Effects of feeding high- and low-fibre fractions of air-classified,solvent-extracted canola meal on diet nutrient digestibility and growth performance of weaned pigs

The dietary energy value of solvent-extracted canola meal (CM) is limited by its relative high fibre content. The fibre-rich hull of canola is denser than the oil-free cotyledons, so these seed components partially fractionate in a stream of air. Air classification thus separates CM into a low-fibre, light-particle fraction and a high-fibre, heavy-particle fraction of interest for feeding monogastric and ruminant species, respectively. Crude fibre (CF), acid detergent fibre (ADF) and neutral detergent fibre (NDF) in light-particle fraction were reduced by 96, 34 and 28% compared with CM (83 CF, 165 ADF, 238 NDF g/kg, as-is). Brassica (B) napus, Brassica juncea, or their fractions were evaluated feeding 288 weaned pigs (7.1 kg) for 37 d as a 2 × 3 factorial with 12 replicate pens per treatment. Wheat-based diets including 200 g of test feedstuff/kg provided 10.5 and 10.0 MJ net energy (NE)/kg and 1.27 and 1.15 g standardised ileal digestible lysine/MJ NE and were fed for 9 and 28 d, respectively. Pen feed added, orts, and individual pig body weight were measured weekly to calculate average daily feed intake (ADFI), average daily gain (ADG), and feed efficiency (G:F). Pen faecal samples were collected on d 16 and 17 to calculate diet apparent total tract digestibility coefficients (CATTD) of dry matter (DM), gross energy (GE), crude protein (CP) and digestible energy (DE) value. Pigs fed B. juncea had 3 and 2% higher (P<0.001) CATTD of DM (0.82 vs. 0.79) and GE (0.84 vs. 0.82) than pigs fed B. napus. Feeding the light-particle fraction increased (P<0.001) CATTD of DM (0.82 vs. 0.79), GE (0.84 vs. 0.82), and CP (0.79 vs. 0.77) by 4, 3 and 3% compared with CM, respectively. For the entire trial, pigs fed B. juncea consumed 33 g/d less (P<0.001) feed (723 vs. 756 g/d), had 0.02 higher (P<0.05) G:F (0.735 vs. 0.718 g:g), but ADG (503 vs. 514 g/d) was not different (P>0.05) compared to pigs fed B. napus. Feeding pigs the light-particle fractions did not affect (P>0.05) ADFI (741 vs. 736 g/d), increased (P<0.05) G:F 0.02 (0.739 vs. 0.721 g:g) and tended to increase (P=0.07) ADG (519 vs. 501 g/d) by 18 g/d compared to CM. In conclusion, air classification of canola meal increased diet nutrient digestibility, but only modestly increased G:F of weaned pigs due to dietary fibre reduction.     

Effect of individual and mixed live yeast culture feeding on growth performance,nutrient utilization and microbial crude protein synthesis in lambs

This study investigated effects of feeding three individual, and a mixed, yeast culture (Kluyveromyces marximanus NRRL3234, Saccharomyces cerevisiae NCDC42, Saccharomyces uvarum ATCC9080 all in a 1:1:1, ratio) on growth performance, nutrient utilization and microbial crude protein (CP) synthesis in feedlot lambs during the post-weaning phase of growth. Sixty weaner lambs (90 ± 3.5 d old and 15.9 ± 0.50 kg BW) were fed for 91 d in five equal groups. The control group of lambs received sterilized culture medium while the treatment groups were fed a yeast culture in addition to a ad libitum total mixed ration (TMR). The yeast culture, dosed at 1 ml/kg body weight (BW) had 1.5–2.0 × 10⁹ live cells/ml. Yeast culture supplementation did not influence intake and digestibility of organic matter (OM), CP, neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose and the metabolizable energy (ME) level of the diets were similar between control and yeast supplemented lambs. Lambs in all groups were in positive N balance, but N intake and N voided in feces and urine, as well as N balance, did not change due to yeast culture supplementation. Urinary allantoin excretion was similar, but purine derivatives absorbed (mM/d) were higher (P<0.05) in yeast culture supplemented lambs. Yeast culture supplementation improved (P<0.05) microbial CP synthesis. Supplementation of SC and mixed yeast improved (P=0.002) BW gain of lambs by 21% and 16% respectively. All yeast culture supplemented lambs had higher feed efficiency in comparison to control lambs. Among the three yeast cultures used, S. cerevisiae had the most potential as a growth promoting feed additive in feedlot lamb production, and it may serve as an alternate to antibiotics and ionophores as a growth promoter of weaner lambs.     

