Rumen degradable nitrogen requirements for optimum microbial protein synthesis and nutrient utilization in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine the rumen degradable nitrogen (RDN) requirement levels for optimum microbial protein synthesis and nutrient utilization in Nellore rams fed on finger millet straw (FMS) based diet. Thirty six Nellore sheep were randomly divided into four groups of nine animals each using the balanced completely randomized design. Animals in all the groups were fed finger millet straw as a basal roughage and groundnut cake (GNC) was offered daily in two equal halves in the morning (8.00 AM) and evening (4.00 PM) as RDN source. The animals in group I (GI) were fed with ad libitum FMS. Animals in group II, III and IV (GII, GIII, and IV) were offered GNC @ 12.4, 16.6, and 21.1 g RDN/kg digestible organic matter (DOM) along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes linearly increased (P<0.05) with increasing level of RDN supplementation while there was no difference in total DM and OM intake/kg W^0.75 among different experimental groups. The digestibility coefficients of DM (P<0.001), OM (P<0.001), crude protein (CP) (P<0.001), ether extract (EE) (P<0.001), neutral detergent fibre (NDF) (P<0.01) and acid detergent fibre (ADF) (P<0.03) increased quadratically with increasing level of RDN supplementation from GI to GIV. The purine derivatives (PD) excretion, microbial purine absorption and microbial nitrogen supply (MNS g/day) linearly increased (P<0.001) as the level of RDN supplementation increased. There was no difference in nitrogen capture efficiency (NCE) and microbial nitrogen to total urinary nitrogen ratio (MN:UN) among the RDN supplemented groups. This study indicated that 12 g RDN/kg digestible organic matter intake (RDN g/kg DOMI) or 18 g RDN/kg OM apparently digested in the rumen (RDN g/kg DOMR) may be adequate for optimum microbial protein synthesis and digestibility of nutrients, there by improved plane of nutrition in sheep fed on finger millet straw based diet.     

Characterizing the ensiling properties of sugarbeets with dry feedstuffs

A study was conducted to evaluate the ensiling characteristics of chopped sugarbeets with dry feedstuffs and the corresponding change in the nutritive composition of the silages with the addition of dry substrates. Pre-calculated amounts of each feedstuff were weighed individually to achieve desired proportions of each silage product and thoroughly mixed for 5 min. After mixing, the silage was distributed evenly into three 19-L buckets and sealed to provide an anaerobic environment. The treatments for this study were arranged in a 4 × 4 + 1 factorial design to determine the effects of DM level and source of dry feedstuff on the ensiling properties of sugarbeets following a 42-d fermentation period. Treatments were ensiled sugarbeets alone (250 g/kg) or based on (1) formulated silage DM concentrations of 275, 350, 425, and 500 g/kg and (2) the inclusion of dry feedstuffs (alfalfa hay, dry-rolled corn, wheat middlings, and wheat straw). Fermentation and nutritive characteristics of ensiled sugarbeets were influenced with the addition of dry substrates. A linear increase (P<0.001) in silage pH was observed with the addition of alfalfa, dry-rolled corn, wheat middlings, and wheat straw to ensiled sugarbeets. Lactic acid increased (P<0.001) with the addition of wheat middlings. Alfalfa addition to sugarbeet silage did not alter (P<0.001) lactate concentration. Concentration of lactate decreased (P=0.01) when corn was added, while wheat straw addition did not influence (P=0.37) lactate. A contrast was used to compare ensiling characteristics of sugarbeets alone (250 g/kg DM) to 350 g/kg DM (sugarbeets with dry substrates). Results indicated fermentative parameters were altered; pH increased (P<0.001) for all dry substrates while lactate was lower (P=0.003) for the sugarbeets ensiled with dry-rolled corn compared with sugarbeets ensiled alone. Alfalfa, wheat straw, and wheat middlings decreased (P<0.001) while dry-rolled corn did not affect (P=0.54) in vitro DM digestion. These results indicate the inclusion of dry feedstuffs with sugarbeets altered fermentation and with the exception of corn, decreased in vitro DM digestion. Nutrient composition and DM content of ensiled sugarbeets was altered with the addition of dry substrates.     

