Effect of diet composition and feed intake level on diet digestibility and ruminal metabolism in growing lambs.

Lambs (29 +/- 2.5 kg) were fed three diets at various intakes to determine whether diet composition or level of intake was reflected in changes in diet digestibility or ruminal fluid characteristics. In Exp. 1, a 90% concentrated, pelleted diet or a whole shelled corn diet with a pelleted protein supplement was fed at three levels of intake: ad libitum and 92.5 and 85% of ad libitum (n = 15). Exp. 2 compared the 90% concentrate diet with diets in which the energy density was diluted to 55 or 72.5% concentrate by including alfalfa hay as a possible method of restricting energy intake (n = 6). Lambs were adapted to diets for 13 d; feces were collected for 6 d and ruminal fluid was collected 0, 3, and 6 h after feeding on the day following fecal collection. Restricting intake in Exp. 1 did not affect DM digestibility or digestibility of CP or starch. Digestibility of ADF was increased (P less than .10) by restricting intake. Ruminal fluid pH, ammonia concentration and VFA concentrations were affected little by either restricted intake level. Digestibility of DM was 4% higher (P less than .001) and starch 5% higher (P less than .001) for the whole shelled corn diet than for the pelleted, high-concentrate diet. Ruminal pH of lambs fed the whole shelled corn diet was higher and fluctuated less than the ruminal pH of lambs fed the high-concentrate, pelleted diet. In Exp. 2, diet digestibility was reduced (P less than .01) and ruminal pH was increased (P less than .002) by addition of hay. Restricted feeding of lambs did not seem to increase diet digestibility or alter ruminal conditions.     

Effect of limited feed intake on growth of subcutaneous adipose tissue layers and on carcass composition in swine

Little is known about the function of individual backfat layers in swine. Our objective in this study was to evaluate differential growth of each backfat layer in pigs fed different amounts of the same diet. Relationships of growth of backfat layers to deposition of carcass protein and ether extract were also studied. Feed intake levels were ad libitum, 92.5% of ad libitum, and 85% of ad libitum for 36 barrows averaging 95 d of age and 37.8 kg of weight at the start of the study. Chemical composition of the carcass soft tissue was determined at the end of the 84-d study. Daily gain tended to decrease (P less than .10) and conversion of feed to gain improved (P less than .15) as feed intake decreased. The daily depositions (g/d) of protein and ether extract were 62.9 and 205 for the ad libitum group, 61.1 and 176 for the 92.5% intake group, and 59.3 and 153 for the 85% intake group, respectively. The compositional effect of limiting feed intake for 84 d was to produce less carcass soft tissue of greater lean content. Overall backfat depths were 31.5, 29.6, and 27.8 mm for the ad libitum, 92.5, and 85% intake groups, respectively. The outer backfat layer differed among groups; the 92.5 and 85% groups were thinner than the ad libitum group. Relative to the ad libitum group, the change in depth of the middle backfat layer was 86 and 75% for the 92.5 and 85% intake groups (P less than .01). The inner backfat layer was not affected significantly by level of feed intake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Proportion of corn silage in diets of feedlot steers fed to achieve stepwise increases in growth.

Two experiments were conducted to investigate the effects of proportion of dietary corn silage during periods of feed restriction on performance of steers. In Exp. 1, Simmental x Angus steer calves (n = 107; initial BW = 273 +/- 3.8 kg) were allotted to 12 pens with eight or nine steers/pen and four pens/treatment. Periods of growth were 273 to 366 kg BW (Period 1), 367 to 501 kg BW (Period 2), and 502 to 564 kg BW (Period 3). In two of the dietary regimens, steers were given ad libitum access to feed throughout the experiment and were fed either a 15% corn silage diet in each period or an 85, 50, and 15% corn silage diet in Periods 1, 2, and 3; respectively. In the third feeding regimen, a programmed intake feeding regimen was used. Steers were fed a 15% corn silage diet in each period. However, feed intake was restricted to achieve a predicted gain of 1.13 kg/d in Period 1 and 1.36 kg/d in Period 2, and feed was offered for ad libitum consumption in Period 3. For the entire experiment, ADG was similar (P = 0.41) among treatments and feed efficiency was lower (P < 0.10) for steers in the corn silage regimen than for steers in the programmed intake and ad libitum regimens. In Exp. 2, Simmental x Angus steer calves (n = 106; initial BW = 233 +/- 2 kg) were allotted by BW to 12 pens (three pens/treatment) and fed in three periods similar to those described in Exp. 1. Four feeding regimens were investigated: 1) AL; steers were offered a 15% corn silage diet for ad libitum consumption in all three periods; 2) PI; DMI was programmed to achieve gains as described in Exp. 1; 3) CS-HLL; programmed intake as described above except diets contained 85, 15, and 15% corn silage in Periods 1, 2, and 3, respectively; and 4) CS-HIL; same feeding regimens as CS-HLL, except diets contained 85, 50, and 15% corn silage in Periods 1, 2, and 3, respectively. Steers were given ad libitum access to feed in Period 3. Overall ADG was lower (P < 0.05) for steers in the CS-HLL and CS-HIL feeding regimens than for steers in the AL and PI regimens; feed efficiency was greatest for steers in the PI regimen. Few effects of feeding regimen on carcass characteristics were observed.     