Effect of substitution of groundnut with high glucosinolate mustard (Brassica juncea) meal on nutrient utilization,growth, vital organ weight and blood composition of lambs

Twenty-four 14-day-old weaner Avivastra (Russian Merino×Nali) male lambs were maintained for 180 days on ad libidum Cenchrus (Cenchrus ciliaris) hay and concentrate mixture (CM) contained groundnut meal (control) and mustard meal (MM group) as major protein source. The two CMs were isonitrogenous (21% CP) and isocaloric (2.78 Mcal ME kg⁻¹ DM), while, CM fed to MM group contained 24.6 mg glucosinolates g⁻¹ DM. Digestibility of nutrients was similar (P>0.05) in the two groups except for CP and hemicellulose, which was higher (P<0.05) in control. Urinary N loss was higher (P<0.01) in control than in MM group, whereas N retention (% of N intake and absorbed) was higher (P<0.01) in MM group compared to control. Dry matter (g kg⁻¹ BW) and glucosinolate intakes were higher in MM fed group, whereas DCP and ME intakes were similar (P>0.05) in the two groups. Average daily gain (ADG) was, however, 22% higher (P<0.01) in control than in MM group. Hemoglobin and albumin contents were lower (P<0.01) in MM group than in control. Serum thiocyanate content was 26.7 μg g⁻¹ in MM fed group, while it was not detected in control group. Thyroid weight was higher (P<0.01) while liver and kidney weights were lower (P<0.01) in MM group. Meat from dissected carcass of control group contained more protein and less fat, whereas the reverse was noticed in MM group. It is concluded that feeding mustard meal as protein supplement reduced growth rate and induced iodine deficiency. Carcass of lambs fed mustard meal had more fat and less protein.     

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.     

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.     

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 partial replacement of concentrates with jackfruit (Artocarpus heterophyllus) leaves on growth performance of kids grazing on native pasture of Tripura,India

Fifteen Black Bengal kids of about 3 months of age and body weight ranging from 3.8 to 4.9 kg were randomly distributed into three groups of five. Kids grazed native pasture 8 h/d. The kids in group I received supplementary concentrate (maize 35%, mustard cake 32%, rice bran 30%, mineral mixture 2% and common salt 1%) at approximately 2% of BW. However, 25 and 50% of the concentrate was replaced with jackfruit leaves for groups II and III, respectively. Total dry matter intake (DMI) was significantly higher in groups II and III than for group I due to greater forage consumption. Digestibility of CP (P < 0.05) decreased and that of NDF increased (P < 0.01) with increasing level of jackfruit leaves in the diet. Digestibility of ADF (P < 0.01), hemi cellulose (P < 0.05) and cellulose (P < 0.01) was higher in groups II and III in comparison to group I. Ruminal pH and TVFA concentration were not significantly different among the groups; however, rumen ammonia-N concentration decreased (P < 0.01) with increased level of jackfruit leaves in the diet. Similarly, plasma urea nitrogen and blood glucose levels were also reduced (P < 0.05) with increasing level of jackfruit leaves in the diet Average daily gain (ADG) was 47.33, 45.11 and 35.56 g/d in groups I, II and III, respectively. ADG and DMI/kg gain were not adversely affected when the level of replacement was restricted to 25%; however, at the 50% of replacement both parameters were adversely affected (P < 0.05). From the results of this experiment, it was concluded that jackfruit leaves might replace 25% of the supplemental concentrate for growing kids grazing in native pasture of northeast India.     