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 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.     

The effect of inclusion of lupins/triticale whole crop silage in the diet of winter finishing beef cattle on their performance and meat quality at two levels of concentrates

This study investigated the performance and instrumental meat quality of finishing beef steers offered grass silage (GS), grass silage:maize silage (GS:MS) and grass silage:lupins/triticale silage (GS:LT). The lupins/triticale silage was grown as either two separate crops in the same field and harvested together (LT1) or grown and harvested as a mixture (LT2). The silages were offered to eighty continental cross beef steers, initial live weight 530 ± 47.7 kg and 18 ± 1.6 months of age and were supplemented with 3 or 6 kg concentrates fresh/head/d. Silage was fed ad libitum with the mixtures offered at a ratio of 60 GS:40 maize silage (MS), LT1 or LT2 on a dry matter (DM) basis and concentrates were offered once (3 kg) or twice (6 kg) daily on top of the silage. Animals were slaughtered in three batches after 100, 117 and 124 d on experiment. The LT1 and LT2 produced yields of 8.7 and 7.5 kg DM/ha and the silages were poorly fermented as demonstrated by high ammonia-N concentration (182 and 173 g/kg total N), low lactic acid (9 g/kg DM) and high pH (5.0 and 4.7). Silage type had no significant effect on slaughter live weight, liveweight gain, carcass gain, forage DM intake (DMI), total DMI or feed efficiency expressed as kg DMI/kg liveweight gain or kg DMI/kg carcass gain. Silage type had no effect on carcass characteristics or instrumental meat quality. The results of this study demonstrate that offering lupins/triticale silage in combination with high quality grass silage (D-value greater than 700) at a ratio of 60 grass silage:40 LT1 or LT2 on a DM basis had no effect on animal performance, carcass characteristics or meat quality parameters relative to high quality grass silage offered alone or in combination with maize silage.     

Supplementation of isonitrogenous oil seed cakes in cactus (Opuntia ficus-indica)–tef straw (Eragrostis tef) based feeding of Tigray Highland sheep

The experiment was conducted at Maichew Agricultural Technical Vocational Education and Training College, Ethiopia. Twenty four male yearling Tigray Highland sheep with mean body weight (BW) of 21 ± 2.6 kg (mean ± S.D.) were used to investigate the effect of different protein sources on feed intake, nutrient digestibility, BW change and carcass parameters in a study comprising of 90 days feeding trial, followed by 7 days of digestibility trial and evaluation of carcass parameters. Six individually fed animals were used per treatment in a randomized complete block design. The treatments consisted of ad libitum feeding of tef (Eragrostis tef) straw plus 172 g dry matter (DM) of cactus (Opuntia ficus-indica) pear (T1, control) and supplementation with 145 g DM cotton seed cake (CSC) (T2), 195 g DM noug seed cake (NSC) (T3) or 149 g DM peanut cake (PNC) (T4) per head per day. The quantity of the supplements was set to supply 62.5 g crude protein (CP). Tef straw DM intake was depressed (P<0.01) as the result of NSC supplementation. Sheep supplemented with CSC and PNC had higher (P<0.001) total DM intake than the control and NSC supplemented ones. Supplementation with NSC and PNC also resulted in higher (P<0.01) apparent digestibility of DM and OM compared to the control treatment. Supplementation with CSC and PNC resulted in better daily BW gain (P<0.001), feed conversion efficiency (FCE) and dressed carcass weight (P<0.01) compared to the non-supplemented diet. Dressing percentage on slaughter weight base was higher (P<0.01) in supplemented sheep than in the non-supplemented ones. Supplementation with PNC also promoted higher (P<0.05) rib-eye muscle area than in the non-supplemented ones. It was concluded that supplementation with 145 g DM CSC and 149 g DM PNC resulted in better feed intake, BW gain and carcass traits in cactus–tef straw based feeding of sheep.     

