In sacco degradation kinetics of fresh and field-cured peanut (Arachis hypogaea L.) forage harvested at different maturities

There is interest in growing peanut (Arachis hypogaea L.) for forage, but little is known about the nutritive value and forage quality of modern cultivars. The objective of this study was to compare the chemical composition and in sacco degradation kinetics of three cultivars of peanuts (cv. ‘C99-R’, ‘Georgia-01R’, and ‘York’) at either stage 2 or 8 maturities when fresh and field-cured. Herbage yield was at least 3000 kg DM/ha for all cultivars at both maturities. Crude protein (CP) was greater (P < 0.0001) at R2 stage than at R8 stage; whereas, neutral detergent fiber (aNDF), acid detergent fiber, and Lignin (sa) were greater (P < 0.01) at R8 than R2 maturity stages. Water soluble carbohydrate and acid detergent insoluble nitrogen was not different (P > 0.07) among cultivars, maturity stage, or harvest forms. In vitro true digestibility was greatest (P < 0.02) for C99-R and least for York. Undegradable intake protein concentration was greatest (P < 0.04) in York and least for C99-R. Maturity had a greater effect on the degradation kinetics than harvest form or cultivar. The dry matter (DM) and CP in the soluble wash fraction (A) and insoluble but degradable fraction (B) and the effective ruminal degradability were greater among all cultivars and both harvest forms of the R2 maturity stage than the R8. The undegradable DM, aNDF, and CP in the undegradable fraction were greatest (P < 0.002) for all three cultivars at R8 maturity. The rate of degradation of DM and CP in the B fraction was faster (P < 0.001) at R2 stage than at R8 stage; whereas, rate of aNDF degradation was not different (P > 0.09) among treatments. Lag of DM, aNDF, or CP degradation was not different (P > 0.1) among treatments. The cultivars C99-R and Georgia-01R are recommended for further feeding trials.     

Effect of elemental nano-selenium on feed digestibility,rumen fermentation,and purine derivatives in sheep

The objective of this experiment was to study the effect of elemental nano-selenium (NS) on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Eight male ruminally cannulated sheep (42.5 ± 3.2 kg of body weight, BW) were used in a replicated 4×4 Latin square experiment in four 20 day periods. Depending on treatment designation, sheep were fed the basal diet supplemented with 0 (control), 0.3, 3 and 6 g of nano-Se/kg dry matter (DM). Ruminal pH (range of 6.68–6.80) and ammonia N concentration (range of 9.95–12.49 mg/100 mL) was decreased (P<0.01), and total VFA concentration (range of 73.63–77.72 mM) was increased linearly (P<0.01) and quadratically (P<0.01) with increasing nano-Se supplementation. The ratio of acetate to propionate was linearly (P<0.01) and quadratically (P<0.01) decreased due to the increasing of propionate concentration. In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis and crude protein (CP) of soybean meal were linearly (P<0.01) and quadratically (P<0.01) improved by feeding nano-Se. Similarly, nutrients digestibility in the total tract and urinary excretion of purine derivatives were also quadratically (P<0.01) changed by increasing nano-Se supplementation. The present results indicated that nano-Se supplementation in basal diet improved rumen fermentation and feed utilization. Nano-Se could also stimulate rumen microbial activity, digestive microorganisms or enzyme activity. The optimum dose of nano-Se was about 3.0 g/kg dietary DM in sheep.     

Effects of considering the rate of comminution of particles and microbial contamination on accuracy of in situ studies of feed protein degradability in ruminants

Ruminal degradation of dry matter (DM) and crude protein (CP) in samples of soybean meal (SBM), barley grain (BG) and lucerne hay (LH) were measured by an in situ ruminal technique considering either only the outflow rate of particles from the rumen (k_p) or, both k_p and rate of particle comminution (k_c). The effect of correction for the microbial contamination using an ¹⁵N technique was also determined for LH. Degradation and transit studies were completed on three wethers cannulated in the rumen and duodenum and fed a mixed diet of LH and concentrate (2:1 on DM), at an intake level of 50 g DM/kg BW^0.75. Transit studies of concentrates and forages were completed with SBM and LH samples marked with Yb and Eu, respectively. Mean values of k_c were higher in SBM than in LH (0.357 versus 0.204 h, P < 0.05). The same trend was observed for k_p (0.0587 versus 0.0452/h; P < 0.1). Apparent estimates of the proportion of rumen undegraded CP obtained using both rates were 0.884, 0.745 and 0.825 of those obtained using only k_p (0.535, 0.247 and 0.303 for SBM, BG and LH, respectively). Differences occurred for SBM and LH (P < 0.01) and for BG (P < 0.05). The pattern of microbial contamination of LH, expressed as a proportion of residual DM or CP, fitted exponential curves with asymptotic values of 0.076 and 0.586, respectively. Correction for microbial contamination reduced (P < 0.05) estimates of undegraded CP from 0.303 to 0.238, which was further reduced to 0.178 (P < 0.01) when the effect of k_c was also considered.     