Utilization of poultry litter pellets in meat goat diets

Forty-eight crossbred meat goats were used to determine if poultry litter pellets could be used as a protein source in the diets of growing meat goats. Goats were fed one of three 19–21% CP diets containing 0 (CON; n = 18), 20% (20PL; n = 12) or 40% poultry litter pellets (40PL; n = 18). In Experiment 1, 38 animals (n = 13 CON; n = 12 20PL; n = 13 40PL) were used. Goats were allowed a 23-day adjustment period and body weight (BW) and feed intake were measured every 7 days for 42 days. In Experiment 2, 10 males fed CON or 40PL (n = 5 per diet) were used in two metabolism trials at 93.7 ± 0.9 (Trial 1) and 121.7 ± 0.9 d of age (Trial 2). Goats were placed in metabolism crates and after a 3-day adjustment period, feed intake and fecal and urine output were measured and sampled daily for 7 days to determine diet digestibility. In Experiment 1, ADG (79 ± 8 g) and feed efficiency (130 ± 12 g per kg) were not influenced by diet. In Experiment 2, for both trials, organic matter and CP digestibility were similar between diets (80 ± 1 and 70 ± 3% for Trial 1, respectively and 63 ± 2 and 75 ± 7% for Trial 2, respectively). Dry matter digestibility was greater (P < 0.05) for CON (81 ± 1 and 82 ± 1% for Trials 1 and 2, respectively) when compared to 40PL (77 ± 1 and 75 ± 1% for Trials 1 and 2, respectively). The ADF (41 ± 4% for CON and 67 ± 4% for 40PL) and NDF (48 ± 4% for CON and 71 ± 4% for 40PL) were greater (P < 0.01) for 40PL compared to CON diet in Trial 1 only. Digestibility (GE) was higher (P < 0.05) for 40PL (83 ± 0.3%) compared to CON (82 ± 0.3%) in Trial 2 only. The poultry litter pellets may be used effectively as a short-term feedstuff for meat goats.     

Comparative studies on dry matter intake,digestibility and nitrogen metabolism between Thai native (TN) and Anglo Nubian × TN bucks

Metabolic experiments were conducted for each Thai native (TN) and Anglo Nubian–TN 50% (AN × TN) bucks, 26.5–38 kg BW and 35–52 months of age, by assigning the following concentrate diets, which had four levels of CP concentrations, T1: 14%, T2: 21%, T3: 28% and T4: 35%, on a DM basis. The animals were fed the concentrates at a rate of 1% of their BW and had ad libitum access to Paspalum plicatulum hay. As the CP level increased, digestibility of CP, N excretion in urine and N retention increased (P < 0.01). No significant differences of DM digestibility among the CP levels of diet and between the breeds of bucks were observed. The AN × TN had higher DM intake than TN (P < 0.05, 40.9 g/(kg BW^0.75 day) versus 36.0 g/(kg BW^0.75 day)), thus N intake of AN × TN was higher than that of TN (P < 0.01, 0.99 g/(kg BW^0.75 day) versus 0.90 g/(kg BW^0.75 day)). Digestibility of CP and blood urea N concentrations of TN were higher than those of AN × TN (P < 0.05, 69.8% versus 64.0% and 32.2 mg/dl versus 26.7 mg/dl, respectively). The AN × TN tended to retain more N than TN in the higher CP feeding condition of T3 (0.19 g/(kg BW^0.75 day) versus 0.11 g/(kg BW^0.75 day)) and T4 (0.25 g/(kg BW^0.75 day) versus 0.17 g/(kg BW^0.75 day)). Digestibility of NDF and ADF, and TDN of TN were higher than those of AN × TN (P < 0.05, 61.1% versus 55.9%, 49.6% versus 43.5% and 65.8% versus 62.4%, respectively). The overall mean DE was 109 kcal/(kg BW^0.75 day), and no significant difference of DE among CP levels nor breeds of bucks was observed. Thai native was superior to AN × TN in digestibility of N and fiber fractions at the maintenance level of DE, which might have overcome inferiority of TN to AN × TN in amount of N and energy intake caused by the lower DMI. It is likely that TN goats are well adapted to fodder shortage condition due to their efficient utilization of nutrients.     