Effects of Feed Intake Restriction on Performance and Carcass Characteristics of Finishing Beef Steers,

Crossbred steers (n = 264, 311 ± 1.6 kg initial BW) were blocked by BW, randomly assigned to one of four treatments (28 pens, 7 pens per treatment), and fed a common 90% concentrate diet to determine the effects of the severity of caloric restriction on animal performance and carcass characteristics. Treatments were 1) ad libitum access to feed for 151 d (AL100); 2) 75% of DMI by AL100 for 65 d, 95% of DMI by AL100 for 65 d, and ad libitum access to feed for 21 d (AL85); 3) 80% of DMI by AL100 for 65 d, 100% of DMI by AL100 for 65 d, and ad libitum access to feed for 21 d (AL90); and 4) 85% of DMI by AL100 for 65 d, 105% of DMI by AL100 for 65 d, and ad libitum access to feed for 21 d (AL95). Feed was offered for AL85, AL90, and AL95 based on DMI by AL100 the previous week. All steers were fed a similar quantity of DM for 4 d prior to initial, interim, and final BW determinations to minimize gastrointestinal fill differences. Overall DMI was greater (P<0.01) for AL100 than for the average of the remaining treatments and decreased linearly (P<0.01) among AL95, AL90, and AL85. Overall ADG (carcass-adjusted) was less (P<0.01) for AL85, AL90, and AL95 than for AL100, whereas overall ADG:DMI (carcass-adjusted) did not differ (P>0.10) between AL100 and the average of the remaining treatments. Overall ADG and ADG:DMI (carcass-adjusted) responded quadratically (P<0.05) with increasing DMI restriction. Hot carcass weight, longissimus area, and kidney, pelvic, and heart fat percentage were greater (P<0.05) for AL100 than for the remaining treatments and responded quadratically (P<0.10) among AL85, AL90, and AL95. Marbling score was greater (P<0.10) for AL100 than for the average of the remaining treatments, and the number of carcasses grading Prime + Choice tended to be higher (P<0.15) for AL100 and AL95. Restricting feed intake of finishing yearling steers to an average of 85 to 95% of ad libitum for 130 d of a 151-d feeding period generally resulted in slower ADG, lesser marbling scores, and carcasses that were lighter and leaner compared with yearling steers allowed ad libitum to feed and harvested after an equal number of days on feed.     

Growth performance, diet apparent digestibility, and plasma metabolite concentrations of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding level

Two experiments, each with 36 barrows with high-lean-gain potential, were conducted to evaluate apparent nutrient digestibilities and performance and plasma metabolites of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets. The low-protein diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis or by feeding 90 or 80% of ad libitum intake. Pigs were fed for 55 d. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis or by feeding 80% of the ad libitum intake. Pigs were fed for 27 d. Pigs fed the CONTROL diet had greater (P < 0.05) ADG and feed efficiency (G/F) than pigs fed the IDEAL (Exp. 1 and 2) and AACON diets (Exp. 2). As the level of feed intake decreased, ADG decreased (P < 0.05), but G/F tended to improve (P < 0.10) for pigs fed 90% of ad libitum in Exp. 1 and for pigs fed 80% of ad libitum in Exp. 2. In Exp. 1, the apparent total tract digestibilities of DM and energy were greater (P < 0.01) for pigs fed the IDEAL diet than for pigs fed the CONTROL diet. In Exp. 2, the apparent total tract digestibility of protein was greatest in pigs fed the CONTROL diet (P < 0.05) and was greater (P < 0.05) in pigs fed the AACON diet than in pigs fed the IDEAL diet. Plasma urea concentrations were lower in pigs fed the IDEAL diet than in pigs fed the CONTROL diet, regardless of feeding level. For pigs fed the CONTROL diet, plasma urea concentrations were lower when feed intake was 80% of ad libitum (diet level, P < 0.01). In summary, pigs fed the IDEAL and the AACON diets gained less and had lower plasma urea concentrations than pigs fed the CONTROL diet. Based on these data, it seems that the growth potential of pigs fed the IDEAL and AACON diets may have been limited by a deficiency of lysine, threonine, and(or) tryptophan and that the amino acid pattern(s) used was not ideal for these pigs.     

