Body weight and tissue gain in lambs fed an all-concentrate diet and implanted with trenbolone acetate or grazed on alfalfa

Targhee x Hampshire lambs (average BW 23 +/- 1 kg) were used in two experiments to determine the effects of finishing on concentrate with an anabolic implant or forage grazing after concentrate feeding on growth, organ and viscera weights, and carcass tissue accretion. In Exp. 1 and 2 lambs were penned by sex and assigned for slaughter at initial (23 kg), intermediate (37 kg), or end BW (ewes, 47.7; wethers 50.4 kg). From 23 to 37 kg BW, lambs were fed all-concentrate diets in drylot (DL) or grazed on alfalfa (ALF). Experiment 1 was a 2 x 2 factorial with 28 lambs; factors were wether vs ewe lambs and unimplanted vs DL implanted with trenbolone acetate-estradiol benzoate. There were no differences in organ and viscera weights due to implant status. However, ADG (P < .03) and lean gain (P < .02) were greater for implanted than for unimplanted wethers (507 vs 357 g and 1,314 vs 656 g, respectively). Ewes did not respond to the implant. Fat accretion was not affected by implantation. Experiment 2 was a 2 x 3 factorial with 42 lambs; factors were wether vs ewe lambs and drylot during growing and finishing phases (DL-DL) vs drylot during growing and alfalfa grazing during finishing (DL-ALF) vs alfalfa grazing during growing and finishing phases (ALF-ALF). In Exp. 2, ADG of DL-DL lambs was greater (P < .01) than ADG of DL-ALF or ALF-ALF lambs. Lambs on ALF-ALF had smaller (P < .05) livers and rumen/reticulum weights but heavier (P < .04) kidney, omasum, small and large intestine, and cecum weights than those on DL. In Exp. 2, DL-ALF and ALF-ALF lambs had overall hindsaddle lean gain equal to those on DL-DL with less mesenteric fat and 100 g less separable fat. Finishing lambs on alfalfa reduced fat accretion without decreasing lean accretion, whereas trenbolone acetate implants for lambs fed concentrate increased BW gain and lean accretion without affecting fat accretion.     

Effects of corn processing and dietary fiber source on feedlot performance, visceral organ weight, diet digestibility, and nitrogen metabolism in lambs

In Exp. 1, early-weaned Targhee and Polypay crossbred lambs (60 ewes and 66 rams; initial BW 24 +/- 1.0 kg) were used in a 2 x 3 factorial experiment to determine the effects of corn processing (whole shelled corn [WSC] or ground and pelleted corn [GC]) in combination with supplemental fiber (none [control]; soybean hulls, SBH [highly digestible]; or peanut hulls, PH [highly indigestible]) on DMI, ADG, feed efficiency, and visceral organ weight. For the total trial, WSC resulted in a 4% increase (P < .01) in ADG vs GC, and supplemental fiber resulted in increased (P < .01) DMI and ADG vs the control diet. Experiment 2 was conducted using 12 Targhee and Polypay crossbred wether lambs (initial BW 25 +/- 7 kg) to determine the effects of corn processing and fiber source in high-concentrate diets on diet digestibility and N retention using the same diets as in Exp. 1. Lambs fed WSC had greater (P < .001) apparent N digestion, true N digestion, and N retention (P < .01) than those fed GC. The apparent digestibilities of DM, OM, and NDF were greater (P < .001) for WSC than for GC diets. Peanut hulls resulted in decreased (P < .01) DM, OM, and NDF apparent digestibilities compared with the control and SBH diets. Starch digestion was not affected (P > .10) by diet. Whole corn resulted in improved DM, OM, NDF, and N digestibility compared with GC. Overall, both the SBH and PH diets resulted in greater DMI and ADG than the control diet, which lacked supplemental fiber.     