Effect of feeding sericea lespedeza (Lespedeza cuneata) on growth performance,blood metabolites,and carcass characteristics of Kiko crossbred male kids

Twenty-four high percentage Kiko crossbred male kids (body weight (BW), 27.8 ± 2.2 kg) were stratified by BW and randomly allocated to one of four experimental treatment groups (n = 6). Diets contained different levels of the condensed tannin (CT) containing forage sericea lespedeza (SL, Lespedeza cuneata) dried meal replacing alfalfa (Medicago sativa) pellets (ALF). Experimental treatments included: the control diet – 0% SL and 30% ALF; 10% SL and 20% ALF; 20% SL and 10% ALF; or 30% SL and 0% ALF as fed. Sericea lespedeza whole plant dried meal, incorporated in the grain mix portion of the diet and the mix was fed daily at 70% of total feed offered, with the remaining 30% consisting of bermudagrass (Cynodon doctylon) hay (BGH). Animals were fed once a day and the intake was adjusted every 3–4 days so that a 4–6% was refused (grain mix/SL and hay). Body weights were taken at the beginning, mid, and end of the study and blood was collected twice, at the beginning and at the end of the study, for complete analysis. The performance period lasted 63 days and at the completion of the study, goats were harvested and carcass characteristics measured. There was no difference in initial or final BW of goats; however, average daily gain (ADG) was higher (quadratic, P = 0.01) in goats consuming either all ALF or SL diets. Average daily dry matter (DM) and CT intake increased (linear, P = 0.04 and P < 0.0001, respectively) as the level of SL increased in the diet; however, body weight gain:feed (G:F, kg/kg dry matter) was lower for 10 or 20% SL diets (quadratic, P = 0.002). Scrotal circumference tended to decrease (quadratic, P = 0.07) in goats fed 10 or 20% SL and height at withers decreased (linear, P = 0.05) with addition of SL. Adjusted body fat thickness decreased (linear, P = 0.02) with added SL. Dressing percentages were low and ranged from 37.6 to 39.1 ± 1.5 for all diets. White blood cells decreased (linear, P = 0.05) and lymphocytes % increased (linear, P = 0.05) with added SL. Serum creatinine kinase and alanine aminotransferase increased (linear, P = 0.01 and P = 0.001, respectively) and serum amylase decreased (linear, P = 0.01) as the level of SL increased. In conclusion, addition of SL up to 30% or CT up to 22.2 mg/kg DM in the diet did not adversely affect growth performance of goats, and it produced lower fat in the carcass.     

Weight gains of meat goat kids on wheat (Triticum aestivum L.) pastures fertilized at different nitrogen levels

Wheat (Triticum aestivum L.) pastures are increasingly being used for cool-season forages to complement range-based goat production systems in southern USA. Because goats are more selective than cattle, ideal nitrogen (N) fertilizer rates already established for wheat grazed by cattle may be different for goats. Weight gains of Boer X Spanish doe kids (average 17 kg) as well as forage yields and crude protein (CP), acid detergent fiber (ADF) and acid detergent lignin (ADL) concentrations were measured for two winter seasons on replicated wheat paddocks fertilized with 0, 56, 112 and 224 kg N/ha per season in split autumn/spring applications at Stephenville, TX, USA. Animals were stocked in the pasture at 20 head/ha from January to April 2003 (478 mm rainfall from September to March) and 2004 (355 mm rainfall). Available forage ranged from 50 to 200 kg/ha in January and from 2300 to 6300 kg/ha in April in the 0 and 224 kg N/ha paddocks, respectively. Crude protein dry matter (DM) concentration ranged from 25 to 34% (0 and 224 kg N/ha, respectively) in January, but down to 13 and 22% across treatments in April. Average daily gains (ADG) over the 90-day trial were similar both years, 68 g per head per day for the 0 N treatment and undifferentiated among the fertilized paddocks, all near 90 g per head per day. Results indicate that N fertilizer rates above 56 kg/ha per season do not increase ADG/kid, but will increase ADG/ha if stocking rates are adjusted for forage production.     