Influence of age at entry and level of concentrate feeding on growth and carcass characteristics of feedlot-finished Tanzanian long-fat-tailed sheep

A 4?×?3 factorial experiment was carried out to evaluate the effects of age at entry to feedlot (AEF) and levels of concentrate feeding (LCF) on body weight gain, feed utilization and killing out characteristics of Tanzanian long-fat-tailed castrate sheep. The AEF points were 9, 12, 15 and 18 months, designated as AEF9, AEF12, AEF15 and AEF18, and the LCF were 50, 75 and 100 % of ad libitum concentrate intake designated as LCF50, LCF75 and LCF100, the last representing ad libitum concentrate intake with 10 % refusal rate. Grass hay as basal diet was offered ad libitum to each sheep. Daily feed intake and weekly live weight were recorded for a period of 84 days. Animals were slaughtered and carcass and non-carcass parameters were recorded. Dry matter intake (DMI) of hay decreased while DMI of concentrate increased (p?<?0.01) with increasing LCF. Daily gain in high level (LCF100) was 93.1 g/day, almost twofold higher than that in low level (LCF50) of feeding (39 g/day). Overall dressing percentage ranged from 40.7 to 46.5 % and increased with increasing AEF. The proportion of carcass bone decreased (p?<?0.05) with increasing AEF while that of fat increased (p?<?0.05) with increasing LCF. Age at entry × level of concentrate feeding interaction was detected for DMI, feed conversion ratio (FCR), slaughter body weight (SBW), muscle/bone ratio and bone (as % cold carcass weight (CCW)), but the effect was not regular. Entering fattening at 18th month seems too late, hence to get in the shortest time the highest output slaughter and carcass weights, fattening should start latest at 15 month.     

早期数量限饲对肉仔鸡生长性能和胴体特性的影响

试验研究了早期数量限饲对肉仔鸡生长性能和胴体品质的影响。200只8日龄艾维茵肉仔鸡被随机分成4组,每组五个重复,每重复10只鸡。对照组基础饲粮根据NRC营养水平配制,试验组肉仔鸡从8日龄开始喂料量分别为对照组的90%、80%和70%,限饲1周后各组恢复自由采食。试验结果表明:在第2周,限饲各组肉仔鸡的体重和日增重分别显著低于对照组(P<0.05);在第3周,限饲90%组完成补偿生长,体重与对照组差异不显著(P>0.05);在第4周,限饲80%和70%组完成补偿生长,体重与对照组差异不显著(P>0.05);5、6、7周及2～7周各组在体重、日增重、日采食量和饲料转化率等方面都无显著差异(P>0.05)。早期数量限饲对肉仔鸡胴体特性没有显著影响(P>0.05)。     

Influence of level of dietary protein or energy on effects of ractopamine in finishing swine.

The effect of ractopamine, a beta-adrenergic agonist, on growth, nutrient utilization, and carcass composition was studied in pigs fed either 18% CP, 12% CP, or 18% CP restricted (RES = 67% of ad libitum) diets. The 18 and 12% CP diets provided 3.52 and 3.68 Mcal of DE/kg, respectively. All pigs were fed a low-protein (12% CP) diet during pretreatment growth from 15 to 60 kg. Ractopamine at 20 or 30 ppm (30 ppm for RES pigs) in the diet was fed from 60 kg live BW until slaughter at 105 kg (9 pigs/treatment). No ractopamine treatment effect (P greater than .05) was observed for either daily gain or gain/feed, although gain/feed was improved by 8% in both of the ad libitum groups. Ractopamine treatment resulted (P less than .01) in an overall reduction of carcass lipid by 8%, an increase of carcass protein by 5%, and a 21% improvement in the efficiency of protein utilization; the greatest changes occurred in the pigs fed the 12% CP diet (-17%, +11%, and +32%, respectively). The ad libitum daily feed intake was 15% less for pigs fed the 12% CP diet than for those fed the 18% CP diet (P less than .01), and there was a 10% reduction in intake of both diets with the addition of ractopamine (P less than .05). Both carcass lipid and protein deposition seemed to be closely related to energy intake (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of feeding growing cattle high-concentrate diets at a restricted intake on feedlot performance

