Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows

Effects of fatty acids of linseed in different forms, on ruminal fermentation and digestibility were studied in dry cows fitted with ruminal and duodenal cannulas. Four diets based on maize silage, lucerne hay and concentrates (65/10/25 dry matter (DM)) were compared in a 4 × 4 Latin square design experiment where the diets were: control diet (C), diet RL supplied 75 g/kg DM rolled linseeds, diet EL supplied 75 g/kg DM extruded linseeds, and diet LO supplied 26 g/kg DM linseed oil and 49 g/kg DM linseed meal. The diets did not differ in total organic matter (OM) and fibre digestibility, in forestomach and intestinal OM digestibility, and in duodenal N flow. Microbial N duodenal flow tended to be lower for RL versus C diet (P<0.1). Extrusion did not reduce ruminal crude protein (CP) degradation in vivo and in situ. Volatile fatty acid concentration and pattern, and protozoa concentration in the rumen, did not vary among diets. Results confirm the absence of a negative effect of a moderate supply of linseed on rumen function, as well as no effect of extrusion on its ruminal CP degradability.     

Nutritive value and voluntary feed intake by goats of three browse fodder species in the Sahelian zone of West Africa

Browsing ruminants have access to different biomass, depending on how high they can reach. Foliage consisting of leaves and green pods from Acacia senegal, Pterocarpus lucens and Guiera senegalensis, was collected according to height above ground accessible to either sheep (0.90 m), goats (1.65 m) or cattle (1.50 m). There was a significant variation in the chemical composition of the biomass between species. The crude protein (CP) content was 114, 157 and 217 g/kg dry matter (DM) and the neutral detergent fiber (aNDF) content 604, 534 and 412 g/kg DM for G. senegalensis, P. lucens and A. senegal, respectively. There was no significant variation in chemical composition according to the height accessible by cattle, sheep or goats. The voluntary intake was studied using eight goats per diet. The six diets consisted of the three browse leaves and two pods (A. senegal and P. lucens) and a control. The leaves were fed combined with hay of Schoenefeldia gracilis (maximum 30%) and the control was pure hay. Apparent digestibilities of the same diets, with the exception of G. senegalensis, were measured using five goats per diet. All browse fodders used in the feeding and digestibility trials were high in CP (105–170 g/kg DM) and lignin (164–234 g/kg DM except A. senegal leaves) and low in fiber (322–590 g/kg DM of NDF) compared to the hay (31 g/kg DM of CP and 755 g/kg DM of NDF). The highest intake was of the P. lucens diet (864 g) and the lowest of the G. senegalensis diet (397 g). The intake of pods from A. senegal was higher (1033 g) than from P. lucens pods (691 g). The apparent digestibility of OM and CP in the browse leaves was 0.63 and 0.57 and 0.63 and 0.64 for A. senegal and P. lucens, respectively, higher than for the hay, which showed higher digestibility of NDF. A. senegal pods had higher digestibility for all nutrients than P. lucens pods. Based on the high CP content and the intake and digestibility characteristics, P. lucens leaves and A. senegal leaves and pods can be recommended as protein supplements to low quality diets.     

Effects of Brosimum alicastrum and Lysiloma latisiliquum mixtures on voluntary intake, nutrient digestibility and nitrogen balance in sheep fed tropical pastures

Effects of supplementing tree foliage mixtures on voluntary intake, apparent digestibility and N balance was evaluated using Pelibuey sheep fed low quality diets. Five treatments were examined in a 5 × 5 Latin square design, which consisted of a basal diet of grass (Sorghum halepense) hay supplemented with Brosimum alicastrum (B) and Lysiloma latisiliquum (L) at the following rates (g DM/kg diet): B264, L0; B198, L66; B132, L132; B66, L198 and B0, L264. Additionally, an in situ degradability evaluation was completed with two ruminally cannulated cows. Neutral detergent fibre (NDF), acid detergent insoluble N (ADIN), lignin(sa) and total phenols (TP) were higher (P<0.01) in L. latisiliquum versus B. alicastrum. Daily intake (g/kg LW^0.75/day) of DM (from 98 to 73) and OM (from 88 to 66) decreased quadratically (P<0.01), whereas CP (from 8.0 to 5.6) and ME (from 7.7 to 5.2, MJ/sheep/day) reduced linearly (P<0.01), as L. latisiliquum increased in the diet. Apparent digestibility of DM (from 0.486 to 0.445), OM (from 0.511 to 0.458) and CP (from 0.417 to 0.198) decreased linearly (P<0.01) and was associated with a low ruminal in situ CP degradability of L. latisiliquum. The decrease in N intake and digestibility induced lower (P<0.01) N retention (from 2.7 to 0.1 g/sheep/day). Although the incremental substitution of B. alicastrum with L. latisiliquum negatively affected intake, rumen degradation, digestibility and N balance, results indicate that this foliage mixture, but with no more than 132 g DM/kg diet of L. latisiliquum, could be used as a supplementation strategy to sheep fed low quality forage without negative effects on voluntary intake.     