Influence of condensed tannins from Brazilian semi-arid legumes on ruminal degradability,microbial colonization and ruminal enzymatic activity in Saanen goats

The present study aimed at determining the influence of condensed tannins present in the Brazilian legume species Mimosa hostilis, Mimosa caesalpinifolia and Bauhinia cheilantha on ruminal degradability, microbial colonization and enzymatic activity. Polyethylene glycol (PEG) was used to reduce the astringency and concentration of soluble condensed tannins. Four ruminally-cannulated Saanen goats (60 ± 8 kg BW) were fed, in two experimental periods, with a hay diet based on the studied legumes treated or non-treated with PEG. Voluntary intake, microbial colonization, DM, CP, NDF, and ruminal degradability of PEG treated and non-treated forage leaves, as well as pH, ammonia and 1,4 β-endoglucanase activity of the rumen content were evaluated. Astringency and soluble tannin concentration of the studied legumes were reduced by approximately 70% and 50%, respectively, with PEG treatment. Average DM intake was higher for the treated diet (16.76 g DM/kg BW/day against 13.06 g DM/kg BW/day). Percentile values for degradation parameters and for potential and effective degradabilities of DM, CP and NDF were also affected by the tannins, but at different intensities. Electron microscopic observations of ruminally-incubated legume leaves showed a more effective microbial colonization of PEG-treated leaves for all legume species. A decrease in pH and an increase in ammonia concentration and in endoglucanase activity in the ruminal content was also observed for PEG-treated diets at all sampling periods. Condensed tannins of the studied legume species have influenced the adhesion conditions, colonization and enzymatic activity of the microbial ecosystem, and consequently the ruminal degradation of the different dietary fractions. For this reason, the reduction in condensed tannin would be of great importance to improve the nutrition of ruminant feeding of these species.     

The effect of dietary crude protein level on intake,growth, protein retention and utilization of growing male Saanen kids

The effects of increasing dietary levels of crude protein on growth, feed intake, feed efficiency and composition of gain in male Saanen kids were studied. Four groups of four kids each initially weighing 12.1±0.18 kg and having a weight gain of 195±16 g/d were penned individually and fed for 73 to 124 days up to 25 kg of BW. They were fed chaffed wheat straw (45 g CP/kg DM) which had been molasses sprayed (10%) and pelleted concentrates containing 8.7, 11.7, 14.4 and 17.6% crude protein (CP) on DM basis, the ratio of straw to concentrate being 1:5. Kids were fed controlled to satiation in which case small amounts of the feeds were offered about five times a day as long as the kids wanted to eat. Retention of protein, fat and energy were calculated from their initial and final concentrations in the empty body homogenates of the slaughtered kids. With increasing CP level in the diet, feed intake increased from 448 to 608 g DM/d, weight gain from 94 to 181 g/d, retention of protein from 9.7 to 27.8 g/d, retention of fat from 9.6 to 19.1 g/d and feed efficiency improved from 4.79 to 3.39 kg DM/kg weight gain. Protein composition of gain increased from 103 to 154 g/kg BWG while fat (103–105 g/kg BWG) remained constant. Regression analyses showed that BWG can be optimized at 136 g CP/kg DM and protein retention at 180 g CP/kg DM, whereas, dietary nitrogen was utilized most efficiently at 120 g CP/kg DM. Extrapolated from the regression equations, maintenance N requirement of the kids at zero N-retention and at zero BWG were 0.38 and 0.16 g N/kg W^0.75, respectively. Recommended dietary CP concentrations and maintenance N requirements depend on the traits desired.     

Effects of total nonstructural carbohydrates and nitrogen balance on voluntary intake of goats and digestibility of gamagrass hay harvested at sunrise and sunset

We evaluated differences in composition of Iuka gamagrass (Tripsacum dactyloides L.) hay harvested at 06:00 (AM harvest) or 18:00 h (PM harvest), and measured how protein supplementation and time of harvest interact to affect the voluntary intake, digestibility, and N balance of goats. Boer cross wethers (n = 28; 24 kg) were randomly assigned to be fed supplement (310 g/kg of crude protein (CP), fed at 110 g/kg of dry matter (DM) intake, 14 goats) or no supplement (14 goats). Within supplemented or not supplemented groups, goats were randomly assigned to a crossover design of AM harvest (seven goats) or PM harvest (seven goats), and housed individually in metabolism crates with free access to water and mineral blocks. They were fed twice daily, with supplement offered 30 min prior to the morning feedings. After a 7-d adaptation, voluntary intake (goats were offered 1100 g/kg of previous day's intake) was measured for 14 d, followed by a 4-d adjustment phase to equalize DM offered between periods, and finally a 5-d digestion and balance phase. After Period 1, goats were switched to their new hay harvest times, and the protocol was repeated. Compared to the AM harvest, the PM harvest had higher (P<0.03) proportions of total nonstructural carbohydrates (TNC, 70.8 g/kg DM versus 59.0 g/kg DM), monosaccharides (37.0 g/kg DM versus 28.6 g/kg DM), di- and polysaccharides (18.5 g/kg DM versus 15.4 g/kg DM) and less neutral detergent fiber (NDF, 700 g/kg versus 710 g/kg). Crude protein (79 g/kg DM) and starch (15.2 g/kg DM) were similar for the PM and AM harvest. Dry matter digestibility was higher (P<0.03) for the PM versus AM harvests (555 g/kg DM versus 531 g/kg DM) and for supplemented versus not supplemented (563 g/kg DM versus 522 g/kg DM). Voluntary gamagrass DM intake (550 g/d versus 548 g/d) and calculated total digestible DM intake (327 g/d versus 313 g/d) were similar for the PM and AM harvest. However, total digestible DM intake during the digestion and balance phase was higher (P<0.01) for the PM versus AM harvest (317 g/d versus 299 g/d). Time of harvest did not affect N intake, digestion, or calculated retention. Compared to no supplementation, the supplement improved (P<0.01) N digestion (6.1 g/d versus 3.7 g/d) and retention (2.2 g/d versus 1.1 g/d). The PM harvest increased DM digested, largely TNC and digestible DM intake by goats due to increased TNC and not because of a 2% increase in DM intake. Providing a protein supplement had very limited effects on intake and digestibility of gamagrass.     