Partial replacement of barley grain for corn grain: Associative effects on lambs’ growth performance

Our objective was to study the positive effects of partial replacement of barley grain for corn in high concentrate diets on growth performance of growing lambs, and to determine the minimum amount of corn needed to produce such effects. Thirty-three male Awassi lambs weaned at 60 days of age were divided into three groups of 11 according to their live weight and offered three isonitrogenous diets. The control diet (B) contained 81 and 14% barley grain and wheat straw, respectively (DM basis). Corn grain replaced barley grain at 10 and 20% of dietary DM for low (LC) and high (HC) corn diets, respectively. Barley had a higher (P < 0.05) rate of digestion (11.5%/h) compared with corn (8.3%/h). The in vitro 30-h digestion extent was also higher (P < 0.05) for barley. The digestion rate for the B diet was higher (P < 0.05) compared with the HC diet, whereas the value for the LC diet was intermediate. Lambs fed LC and HC diets consumed more (P > 0.05) DM (average = 855 g/day) compared with lambs fed B diet (757 g/day). DM and CP digestibilities were similar among diets and averaged 67.0 and 64.2%, respectively. Final BW, BW change and average daily gain (ADG) for lambs fed HC were higher (P < 0.05) compared with B and LC. Moreover, lambs that consumed LC tended (P = 0.12) to grow faster than lambs fed B. Feed to gain ratio was lower (P < 0.05) for lambs fed HC (4.6) compared with B and LC (5.2). In summary, positive associative effects of partial replacement of barley with corn in high concentrate diets for fattening sheep were detected. However, a minimum of 20% replacement of dietary DM from barley with corn was needed to positively improve both performance and feed efficiency.     

Growth,intake, diet digestibility,and nitrogen use in three hair sheep breeds fed alfalfa hay

Pen feeding and metabolism trials were conducted to determine intake, diet digestibility and nitrogen (N) use in three hair sheep breeds with differing growth potential offered an alfalfa hay diet. For pen feeding, 24 6-mo-old wether lambs, equally representing the Barbados Blackbelly, Katahdin, and St. Croix breeds, were paired by breed, placed in 12 enclosed cement-floor pens (2.5 m × 3.5 m), and offered chopped alfalfa (Medicago sativa L.; 17.6% CP, 50.4% NDF, and 36.4% ADF) ad libitum. Lambs were allowed a 14-d adaptation period to pens and diets, and remained on trial for 56 d. Starting body weight (BW) was different (P < 0.05) among breeds (Barbados Blackbelly: 23.8 kg; Katahdin: 36.5 kg; St. Croix: 29.1 kg). Daily gain was not different (P < 0.10) between Katahdin (131 g/d) and St. Croix (117 g/d), but both were higher (P < 0.05) than Barbados Blackbelly (87 g/d). Daily dry matter hay intake was similar among breeds (107–109 g/kg BW^0.75), and feed to gain ratio ranged from 8.7 in St. Croix and 9.1 in Katahdin to 10.5 in Barbados Blackbelly, but was not different (P > 0.10) among breeds. Six lambs per breed were used in the metabolism trial. Total DMI was greater (P < 0.01) for Katahdin (1196 g/d) than St. Croix (907 g/d) and Barbados Blackbelly (858 g/d), but was not different (P > 0.10) adjusted for body weight (mean: 71 g/kg BW^0.75). Coefficients of apparent digestibility for DM (P < 0.06), OM (P < 0.06), N (P < 0.05), NDF (P < 0.08), and ADF (P < 0.08) were higher for Katahdin compared to Barbados Blackbelly with St. Croix intermediate. Intake of N (P < 0.01), feces N (P < 0.08), urine N (P < 0.01), absorbed N (P < 0.01), and retained N (P < 0.05) also were greater for Katahdin compared to St. Croix and Barbados Blackbelly. Blood glucose, urea-N, and creatinine were not different (P > 0.10) among breeds. Breeds differed in their growth performance in line with breed mature size, and differences were observed in N digestibility and absorption.     