Effects of different forms of Acacia saligna leaves inclusion on feed intake, digestibility and body weight gain in lambs fed grass hay basal diet

The study was undertaken to determine the effects of different forms of Acacia saligna leaves inclusion on feed intake, digestibility and body weight gain in lambs fed grass hay basal diet. Twenty local ‘Farta’ yearling male lambs weighing 17.4 ± 0.10 kg (mean ± SD) were randomly allocated to four dietary treatments consisting of daily feeding of lambs in T1 with 700 g grass hay (dry matter basis), and daily free choice feeding of lambs in T2, T3, and T4 with 700 g grass hay + 700 g fresh, wilted, and dried A. saligna leaves, respectively. Inclusion of different forms of A. saligna leaves improved (P<0.01) the daily intake of total DM by 8–9% and that of OM and CP by 7 and 38%, respectively compared to the control. The daily intake of NDFom was lower (P<0.01) by 1–2.3%, whereas that of the ADFom intake declined (P<0.01) by 1.3–3.4% for lambs on wilted and dried forms of A. saligna leaves. Inclusion of A. saligna leaves replaced the intake of the grass hay by 26–27% of the total diet and reduced (P<0.05) apparent digestibility coefficient of the total DM by 9, 7, and 4%, OM by 7, 6 and 4%, and CP by 12, 12, and 9%, but improved (P<0.05) apparent digestibility coefficient of NDFom by 3–4% compared to the control diet. Dried A. saligna leaves improved (P<0.05) apparent digestibility of DM, OM and CP compared to fresh A. saligna leaves. Lambs fed on hay alone lost (P<0.05) body weight, while the lambs supplemented with A. saligna leaves gained (P<0.05) weight. The results of this study revealed that A. saligna leaves could be best included in the grass hay based feeding in dried form at the rate of 265 g/kg DM for improved nutrient utilization and growth performance of yearling lambs.     

The potential of Commelina benghalensis as a forage for ruminants

To evaluate the potential of Commelina benghalensis as a forage for ruminants, effects of plant maturity on chemical composition, rumen degradability as well as its increased dietary inclusion level on intake, digestibility and N balance in sheep fed Sorghum almum were investigated with forage obtained from the wild, re-established and harvested at 6, 10 and 14 weeks of growth. Composite herbage samples were analyzed for dry matter (DM), chemical components, total extractable phenolics (TEP) and amino acid content. In sacco rumen degradability measurements used six individually confined wethers (8 ± 0.5 months of age; 21 ± 2.6 kg live-weight (LW)) fitted with rumen cannulae and fed a ration of 3:1 fresh S. almum and Medicago sativa hay (about 1:2 on a DM basis). In sacco bags containing 5 g each of dry herbage were inserted into the rumen and withdrawn sequentially after 0, 12, 24, 36 and 48 h. Metabolizable energy (ME) was estimated from 24 h in vitro gas production. In the digestibility study, 12 wethers fitted with rumen canula were housed in metabolic crates and allotted to four treatment diets (i. e., D0, D10, D20 and D30) constituted from fresh S. almum and pre-wilted C. benghalensis in a randomized complete block design. The control diet (D0) was 3 kg fresh S. almum (≈535.5 g DM/wether/d about 30 g/kg LW), whereas D10, D20 and D30 were D0 +300, 600 or 900 g of wilted C. benghalensis (≈34, 68 or about 102 g DM/wether/d), respectively. The study lasted for 21 d. Dry matter, fibre and TEP content increased (P<0.001) with maturity of the forage, whereas those of CP and EE decreased (P<0.0001) over the same period. Amino acids (AA) also declined with maturity (P<0.05). Rumen degradability of DM and OM were unaffected, but DM intake increased linearly (P<0.0001) at a decreasing rate (Q: P<0.05) and DM digestibility (DMD) and N intake increased linearly (P<0.01 and P<0.0001, respectively) as level of C. benghalensis in the diet increased. Results indicate that advancing maturity affected chemical composition, but not rumen degradability, of C. benghalensis and also demonstrated that inclusion of C. benghalensis in S. almum diet improved intake, digestibility and N intake, suggesting its potential use as a feed supplement.     