Comparison of the effects of three methods of harvesting and storing alfalfa on nutrient digestibility by lambs and feedlot performance of steers

Two lamb digestion and three steer growth experiments were conducted to study the feeding value of alfalfa harvested as direct-cut silage (DCS) with grain added prior to ensiling or as low-moisture silage (LMS) or hay with grain added at feeding. In all experiments, alfalfa-grain mixtures contained approximately 50% alfalfa and 50% concentrate (dry matter [DM] basis). In Exp. 1, lambs fed DCS alone consumed less DM than lambs fed LMS or hay alone or any of the alfalfa-grain mixtures. Apparent digestibilities of DM and fiber components were higher (P less than .05) for DCS than for LMS or hay. Lambs that were fed LMS digested more (P less than .05) DM and fiber components than lambs fed hay. Addition of grain resulted in increased (P less than .05) DM digestibility and decreased (P less than .05) digestibilities of neutral detergent fiber and acid detergent fiber. In Exp. 2, growing steers (271 kg) fed DCS-grain had increased (P less than .05) weight gains compared with steers fed hay-grain. Steers fed any of the alfalfa-grain mixtures gained weight more rapidly (P less than .05) than steers fed corn silage (CS)-based diets. In a third experiment, finishing steers (283 kg) fed DCS-grain, LMS-grain, hay-grain or CS-based diets performed similarly (P greater than .05), although steers fed DCS-grain had higher (P less than .05) dressing percentages and yield grades than steers that were fed the other three diets and were fatter (P less than .05) than those fed LMS-grain or CS. In Exp. 4, lambs fed DCS-grain or LMS-grain had higher (P less than .05) apparent DM and organic matter digestibilities than lambs fed CS-based diets with similar forage:grain proportions. In Exp. 5, finishing steers (326 kg) fed DCS-grain gained similarly (P greater than .05) to steers fed LMS-grain or an 85% concentrate diet based on high-moisture corn. Steers fed CS diets had lower (P less than .05) gains and increased (P less than .05) feed per gain compared with steers fed DCS-grain, LMS-grain or high-moisture corn.     

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.     

Variation in food selection among lambs: effects of basal diet and foods offered in a meal.

In studies of behavior and nutrition, we typically determine nutritional needs and formulate diets for the average member of the herd, not for specific individuals within a herd. Nevertheless, variation among individuals could affect productivity of the group if the diet diverges too much from what individuals at the extremes prefer to eat. Thus, it is important to determine the degree to which individuals within a group vary in their food preferences when offered alternatives. Our first objective was to determine the degree to which lambs differed in preference for foods high in energy (barley) or protein (alfalfa) (Exp. 1). When we offered lambs barley and alfalfa for ad libitum consumption for 25 d, individuals varied in the amounts of barley (range: 221 to 991 g/d) and alfalfa (range: 51 to 558 g/d) they consumed (P < .0001). At one extreme, individuals preferred a diet of 6% alfalfa and 94% barley; at the other extreme, individuals preferred a diet of 70% alfalfa and 30% barley. Our second objective was to determine whether lambs from Exp. 1 compensated, when fed a basal diet that was lower in alfalfa than they preferred, by ingesting foods higher in alfalfa when offered a meal (Exp. 2). Lambs were ranked according to the percentage of alfalfa (range from 6 to 70%) and barley (range from 94 to 30%) they ate during Exp. 1 and then assigned alternately to two treatments: 1) basal diet with similar proportions of alfalfa and barley consumed ad libitum (preferred diet) or 2) basal diet with 10% less alfalfa than consumed ad libitum (low-alfalfa diet). We then conducted three trials in which lambs fed the different basal diets were offered a meal for 15 min/d for 2 d of two foods that differed in barley and alfalfa. During Trial 1, when we offered barley and alfalfa, lambs in both groups preferred barley (138 g) to alfalfa (46 g) (P < .05). During Trial 2, when the test foods (barley and alfalfa) were diluted with grape pomace (20%), lambs fed the preferred basal diet ate more barley (116 vs 64 g) and less alfalfa (48 vs 87 g) than lambs fed the low-alfalfa basal diet (P < .05). During Trial 3, when we offered a food high in barley (80% barley and 20% pomace) and a food high in alfalfa (70% alfalfa, 14% cornstarch, and 16% pomace), lambs fed the preferred basal diet ate more of the high-barley food (124 vs 73 g) and less of the high-alfalfa food (45 vs 98 g) than lambs fed the low-alfalfa basal diet (P < .05). Collectively, these results illustrate that lambs varied greatly in their preferences for foods that differ in energy (barley) and protein (alfalfa), and that when their preferred basal diet was altered, lambs compensated by ingesting food that complemented their basal diet during a daily meal. The addition of grape pomace in Trials 2 and 3 reduced the protein content of the high-barley and high-alfalfa foods such that the high-barley food was only marginally adequate to meet needs compared with the high-alfalfa food. Lambs fed the low-alfalfa basal diet compensated by eating more of the high-alfalfa food than lambs fed the preferred basal diet.     