Effect of the supplementation of a high-concentrate diet with sunflower and fish oils on ruminal fermentation in sheep

This study was conducted to test the hypothesis that the supplementation of a high-concentrate diet with lipids, reportedly a good strategy for improving the nutritional value of ruminant-derived products, may not necessarily be associated with detrimental effects on ruminal fermentation in sheep. Four ruminally cannulated adult ewes were fed a high-concentrate diet, with no oil (Control diet), for a 14-day adaptation period. Afterwards, they were fed the same basal diet but supplemented with sunflower oil [20 g/kg fresh matter (FM)] and fish oil (10 g/kg FM) (SOFO diet) for a further 11 days, to investigate the impact of the addition of oils on the ruminal fermentation of the diet. On days 0 (Control), 3 and 10 of the experimental period rumen fluid was sampled at 0, 1.5, 3, 6 and 9 h after the morning feeding, for analysis of pH, and ammonia, lactate and total volatile fatty acid (VFA) concentrations. Alfalfa hay was incubated in situ, using the nylon bag technique, for 12 and 24 h to examine the effect of oil supplementation on ruminal disappearance of dry matter (DM), crude protein (CP) and neutral-detergent fibre (NDF). On days 0 and 11, rumen fluid was collected just before the morning feeding and used to incubate alfalfa hay and the Control and SOFO diets by means of the in vitro gas production technique. The mean concentrations of acetate (87.8 mmol/L vs. 73.7 mmol/L) and butyrate (21.2 mmol/L vs. 17.7 mmol/L) were reduced by oil supplementation (P < 0.05) and the total VFA showed a tendency (P = 0.098) to be lower with the SOFO diet (139.0 mmol/L vs. 122.1 mmol/L). However, none of the other in vivo ruminal fermentation parameters were affected by the treatment (P > 0.10). The oil supplementation affected neither in situ rumen disappearance of DM, CP and NDF of alfalfa hay, nor rates of gas production (P > 0.10). On the other hand, a little, but significant reduction in cumulative gas production was observed when the experimental diets were incubated with rumen fluid derived from animals fed the oil-rich diet (P < 0.05).Overall, the results suggest that the supplementation of high-concentrate diets with sunflower oil (20 g/kg FM) plus fish oil (10 g/kg FM) had little effect on ruminal fermentation and therefore its use to improve the nutritional value of ruminant-derived products cannot be precluded.     

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.     

The effect of variety on maize grain and crop residue yield and nutritive value of the stover

Eight varieties of maize, namely Awassa 511 (A511), Birkata, composite of best families (CBF), Dendane, drought tolerant population (DTP1), Guto, Katumani and Keroshet planted in 1995 cropping season were compared for grain and crop residue yield and nutritive value of the stover. Significant differences (p < 0.05) were observed in grain and crop residue yields of the varieties. Grain yield was highest (6.99 t ha⁻¹) in DTP1 and lowest (2.21 t ha⁻¹) in Keroshet. Stover and total crop residue yields were significantly higher (p < 0.05) in A511 than in CBF and Dendane. The stem was the largest portion in the stover varying from 31% in Dendane to 50% in A511. The stover of Birkata showed a high crude protein (CP) and low ash and fibre contents compared to the other varieties. The CP content varied from 28 g kg DM⁻¹ (Guto) to 61 g kg DM⁻¹ (Birkata). Crop residue yield and quality parameters, except CP content of the stover, were not negatively correlated with grain yield. The potential utility index varied from 61% (Keroshet) to 74% (CBF). The varieties with higher potential utility indices, except Guto, also had relatively higher solubility, 48 h DM degradability and effective degradability compared to the other varieties. The overall results showed evidence of varietal differences in grain and stover yield and stover quality and indicated the possibility of selecting for maize varieties that combine high grain yield and desirable stover characteristics.     