Assessment of a brown midrib (BMR) mutant gene on the nutritive value of sudangrass using in vitro and in vivo techniques

The brown midrib (BMR) gene has been reported to reduce the lignin concentration in plants, which contributed to increased fiber digestion in ruminants. Three studies were completed to compare the digestibility of a BMR mutant of sudangrass (sorghum bicolor subsp. Drummondii) versus a non-BMR (‘Piper’) variety when included in diets fed to sheep (Study 1), to complete a rumen in vitro assessment of sheep and lactating cow diets (Study 2), and to compare digestibility when included in the diet fed to lactating dairy cows (Study 3). Four wether sheep were used in a 2 × 2 Latin square experiment (Study 1) with total fecal collection to determine total tract apparent digestibility of pelleted Piper (P) and BMR (P-BMR) sudangrass hays. Forage pellets consisted of either P-BMR or P hay with added urea to meet the maintenance crude protein (CP) requirement of the sheep. Digestibility of organic matter (OM; P<0.01), dry matter (DM; P<0.01), acid detergent fiber (ADF; P<0.05), and neutral detergent fiber (aNDFom; P<0.07) was higher for P-BMR than P sudangrass. In vitro rumen digestibility of aNDFom using cattle rumen fluid was higher at 24 (P<0.01), 48 (P<0.01) and 72 h (P<0.01) of fermentation for P-BMR versus P (Study 2). Four lactating Holstein dairy cows (251 ± 30 days in milk) and fitted with ruminal and duodenal cannulae were used in a 4 × 4 Latin square experiment. Total mixed rations (TMR) contained 180 g/kg DM shredded sudangrass hay and 180 g/kg sliced alfalfa hay, but the proportion of P to P-BMR sudangrass varied as 100:0, 66:34, 34:66, or 0:100. Yields of milk and milk protein were highest at the 66:34 level (Quadratic: P=0.06 and 0.07, respectively), but composition of milk fat, protein and lactose, as well as DM intake, did not differ (Study 3), probably because forestomach and total tract apparent digestion of aNDFom and OM did not differ due to sudangrass source.     

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 soybean hulls inclusion on intake, total tract nutrient utilization and ruminal fermentation of goats fed spineless cactus (Opuntia ficus-indica Mill) based diets

A study was conducted to evaluate soybean hulls (SH) as a replacement of tifton bermudagrass hay (TH) in diets of goats containing high levels of spineless cactus. Ten mature bucks (five ruminally fistulated) were used in a 5 × 5 Latin square experiment with 21-day periods. Soybean hulls replaced 0, 250, 500, 750 and 1000 g/kg of TH in the experimental diets. All diets contained 600 g/kg spineless cactus (dry matter basis). Intakes of dry matter (DM), organic matter (OM) and non-fiber carbohydrates and chewing activities decreased linearly (P < 0.01) as the level SH in the diet increased. In vivo digestibility of DM, OM and neutral detergent fiber increased linearly (P < 0.01) as the level of SH in the diet increased. Addition of SH linearly increased (P < 0.05) N retention without affecting microbial N supply (g/kg of digestible OM intake) to the small intestine. Ruminal pH and NH₃-N decreased linearly (P < 0.05) while total volatile fatty acid (VFA) concentration increased linearly (P < 0.05) as proportion of SH in diets increased. It was concluded that inclusion of SH in cactus-based diets had a negative impact on intake and chewing activities but improved total tract nutrient utilization by goats. Replacing TH with SH resulted in a concentrate type ruminal fermentation (i.e., low ruminal pH and high VFA concentration).     

Effects of corn distillers dried grains with solubles and xylanase on growth performance and digestibility of diet components in broilers