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.     

Effects of diet forage:concentrate ratio and metabolizable energy intake on visceral organ growth and in vitro oxidative capacity of gut tissues in sheep

We used 28 crossbred wether lambs to determine the effects of dietary forage:concentrate ratio and metabolizable energy intake on visceral organ growth and oxidative capacity of gut tissues in lambs. Lambs were assigned randomly to a factorial arrangement of dietary treatments consisting of pelleted diets containing either 75% orchardgrass or 75% concentrate fed once daily at either .099 or .181 Mcal ME x (kg BW(.75))(-1) x d(-1). After a 52-d feeding period, lambs were slaughtered to obtain measurements of visceral organ mass and composition and oxidative capacity of isolated epithelial cells. Lamb performance, as measured by DMI, ADG, and efficiency of gain, was greater (P = .0001) for both diets at high ME intake. Likewise, lambs fed 75% concentrate gained faster and more (P < or = .01) efficiently than lambs fed 75% forage. Total digestive tract (TDT; includes rumen, reticulum, omasum, abomasum, and intestines) weight increased (P = .0001) with ME intake and was greater (P = .03) in lambs fed 75% forage than in those fed 75% concentrate. As a percentage of empty body weight (EBW), TDT weight increased with ME intake in lambs fed 75% forage, but it was unaffected by ME intake in lambs fed 75% concentrate (diet x intake, P = .03). Liver weight increased (P = .0001) with ME intake and was greater (P = .005) in lambs fed 75% concentrate vs 75% forage; however, liver weight as a percentage of EBW was increased (P = .0002) with ME intake but was unaffected by diet. Greater ME intake increased (P < or = .02) small intestinal (SI) epithelial and muscle mass of 15-cm sections, whereas jejunal epithelial mass was greater (P = .01) for lambs fed 75% forage vs 75% concentrate. Rumen epithelial concentrations of DNA and RNA increased (P < or = .02) with greater ME intake, whereas SI concentrations of DNA and RNA were largely unaffected by diet or ME intake. The activity of Na(+)-K(+)-ATPase increased in ileal epithelium (P < or = .02) with ME intake and concentrate in the diet, but activity in ruminal epithelium increased (P = .05) with concentrate. Total oxygen consumption by isolated ruminal and intestinal epithelial cells was unaffected by treatment. These data suggest that ME intake and level of dietary forage affect ruminal and intestinal growth via changes in cellular hyperplasia. Additionally, this study supports the concept that ME intake and diet composition alter gut energy expenditure, at least in part, through changes in mass rather than mass specific metabolism.     

Alpha-tocopherol concentrations and case life of lamb muscle as influenced by concentrate or pasture finishing

Two experiments were conducted to evaluate alpha-tocopherol accumulation in muscle of lambs finished on pasture or concentrates. The objective for Exp. 1 was to compare accumulation of alpha-tocopherol in the longissimus muscle of pasture-fed lambs to that of lambs fed three concentrations (15, 150, and 300 IU/kg of DM) of supplemental vitamin E (all rac alpha-tocopheryl acetate) in all-concentrate diets. The objective in Exp. 2 was to investigate the effect of duration of supplemental vitamin E feeding on alpha-tocopherol content and color change during display case storage of lamb muscle. Treatments evaluated in Exp. 2 were: 15 IU of supplemental vitamin E/kg DM fed to finish; 15 IU/kg followed by 300 IU/kg of DM during the last 21 d; and 15 IU/kg DM until 7 d prior to finish, then 300 IU/kg DM. In Exp. 1, alpha-tocopherol concentration of rotational grazed alfalfa and perennial ryegrass averaged 137 and 169 mg/kg of DM. Vitamin E treatments for lambs fed concentrate diets did not affect ADG (P > 0.15), but ADG was greater (P < 0.01) for concentrate-fed lambs than for grazing lambs. For the concentrate-fed lambs, alpha-tocopherol in longissimus muscle increased quadratically (P < 0.05) as dietary concentrations of vitamin E increased. Predicted maximum alpha-tocopherol concentration in muscle occurred at about 400 IU/kg of diet DM. Longissimus muscle from lambs grazing alfalfa or ryegrass had similar (P > 0.50) alpha-tocopherol concentrations, and those concentrations were similar to values obtained when the concentrate diet supplemented with 150 IU of vitamin E/kg was fed. In Exp. 2, no differences (P > 0.10) in ADG were observed. Concentrations of longissimus alpha-tocopherol were highest when 300 IU supplemental vitamin E was fed for 21 d prior to slaughter. During a 6-d display period, semimembranosus steaks from lambs fed 300 IU of supplemental vitamin E/kg for either 7 or 21 d had higher a* and b* color readings than steaks from lambs fed 15 IU/kg of supplemental vitamin E. Increased consumption of vitamin E either via pasture or supplementation results in higher alpha-tocopherol concentrations in meat.     