In vitro evaluation of the fermentation characteristics of the carbohydrate fractions of hulless barley and other cereals in the gastrointestinal tract of pigs

An in vitro model was used to study the fermentation characteristics of carbohydrate fractions of hulless barley (hB), in comparison to hulled barley (HB), hulled oat and oat groats (OG) in the pig intestine. For this purpose, 6 hulless barley cultivars (hB), varying in β-glucan content (36–99 g/kg DM), were compared to 3 HB cultivars, 2 oat groat samples (OG), 3 oat varieties and a reference sample of wheat. The residue of a pepsin–pancreatin hydrolysis was incubated in a buffered mineral solution inoculated with pig faeces. Gas production, proportional to the amount of fermented carbohydrates, was measured for 48 h and kinetics modelled. The fermented solution was subsequently analyzed for microbial production of short-chain fatty acids (SCFA) and ammonia. In vitro dry matter degradability varied according to ingredient (P<0.001). Higher values were observed for OG, ranging from 0.88 to 0.99 as compared to oat, hB and HB, for which degradability ranged from 0.63 to 0.73, 0.68 to 0.80 and 0.69 to 0.71, respectively. A “cereal type” effect (P<0.05) was observed on fermentation kinetics parameters. Total gas production was higher (P<0.05) with hB (224 ml/g DM incubated) than with HB and oat (188 and 55 ml/g DM incubated, respectively). No difference was observed between hB cultivars (P>0.05) for total gas production but differences (P<0.001) were found for lag time and the fractional rate of degradation. Hulless barley cultivar CDC Fibar (waxy starch) and CDC McGwire (normal starch) started to ferment sooner (lag time of 0.7 and 0.9 h, respectively) than SH99250 (high amylose starch; 1.7 h). The fractional rate of degradation was similar in both hB and OG (0.15/h on average), which was higher than that of HB (0.12/h). The production of SCFA was also higher (P<0.05) with hB (6.1 mmol/g DM incubated, on average) than with HB and oat (4.9 and 2.9 mmol/g DM incubated, respectively). Similar trends were found for SCFA production expressed per g fermented carbohydrates, with higher butyrate and lower acetate ratio. In contrast, oat fermentation generated higher (P<0.05) ammonia concentration (1.4 mmol/g DM incubated, on average) than hB (1.0 mmol/g DM incubated). In summary, hulless barleys, irrespective of cultivar type had higher in vitro fermentability and produced more SCFA and less ammonia than hulled barley and oat. Thus, hulless barleys have a better potential to be used in pig nutrition to manipulate the fermentation activity in the intestine of pigs.     

In vivo and in situ digestibilities and nitrogen balance of Buddleia skutchii as a sole component and mixed with Pennisetum clandestinum in sheep diets

The objective of this work was to evaluate the intake (I) of all Buddleia skutchii foliage (BSF), collected from three different sites (places: A, B and C) in feeding sheep (phase 1), and in combination with Pennisetum clandestinum (Pc) (phase 2). Trials of feed intake, in vivo dry matter digestibility (IVDMD), and digestibilities of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and nitrogen balance were carried out during phase 1. Diet was given to nine Creole male lambs of 23(±3) kg body weight (BW), located in individual metabolism crates. During phase 2, four treatments were evaluated (T1 = 100% Pc, T2 = 20% BSF + 80% Pc, T3 = 40% BSF + 60% Pc and T4 = 60% BSF + 40% Pc) in a 4 × 4 Latin square design, using four ruminal cannulated Creole male rams of 50 ± 2 kg BW and remained in individual metabolism crates. In vivo digestibility (DM, CP and gross energy (GE)) and kinetics of in situ disappearance of DM were evaluated. The results in phase 1 indicated that BSF from Site B had relatively higher CP (14.9%), ADF (50.6%) content and nitrogen retention (1.93 g d⁻¹). On the other hand, the lambs showed intake levels of 376.29 g d⁻¹ DM, 56.21 g d⁻¹ CP, 206.24 g d⁻¹ ADF and 1418.21 kcal gross energy (P > 0.05); and digestibilities of 54.23% DM, 47.17% CP and 39.31% NDF. Therefore, BSF from Site B was selected for the second phase of this work as the best result. We observed that the nutrition quality of the diets was higher as a result of increasing BSF concentration in the diet. When sheep were fed on 40% BSF–60% Pc, DM intake levels of 900.6 g d⁻¹, and DM, CP and GE digestibility of 70.0, 52.82 and 55.1%, respectively, were observed. There were not significant differences among diets, and in situ disappearance, K_d and K_p, but the diet with 60% of BSF presented higher ruminal digestibility (42.3%). The results allowed to validate the local knowledge on BSF as a promising forage species, and showed that BSF should be incorporated in a sheep production system.     