The objective of this study was to investigate the effect of corn distillers dried grains with solubles (cDDGS) and xylanase in corn-based diets on growth performance and digestibility of diet components in broiler chickens. The experiment was a 3×4 factorial design with diets containing 3 levels of cDDGS (0, 100 and 200 g/kg) and 4 levels of xylanase (0, 1200, 2400 and 3600 U/kg). The diets were fed to 720 Cobb 500 chicks for 42 days. Excreta was collected at 18–21 days to measure coefficients of total tract apparent digestibility (CTTAD) and ileal digesta was collected at 42 days to measure coefficients of ileal apparent digestibility (CIAD). Dietary cDDGS caused poor (P<0.05) feed conversion ratio (FCR) of broilers from 1 to 21 and 22 to 42 days, but increased (P<0.05) feed intake (FI) at 1–21 days. Inclusion of xylanase increased (P<0.05) FI by 4–5% at 1–21 days, and did not affect (P≥0.05) FCR in either period. In the two growing periods, cDDGS decreased (P<0.05) the CTTAD of dry matter (DM), and the CIAD of DM and hemicelluloses, whereas xylanase increased (P<0.05) the digestibility of DM and hemicellulose by 5% and 20%, respectively. There were significant interactions (P<0.05) between cDDGS and xylanase for BWG and energy digestibility. In comparison with the 100 g/kg cDDGS diet, the inclusion of 200 g/kg cDDGS led to poorer (P<0.05) FCR at 22–42 days, and lower (P<0.05) CTTAD of DM at 18–21 days. There were no differences (P≥0.05) in most growth parameters between the doses of xylanase at 1200, 2400 and 3600 U/kg. Xylanase at 2400 U/kg increased (P<0.05) CTTAD of DM compared with the lower dose, but 3600 U/kg xylanase showed no further improvement (P≥0.05) on digestibility measurements. The results suggest that supplementing xylanase to diets containing cDDGS can improve growth performance and digestibility of diet components in broilers.     

Impact of wheat grinding and pelleting in a wheat–rapeseed meal diet on amino acid ileal digestibility and endogenous losses in pigs

The purpose of the current experiment was to investigate the impacts of grinding and pelleting procedures applied to wheat in a wheat–rapeseed meal diet on the coefficients of standardized ileal digestibility, i.e., apparent digestibility corrected for basal endogenous losses (CSID), and true ileal digestibility, i.e., apparent digestibility corrected for total endogenous losses (CTID), of nitrogen (N) and amino acids (AA) in pigs. Ileal digestibility was measured by collecting digesta from pigs fitted with ileorectal anastomoses. Four diets, involving four technological treatments applied to wheat, were compared in vivo according to a 4 × 4 Latin square design (four pigs each fed four diets during four successive periods of 1 week). The technological treatments of wheat were two grinding procedures and two pelleting processes. Wheat was ground to obtain mean flour particle sizes of 1000 and 500 μm, leading after mixing with rapeseed meal and minerals-vitamins premix to the first and second diets named “coarse” and “fine”, respectively. Part of the 500 μm wheat flour was pelleted through dies of same screen diameter (4 mm) but different thicknesses, 16 and 20 mm, inducing a low and high compression ratio, leading after mixing with rapeseed meal and premix to the third and fourth diets named “LCR” and “HCR”, respectively. Basal endogenous losses were determined by feeding a protein-free diet during the 5th week of the experiment. Total endogenous losses were measured by way of the isotopic dilution method using ¹⁵N-labeled wheat and rapeseed meal. Decreasing wheat particle size from 1000 to 500 μm improved (P<0.05) the coefficient of ileal digestibility of dietary energy (0.707 versus 0.665), organic matter (0.718 versus 0.677) and dry matter (0.681 versus 0.645), but neither AA CSID nor N retention. The pelleting processes did not further increase (P>0.10) energy or organic matter digestibility but improved (P<0.05) N and AA CSID (0.785 versus 0.759 for N and 0.725 versus 0.679 for lysine, with HCR versus fine diet, respectively). Pelleting wheat flour at higher compression ratio (HCR versus LCR diet) was more efficient to improve dietary N and AA digestibility values due to a significant decrease in ileal specific, i.e., total minus basal, N and AA endogenous losses (P<0.05) associated with an increase in CTID. It is concluded that pelleting wheat fine flour at high compression ratio allows maximizing AA digestibility and availability of a wheat–rapeseed meal diet.     

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.     

The chemical composition of Phyllanthus discoideus and its effect on the ruminal ammonia and volatile fatty acid concentration when fed to west african dwarf sheep

The feeding value of Phyllanthus discoideus (also called Margaritaria discoidea) leaves was evaluated using eight two‐year‐old West African Dwarf sheep fed natural grass hay. Four of the animals were fistulated ruminally and used for ammonia and volatile fatty acid determination in the fluid. Dried leaves of Phyllanthus discoideus were offered at two levels (25% and 50% of DMI, diets D25% and D50%, respectively) as supplements to the basal hay diet. The CP content of the control, D25% and D50% diets were 11.5, 12.6 and 13.6%, respectively, and their digestible energy amounted to 58.2, 61.1 and 56.9%, respectively. Rumen liquor was sampled one hour before and one, three and five hours after the morning feeding.

Sheep fed the control diet had a higher ruminai ammonia concentration than those fed diet D25%. Similarly, ruminai ammonia concentration was higher in sheep fed the control diet than those fed the diet D50%. Five hours after feeding the ruminai ammonia concentration was significantly lower than one hour after feeding.