Effects of dietary sewage solids on feedlot performance, carcass characteristics, serum constituents and tissue elements of growing lambs

Twenty fine-wool wether lambs were allotted randomly at weaning to be fed a conventional diet (CD) formulated for growing lambs, or the same basal mixture plus dried gamma-irradiated solids from primary sewage sludge (SS) incorporated as 7% of the dry matter. Feedlot performance and chemical elements in whole blood were monitored during 90 d, after which lambs were slaughtered and carcass data were collected. Concentrations of Ag, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb and Zn were measured in livers, kidneys, bones, spleens and muscles. Sewage solids in the diet did not affect performance appreciably, although dressing percentages from lambs fed SS were 4% lower than CD-fed animals (P less than .05). Rib eye areas, fat thicknesses, quality and yield grades were similar (P greater than .05). Element concentrations in whole blood at weaning, after 56 d of the feeding trial and at slaughter did not differ (P greater than .05) between dietary groups. Serum chemistry determinations showed no biologically meaningful patterns related to diets. Lambs fed SS had higher (P less than .05) concentrations of Cu in livers (51.1 vs 34.3 +/- 3.8 micrograms/g, mean +/- SE) and Pb in kidneys (4.0 vs 2.2 +/- .3 micrograms/g) and lower (P less than .05) Mg in kidneys (.69 vs .72 +/- .01 mg/g). None of the elements in spleen and muscle tissue differed (P greater than .05) between diet groups. Lambs fed SS had elevated (P less than .05) bone Co, Cu, Fe, K and Na compared with those of CD.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Effects of dietary canola seed and soy lecithin in high-forage diets on performance, serum lipids, and carcass characteristics of growing ram lambs

Phospholipids (soy lecithin) are important in the emulsification of lipids and may be able to escape the rumen and influence the absorption of fatty acids in the small intestine. The objectives of this study were to determine the influence of dietary canola seed (high in unsaturated fatty acids) and soy lecithin in high-forage diets on performance, serum lipid metabolites, and carcass characteristics of growing ram lambs. Forty-three Hampshire- or Suffolk-sired ram lambs were weaned at 60 d of age (average 23.6 kg BW) and assigned to a 2 x 2 factorial arrangement of the following treatments (% of DM): 1) basal diet (control = BAS); 2) BAS with 6% whole canola seed (CS); 3) BAS with 4.9% deoiled soy lecithin (SL); and 4) BAS with 6% CS and 4.8% SL (CSSL). The BAS diet consisted of 70% forage and 30% concentrate and contained 15% CP and 2.2 Mcal of ME/kg. Lambs had ad libitum access to their diet to an average final BW of 52.1 kg. Lambs were bled by jugular venipuncture on d 0, at 4-wk intervals, and 1 d before slaughter. Dry matter intake was not affected by treatment; however, energy intake (Mcal of ME/d) was greater (P less than .01) for lambs fed SL. Feeding SL and(or) CS to growing ram lambs increased (P less than .02) serum lipid concentrations. Carcasses from lambs fed SL were fatter, as evidenced by greater dressing percentage and subcutaneous fat thickness. Feeding CS to growing lambs had little effect on performance and carcass characteristics compared with feeding SL, which resulted in greater energy intake and fatter carcasses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary protein level and clinoptilolite on the weight gain and liver mineral response of growing lambs to copper supplementation

