadratic; P < 0.02), with ADG by heifers fed 10% GERM slightly greater than those fed control but least for heifers fed 15% GERM. Increasing GERM improved (quadratic; P < 0.03) G:F of heifers, with heifers fed 10% GERM having the greatest G:F. Increasing GERM decreased HCW (linear; P < 0.02), marbling score (linear; P < 0.01), and the percentage of carcasses grading USDA Choice (linear; P < 0.01). The addition of vitamin E increased (P < 0.04) the percentage of carcasses grading USDA Select and decreased (P < 0.01) the percentage of carcasses grading USDA Standard. These data suggest that GERM can serve as a supplemental fat source in cattle finishing diets, and that the effect of vitamin E did not depend on source or concentration of supplemental fat.     

Corn oil or corn grain supplementation to steers grazing endophyte-free tall fescue. I. Effects on in vivo digestibility, performance, and carcass quality

Twenty-eight Angus (289 +/- 3.8 kg) steers were used in a completely randomized design to evaluate the effect of isocaloric supplementation of 2 different energy sources to steers rotationally grazing tall fescue pastures for 197 d in comparison to positive and negative controls. Steers were supplemented with either corn grain (0.52% BW on a DM basis; PC) or soybean hulls plus corn oil (0.45% BW on a DM basis + 0.10% BW on an as-fed basis; PO) using Calan gates for individual intake measurement. Negative, pasture only (PA), and positive, high-concentrate control diets (85% concentrate:15% roughage on DM basis; C) were also included in the study. Steers on PC, PO, and PA treatments were managed together under a rotational grazing system, whereas C steers were fed a high-concentrate diet for the final 113 d using Calan gates. Forage DMI and apparent DM and NDF digestibility for the grazing treatments were evaluated using Cr(2)O(5) and indigestible NDF as digesta markers. Energy supplementation decreased (P = 0.02) forage DMI (% of BW) with respect to PA, but not (P = 0.58) total DMI. There were no differences (P = 0.53) among grazing treatments on apparent total DM digestibility. However, NDF digestibility was less (P < or = 0.05) in PC than in PO and PA; the latter 2 treatments did not differ (P > 0.05). Overall ADG was greater (P < 0.01) in supplemented, regardless of type, than in nonsupplemented grazing treatments. During the final 113 d, ADG was greater (P < 0.01) in C than in the grazing treatments. Overall supplement conversion did not differ (P = 0.73) between supplement types and was less (P = 0.006) than C. Carcass traits did not differ (P > 0.05) between energy sources. Dressing percentage and HCW were greater (P < 0.01) in supplemented cattle than in PA. Fat thickness and KPH percentage for PA were less (P < 0.05) than for PO but did not differ (P > 0.14) from PC. Marbling score, LM area, and quality grade did not differ (P > 0.05) between grazing treatments. Hot carcass weight for C was heavier (P < 0.001) than for pastured cattle. Quality and yield grades of C carcasses were also greater (P < 0.001) than carcasses from pastured steers. Energy supplementation, regardless of source, to grazing steers increased ADG, dressing percentage, and carcass weight compared with PA steers; however, supplemented steers had less ADG, efficiency, dressing percentage, and carcass weight compared with high-concentrate finished steers.     

舍饲与放牧育肥对绒山羊成年母羊育肥和屠宰性能的影响

试验主要研究了放牧育肥与舍饲育肥两种饲养模式对绒山羊育肥性能、营养物质表观消化率及屠宰性能的影响。从内蒙古白绒山羊种羊场淘汰母羊中选择平均体重为(40.38±0.84)kg的5岁阿尔巴斯白绒山羊60只随机分为对照组和试验组,对照组进行放牧育肥,试验组进行舍饲育肥,饲喂全混合日粮。育肥期为60 d。在育肥试验开始20 d和试验结束时,分别从试验组和对照组中选择6只羊进行消化试验,采用内源指示剂法测定营养物质的消化率。在育肥试验结束时,分别从对照组和试验组中随机选取6只羊进行屠宰,测定屠宰性能指标。结果表明,与放牧育肥相比,舍饲育肥可显著增加绒山羊成年母羊的全期日增重、干物质采食量(DMI)与饲料转化效率(P<0.05),分别较放牧育肥组增加了1.02%、137.50%与107.58%;显著增加母羊对日粮总能(GE)、消化能(DM)、粗蛋白(CP)、钙(Ca)和磷(P)等营养物质表观消化率(P<0.05);但显著降低了中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的消化率(P<0.05)。舍饲育肥组的胴体重、屠宰率、净肉重、净肉率和眼肌面积均显著高于放牧育肥组(P<0.05),分别较放牧育肥组提高了55.57%、25.89%、67.97%、35.64%和46.18%。舍饲育肥母羊的内脏总重、胃重、肠总重与皮重显著高于放牧育肥组(P<0.05),但所占体重的比例均显著低于放牧育肥母羊(P<0.05)。按照代谢体重表示,舍饲育肥母羊的营养物质进食量DE为1.18~1.25 MJ/(W0.75·kg)、CP为12.37~16.29 g/(W0.75·kg)、Ca为0.43~0.63 g/(W0.75·kg)、P为0.17~0.25 g/(W0.75·kg)时,绒山羊成年母羊具有较好的育肥性能与屠宰性能,经济效益显著。