The VFA concentrations in rumen fluid of sheep fed the control diet was inferior to those fed diets D25% and D50%. Sheep fed diet D50% showed significantly higher VFA concentrations than those fed diet D25%. Digestibility of organic matter and digestible energy did not show any significant difference. However, a marginal increase in organic matter digestibility of 3.5% was observed in diet D25% compared with the control diet. There was no significant difference in the N‐digestibility in sheep fed the control, D25% and D50% diets. Nevertheless, a marginal improvement in N‐digestibility (1.5%) and N‐retention (2.7%) was observed with the highest level of Phyllanthus discoideus (D50%).

In conclusion, Phyllanthus discoideus appears as a particularly valuable feedstuff because it contains low levels of condensed tannins (12.8 g/kg), high CP content (156 g/kg) and a relatively high GE content (19.3 kJ/gDM). Although the improvement in N‐digestibility and N‐retention were only marginal the feeding of Phyllanthus discoideus could be justified under extreme shortage of feed resources during dry season. It should also be mentioned that a much more pronounced effect by supplementation with Phyllanthus discoideus could be expected when poor quality grass hay prevalent in West Africa during the dry season is fed. Phyllanthus discoideus could serve as a supplement to poor quality grass at 25% to 50% of supplementation.     

Effect of feeding different levels of wilted cassava foliage (Manihot esculenta,Crantz) on the performance of growing goats

The effects of feeding different levels of wilted cassava foliage (Manihot esculenta, Crantz) on growth and diet digestibility were studied using local male growing goats with an average body weight of 14.5 kg. Thirty-two animals were randomly allocated to four groups of eight animals in a growth experiment, and four animals were assigned to a 4 × 4 Latin Square design to study digestibility. The four diets in both the growth and the digestibility studies were Gamba grass (Andropogon gayanus) as a sole diet offered ad libitum (control) or supplemented with wilted cassava foliage (WCF) at 20%, 30% and 40% of an expected daily DM intake of 3% of BW. Dry matter (DM) intake was significantly lower in the control group and increased with the level of WCF in the diet, while the DM intake of Gamba grass was not significantly changed. Total DM intake and DM intakes from Gamba grass were 472, 546, 584 and 616 g/d and 472, 457, 457 and 470 g/d for the control and treatments with 20%, 30% and 40% of WCF in the diet, respectively. The inclusion of WCF in the diet increased the apparent digestibility of DM, organic matter, N, Neutral detergent Fibre and Acid Detergent Fibre, and resulted in a higher N-retention. The average daily gains of animals fed diets with WCF were significantly higher than in the control group. The highest gain was recorded in goats with 40% of WCF in the diet (55.0 g/d) and lowest for the control (28.9 g/d). In conclusion, supplementing a basal diet of Gamba grass (Andropogon gayanus) with WCF improved DM intake, digestibility, N-retention and weight gain. The inclusion level of WCF in the diet can be up to 30%–40% of diet DM (21%–24% of total DM intake).     

Effects of inclusion of neutral detergent soluble fibre sources in diets varying in forage particle size on feed intake, digestive processes, and performance of mid-lactation Holstein cows

The aim of this study was to evaluate effects of partial replacement of neutral detergent soluble fibre (NDSF) for starch in diets varying in particle size (PS) of alfalfa hay on chewing activities, ruminal fermentation, nutrient digestibility and performance in mid-lactation dairy cows. Eight multiparous Holstein cows (146 ± 6.0 d in milk; 36.7 ± 2.57 kg milk/d) were used in a replicated 4 × 4 Latin square design with four 21 d periods with the last 7 d for data collection. The experiment was a 2 × 2 factorial arrangement with 2 levels of NDSF (low = 85 g/kg or high = 130 g/kg diet dry matter) each combined with 2 PS (short = 20 mm or long = 40 mm) of alfalfa hay. Results show that forage PS alone, or in combination with NDSF inclusion, had no effect on dry matter (DM) intake. Although total chewing, eating and ruminating times were not affected by treatments, eating time per kg of neutral detergent fibre (NDF) ingested was higher in long versus short alfalfa hay-based diets (P<0.05). Feeding long forage PS increased sorting of the diet against particles >19 mm, and in favor of those <8 mm (P<0.05). Feeding diets high in NDSF lowered DM intake (P<0.05), but increased apparent digestibility of all nutrients including NDF (P<0.05) independent of forage PS. Ruminal pH and concentrations of total volatile fatty acids were unaffected by dietary treatments, however the proportion of butyrate was higher in ruminal fluid of cows fed high NDSF diets (P<0.05). Changes in milk composition included lower milk crude protein content in high NDSF diets and higher lactose content for short hay-based diets (P<0.05). That milk yield and milk energy output were similar in low versus high NDSF diets suggests that high NDSF-fed cows had higher energy efficiency due to lower DM intake. Results suggest that, independent of forage PS, NDSF sources can be successfully included to partly replace starchy grains in diets exceeding minimum fibre recommendations.     