Growing male Synthetic I (1/2 Finnish Landrace x 1/4 Dorset x 1/4 Rambouillet) lambs were used in two experiments (64 lambs in Exp. 1 and 63 in Exp. 2) to test the hypothesis that dietary CP level (9 or 14% of diet as fed) and(or) clinoptilolite (clino; 0 or 2% of diet) affects growth and tissue mineral concentrations of growing lambs fed supplemental Cu. Lambs were individually fed their respective diets ad libitum and killed after 12 wk (Exp. 1) or 16 wk (Exp. 2) to obtain carcass measurements, organ weights and liver mineral concentrations. In Exp. 1, 20 ppm added Cu (as CuSO4.5H2O) increased mortality and depressed BW gain (P less than .01) and daily feed intake (P less than .05) in the presence or absence of clino and at both levels of CP. Liver Cu concentration was greater (P less than .01) in lambs fed added Cu than in those not fed Cu (408 ppm vs 110 ppm, respectively). Neither CP nor clino affected liver Cu concentration. Clinoptilolite increased daily gain of lambs fed high CP but not low CP (P less than .01). In Exp. 2, clino in the diet had no effect on daily gain or daily feed, but 20 ppm Cu addition depressed daily gain (P less than .01) and gain/feed (P less than .07). Organ weights and levels of trace elements other than Cu in the liver generally were not affected by diet in either experiment. It is concluded that high dietary CP or 2% dietary clino did not protect against toxic signs of Cu when Cu was added to the basal diet (10 ppm Cu) at 10 or 20 ppm.     

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.     

Effect of whole-crop pea (Pisum sativum L.) silages differing in condensed tannin content as a substitute for grass silage and soybean meal on the performance, metabolism, and carcass characteristics of lambs

Two experiments were conducted to investigate the effect of inclusion of whole-crop pea (WCP) silages, differing in condensed tannin content, as a substitute for grass silage (GS) and soybean meal on lamb metabolism, performance, plasma metabolites, digestibility, and carcass characteristics. In both experiments lambs were offered either solely GS or a 50:50 mix on a DM basis of GS with either low-tannin (LTPS) or high-tannin (HTPS) pea silage ad libitum. Each forage mix was fed with either 400 g/d of low-protein (LP) concentrate or 400 g/d of LP with an additional 200 g/d of pelletized soybean meal (HP), resulting in 6 dietary treatments. Experiment 1 examined the effects of the diets on metabolism, digestibility, and N balance using 6 lambs in 4 periods of 21 d in an incomplete crossover design. Experiment 2 used 48 lambs and examined the effects of the diets on ADG, plasma metabolites, and carcass characteristics over 56 d. Both experiments were analyzed using a 3 × 2 factorial arrangement of treatments. In Exp. 1, lambs offered the LTPS diets had a greater (P < 0.05) digestibility of DM and OM than those offered the GS diets. Lambs offered the WCP silages had an increased (P < 0.05) N intake, N output, and digestibility of GE compared with those offered GS. Mean N digestibility was greatest (P < 0.05) in lambs offered LTPS. Lambs offered HP diets had increased (P < 0.001) digestibility of DM, OM, GE and N, and N- intake, output, retention, and digestibility compared with those offered the LP diets. In Exp. 2, there was no effect (P > 0.05) of forage type on intake, slaughter BW, or feed conversion efficiency (FCE). However, lambs offered the LTPS had a greater (P < 0.05) ADG than those offered the GS diets. Feeding diets containing HP increased (P < 0.001) total DMI, slaughter BW, ADG, and FCE. Lambs offered the WCP had a greater (P < 0.05) plasma β-hydroxybutyrate and urea concentration compared with those offered the GS diets. Feeding lambs HP diets increased (P < 0.05) plasma urea and total protein. Forage mix had no effect (P > 0.05) on carcass composition except for fat depth, which was greater (P < 0.05) in lambs offered WCP silage. Diets containing the HP increased (P < 0.05) carcass weight, hind leg circumference, chop dimensions, and kidney weight. It was concluded that lambs offered LTPS performed better than those offered GS and that LTPS has a concentrate sparing effect. Additionally, the increased tannin concentration in HTPS did not increase performance over lambs offered either GS or LTPS.     