Ruminal degradability,digestibility, energy content,and influence on nitrogen turnover of various Mediterranean by-products in fat-tailed Awassi sheep

Livestock husbandry in the dry areas of the Mediterranean basin is facing scarcity and fluctuation of feed supply and feed prices. At the same time the local agro-food industry is expanding and its by-products might be used as alternatives to traditional feed resources, but their nutritional value is not well known. Therefore, four by-products typical for the Mediterranean area were tested in vitro (n = 3 per diet or feed), in sacco (n = 6) and in vivo (n = 6) either individually or in a proportion of 0.34 of the total diet. The test feeds (broken lentils, sugar beet pulp, tomato pomace and crude olive cake) were compared to a barley–wheat bran mixture (control). Forage (barley straw) made up proportionately 0.5 of the diet. For all experiments either rumen canulated or intact castrated male Awassi sheep were employed. The thirty sheep used in the in vivo experiment weighed on average 42 kg. The animals were fed 1.1 kg dry matter (DM)/day and had free access to water. Large compositional differences (g/kg DM) between the batches of test feeds used in the present study were found in crude protein (from 79 to 245; for olive cake and broken lentils), neutral detergent fiber (aNDFom; from 283 to 584; for broken lentils and olive cake) and non-fiber carbohydrates (from 109 to 436 for tomato pomace and olive cake and to broken lentils). Two feeds (tomato pomace and olive cake) were rich in ether extract; sugar beet pulp was rich in calcium. Broken lentils had the highest effective degradabilities (ED). Olive cake was lowest in ED of OM and aNDFom (0.39 and 0.32, respectively). Olive cake caused refusals of concentrate (lower proportionate concentrate intake compared with the control, P<0.001). The apparent nutrient digestibility of broken lentils and sugar beet pulp was similar (P<0.001) to the control and lower (P<0.001) for tomato pomace and olive cake. Metabolizable energy (ME; MJ/kg DM) was determined by various ways and always showed a very low value for olive cake (1–2). Broken lentils and sugar beet pulp had ME contents higher (P<0.001) than that of tomato pomace. The study showed that some by-products were promising as alternatives to traditional concentrate ingredients, while others, especially olive cake, might be only used at low levels.     

Effects of form of leftover khat (Catha edulis) on feed intake,digestion, and growth performance of Hararghe Highland goats

Khat (Catha edulis) is a lucrative cash crop in many African countries and other areas of the world. Leftover khat can be used as a feedstuff for ruminants, although seasonal production limits the extent of utilization. Practical methods of feed conservation to preserve nutritional value would be beneficial. Thus, a study was conducted to investigate effects of feeding different forms of leftover khat on intake, digestion, and growth performance of a tropically adapted indigenous goat genotype of eastern Ethiopia. Twenty-four (six per treatment) individually housed Hararghe Highland yearling male goats with an initial body weight of 18 ± 0.4 kg were used in an on-station experiment, and 32 similar yearlings with an initial body weight of 19 ± 0.4 kg were employed under on-farm conditions. The on-farm experiment occurred at two villages, with four farmer groups (two farmers per group co-managing animals) per village. Four animals in each farmer group were subjected to each of the four different treatments. Experiments were 90 days in length, with inclusion of a subsequent 10-day period on-station to determine digestibility. Khat in fresh, dry, and silage forms was fed at 1.5% body weight (dry matter; DM), whereas control animals did not receive khat. Animals on-station consumed grass hay ad libitum and those on-farm grazed/browsed surrounding areas. Grass hay DM intake on-station was greater (P < 0.05) without than with khat (528, 358, 387, and 368 g/day; SE = 20.3), although total DM intake was increased by feeding khat regardless of form (528, 649, 622, and 639 g/day for control, fresh, dry, and silage, respectively; SE = 22.9). Digestibility of organic matter was increased (P < 0.05) by feeding each form of khat (62.3%, 75.7%, 75.2%, and 72.4% for control, fresh, dry, and silage, respectively; SE = 1.63). Nitrogen balance was increased by fresh and ensiled khat (P < 0.05) (?0.54, 2.07, 0.80, and 0.86 g/day for control, fresh, dry, and silage, respectively). Average daily gain (ADG) was increased by khat regardless of form on-station (13, 49, 33, and 39 g; SE = 4.6), and on-farm ADG was less for control than for fresh and dry forms (P < 0.05) (32, 56, 47, and 42 g for control, fresh, dry, and silage, respectively SE = 2.0). The ratio of ADG:DM intake on-station was lower for control than for fresh (P < 0.05) and silage (P < 0.05) (26, 76, 54, and 61 g/kg for control, fresh, dry, and silage, respectively; SE = 7.6). In conclusion, feeding leftover khat to Highland goats consuming low to moderate quality forage-based diets can increase growth performance. Khat can be preserved for use as a feedstuff throughout the year by drying or ensiling without marked effect on performance.     