Effect of different levels of concentrate allowances on rumen fluid pH,nutrient digestion,nitrogen retention and growth performance of weaner lambs

This experiment was conducted for 90 d to assess the effect of feeding graded levels of concentrate allowance on rumen fermentation characteristics, performance and nutrient utilisation of weaner lambs on restricted or high concentrate allowance using 60 weaner lambs of initial average live weight of 13.90 kg BW in a randomized design. The experimental treatments were 15 or 25 g kg⁻¹ BW or ad libitum concentrate allowance. Roughage source which contained Khejri (Prosopis cineratia) and Siris (Albizia lebback) leaves in 50:50 ratio was offered ad libitum to all the animals. Lambs supplemented with 15 g or ad libitum concentrate had similar dry matter intake (4.2 kg/100 kg BW) but significantly (p < 0.01) lower than 25 g concentrate supplemented group (4.9 kg/100 kg BW). Organic matter and CP intakes increased with increasing concentrate supplementation. Apparent digestibilities of dry matter, organic matter, CP, NDF, ADF and cellulose were significantly (p < 0.01) higher in ad libitum concentrate supplemented than 15 and 25 g concentrate supplemented lambs. Daily ME intake was significantly (p < 0.05) higher in 25 g and ad libitum concentrate supplemented lambs while ME intake kg⁻¹ gain was lower in ad libitum concentrate supplemented lambs (57 MJ kg⁻¹ gain) than those supplemented with 15 or 25 g concentrate (91 MJ kg⁻¹ gain). Generally, average daily gain increased with increasing levels of concentrate supplementation. Ad libitum concentrate supplemented lambs had significantly (p < 0.01) higher daily gains (151 g) than 15 and 25 g concentrate supplemented lambs (77 and 98 g, respectively). Feed efficiency was similar for 15 and 25 g concentrate supplemented lambs but significantly (p < 0.01) lower than the ad libitum concentrate supplemented lambs. All animals were in positive N-balance and the N-balance increased with increasing concentrate supplementation. Mean rumen fluid pH was significantly (6.6, p < 0.01) lower in ad libitum concentrate supplemented lambs compared to 15 or 25 g concentrate fed lambs (6.9). Rumen NH₃-N and total-N-concentrations peaked at 3 h post-feeding. Optimum rumen fluid pH, better nutrient digestibilities, higher N-retention improved growth by 49% of ad libitum concentrate fed lambs.     

Performance of West African dwarf goats fed Guinea grass–Verano stylo mixture,N-fertilized and unfertilized Guinea grass

The supplementary values of Verano stylo in a mixed Guinea grass (Panicum maximum cv. Ntchisi)–Verano stylo (Stylosanthes hamata cv. Verano) diet from a sown grass–legume mixture and N fertilized grass were compared in West African dwarf (WAD) goats. Liveweight (LW) gain, feed intake, digestibility and N utilization were determined using 15 goats in two trials lasting for 98 days. Goats were fed Guinea grass–Verano stylo mixture (GSM), N-fertilized (NFG) and unfertilized grass (UFG). The goats were divided into three groups of five animals each and randomly allocated to the dietary treatments in a randomized complete block design. Total DM and OM intakes of the goats did not vary significantly among the forage diets and averaged 55.1 and 50.4 g kg⁻¹ W^0.75 per day, respectively. CP intake (g kg⁻¹ W^0.75 per day) was highest with NFG (5.6) followed by GSM (4.8) and the UFG (3.5). Total N excreted followed the same trend as the CP intake. There was no significant difference between N-retention of GSM and NFG (28.5 and 26.7%), but goats on UFG had a negative N balance (−9.16%). Animals on GSM had significantly higher liveweight gain (31.9 g per day) than those of NFG (25.1 g per day) and UFG (21.9 g per day) which also differed significantly. The digestibilities of total DM, OM, CP, NDF were higher with GSM than NFG or UFG. It is concluded that growing Verano stylo in mixture with Guinea grass is a better option for improving the feed quality of forage diets for goats than direct application of inorganic fertilizer at 200 kg N ha⁻¹ to the pure grass.     