Effects of exogenous enzymes on apparent nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fed diets with high inclusion of plant-based protein

Plant-based protein ingredients are increasingly used in feed for carnivorous fish as replacement for fish meal. This study investigated if supplementing diets with high inclusion levels of plant-based protein with three different enzymes could improve the apparent nutrient digestibility in juvenile rainbow trout (Oncorhynchus mykiss). Three diets with high inclusion levels of either de-hulled, solvent extracted soybean meal (344 g/kg), sunflower meal (246 g/kg), or rapeseed meal (264 g/kg) were produced and feed batches were coated post-extrusion with the different enzymes: β-glucanase at 67 mg/kg, xylanase at 208 mg/kg, protease at 228 mg/kg, or a combination of the three enzymes at the same doses. Three consecutive digestibility trials were carried out using a flow-through, modified Guelph System. Each trial was designed to include five dietary treatment groups: a non-supplemented control diet and 4 diets supplemented with either β-glucanase, xylanase, protease or a combination of the three enzymes. Diets were fed to triplicate tanks and two faecal sampling periods for digestibility measurements for each tank were scheduled. Each experiment comprised a 10-day digestibility trial succeeded by a water sampling period for measuring the dissolved nitrogen (N) output. Each experiment lasted 17–19 days in total.Apparent digestibility coefficients (ADCs) of protein, fat, ash, phosphorus and dry matter (DM) were derived from the three digestibility trials, along with calculations of the specific growth rate (SGR, %/d) and feed conversion ratio (FCR). Nitrogen mass-balance and energy retention were evaluated for each dietary treatment group to elucidate on the utilization of digested nutrients and energy.Enzyme supplementation had only moderate effect on apparent nutrient digestibility in the sunflower and rapeseed experiments, while β-glucanase and protease improved the apparent digestibility of all dietary nutrients in the soybean experiment (P<0.05). The effect was more pronounced for lipid than for other nutrients. β-Glucanase had a positive effect on energy retention in the soybean experiment (P<0.05), while there were no effects on nitrogen retention or fish performance in any of the three experiments (P>0.05) during the short feeding periods. The study thus provides preliminary results on the potential of β-glucanase and protease to increase apparent nutrient digestibility of soybean meal in fish feed.     

Digestibility,nitrogen balance,and blood metabolites in llama (Lama glama) and alpaca (lama pacos) fed barley or barley alfalfa diets

To determine the effect of barley diets on digestibility, nitrogen balance, and blood metabolites, mature gelded llamas and alpacas (n = 8; 4 llamas, 36 ± 4 months, 90 ± 10.7 kg; 4 alpacas, 24–36 months, 50 ± 4 kg) were randomly fed 100% barley (B) and 20% alfalfa/80% barley (BA) hay. Animals were housed in metabolism crates and diets were fed for a 7 days adjustment period followed by a 5 days collection period. Feed, feed refusal, feces and urine were collected, dried and N content determined by combustion analysis. Blood samples were collected on day 12 at 30 min intervals over a 6 h period. Plasma was harvested and analyzed for electrolytes (Na, K, Cl, Ca, Ca²⁺, P, Mg), metabolites glucose, non-esterified fatty acids (NEFAs), urea N, creatinine, albumin, total protein (TPP), osmolality (Osm). Plasma glucose, urea N, albumin, osmolality, electrolyte and metabolite levels were similar between species, and were unaffected by diet. On a metabolic weight basis, only diet was significant for N intake, urinary and fecal N, and total N excreted. Dry matter intake was not significantly different; however, BA consumption was greater than B, (B) 1272 g N/day and (BA) 1636 g N/day for llamas, and for alpacas (B) 835 g N/day and (BA) 1034 g N/day, respectively. Nitrogen intake followed the same pattern, (B) 21.4 g N/day and (BA) 33.9 g N/day, respectively for llamas, and (B) 13.6 g N/day and (BA) 20.6 g N/day, respectively for alpacas (diet, P < 0.002). Diet affects were significant for urine N excretion (P < 0.02), (B) 11.2 g/day and (BA) 18.2 g/day for llamas, and (B) 6.8 and (BA) 10.8 g N/day for alpacas. Fecal N excretion was different for diet (P < 0.03), with fecal excreted N of 9.0 g N/day and 11.9 g N/day for B and BA in llamas, and 5.9 g N/day and 9.1 g N/day for B and BA respectively in for alpacas, respectively. Nitrogen retention, DM digestibility and N digestibility were unaffected by diet or species. However, the llamas in this study displayed an increase in nitrogen intake of 64.6% between the B and BA diets with a 381% increase in N retention. Alpacas increased their N intake by 57.4% when they consumed the BA forage, which only increased N retention by 22.2%. These species differences indicate that alpacas have a lower N requirement to meet metabolic needs than llamas, which are likely related to the smaller body size of the alpaca. When examining the biological value of N from the respective diets, alpacas and llamas had a value of 56.2% when consuming barley. The BA diet had a higher biological value of 65.0% in llamas compared to 57.4% in alpacas. Therefore, on the basis of this study, extrapolations between llamas and alpacas with respect to nitrogen requirement and balance are not valid.     