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.     

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.     

Effect of dietary cobalt supplementation on plasma and rumen metabolites in Mehraban lambs

Two experiments were conducted to study the effects of different levels of dietary cobalt on performance, plasma and rumen metabolites and nutrient digestibility in Mehraban male lambs. Experiment 1: 28, 8–9-month-old lambs were randomly divided into four groups. Animals were fed a basal diet containing 0.088 mg Co/kg DM and were supplied with 0 (control), 0.25, 0.50, or 1.00 mg Co/kg DM as reagent grade CoSO₄·7H₂O. The experiment lasted for 70 days. Experiment 2: four lambs from each group in Experiment 1 were randomly allocated to the individual metabolic crates to measure the effects of dietary Co on nutrient digestibility. Final body weight, average daily gain and gain efficiency were higher (p < 0.05) in the group supplemented with 0.50 mg Co/kg DM compared to other groups. Plasma glucose and vitamin B₁₂ concentrations increased (p < 0.05) at all levels of Co supplementation on day 68 of the experiment and for vitamin B₁₂ were higher (p < 0.05) at 0.50 and 1.00 mg Co/kg DM compared to 0.25 mg Co/kg DM. There was no significant difference among treatments for TVFA and ruminal fluid pH. Digestibility of dry matter, organic matter, crude protein and neutral detergent fiber increased (p < 0.05) by Co supplementation, but did not differ among Co supplied treatments. The obtained results showed that lambs fed the control diet containing 0.088 mg Co/kg DM had a reduced appetite and gained less than the supplemented animals, suggesting that the level of 0.088 mg Co/kg DM was inadequate for normal growth of Mehraban male lambs, and a total level of 0.58 mg Co/kg DM might be optimum level for enhancing performance.     

Utility of buckwheat (Fagopyrum esculentum Moench) as feed: Effects of forage and grain on in vitro ruminal fermentation and performance of dairy cows

Buckwheat is of high value in crop rotations and overall agricultural ecology because of strong rooting and intensive flowering properties, but it is rarely cultivated and information on its nutritional value to ruminants is scarce. The contents of net energy for lactation (NEL), as estimated with the Hohenheim Gas Test (n = 3), were 4.3, 4.9 and 7.5 MJ NEL/kg dry matter (DM) for fresh and ensiled whole buckwheat plants and buckwheat grain, respectively. In two experiments with the Rumen Simulation Technique (Rusitec), ruminal fermentation characteristics of buckwheat forages and buckwheat grain (n = 4/diet) were evaluated. In the first experiment, 0, 300 or 600 g/kg of a pure hay diet were replaced by either fresh or ensiled buckwheat to create five diets. Neither form of buckwheat forages had effects on in vitro ruminal degradability and short chain fatty acid (SCFA) concentrations and composition. The use of fresh buckwheat reduced ruminal ammonia concentrations and enhanced estimated microbial N growth efficiency. These differences did not occur with silage, indicating a change in nutritional value by ensiling. Fresh buckwheat reduced the number of bacteria in the incubated fluid, while ensiled buckwheat reduced that of holotrich protozoa. Methane formation was not influenced by the buckwheat forages. In the second experiment, wheat meal (400 g/kg dietary DM), was replaced stepwise (0.5 and 1.0) by buckwheat grain meal. This did not cause differences in parameters of nutrient degradability, relative N efficiency and total amount and composition of SCFA. Holotrich protozoa counts increased, but total gas formation decreased with increasing dietary level of buckwheat grain. In a final experiment, cows yielding about 40 kg milk/day were fed mixed silage-concentrate diets (n = 4). A control diet contained no buckwheat. In a second diet, maize silage was partly substituted by buckwheat silage (98 g/kg dietary DM). In a third group, part of the energy concentrate was substituted by buckwheat grain meal (94 g/kg). There were no effects on feed intake, milk yield and milk composition. Buckwheat proved to be a plant that offers different feeds of a quality sufficient to be considered suitable in ruminant nutrition.     