Effects of feed intake on enteric methane emissions from sheep fed fresh white clover (Trifolium repens) and perennial ryegrass (Lolium perenne) forages

Published analyses of enteric methane (CH₄) emissions from sheep and cattle show an inverse relationship between feed intake and CH₄ yield (g CH₄/kg dry matter (DM) intake), which suggests opportunities for reducing CH₄ emissions from feed eaten and per unit of animal production. Most relationships between feed intake and CH₄ yield have been based on animals fed conserved feeds, especially silages and grains. Our research is a series of experiments with fresh white clover (Trifolium repens) and perennial ryegrass (Lolium perenne; ryegrass) forages fed to sheep at a range of feed intake levels. This study was comprised of four experiments where good quality freshly harvested white clover or ryegrass were fed to sheep over a three-fold range in DM intake, and CH₄ emissions were measured in respiration chambers for two consecutive days in each experiment. Measurements were made from 16 sheep in Experiment 1 (fed at 1.6 × metabolizable energy requirements for maintenance; ME_m), 28 sheep in Experiment 2 (at 0.8 and 2.0 × ME_m), eight sheep and two measurement periods in Experiment 3 (at 1.6 × ME_m), and 30 sheep in Experiment 4 (fed at 0.8, 1.2, 1.6, 2.0 and 2.5 × ME_m). Prior to each experiment, sheep had a 10 d acclimatization period to diets. Apparent digestibility was measured over 7 d from sheep in Experiments 1, 3 and 4, along with collection of rumen digesta for volatile fatty acid (VFA) determination. Although CH₄ yields differed when sheep were fed white clover or ryegrass at similar intakes, the differences were inconsistent and mean values similar across all experiments. This, and a similar structure of all experiments, enabled combined analysis of data from all four experiments using the restricted maximum likelihood (REML) procedure to estimate effects of feed intake level on digestibility, digestible nutrient intake, gas emissions, and VFA concentrations in the rumen. The REML analysis showed that when DM intake increased from 0.40 to 1.60 kg/d, the predicted responses were an increase in CH₄ production (g/d) of 187% (12.4–35.6 g/d; P<0.001), and a decline in CH₄ yield of 21% (25.6–20.2 g/kg DM intake; P<0.001). High feed intake levels were associated with increased molar proportions (mM of total VFA) of propionate from 0.17 to 0.21 (P=0.038). Single and multiple regressions were completed on the data from all experiments, with organic matter (OM) intake predicting 0.87 of the variation in CH₄ production, and molar proportion of propionate predicting 0.60 of the variation in CH₄ yield. Increasing feed intakes by 1 kg/d of DM reduced CH₄ yield by 4.5 g/kg DM intake. Plant chemical composition was weakly related to CH₄ yield. High intakes of fresh forages will lower CH₄ yield from fermentation, but effects of feed composition on CH₄ emissions were minor. The interaction between effects of feed intake and rumen function requires further investigation to understand relationships with CH₄ emissions.     

In vitro estimations of the rate and extent of ruminal digestion of starch-rich feed fractions compared to in vivo data