Digestibility and dry matter intake of diets containing alfalfa and kenaf

Two experiments were conducted to determine the dietary value of pellets containing kenaf (Hibiscus cannabinus cv. 'Everglade 41') hay. Averaged across both experiments, kenaf pellets contained 82.6% kenaf hay, 16.6% liquid molasses, and 0.8% mineral oil. The chemical composition of the kenaf pellet was 12.6% crude protein (CP), 41.2% neutral detergent fiber (NDF), and 14.4% acid detergent fiber (ADF). In Exp. 1 (digestion and N balance trial), 18 lambs (body weight [BW] = 36.4 kg) were blocked by BW. Lambs were randomly assigned within a block to Diet 1 (59.5% corn and 40.5% alfalfa pellet), Diet 2 (59.7% corn, 28.4% alfalfa pellets, and 11.9% kenaf pellets), or Diet 3 (59.6% corn, 16.5% alfalfa pellets, and 23.9% kenaf pellets). Diets were formulated so that CP was the first-limiting nutrient. Each diet was limit-fed at 2.4% of BW. Replacing alfalfa pellets with kenaf pellets tended to decrease (P = 0.10) CP and ADF intakes, but increased (P = 0.01) DM digestibility. Diet had no effect (P = 0.33) on N balance. In Exp. 2 (dry matter [DM] intake trial), 32 lambs (BW = 30.4 kg) were blocked by gender and BW. Within a block, lambs were randomly assigned to one of four diets in a 2 x 2 factorial arrangement. Main effects were hay (bermudagrass or fescue) and supplemental protein source (kenaf or alfalfa pellets). Lambs were housed in individual pens with ad libitum access to the assigned hay. Supplemental protein was fed (185 g of DM) once daily. Hay intake was measured weekly for 8 wk. Lambs consumed more (P = 0.002) fescue than bermudagrass hay (743 vs 621 g/ d). Lambs fed fescue hay gained weight more rapidly (P = 0.001) than lambs fed bermudagrass hay (120 vs 72 g/d). Hay intake and ADG were similar (P = 0.90) for lambs fed alfalfa or kenaf pellets. Kenaf hay mixed with molasses and mineral oil can be formed into a pellet. In the diets used in this experiments, kenaf pellets can replace alfalfa pellets in diets fed to lambs without altering forage intake, gain, or N retention.     

Effects of supplementing with calcium salts of palm oil fatty acids or hydrogenated tallow on ewe milk production and twin lamb growth

Two experiments were conducted with Polypay ewes nursing twin lambs to evaluate the effects of supplementing fat (calcium salts of palm oil fatty acids or hydrogenated tallow) on ewe lactation. In Exp. 1, ewes were fed a 52% concentrate:48% hay-based diet (as-fed basis) consisting of alfalfa hay (n = 4), endophyte-free fescue hay (n = 4), or fescue hay with 3.7% fatty acids (n = 4) from d 4 to 56 of lactation. In Exp. 2, ewes were fed similar diets that had endophyte-free fescue hay (n = 6), fescue hay with 3.7% fatty acids (n = 5), or fescue hay with 3.1% tallow (n = 6) from d 14 before lambing until d 57 of lactation. Diet formulations with supplemental fat were more nutrient dense, and treatments were fed to meet ewe nutrient requirements; this caused diets with added fat to be offered at 10 and 17% lower rates than unsupplemented diets in Exp. 1 and 2, respectively. Lambs were maintained to consume only ewe milk. Ewe milk production and composition were determined using a portable milking machine following a 3-h separation from lambs. In Exp. 1, milk fat content was increased (P < 0.01) when ewes consumed fescue hay with fatty acids vs. the fescue hay diet (11.4 vs. 8.3%). Ewes fed fescue hay with fatty acids lost the most (P < 0.05) weight over lactation (-8.6 kg) compared with ewes fed the alfalfa hay (-2.4 kg) and fescue hay (-3.8 kg) diets. Other milk measures, lamb gain, and production efficiencies were not changed. In Exp. 2, ewes supplemented with fatty acids produced more (P < 0.05) milk fat than those fed tallow (290 vs. 210 g/d). The proportion of synthesized milk fat 14:0 was decreased (P < 0.01), but the percentage of incorporated 16:0 increased (P < 0.05) when fatty acids were fed. Dietary fat digestibility by ewes was increased (P < 0.01) by fatty acid supplementation but decreased (P < 0.01) when tallow was added. Although ewe weight measures were not changed in Exp. 2, twin lamb gain per ewe organic matter intake was most efficient (P < 0.05) when ewes were supplemented with fatty acids. Results suggest that feeding hydrogenated tallow decreased nutrient availability for ewe milk fat production. A complete diet based on endophyte-free fescue hay can replace a traditional alfalfa hay diet, whereas supplementing with the calcium salts of palm oil fatty acids may be more feasible when energy is limiting during ewe lactation.     