Performance of rabbits on Guinea grass and Verano stylo hays in the dry season and effect of concentrate supplementation

The feasibility of using Verano stylo (Stylosanthes hamata cv. Verano) and Guinea grass (Panicum maximum cv. Ntchisi) hays and their replacement values in concentrate diets for rabbits were determined. The intake and growth of the rabbits were monitored over a 7-week growth study following a 2-week adaptation period, while nutrient digestibility was determined over a 5-day period during the eighth week of the study. The DM intakes of the rabbits during the growth study were 53.1 g/day of the grass + concentrate (50 : 50) diet, 56.0 g/day of the all-concentrate diet and 64.8 g/day for the Verano stylo + concentrate (50 : 50) diet. The respective weight gains were 5.13, 8.44 and 8.35 g/day. Lower DM intake and consistent losses in weight of the animals were recorded on Verano stylo or Guinea grass alone. Verano stylo hay was better than Guinea grass hay. Thus, concentrate supplementation of forage diets is necessary for rabbits. Replacement of 0.50 of the concentrate with Verano stylo hay gave a similar performance to that for the all-concentrate diet. It is, therefore, possible to reduce the use of concentrates in the diets for growing rabbits in the dry season by replacing part of the diet with Verano stylo hay.     

Effects of supplemental urea sources and feeding frequency on ruminal fermentation,fiber digestion,and nitrogen balance in beef steers

The objective of two experiments was to evaluate non-protein N supplementation with protected urea sources in terms of rumen fermentation products, nutrient digestibility, and N balance in ruminally fistulated beef steers (initial bodyweight 239 ± 18 kg) fed switchgrass hay. Experiment 1 compared urea with Optigen II^®, and Experiment 2 compared urea with RumaPro^®. In both experiments, supplements (400 g/kg of daily dietary dry matter) were fed once daily or every 2 h in a balanced design. Supplements contained soybean hulls, corn grain, vitamins, and minerals as well as non-protein N sources. Non-protein N provided 0.18 g/g of dietary N. Switchgrass hay was fed once daily, at the same time as the supplement in the once-daily treatments. Dry matter intake (4.1 kg/d in Experiment 1, 4.5 kg/d in Experiment 2), dry matter digestibility (P<0.25, 0.58 ± 0.014 g/g in Experiment 1, 0.58 ± 0.010 g/g in Experiment 2), N balance (P<0.83, 11.3 ± 1.9 g/d in Experiment 1, 11.8 ± 3.6 g/d in Experiment 2), ruminal ammonia concentrations (P<0.29, 15.2 ± 1.4 mM in Experiment 1, 11.8 ± 0.6 mM in Experiment 2), and ruminal short-chain fatty acid concentrations (P<0.13, 77.7 ± 3.0 mM in Experiment 1, 75.4 ± 3.0 mM in Experiment 2) were not affected by feeding protected urea sources. Providing a steady supply of ruminally degradable N by feeding supplement every 2 h vs once daily decreased ruminal ammonia concentrations by approximately one-half by 4 h after feeding hay (P<0.01 in both experiments) and increased (P<0.02 in Experiment 1, P<0.08) in Experiment 2) apparent digestibility of dry matter (0.58–0.62 in Experiment 1, 0.56–0.61 in Experiment 2) and dietary fiber components.     