An experiment was conducted to study the rumen digestion characteristics of whole feeds (WF) and the neutral detergent fibre (aNDF) and neutral detergent soluble (NDS) fractions of a range of starch-rich feeds using an automated in vitro gas production (GP) technique. In addition, the ruminal digestibility values predicted from the GP data were compared to previously acquired in vivo data. Nine feeds with starch concentrations ranging from 389 to 712 g/kg dry matter and with known in vivo digestibilities were subjected to neutral detergent extraction. The GP for each WF and the corresponding aNDF fractions were measured in duplicate in buffered rumen fluid during 72 h on two occasions. The fermentation residues were collected and analyzed for aNDF concentration to estimate their true organic matter (OM) and NDF digestibility. The GP from the NDS fraction was calculated by subtracting the GP from the aNDF fraction from the GP of the WF. A three-pool Gompertz model was fitted to the GP profiles (R² = 0.99) and a two compartment, mechanistic and dynamic rumen model was used to predict the digestibility of the potentially digestible feed fraction and the effective digestion rate (k_d). The true OM and NDF digestibility determined for the WF ranged from 0.804 to 1.011 and from 0.362 to 1.107, respectively. The NDF digestibility determined for the aNDF fraction ranged from 0.410 to 0.985. The effective k_d values estimated using GP data varied from 0.118 to 0.282/h for the WF and from 0.123 to 0.301/h for the NDS fraction, and were less (P<0.05) for maize compared to small grains (SG) but did not differ between barley and wheat (P>0.05). The effective k_d values for the aNDF fraction ranged from 0.039 to 0.082/h and did not differ (P>0.05) either between maize and SG or between barley and wheat. The predicted ruminal NDS digestibility determined using GP data closely matched the in vivo data describing starch digestion (R² = 0.81). The effective k_d values for the WF were strongly related (R² = 0.94) to those for the NDS fractions. The results indicate that when measured with the GP technique, the differences in the digestion characteristics of maize and small grains are less than those previously reported in studies using the in situ method. It is concluded that the predicted NDS digestibility determined using GP data corresponded well to the in vivo starch digestibility. Our results also suggest that the first order digestion rates of NDS (starch) in starch-rich feeds can be accurately determined by incubating WF samples in the GP system and using the GP kinetic data in a dynamic, mechanistic rumen model.     

Nutritional characterization of Mucuna pruriens: 3. Effect of replacing soybean meal with Mucuna on intake,digestibility, N balance and microbial protein synthesis in sheep

Mucuna pruriens seeds have relatively high crude protein (CP) concentrations, but little is known about their potential to replace commonly used CP supplements in ruminant rations. The aim of this experiment was to determine effects of replacing soybean meal (SB) with Mucuna on the performance of lambs. Forty Rambouillet lambs (33.2 ± 5.73 kg) fed a basal diet of maize grain, cottonseed hulls and urea were randomly assigned to one of four supplements formulated by substituting 0 (SB), 330 (Lo), 670 (Med) or 1000 g/kg (Hi) of soybean meal with rolled Mucuna seeds. Lambs were housed individually in metabolic crates and allowed ad libitum access to isocaloric (metabolizable energy=11.7 MJ/kg dry matter, DM) and isonitrogenous (CP = 146 g/kg, DM) diets for 14 d of adaptation and 7 d of total fecal collection. Fecal egg counts and coccidian oocyst scores were determined on d 14. Dry matter intake (1.7 kg/d versus 1.5 kg/d; P<0.05), CP digestibility (774 g/kg versus 714 g/kg DM; P<0.05) and N retention (28.0 g/d versus 20.4 g/d; P<0.01) were higher and amylase-pretreated neutral detergent fiber digestibility (617 g/kg versus 686 g/kg DM) was lower (P<0.05) in sheep fed SB versus Mucuna diets. However, supplementary protein source did not affect rumen pH, blood urea N or glucose concentration, or fecal egg counts. Increasing the level of Mucuna supplementation increased (P<0.05) level and efficiency of microbial protein synthesis, ruminal fluid acidity, total volatile fatty acid concentration, decreased (P<0.05) coccidian oocyst scores, and tended (P<0.10) to increase N retention. Therefore, SB is a better supplement than Mucuna to support performance of lambs. Nevertheless, Mucuna seeds are a promising CP supplement for situations where cost or availability precludes use of SB in ruminant rations.     

Effects of daily protein intake levels on the oral stereotypic behaviours in energy restricted lambs

Effects of daily protein intake levels on oral stereotypic behaviours (OSB) in energy restricted lambs were investigated. Thirty-eight male lambs were randomly allotted to three treatments. Lambs in the first group (AL) received their ration (12.1 MJ ME/kg DM; 148.6 g CP/kg DM) at ad libitum level, whereas the second group (RP1) (12.1 MJ ME/kg DM; 177.4 g CP/kg DM) and the third group (RP2) (12.1 MJ ME/kg DM; 214.9 g CP/kg DM) received their rations at restricted levels. Recording of behaviours was carried out once a week using time sampling technique during a 7-week experimental period. OSB were significantly (P<0.001) affected by the treatments. RP2 group showed higher oral stereotypies than the others. It was concluded that increasing the daily protein intake under energy restricted conditions may have additive effects on the development of stereotypic oral behaviours.     

Effects of groundnut stover or Bermudagrass hay supplementation to doe kids on winter hardwood range