Comparison of characteristics of lambs fed concentrate or grazed on ryegrass to traditional or heavy slaughter weights. I. Production, carcass, and organoleptic characteristics

The objectives of this study were to determine the effects of finishing lambs on concentrate (C) or by grazing ryegrass forage (F) to slaughter end weights of 52 (N) or 77 kg (H) on carcass characteristics and organoleptic properties. This experiment included 64 Targhee x Hampshire lambs (average BW = 24 +/- 1 kg) in a 2 x 2 x 2 factorial arrangement of treatments to compare wethers vs. ewes, C vs. F, and N vs. H slaughter weights. No interactions (P > 0.10) were observed between gender and other main effects. Hot carcass weight and dressing percent were greater (P < 0.001) for C- than for F-fed lambs. Backfat thickness also was greater (P < 0.001) for lambs fed C than for those fed F. Moreover, USDA lean quality score and USDA yield grades were higher (P < 0.001) for C- than for F-fed lambs, as well as for lambs slaughtered at H vs. N market weights. There was a higher (P < 0.005) incidence of off odors and off flavors in cooked muscle from F- vs. C-fed lambs, and also from H vs. N slaughter-weight lambs. The heavy C-fed lambs had juicier (P < 0.001) meat than other treatment combinations. Cooked meat from C-fed lambs received higher (P < 0.001) overall acceptability scores. Concentrate-finished lambs produced fatter carcasses and more palatable meat than forage-finished lambs; however, forage finishing allowed for slaughter at heavier weights without excessive fat deposition.     

Nutrients intake,digestibility, nitrogen balance and growth performance of sheep fed different silages with or without concentrate

The experiment was conducted to investigate the influence of maize (Zea mays), sorghum (Sorghum bicolor) and millet (Pennisetum americannum) silages with or without concentrate on nutrients intake, digestibility, nitrogen balance and weight gain in Sipli sheep. Six experimental diets were formulated having 100% maize silage (MS), maize silage and concentrate as 50:50 (MSC), 100% sorghum silage (SS), sorghum silage and concentrate as 50:50 (SSC), 100% millet silage (MiS) and millet silage and concentrate as 50:50 (MiSC), respectively. For this purpose, 24 Sipli lambs were randomly allotted to six experimental diets in a completely randomized design for 90 days, four lambs per diet. The results indicated that among various silage diets, lambs fed MS diet consumed higher dry matter (DM) than those fed SS and MiS diets. Likewise, lambs offered MSC had higher dry matter intake than those fed SSC and MiSC diets. Crude protein (CP) and neutral detergent fibre (NDF) consumed by the lambs also followed the similar trend. Higher DM, CP and NDF digestibilities were also observed in lambs fed MS and MSC diets than those fed SS, SSC, MiS and MiSC diets. Overall digestibilities of DM, CP and NDF were higher in experimental diets containing silage with concentrate. Lambs fed MS diet had 2.79 g/day and 4.45 g/day higher N retention than those fed SS and MiS, respectively. Similarly, lambs fed MSC diet had 2.24 g/day and 5.12 g/day higher N retention than those fed SSC and MiSC diets, respectively. The results showed that lambs fed MSC gained more daily weight gain had better feed conversion ratio than those fed MS, SS, SSC, MiS and MiSC diets. The findings of the present study indicated that lambs fed MSC diet had higher nutrients intake, digestibility, nitrogen balance and weight gain.     