Three trials were conducted to compare effects of restricted intake of high-concentrate diets vs ad libitum intake of corn silage diets during the growing phase on feedlot cattle performance. In Trial 1, 120 steers (initial BW, 246 kg) were fed 1) a corn silage-based diet ad libitum, 2) a high-moisture corn-corn silage-based diet with intake restricted to a level 20% less than that of the corn silage diet or 3) a high-moisture corn-based diet with intake restricted to a level 30% less than that of the corn silage diet. Steers fed the 20% restricted corn-corn silage-based diet tended (P = .07) to gain slower than those fed the corn silage or 30% restricted high-concentrate diet. Feed efficiency and diet digestibility were greatest for steers fed the 30% restricted-intake, high-concentrate diet (P less than .01). Performance of steers during the subsequent 118-d finishing period was not affected (P greater than .65) by source of energy during the growing period. In Trial 2, ADG of steers fed the 30% intake-restricted, high-concentrate diet was lower (P less than .01) than that of steers with ad libitum access to corn silage. During the 84-d growing period, steers fed supplemental blood meal had 8.3% greater gains and a 6% greater efficiency of feed use than those fed supplemental soybean meal (P less than .01). Monensin did not affect (P = .82) performance of steers fed 30% restricted-intake diets. During the 76-d finishing period, gains and feed conversion were improved (P less than .01) for steers fed the restricted-intake diet in the growing period compared with those given ad libitum access to corn silage. During the growing period in Trial 3, ADG of steers restricted-fed an all-concentrate diet were slightly greater (P less than .10) than ADG of those given ad libitum access to corn silage. Gains did not differ (P = .37) during the subsequent finishing period when steers were switched to 85 or 100% concentrate diets. We concluded that intake of all concentrate diets can be restricted to achieve gains equal to those of steers given ad libitum access to corn silage-based diets without detrimental effects on finishing performance.     

Intake restriction strategies and sources of energy and protein during the growing period affect nutrient disappearance, feedlot performance, and carcass characteristics of crossbred heifers.

Two trials were conducted to evaluate intake restriction, energy, and protein source on the performance and carcass merit of heifers limit-fed corn gluten feed. Trial 1 crossbred heifers (n = 140) were allotted to ad libitum wet corn gluten feed (WCGF)-hay, ad libitum WCGF-corn, WCGF-corn continuously limit-fed to achieve a gain of 1.1 kg/d or WCGF-corn fed in the following sequence: 70% of ad libitum for 20 d, ad libitum for 20 d, and 2 d common intake during the 84-d growing period. One-half of these restricted-refed heifers received a rumen-undegraded protein supplement, and the other half received a rumen degraded protein supplement. Heifers were fed a common finishing diet ad libitum subsequent to the growing period. Heifers offered ad libitum WCGF-hay and WCGF-corn were slaughtered at a common compositional fat end point. Heifers limit-fed WCGF-corn were slaughtered at the same time as heifers offered ad libitum WCGF-corn, regardless of subcutaneous fat cover. Limit-feeding WCGF-corn diets to growing heifers reduced ADG (P < or = 0.01) but did not compromise feed efficiency. Method of intake restriction, continuous or ad libitum-interrupted, and supplemental protein source did not affect combined growing-finishing performance. However, when fed for a common length of time, the average of the limit-fed heifers had lighter carcass weights (P < or = 0.01) and lower (P = 0.04) marbling scores. Heifers offered ad libitum WCGF-hay gained slower (P < or = 0.01) and less efficiently (P < or = 0.01) than heifers offered WCGF-corn. Trial 2 crossbred heifers (n = 222) were allotted to dry corn gluten feed (DCGF)-corn ad libitum or restricted to 80% of ad libitum for 42, 84, or 126 d; or ad libitum corn silage or DCGF-corn silage at 80% of ad libitum for 84 d. Feed efficiency (P = 0.07) and ADG (P = 0.08) tended to behave quadratically, being poorer for heifers limit-fed for 126 d during the growing period. Heifers limit-fed DCGF-corn gained more efficiently (P = 0.05) than heifers grown on ad libitum corn silage. Limit-feeding CGF-corn to growing beef heifers can be used to achieve moderate rates of gain without compromising feed efficiency. However, limit-feeding during the growing period may result in lighter weight carcasses with lower quality grades if not fed to the same fat end point as heifers grown with free access to concentrate.     