Goats in north-central Texas raised on rangeland often face winter forage quantity and quality deficits that may be mitigated by feeding hay or stover. Groundnut (Arachis hypogea) stover (8% CP, 35% ADF, 43% NDF and 8% acid detergent lignin (ADL) DM basis) and bermudagrass (Cynodon dactylon) hay (12% CP, 33% ADF, 73% NDF, and 5% ADL DM basis) were tested at Stephenville, Texas as 0.0, 0.5, or 2.0% BW supplement/substitution diets on 18 kg Boer X Spanish doe kids browsing native hardwoods (8 ha⁻¹). Both hay and stover were fed ad libitum in a traditional feedlot, using a complete formulated feed ration as a control. Trials ran for 10 weeks from January to March in 2003 (134 mm rainfall) and in 2004 (182 mm rainfall). Goats receiving 0.5% and 2% BW bermudagrass or 2% BW groundnut stover had greater ADG than those in the control and 0.5% BW groundnut paddocks (P < 0.05). Goats fed complete ration in the drylot had greater (P < 0.05) ADG than those eating either hay or stover ad libitum. Bermudagrass hay rejected by goats in the hardwood trial was 20% lower in CP, 7% greater in NDF, 8% greater in ADF, and 9% greater in ADL than the original fed hay; groundnut stover refusals were 21% lower in CP, 12% greater in NDF, 19% greater in ADF, and 20% greater in ADL concentration than the stover when fed. Supplementing goats on hardwood range with bermudagrass hay or groundnut stover may improve ADG when browse is scarce or of poor quality.     

Influence of undegraded intake protein on intake,digestion, serum hormones and metabolites,and nitrogen balance in sheep

In Exp. 1, 20 ewes of mixed breeding were fed grass hay : straw mixtures, assigned to one of four supplemental treatments and evaluated during six collection periods. Supplemental treatments were control (no supplement), and low, medium, and high levels (5.2%, 22.1%, and 41.3% of DM, respectively) of undegraded intake protein (UIP). Supplements were formulated to be similar in degraded intake protein (DIP; 21%). Digestibilities of DM, OM, and CP were increased (P < 0.10) with protein supplementation and in medium and high compared with low UIP supplemented ewes. Digestibility of CP also was increased (P < 0.10) in ewes on high compared with medium treatments. Serum insulin was not influenced (P > 0.10) by UIP treatment, except in collection period four. In contrast, serum glucose and growth hormone were not influenced (P > 0.10) by UIP treatment. In Exp. 2, four wether lambs fed the same treatments as in Exp. 1, were used in two 4 × 4 Latin squares trials. In trial 1 lambs received a grass hay diet (6.7% CP) and in trial 2 lambs were fed 40 : 60 blend (6.6% CP) of grass hay and spring wheat straw. In both trials, N intake, urinary N, N digestion, apparent N absorption, and N retention were increased (P < 0.10) with protein supplementation. In addition, in trial 1, urinary N, N digestion, and apparent N absorption were increased (P < 0.10) in medium and high compared with low UIP and also in high compared with medium UIP treatments. In trial 2 of Exp. 2, total feed intake (g/kg BW), digestibility of DM and OM, BW, and fecal N were increased (P < 0.10) with protein supplementation. Organic matter digestion, BW, N intake, and N retention were increased by medium and high compared with low UIP. Fecal N, BW, N intake, and N retention were increased (P < 0.10) in high compared with medium UIP. These data indicate that increasing levels of UIP supplementation increases DM, OM, and CP (N) digestibility, serum urea N concentration, and N retention in sheep fed low quality forage.     

Effect of feeding schedule on apparent energy and amino acid digestibility by growing pigs

An experiment was conducted to investigate the effects of feeding schedule on dry matter (DM), gross energy (GE), crude protein (CP), and amino acid (AA) digestibility by growing pigs. Six growing castrates (initial body weight: 40.5 ± 2.25 kg) were equipped with a T-cannula in the distal ileum and allotted to a repeated 3 × 3 Latin square design with three animals and three periods in each square. A maize–soybean meal based diet (181 g CP/kg) was formulated and fed to the pigs in three different feeding schedules; i.e., one meal per day, two meals per day, or free access to feed. Pigs fed one or two meals per day were allotted a daily amount of feed equivalent to three times the maintenance energy requirement. Fecal and ileal samples were collected from all pigs in each period. The coefficients of ileal apparent digestibility (CIAD) for DM, GE, CP, and AA were calculated as were the coefficients of total tract apparent digestibility (CTTAD) of DM and GE. Results of the experiment showed that there were no differences in the CIAD for DM, GE, or for any of the AA among the three feeding schedules. In contrast, pigs given free access to the diet had lower (P<0.002) CTTAD for DM and GE compared with pigs fed a restricted amount of feed either once or twice daily. Therefore, the concentration of digestible energy in the diet was lower if calculated from pigs given free access to the diet compared with pigs fed the diet once or twice daily (14.38 MJ/kg versus 14.83 MJ/kg and 15.13 MJ/kg). It is concluded that the feeding schedule does not influence the CIAD for DM, GE, CP, or AA by pigs. Therefore, any of the three feeding schedules that were used in the current experiment may be used in experiments aimed at measuring CIAD in pigs. However, if the CTTAD of DM and GE are measured, it is recommended that pigs are given free access to feed.     