Influence of dietary palm oil supplementation on serum lipid metabolites, carcass characteristics, and lipid composition of carcass tissues of growing ram and ewe lambs.

The objective of this research was to determine the influence of dietary palm oil supplementation on carcass characteristics and lipid composition of tissues from growing lambs. Twenty-eight Suffolk x Hampshire lambs were weaned at 60 d of age (average 36 kg BW) and assigned to a 2 x 2 factorial arrangement consisting of diet (control [NPO] or 10.6% added dietary palm oil [PO]) and sex (ram vs ewe). The NPO diet (77% forage and 23% concentrate) contained 11.2% CP and 2.66 Mcal of ME/kg. Palm oil replaced molasses in the PO diet. Lambs were individually given ad libitum access to feed for 60 d to a final BW average of 50.1 kg. Lipid composition of the longissimus muscle and corresponding subcutaneous (s.c.) adipose tissue was determined by gas-liquid chromatography (GLC). Lambs fed PO were fatter (P less than .01) than lambs fed NPO (.77 vs .56 cm, s.c. fat). Diet had no effect on cholesterol content of lean tissue; however, feeding PO increased the saturated fatty acids of lean tissue. The s.c. fat from lambs fed PO had less (P less than .01) cholesterol (64.79 vs 89.67 mg/100 g) and more saturated fatty acids than that from lambs fed NPO. Ewes were fatter (P less than .01) than rams, yet they had less cholesterol content in the s.c. adipose tissue (68.71 vs 85.74 mg/100 g). High amounts of dietary palm oil fed to growing lambs caused changes in fatty acid deposition and cholesterol metabolism and may be a useful investigative tool to study lipid metabolism in growing ruminants.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synchrony of nutrient supply to the rumen and dietary energy source and their effects on the growth and metabolism of lambs

The objective of the current series of experiments was to assess the effects of dietary synchrony of OM and N supply to the rumen, achieved by altering the sequence of feeding individual ingredients and in diets with different energy sources, on the metabolism and performance of growing lambs. In Exp. 1, the in situ degradability coefficients of OM and N were determined for five feed ingredients and subsequently was used to formulate two diets, based either on barley or sugar beet pulp, to have a similar predicted nutrient content. Within each diet, specific ingredients were shifted between the 0900 and 1600 feeding to provide either a synchronous, intermediate, or asynchronous supply of OM and N to the rumen. In Exp. 2, these diets were fed at a restricted level to 48 growing lambs with an initial live weight of 25.1 +/- 4.22 kg and a slaughter weight of 41.4 +/- 1.94 kg. There was no significant effect of dietary treatment on live weight gain or feed conversion efficiency. Lambs fed the synchronous diets deposited more kidney knob and channel fat than lambs on the asynchronous or intermediate diets (P < 0.05), whereas lambs fed the barley-based diets deposited more carcass (P < 0.05) and noncarcass (P < 0.001) fat than lambs on the sugar beet-based diets. Lambs fed the asynchronous diets retained less energy over the course of the experiment than lambs on the intermediate or synchronous diets (P < 0.05), and had a lower energy efficiency (0.079, 0.097, and 0.093 MJ retained/ MJ of intake, respectively, P < 0.05). Lambs fed the barley-based diets retained more energy than lambs on the sugar beet-based (P < 0.001) and had a higher energy balance (0.095 vs. 0.084 MJ retained/MJ intake, respectively; P < 0.01). Plasma ammonia concentrations mirrored ruminal ammonia concentrations on the barley-based diets, but not sugar beet-based diets. In Exp. 3, lambs fed the sugar beet-based diets had a higher digestibility of OM and NDF (P < 0.001). By contrast, lambs on the barley-based diets had a higher level of purine derivative excretion and microbial N production (P < 0.001). The results indicate that neither dietary synchrony nor energy source significantly influenced growth rate. However, both the asynchronous and sugar beet pulp-based diets resulted in a lower efficiency of dietary energy use, and the avoidance of asynchronous patterns of nutrient release within the rumen can improve energy efficiency in growing lambs.