Effects of compensatory growth on some body component weights and on carcass and noncarcass composition of growing lambs.

A trial was conducted in 1983 and repeated in 1984 to measure effects of restricted feed intake and realimentation on weights of organs and on carcass and noncarcass composition. A total of one hundred six weaned lambs from two breeds (Timahdit and D'man) and a breed cross (Ile de France x D'man) were used in both years. Lambs were allotted to one of six feed intake regimens: HH (ad libitum access to feed from 21 to 30 kg); HM (ad libitum access to feed from 21 to 26 kg then 70% ad libitum to 30 kg); MH (70% ad libitum from 21 to 26 kg then ad libitum to 30 kg); MM (70% ad libitum from 21 to 30 kg); LH (restricted to lose weight from 21 to 17 kg then ad libitum to 30 kg); and LM (restricted to lose weight from 21 to 17 kg then 70% ad libitum to 30 kg). Weights of visceral organs and mesenteric and kidney fat showed dramatic responses to alteration of feed allowances. After recovery from 20% live weight loss, weight of liver equaled or exceeded that of both the ad libitum and 70% refed lambs. Mesenteric and kidney fat did not. Refeeding was accompanied by an increase in water (P less than .05) and a decrease in fat (P less than .01) of both carcass and noncarcass components. These results indicate that weight loss of lambs incurred during feed shortage was largely in internal organ weights, and that these lambs can recover these losses during realimentation and undergo compensatory growth with better feed efficiency and lean carcasses.     

Relationship between the activity of mitochondrial respiratory chain complexes and feed efficiency in fat-tailed Ghezel lambs

This study was conducted to investigate relationships between mitochondrial respiratory chain complex activities, feed efficiency, and carcass traits in sheep. A group of Ghezel male lambs sired by a single ram were randomly allotted to individual pens. The lambs were fed ad libitum with a fattening diet containing 30% roughage (corn silage and alfalfa hay) and 70% concentrate for 70 d to individually phenotype each lamb for feed conversion ratio (FCR), adjusted FCR (aFCR), and residual feed intake (RFI). The lambs were then humanely killed and the liver, abdominal fat, pelvic fat, cardiac fat, warm carcass weight, and cold carcass weight, as well as the cross-sectional area of the LM and the fat depth over the 12th rib, were determined. A portion of LM was obtained to determine mitochondrial protein and respiratory chain complex activities (complexes I to V). Statistical analysis was carried out based on lambs exhibiting high and low RFI (n = 8), FCR (n = 8), or aFCR (n = 8) phenotypes. The lambs exhibiting the high-RFI phenotype consumed 110 g more feed daily (P < 0.05) than did the phenotype exhibiting low RFI, with no difference in ADG. Conversely, there was no difference in feed intake between the low- or high-FCR groups, but sheep exhibiting the low-FCR phenotype gained 70 g more (P < 0.05) per day compared with those exhibiting the high-FCR phenotype. It was determined that all 5 respiratory chain complex activities were greater (P < 0.05) in sheep exhibiting the low-RFI phenotype compared with those exhibiting the high-RFI phenotype, with significant (P < 0.001) negative correlation coefficients between RFI and respiratory chain complex activity. When efficiency was assessed using FCR, only activities of respiratory chain complexes III, IV, and V were less (P < 0.05) in the low-FCR phenotype compared with the high-FCR phenotype, and there were no differences (P > 0.1) in respiratory chain complex activities between groups when FCR was adjusted for metabolic BW (aFCR). There were no differences (P > 0.1) in carcass traits among any of the feed efficiency phenotypes. The results suggest that the inclusion of respiratory chain complex activities in breeding programs may be helpful in selecting for sheep exhibiting the low-RFI phenotype.     