Effect of rare earth elements on in vitro rumen microbial fermentation and feed digestion

The objectives of this study were to investigate the effects of rare earth elements (REEs) on in vitro rumen fermentation, gas production, microbial protein synthesis and nutrient digestion using in vitro batch culture and continuous culture technique. A mixture of REE containing (g/kg) 380 g of LaCI₃·6H₂O, 521 g of CeCI₃·6H₂O, 30 g of PrCI₃·6H₂O and 69 g chlorides of other light REEs. The experimental diet consisted of 885 g/kg barley grain, 84 g/kg barley silage and 31 g/kg supplement (dry matter (DM) basis). Diet supplemented with different dosages of REE (control, no additional REE; low, 400 mg/kg REE; and high, 800 mg/kg REE, DM basis) were incubated for 4, 8, 14 and 24 h in diluted rumen fluid. At the end of 24 h of incubation, gas production and concentration of volatile fatty acid (VFA) linearly increased with increasing REE supplementation; whereas, influence of REE supplementation on VFA profile was marginal. Dry matter disappearance was not affected (P>0.10). Six dual-flow continuous culture fermenters were used in a replicated 3 × 3 Latin square with same treatments and same diet used in the batch culture. Mean ruminal pH (5.71) and total VFA (93.6 mM) concentration were not affected by supplementation of REE. The molar proportion (mol/100 mol) of acetate (39.1) and propionate (50.5) was similar among the treatments. However, the proportion (mol/100 mol) of butyrate was higher with the high REE (6.6) than with low REE (5.3) or the control (5.8). Ruminal true digestibilities of organic matter (OM) (0.785, 0.811 and 0.828), acid detergent fibre (0.360, 0.431 and 0.432) and crude protein (0.496, 0.590 and 0.589) for control, low and high REE, respectively, linearly increased with increasing REE supplementation, whereas, the increase in ruminal digestibility from low to high dosage of REE was minimal. Microbial nitrogen (N) production (g/day) and microbial efficiency (g N/kg of truly fermented OM) were not affected by treatments. Improvement of ruminal digestibility of OM due to REE supplementation was attributed to the increase in digestibility of fibre and degradability of protein. The results suggest that REE supplementation improved ruminal fibrolytic and proteolytic activities.     

Production efficiency and feeding behavior of Awassi lambs and Baladi kids fed on a high concentrate diet

Fifteen Awassi lambs and 15 Baladi kids (males, averaging 14.3 kg) were used to study the differences in feeding behavior and performance of sheep and goats fed a concentrate finishing diet (CP = 16 kg/100 kg DM, ME = 2.85 Mcal/kg DM) in a complete randomized design experiment lasting 60 days. Dry matter (DM) and organic matter (OM) intakes were significantly (P < 0.05) higher in lambs. Kids had higher (P < 0.05) apparent OM, crude protein (CP) and gross energy digestibilities. No significant (P > 0.05) differences were observed in apparent neutral detergent fiber (NDF) digestibility, eating, chewing and ruminating times. However, eating and ruminating times (as min/kg NDF intake) was significantly (P < 0.05) higher in kids. Final body weight and average daily weight gain were significantly (P < 0.05) higher in lambs while kids had significantly (P < 0.05) lower feed to gain ratio. Feed cost per kilogram weight gain for kids was better than that for lambs. Results demonstrated that Awassi lambs consumed more feed and grew faster than Baladi kids. However, kids were more efficient feed converters than lambs.     