Common vetch varietal differences in hay nutritive value,ruminal fermentation,nutrient digestibility and performance of fattening lambs

In some lower rainfall regions of the world (300–750 mm), common vetch (Vicia sativa L., hereafter referred to as vetch) has been shown to have yields competitive with alternate crops and provide high-quality hay for ruminant diets, but there are few studies of vetch performance as a livestock feed, or of vetch varietal differences in livestock feeding value. This study evaluated vetch varietal differences in hay nutritive value, ruminal fermentation properties, nutrient digestibility, nitrogen retention and animal performance in fattening lambs consuming a diet comprising 20% vetch. Fifty male Hu lambs with an initial BW of 17.7 ± 0.27 kg and 2–3 months of age were assigned randomly into five groups of 10 lambs, and each allocated one of five dietary treatments for 67 days (10 days of adaptation and a 57 day experimental period). All diets contained 30% maize stover, 50% concentrate, and with a different forage source (on an as-fed basis): 20% alfalfa hay (Control), 20% vetch 333A (C333A) hay, 20% vetch Lanjian No. 1 (CLJ1) hay, 20% vetch Lanjian No. 2 (CLJ2) hay, or 20% vetch Lanjian No. 3 (CLJ3) hay. Hay CLJ3 had greater contents of ash, CP, ether extract, in vitro organic matter digestibility and metabolizable energy, and lower cell wall contents (P < 0.05) than those of C333A and CLJ1 hays, but similar to the CLJ2 hay (P > 0.05). Compared to the Control diet, the CLJ2 and CLJ3 diets resulted in greater (P < 0.05) final BW, average daily gain, total tract apparent digestibility of CP and NDF, and nitrogen balance, both when expressed as g/day and relative to nitrogen intake, while animal performance when fed diets with C333A or CLJ1 diet did not differ (P > 0.05) from the Control diet. No differences (P > 0.05) were observed between dietary treatments with respect to average daily feed intake, ruminal pH, total volatile fatty acid contents and molar proportions of acetate, butyrate, valerate, isobutyrate, and isovalerate, or total tract apparent digestibility of DM, organic matter, and ADF. The feed efficiency of tested feeds ranked CLJ3 = CLJ2 > CLJ1 > Control with C333A intermediate between CLJ1 and Control. In summary, considering hay quality, nutrient digestibility and animal weight gain, performance as a ruminant feed of hays from recently released vetch cultivars Lanjian No. 2 and Lanjian No. 3 was superior to the older cultivar C333A and the alfalfa control.     

Digestibility and utilisation of diets composed of wet distillers' solids or soyabean meal and supplemented with liquid lysine product for growing pigs

A digestibility and balance trial was carried out to study the nutrient digestibility and utilisation of protein and energy in wet distillers' solids derived from barley or soyabean meal. Eight growing pigs (30–72 kg liveweight) were used in an 8 × 6 cyclic change-over experimental design, in which eight experimental diets were arranged 2 × 2 × 2 factorially. The corresponding factors were the protein source (wet distillers' solids (DS) or soyabean meal (SBM)), protein supply (130 or 162 g crude protein (CP) kg⁻¹ dry matter (DM)) and liquid lysine product supplementation.DS and SBM contained 565 g and 485 g CP kg⁻¹ DM, respectively, and the respective lysine contents in CP were 39 g and 64 g per 160 g N. The liquid lysine product contained 527 g CP kg⁻¹ DM and lysine in CP 193 g per 160 g N.No differences were found in the total tract digestibility of the nutrients or energy among diets composed of DS or SBM without lysine supplementation. Those diets with liquid lysine product supplementation, however, had opposite effects on the digestibility of the diets composed of the different protein sources. Lysine supplementation improved the digestibility of ash (P < 0.001), ether extract (P < 0.05) and crude carbohydrates (CCH) (P < 0.05) in diets composed of DS and adversely impaired the digestibility of organic matter and CCH (P < 0.05) in diets composed of SBM. The calculated digestibility of CP and gross energy were respectively 91.2% and 88.3% in SBM and 90.2% and 85.0% in DS. The digestible and calculated net energy contents were respectively 18.16 MJ kg⁻¹ DM and 10.73 MJ kg⁻¹ DM for SBM and 19.31 MJ kg⁻¹ DM and 10.40 MJ kg⁻¹ DM for DS.The pigs on the diets composed of DS had higher total (P < 0.001) and urea (P < 0.01) nitrogen (N) excretion in urine and lower daily retention of N (P < 0.001) than the pigs on the diets composed of SBM. The liquid lysine product supplementation of the diets decreased the total and urea N excretion in urine (P < 0.001) and improved the daily N retention (P < 0.001). With lysine supplementation, the protein utilisation of the diets composed of DS was improved to the level of the diets composed of SBM. No differences were observed in the utilisation of energy among the diets composed of different protein sources.It is concluded that DS is highly digestible, but its protein is efficiently utilised only with lysine supplementation.