Chewing patterns and digestion in sheep submitted to feed restriction

Two experiments were conducted to evaluate the relationship among the level of feed intake, chewing pattern, and diet digestibility in sheep fed a moderate‐concentrate diet. The first experiment was conducted using six male lambs at a replicated 3 × 3 Latin square design to evaluate diet digestibility and microbial N synthesis according to the level of intake: ad libitum, or restricted to either 70 or 55% of the ad libitum intake. In the second experiment, fifteen male lambs were housed in individual stalls, in a completely randomized design, and fed one of the three levels of dry matter intake (DMI). Chewing patterns were then evaluated for 24 h using a regular 5‐min interval observation technique, two times during the experimental period. Decreasing level of feed intake resulted in increased apparent digestibility of dry matter, organic matter, crude protein, and neutral detergent fibre, as well as of the true digestibility of organic matter. Total time spent eating and ruminating decreased with feed restriction. However, lambs fed at restricted levels of intake presented a higher rate of eating (g DMI/min) than those fed ad libitum, and spent more time ruminating each gram of DM (min/g DMI). In conclusion, our results suggest that a more effective chewing during rumination activity can have an important role on feed digestion in animals submitted to feed restriction.     

Performance and individual feed intake characteristics of group-housed sows fed a nonstarch polysaccharides diet ad libitum during gestation over three parities

The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance.     

Effect of fibrolytic enzyme inclusion in high concentrate fattening diets on nutrient digestibility and growth performance of Awassi lambs

The objective of this study was to study the effect of fibrolytic enzyme (FE) inclusion on nutrient digestibility and growth performance of Awassi lamb fed on a high concentrate diet. Thirty weaned Awassi lambs (initial body weight = 20.4 ± 3.0 kg) were fed a high concentrate diet (with or without the addition of FE (15 lambs/treatment)) for 60 d in a completely randomized design. The diet contained 17, 7, 58.5, 15, and 2.5% wheat straw, wheat bran, barley grain, soybean meal and minerals, respectively. Lambs were fed ad libitum twice daily at 08:00 and 15:00 h. Dry matter, OM, CP, and NDF intakes were all similar (P > 0.05) for lambs fed diet with or without the FE and averaged 1078, 941, 171, and 432 g/d, respectively. Metabolizable energy intake was also not affected (P > 0.05) by the enzyme supplementation and averaged 2.87 Mcal/d. Dry matter, OM, CP, and NDF digestibilities were all unaffected (P > 0.05) by the enzyme inclusion and averaged 64.8, 67, 65.7 and 60.4%. Final body weight, average daily gain, and feed to gain ratio were all unaffected (P > 0.05) by the FE inclusion and averaged 34.9 kg, 222 g/d, and 5.4, respectively. In summary, FE treatment of high concentrate diet for lambs had no effect on nutrient intake or any of the growth performance parameters. Therefore, supplementing such diets with FE for fatting Awassi lambs is not recommended.     

Effects of diet and Aspergillus oryzae extract or Saccharomyces cervisiae on growth and carcass characteristics of lambs and steers fed to meet requirements of natural markets

Two studies were conducted to determine the effects of diet and feed additive on growth and carcass characteristics of lambs and cattle destined for all natural markets. In Exp. 1, 48 Dorset × Hampshire lambs (initial BW 29.4 ± 0.1 kg) were used in a randomized complete block experiment to determine the effects of Aspergillus oryzae extract, Amaferm (AMF) supplementation (1 g/d) in an 85% concentrate diet on growth and carcass characteristics. Lambs were allotted to 12 pens (4 lambs per pen), and blocked by sex and BW. Lambs were fed until the average BW of each pen reached a target BW (55.4 kg for wethers and 50.0 kg for ewes), at which time the entire pen of lambs was slaughtered. Amaferm resulted in a greater (P=0.07) G:F. In Exp. 2, 168 crossbred steers (initial BW 300 ± 0.7 kg) were used in a trial with a 3 × 2 factorial arrangement of treatments to examine the effects of 0.5 g/d of Saccaromyces cervisiae boulardii CNCM 1079-Levucell SB (LEV), or 3 g/d of AMF with 2 corn sources, dry whole-shelled corn or high moisture corn, on growth and carcass characteristics. Neither LEV nor AMF improved (P>0.10) carcass characteristics compared with control or non-feed-supplemented steers. Addition of LEV to high-concentrate, corn-based diets did not improve (P>0.10) growth performance of feedlot steers. However, addition of AMF to a diet composed of dry whole-shelled corn resulted in an improvement (P<0.05) in G:F (0.208 vs. 0.194). Results indicate that at the amounts fed, AMF may improve G:F for lambs and steers fed dry corn-based finishing diets.     