Effect of level of fibre on performance and digestion traits in growing rabbits

An experiment was conducted to determine the effects of level of fibre on production performance, gastrointestinal tract development, caecum fermentation and fibrolytic activity in weaner to 2-month-old New Zealand rabbits. One hundred weaner rabbits were allocated in individual cages for five treatments in which they were fed each diet with ADF at 130 (NDF, 274.1; ADL, 39.7; CP, 158.4; EE, 26.8; starch, 252.5 g/kg), 160 (NDF, 292.9; ADL, 41.9; CP, 160.3; EE, 25.6; starch, 249.4 g/kg), 190 (NDF, 312.4; ADL, 50.5; CP, 157.6; EE, 24.2; starch, 218.2 g/kg), 220 (NDF, 343.9; ADL, 51.2; CP, 158.5; EE, 22.2; starch, 217.6 g/kg), and 250 g/kg (NDF, 375.7; ADL, 66.0; CP, 156.9; EE, 22.4; starch, 220.8 g/kg) original matter basis, respectively. The results were: ADG and F/G deteriorated with increasing fibre (P<0.05); ADI increased with increasing dietary ADF (P=0.002). The stomach relative weight (g/kg LW), small intestine relative weight (g/kg LW), caecum weight, caecum content weight and caecum relative weight (g/kg LW) all increased with increasing ADF (P=0.003, 0.007, 0.002, 0.010 and <0.001, respectively). Quadratic effects of level of ADF on the villus height, villus height/crypt depth of the duodenum and the villus height/crypt depth of the jejunum were obtained; cubic effects of level of ADF on the crypt depth of the jejunum and the villus height/crypt depth of the ileum were obtained. Cubic effects of level of ADF on the pH, the butyric acid (% total VFA) and C2/C4 were obtained. The NH₃–N concentration dropped and the acetic acid (% total VFA) increased when the dietary ADF increased (P<0.001). The fibrolytic activity measured in the caecal contents increased when the dietary ADF increased (P<0.001). Providing a ration consisting mainly of clover meal, wheat straw and peanut hulls, the optimum dietary ADF content for weaner to 2-month-old growing meat rabbits was shown to be 190 g/kg feed.     

In situ degradability of seven plant protein supplements in heifers fed high concentrate diets with different forage to concentrate ratio

Four Holstein heifers (297.5 ± 27.7 kg BW) fed high concentrate diets were used in a crossover experiment in order to characterize the rumen fermentation pattern, and to estimate by the in situ method rumen degradation kinetics of alfalfa hay and seven plant protein supplements: solvent-extracted soybean meal, solvent-extracted sunflower meal, peas (Pisum sativum L.), lupin seeds (Lupinus sp.), broadbean (Vicia faba L.), horsebean (Vicia faba L. var equina) and vetch (Vicia sativa L.), in high concentrate diets with different forage to concentrate ratio. Heifers were fitted with a ruminal cannula. The experiment was performed in two 30-day periods, 15 days of diet adaptation and 15 days of sampling. At each period, heifers were offered one of two total mixed rations (12:88 versus 30:70 forage to concentrate ratio), two heifers per diet, on ad libitum basis. After the first period, heifers switched treatments. Intake of dry matter (DM), organic matter, crude protein and neutral detergent fibre (NDF), expressed as kg/day, did not differ between treatments, but DM intake, expressed as g/kg metabolic body weight (BW), was higher in the 12:88 diet. Average rumen pH was 6.0 in both diets, and the time pH was below 5.8, which is considered as a critical threshold for fibre degradation, was the same for both treatments (10.4 ± 1.6 h). Average ammonia nitrogen and volatile fatty acid (VFA) concentrations did not differ between treatments and individual VFA proportions were typical of high concentrate diets. Average effective degradability of DM (0.62 ± 0.02) and NDF (0.25 ± 0.03) of alfalfa hay were low and no differences were detected between treatments. The same extent of NDF degradation, together with the same proportions of VFA would indicate that both diets had the same fibrolytic activity. Forage to concentrate ratio did not affect rumen nitrogen degradability of any protein supplements incubated in situ. Corrected effective degradability for small particle losses of sunflower meal (0.78) was higher than legume seeds, which were not statistically different between each other and ranged from 0.63 to 0.66. Soybean meal had the lowest degradability value (0.61). These nitrogen degradation values must be considered more valid for beef cattle formulation of high concentrate diets than data obtained with forage diets.