Seed and forage yield,and forage quality determinants of nine legume shrubs in a non-tropical dryland environment

The objective was to identify legume shrub species for development of agroforestry technologies based on seed and forage (leaves and twigs < 10 mm diameter) yield, and determinants of forage quality. Ten individual plants of Bituminaria bituminosa ‘Ecotypes 1’, B. bituminosa ‘Ecotypes 2’, Medicago citrina, and M. arborea from Spain; Colutea istria and Onobrychis aurantiaca from Syria; C. istria from Jordan; Chamaecytisus mollis from Morocco; and Coronilla glauca from France were randomly selected from plots established in a non-tropical dryland environment in northwest Syria in 2000. Five individual plants of each species were cut back to 0.5 m above ground in March 2004. Coppice regrowths were pruned in December 2004 and April 2005 to determine forage yield and proportion of forage in the total above ground biomass (PEFB). Forage samples were analyzed for concentrations of crude protein (CP), lignin(sa), acid detergent fibre (ADFom), neutral detergent fibre (aNDFom), in vitro organic matter (OM) digestibility (IVOMD), and in vitro 24 h gas production (IVGP24h). Matured seeds were hand harvested from the remaining five plants of each species to estimate seed yield. Forage (21–250 kg DM/ha) and seed (0–200 kg DM/ha) yields; PEFB (0.22–0.96); and concentrations of CP (85–115 g/kg DM), lignin(sa) (14–42 g/kg DM), ADFom (94–170 g/kg DM), aNDFom (122–217 g/kg DM), IVOMD (456–617 g/kg OM), and IVGP24h (27–42 ml 200 mg/DM) varied (P<0.05) among shrub species. The IVOMD and IVGP24h were positively correlated (r = 0.75, P<0.032), whereas IVOMD and IVGP24h were negatively correlated with ADFom, lignin(sa) and aNDFom. In terms of forage and seed yields and determinants of forage quality, C. istria from Jordan, M. arborea, B. bituminosa ‘Ecotype-2’, C. istria and O. aurantiaca have higher potential than C. mollis, C. glauca and B. Bituminosa ‘Ecotype-1’ for the development of agroforestry technologies in non-tropical dry areas.     

Influences of the number of fetuses and levels of CP and ME in gestation and lactation supplements on performance of Spanish does and kids during suckling and post-weaning

Forty-eight mature US Spanish does (40 kg BW), from a herd selected for cashmere fiber growth, were used to investigate influences of the number of fetuses and levels of ME and CP in supplements during gestation and lactation on doe and kid performance. At 60 days of gestation, does with single or twin fetuses consumed mature Bermudagrass hay ad libitum and 1% BW (DM basis) of supplements with 18.6% or 28.5% CP (LP and HP, respectively) and 2.2 or 2.8 Mcal/kg ME (DM basis; LE and HE, respectively). The HE-HP supplement was offered at 1.5% BW (DM basis) for 15 days after birth, and does received the same supplement treatments as in gestation thereafter until weaning at 50 days after parturition. For a 50-day post-weaning period, kids consumed ad libitum the HE-LP supplement. BW at 90 days of gestation (41.4 vs 38.4 kg; P<0.10), BW before parturition (46.1 vs 41.7 kg; P<0.05), BW loss from parturition to day 21 of lactation (8.38 vs 5.25 kg; P<0.05), litter birth weight (5.47 vs 2.75 kg; P<0.05) and plasma concentrations of β-hydroxybutyrate (0.33 vs 0.29 mM; P<0.05) and NEFA (538 vs 434 mEq/l; P<0.05) were greater for does with twin vs single kids. BW at weaning was similar between single and twin kids (P>0.10; 8.31 and 7.63, respectively). Kid BW and cashmere fiber weight after the post-weaning period were affected by interactions (P<0.05) between number of fetuses and supplement ME level; kid BW was 12.3, 14.7, 14.6 and 13.2 kg (SE = 1.12 and 0.68 kg for singles and twins, respectively), and kid cashmere weight was 86, 109, 106 and 102 g (SE = 8.5 and 5.0 g for singles and twins, respectively) for single-HE, single-LE, twin-HE and twin-LE, respectively. In conclusion, effects of supplements differing in levels of ME and in ingredient composition for US Spanish does in gestation and lactation had dissimilar impacts on post-weaning BW and cashmere weight of single and twin kids. However, because of the limited number of observations and the high variability among animals in measures such as cashmere fibre growth, further experimentation concerning the potential for effects of nutritional plane of does on cashmere growth by kids is warranted.     

Ruminal starch digestion characteristics in vitro of barley cultivars with varying amylose content