Growth, carcass composition and selected hormone concentrations of restricted-and ad libitum-fed pigs

Two barrows and two gilts were selected from each of five different crossbred litters and allotted to either ad libitum- or restricted-fed treatments. Pigs fed at a level of 81% ad libitum intake grew slower (P less than .05), had less tenth-rib backfat (P less than .05), more percent muscle (P less than .05), an increased growth hormone (GH) secretion in response to glucose challenge at 50 kg (P less than .05) and decreased insulin secretion in response to glucose challenge at 50 and 100 kg (P less than .05) than ad libitum fed pigs. Hormone secretion response was also significantly affected by weight, with growth hormone decreasing and insulin increasing as pigs grew from 50 to 100 kg. No sex effects of sex X treatment interactions were found for hormone response (P greater than .10). There were no differences between treatments in feed efficiency, total feed intake on test, loin eye area, dressing percentage, or carcass length (P greater than .10). Carcass composition of barrows and gilts was affected differently by restricted nutrient intake.     

Fattening performance and carcass traits of Chios male lambs fed under traditional and intensive feeding conditions

This study was carried out to compare the fattening performance and carcass traits of Chios male lambs fed under traditional and intensive feeding conditions. In the study, a total of 34 lambs were randomly separated into traditional (T) and intensive (I) groups in equal numbers. Lambs in group T were fed on ration prepared in local style and grazed in olive grove for 8 h/day. On the other hand, lambs in group I were fed on 255 g alfalfa hay animal⁻¹ day⁻¹ and ad libitum mixed feed. After a period of 8 weeks, lambs were transported to the slaughterhouse. The results showed that Chios lambs fed under intensive conditions has better performance and produced heavier carcass compared to those fed under traditional conditions. However, consumption of concentrate feed mixture was about twice as much in group I as in group T. Total feed consumption and feed conversion ratio was similar in each group. The values of carcass traits of lambs in group I were found to be significantly higher than those of group T. On the other hand, carcass fat thickness was slightly lower in group T. Traditional condition is considered to respond to better to consumer demands for lean lamb carcass.     

Vinasse added to the concentrate for fattening lambs: intake, animal performance, and carcass and meat characteristics

Twenty-four Merino lambs (mean BW 15.4 ± 0.13 kg, 6 to 7 wk old) were used to study the effects of the addition of 0 (control), 100 (V10), and 200 (V20) g of vinasse per kilgram of concentrate on intake, animal performance, biochemical blood profile, and carcass and meat characteristics. Lambs were assigned to 1 of 3 experimental diets and fed barley straw and the corresponding concentrate ad libitum. When the animals reached 25 kg of BW, a sample of blood was taken and the lambs were slaughtered. Feed intake, growth rate, biochemical blood profile, and carcass and meat characteristics were assessed. Lambs that received the concentrates with vinasse showed a reduced concentrate intake (linear contrast, P = 0.029) and ADG (linear contrast, P = 0.004) and an increased length of fattening period (linear contrast, P = 0.002) as well as feed:gain ratio (linear contrast P = 0.011). Vinasse enhanced ruminal pH (orthogonal contrast control vs. V10 + V20; P = 0.007). Plasma glucose concentrations declined in lambs fed vinasse (linear contrast, P = 0.003), whereas plasma urea concentration increased in animals fed vinasse (linear contrast, P = 0.036). The plasma concentrations of creatinine, triglycerides, and lactate and the enzyme profile studied (alkaline phosphate, alanine transaminase, glutamate oxal-acetate transaminase, γ-glutamyl transpeptidase, and lactate dehydrogenase) were not modified in response to vinasse inclusion. Lambs in the vinasse groups had less Na(+) and nitrate and greater K(+) and nitrite plasma concentrations (linear contrasts, P < 0.05). None of the carcass characteristics studied was affected by vinasse (P > 0.10). Meat chemical composition and characteristics were unaffected (P > 0.10), but shear force was greater for lambs that received vinasse (orthogonal contrast, control vs. V10 + V20, P = 0.007). The addition of 100 or 200 g vinasse/kg of concentrate for fattening lambs reduced feed intake and growth rate and increased the feed:gain ratio and meat toughness without affecting any other carcass and meat characteristics.