Ensiled alkali-treated straw. I. Effect of level and type of alkali on the composition and digestibility in vitro of ensiled barley straw

In three experiments barley straw chopped to 5 cm nominal particle length was ensiled in laboratory silos for 90 days after treatment with alkali. In the first two experiments, NaOH was added at 0, 1.05, 2.10, 3.15 or 4.20 g per 100 g straw dry matter (DM) (Experiment 1) or at 0, 2.5, 5.0, 7.5 and 10.0 g per 100 g straw DM (Experiment 2) in solutions at either 60 ml or 120 ml solution per 100 g straw DM. Digestibility in vitro of organic matter (OM) and digestible OM in DM (DOMD) increased with increasing level of NaOH. The effect of volume of solution on digestibility was small. The pH of the straws decreased during storage. The content of neutral detergent fibre decreased as the level of NaOH increased, but there was relatively little change in the contents of acid detergent fibre or acid detergent lignin. Lactate and acetate were detected in all silages, and butyrate was present in silages made from straws treated with less than 5 g NaOH per 100 g straw DM. On opening the silos little moulding was seen and the temperature of the straws remained close to ambient in both experiments throughout 16 days of subsequent exposure to air.In the third experiment, the comparative effects of Ca(OH)₂ and KOH were studied alone and in combination ($\text{50}\text{50}$ by weight) with NaOH. KOH mixed with NaOH gave levels of DOMD in vitro similar to those obtained with NaOH alone. Ca(OH)₂, whilst improving DOMD, was slightly less effective than the other alkalis.The optimum level of alkali for the treatment of barley straw prior to ensiling appeared to be 7.5 g/100 g straw DM. At this level of addition, DOMD in vitro would be expected to be about 65%. Ca(OH)₂ is worth further attention as an alternative to NaOH.     

The effect of replacing rice straw with dry wormwood (Artemisia sp.) on intake,digestibility, nitrogen balance and ruminal fermentation characteristics in sheep

This study examined the effect of substituting dry wormwood (Artemisia sp.) for rice straw in sheep diets on intake and apparent digestibility in vivo, nitrogen (N) balance and ruminal fermentation characteristics. Four Corriedale×Polwarth sheep (51.7 ± 1.3 kg) were individually housed in metabolism cages and fed diets (ad. libitum) with a 70:30 forage to concentrate ratio (DM basis), in which the basal rice straw was substituted with 0 (Control), 30 (LW), 50 (MW) or 100 (HW) g/kg of dry wormwood. The experimental design was a 4×4 latin square design in which 10 days of dietary adaptation was followed by 6 days of total feces and urine collection in each period. Rumen fluid was collected from a stomach tube at −0.5, 0.5, 1, 2, 4, and 8 h after the morning feed on day 6 of each collection period and analyzed for volatile fatty acids (VFA). The intakes of dry matter (DM), organic matter intake (OM), crude protein (CP), ether extract (EE), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were higher (P<0.05) in sheep fed diets containing wormwood, than those fed the Control diet. Compared to the Control diet, CP digestibility was higher (P<0.05) in sheep fed MW and N intake, retained N, EE digestibility, urinary purine derivatives and microbial N yield were higher (P<0.05) in sheep fed diets, containing wormwood. Rumen pH was unaffected by treatment. Rumen NH₃-N and VFA concentrations were similar across treatments except that most values for diets containing wormwood were higher (P<0.05) than those for the control diet within the first 2 h of feeding. The non-glucogenic acid ratio was also similar across Control, LW and MW treatments, but it was generally lower in MW versus the Control treatment. In conclusion, substituting wormwood for rice straw in the sheep diets increased feed intake, rumen fermentation, in vivo digestibility, N retention and microbial N yield, particularly at the medium and high levels of wormwood inclusion.     