Three experiments were conducted to study effects of amylose/amylopectin ratios and starch particle size on ruminal digestion characteristics of barley starch using an automated in vitro gas production system. In Experiment 1, starch digestion characteristics were measured in 12 barley cultivars with different amylose/amylopectin ratios, both as milled grain and as purified starch isolated from the original grain samples. The same 12 cultivars, harvested 1 year later from the same locations, were used in Experiment 2. Gas production was measured in milled samples, and in neutral detergent fibre (NDF) extracted from the same samples. The objective of this approach was to estimate gas production from neutral detergent solubles (NDS) as an approximation of starch. This was done by subtracting the NDF gas curve from the total gas production curve. In Experiment 3, starch digestion characteristics were measured for large and small starch granules from nine of the original cultivars used in Experiment 1. The gas curves obtained were fitted to a three-pool Gompertz model, and the effective rate of digestion (kd) was estimated with a two-compartmental rumen model. In Experiment 1, the effective starch kd for milled barley and purified starch were 0.122 and 0.118/h, respectively. Barley cultivars with low amylose (LA) had a higher effective kd (0.148/h) compared with cultivars with normal amylose (NA) (0.115/h) and high amylose (HA) (0.102/h) (P=0.010). Results obtained with milled barley were supported by the purified barley starch sample results, but differences were smaller and only numerically different. In Experiment 2, the ranking of the amylose groups was consistent with those in Experiment 1 (i.e., LA > NA > HA) (P=0.096). However, these differences were not reflected in the effective kd for the NDS fraction (P=0.366). Thus, factors other than those related to starch per se, or other structural features, are apparently important. Barley cultivars in the LA group had a higher effective kd for aNDF (0.098/h) than did NA and HA barley (0.060 and 0.055/h, respectively). Thus, the effect of the amylose group on the effective kd for aNDF corresponded well with the milled barley results. The NDF fraction, directly or indirectly, has a clear impact on the ruminal digestion rate of barley starch. There was no difference in the effective kd for starch between the small (0.126/h) and large (0.129/h) starch granules.     

Meat quality in goats as influenced by dietary protein and energy levels,and postmortem aging

The objectives of this study were to determine effects of different dietary treatments and postmortem aging on meat quality characteristics in goats. Twenty castrated dairy goats (BW = 30.7 ± 6.80 kg, age 10 months) were subjected to one of four dietary treatments for 82 days (treatment): (i) 2.5 Mcal/kg DM DE and 12% CP, (ii) 2.5 Mcal/kg DM DE and 18% CP, (iii) 2.9 Mcal/kg DM DE and 12% CP, or (iv) 2.9 Mcal/kg DM DE and 18% CP. At the end of the feeding trial, the animals were slaughtered to evaluate meat quality. Longissimus muscle pH and temperature were measured at 0, 3, 6, 9, 12, 15, 18, and 24 h postmortem (time). Sarcomere length (1.65 μm), total collagen (4.17 mg/g), and heated calpastatin (44.7 units) measured at 24 h postmortem were not influenced by treatment (P > 0.05). Warner–Bratzler shear force values, collagen solubility, and cooking losses of loin/rib chops (2.5 cm thick) aged for 1, 3, or 6 days postmortem were not influenced by treatment (P > 0.05) or aging time (P > 0.05). Postmortem sampling time affected muscle pH and temperature decline (P < 0.01), but there was no effect of treatment. There was a trend toward a treatment × time interaction (P < 0.06) in muscle pH. Temperature and pH declines followed cubic (P < 0.01) and linear (P < 0.01) trends, respectively. Average muscle temperature declined rapidly and reached 14.5 ± 2.0 °C at 3 h postmortem, while the pH was still high (6.60 ± 0.087). In conclusion, diet did not influence meat quality characteristics, and shear force values of chevon did not decrease due to postmortem aging. Rapid heat dissipation from goat carcasses during too rapid chilling may have caused cold shortening of muscles resulting in meat that did not respond to aging.     

Chemical characterization,in vitro dry matter and ruminal crude protein degradability and microbial protein synthesis of some cowpea (Vigna unguiculata L. Walp) haulm varieties

A study was carried out to evaluate the chemical composition, in vitro apparently and truly degraded dry matter (DM), utilizable crude protein at the duodenum (uCP) (total CP at the duodenum minus endogenous CP), methane production, and short chain fatty acid production of haulms of six cowpea varieties. The study was arranged in a 2 × 2 × 2 factorial design, with three replicates. Three improved (ITA2, ITA6 and ITA8) and three commercial (Oloyin, Peu and Sokoto) cowpea varieties harvested during wet and dry seasons were used for the study. After an initial gas test to evaluate 96 h gas production profiles of haulms with and without polyethylene glycol (PEG), the time to half maximal gas production was calculated and a second incubation conducted with fermentation stopped at substrate specific half time (t_1/2) and 24 h for each substrate. True DM degradability was measured from incubated residues and combined with gas volume to estimate the partitioning factor. Crude protein flow to the duodenum was estimated by combining gas volume with the measured ammonia nitrogen in the incubated fluid. Addition of PEG did not have any effect (P>0.05) on all the variables determined. Interaction between group (improved vs. commercial) and season was observed for CP (P=0.002), lignin (P=0.003) and hemicellulose (P=0.030) contents of the haulms. A group × season interaction was also observed for some of the variables at both substrate specific t_1/2 and 24 h. Commercial cowpea haulms had greater (P=0.002) microbial mass and produced less (P<0.05) methane than the improved cowpea haulms. The improved cowpea haulms were less (P<0.001) degraded in the rumen and as a result ensured greater (P<0.001) amount of uCP. The results validated that cowpea haulm is an important agro-based by-product that is adequate in protein and energy to sustain ruminant animal production in Nigeria and other Sub-Saharan African countries during the extended dry season.