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).     

Effect of feeding protected fat and proteins on milk production,composition and nutrient utilization in Murrah buffaloes (Bubalus bubalis)

Objective of this study was to investigate the effect of feeding protected fat and proteins on milk production, composition and nutrient utilization in Murrah buffaloes (Bubalus bubalis). Eighteen buffaloes were divided into two groups (9 each) on the basis of most probable production ability. Buffaloes in control group (C group; most probable production ability 2204 kg) were fed chaffed wheat straw, chopped maize fodder and concentrate mixture as per requirements. Buffaloes in supplemented group (S group; most probable production ability 2211 kg) were fed same ration as C group plus 2.5% rumen protected fat (on dry matter intake basis) and formaldehyde treated mustard and groundnut oil cake (1.2 g formaldehyde/100 g crude protein) in place of unprotected cakes. Group S buffaloes were supplemented rumen protected fat and protein 60 days pre-partum to 90 days postpartum and persistence of milk production was monitored up to 210 days of lactation. Milk yield during supplementation period (90 days) in S group was 13.11 kg/d and was 19% higher (P<0.01) than the C group (11.01 kg/d), whereas after supplement withdrawal (120 days), it was 11.04 kg/d and was 15% higher (P<0.01) than the C group (9.61 kg/d). There was no effect on total solid, protein, solid-not fat (SNF) and lactose contents in the two groups, whereas milk fat yield was increased (P<0.05) and level of milk urea nitrogen was decreased (P<0.01) in S group. Moreover, the supplement produced noticeable changes in the fatty acid profile of the milk fat, i.e., reduction in the concentration of saturated fatty acids (SFA) by 19% and an increase in that of unsaturated fatty acids (USFA) by 36%. Besides, digestibility of dry matter, crude protein, acid detergent fiber and neutral detergent fiber were not affected, whereas ether extract digestibility was higher (P<0.05) in S group. There was no effect on plasma glucose, non-esterified fatty acids, triglycerides and cholesterol concentrations between two groups, whereas blood urea nitrogen concentration was lower (P<0.01) in S group. Supplementation of protected nutrients to buffaloes increased milk production and unsaturated fatty acids content in milk fat and persistence of lactation after supplements were withdrawn.     

Influences of flavomycin,ropadiar, and saponin on nutrient digestibility,rumen fermentation,and methane emission from sheep

This study focused on the effects of three additives given together with a hay/concentrate-based diet on nutrient digestibility, rumen fermentation, and methane emission from sheep. The basal diet consisted of 1.29 kg mixed hay and 0.43 kg concentrate mixture based on dry matter (DM). Treatments consisted of control (no additive), flavomycin⁴⁰ (250 mg/d), ropadiar from an oregano extract (250 mg/d), and saponin in the form of a yucca schidigera extract (170 mg/d). Results indicated that intake and digestibility were unaffected by treatments (P>0.05). The NH₃-N concentration of rumen liquor was lower (P<0.05) for additive treatments versus the control treatment. Higher concentrations of volatile fatty acid (VFA) were observed in the saponin (75.8 mmol/L) and ropadiar (73.1 mmol/L) treatments. The proportion of individual fatty acid of rumen liquor was unchanged, whereas lower ratio of acetate to propionate in the saponin treatment was observed (P<0.05). The average methane production expressed on digested organic matter (OM) and neutral detergent fiber (aNDFom) basis were decreased by approximately 3.3 and 12.0 g/kg, respectively in saponin, and 4.2 and 11.9 g/kg in ropadiar treatment compared to the control. Methane production was positively correlated with the concentrations of NH₃-N, and negatively correlated with total VFA and the proportion of propionate of rumen liquor (P<0.05). The study found that saponin and ropadiar could have the potential to reduce rumen methanogenesis in sheep.     

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.