Rhodes Grass Hay Research Articles

The essential oil blend Agolin Ruminant L reduces methane production in vitro and in vivo when included in the drinking water of cattle.

Two experiments were conducted to determine the potential for the essential oil blend Agolin Ruminant L (Agolin) to reduce enteric methane (CH4) emissions from beef cattle when delivered via the drinking water. Experiment 1 evaluated aqueous solutions of Agolin (50mg/L) and a non-protein nitrogen and mineral solution (uPRO ORANGE [uPRO]; 1.7mL/L) individually and in combination, where Agolin was added to concentrated uPRO at 3, 4.5, 6% Agolin (w/w) prior to dilution with water at 1.7mL/L, for a total of five treatments. These were incubated for 48h with a medium-quality Rhodes grass (Chloris gayana) hay substrate, with gas production, CH4 concentration in gas, and digestibility measured in vitro. In Exp. 2, Droughtmaster steers (n = 24) were fed a basal diet of Rhodes grass hay and were allocated to one of three water treatments (n = 8/treatment) supplemented with either uPRO (2.27mL uPRO/L water), or one of two inclusion rates of Agolin in combination with uPRO (2.27mL uPRO and 6 µL Agolin/L water or 2.27mL uPRO and 24 µL Agolin/L water) with enteric CH4 emissions, feed and water intake, and live weight gain (LWG) measured over 56 d. In Exp. 1, the inclusion of Agolin in uPRO at 6% w/w resulted in a reduction in CH4 production (15.8%; P = 0.003) and the proportion of CH4 in the gas produced (24.5%; P < 0.001). In Exp. 2, steers consuming the lower quantity of Agolin via drinking water had a 16.4% (P = 0.0027) reduction in CH4 production over the experiment, declining from 140g/d during week 1 to 117g/d in week 8. This inclusion rate of Agolin in the drinking water also resulted in a 25g (17.6%) CH4/d decrease in emissions by steers compared to control steers (P = 0.0205). However, no significant differences in CH4 yield (g CH4/kg dry matter intake), or CH4 intensity (g CH4/kg LWG) by steers was observed between treatments. These results demonstrate that Agolin reduces CH4 emissions when mixed in aqueous solution under in vitro and in vivo conditions, providing a potential method to reduce enteric CH4 emissions from cattle in extensive production systems.

Undegradable dietary protein limits growth and carcass yields in crossbred Boer kids fed Desmanthus hay or Rhodes grass (Chloris gayana) hay supplemented with urea and/or cottonseed meal

Context Low-protein tropical forages required protein supplementation, which might affect growth of meat goats. Aims This study was aimed to compare liveweight gain, carcass/non-carcass yields and meat quality in crossbred Boer kids fed isonitrogenous diets varying in undegradable (UDP) and rumen-degradable (RDP) dietary protein sources. Methods Twenty-five female crossbred Boer kids were randomly allocated into the following five dietary treatments: Rhodes grass (Chloris gayana) hay supplemented with urea (U), urea plus cottonseed meal (UCSM), cottonseed meal (CSM), gliricidia (Gliricidia sepium) (Gliri) or Desmanthus (Desmanthus leptophyllus) only (Desman). The diets were formulated to supply 135 and 195 g crude protein/kg DM for the two experiments. Experiment 1 lasted 78 days and the dietary UDP:RDP ratio (g/kg DM) was 35:102 (U), 37:100 (UCSM), 40:97 (CSM), 55:82 (Desman) and 46:91 (Gliri). Experiment 2 lasted 138 days and the dietary UDP:RDP ratio (g/kg DM) was 45:150 (U), 52:143 (UCSM), 58:137 (CSM), 83:112 (Desman) and 71:124 (Gliri) respectively. Data were subjected to one-way ANOVA and general linear model. Key results After 138 days of supplementation, the Desman goats had the highest liveweight gain (83 g/day) and heaviest cold carcass weight (12.1 kg) in Experiment 2. This was followed, in descending order, by CSM (58 g/day and 9.6 kg), UCSM (48 g/day and 7.8 kg), Gliri (41 g/day and 7.6 kg) and U (6 g/day and 6.0 kg). Heavier carcass weight was associated with larger eye-muscle area and fat depth at the 12th rib. Aus-meat Beef Colour Standard scores of 3–4 for the eye muscle of the Desman and CSM goats compared with scores of 1C-2 in the other goats meant that the darker meat in Desman and CSM diets was associated with heavier carcass weight and a more rapid rate of decline in carcass pH. Conclusions Crossbred Boer kids fed high dietary UDP had higher intakes of UDP, RDP, metabolisable protein (MP) and metabolisable energy (ME), even though an isonitrogenous diet was offered. The Desman kids had higher liveweight gain, heavier carcass yield, greater eye-muscle area, thicker fat depth and heavier mass of non-carcass components. Implications The higher liveweight gain and carcass/non-carcass yields for Desman goats than for others was associated with increased DM, UDP, RDP, MP and ME intakes.

Supplementation of crossbred boer goats with cottonseed meal and/or urea enhances estimated metabolizable protein intake, crude protein digestibility and nitrogen retention

This study aimed to determine feed intake, apparent digestibility, and nitrogen retention of crossbred Boer bucks supplemented with urea or cottonseed meal (CSM)when fed tropical Rhodes (Chloris gayana) grass hay (RGH) as a basal diet. Twelve eight-month-old bucks (23.9±1.1 kg live weight) were allocated to one of the four dietary treatments in a randomised block design. The treatments were 1) maize supplement (Control); or maize plus 2) urea supplement (M+U), 3) urea and CSM (M+UCSM); and (4) CSM (M+CSM). All bucks were held in individual metabolism crates for 21 days (11 days of adaptation and 10 days collection period) with ad libitum access to RGH and fresh drinking water in addition to the supplements. A one-way ANOVA and Duncan’s multiple range tests were used to test for differences between means at a significance level of P &lt; 0.05. Results indicated higher feed intake, apparent digestibility of crude protein and digestible nutrient intake in goats supplemented with M+CSM and M+UCSM, but not M+U alone. Supplementation with M+CSM increased nitrogen retention by 300%. Supplementation with M+UCSM and M+CSM increased the total feed intake of Boer goats on tropical grass hay by 13 and 20%, respectively. Supplementation with M+U, M+UCSM, and M+CSM improved the apparent digestibility of crude protein by 9.7, 15.7 and 15.1%, respectively. It can be concluded that total feed intake and nutrient digestibility was increased on growing Boer goats fed RGH as a basal diet supplemented with true protein from CSM or a mixture of true protein and rumen degradable protein from urea.

Replacing ground Rhodes grass hay with soyhulls in the pelleted diet: effects on ingestive behavior, nutrient digestibility, blood metabolites, growth performance, and economic viability of intensive fattening Lohi lambs.

This study aimed to evaluate the effects of replacing soyhulls (SH) for ground Rhodes grass hay (RGH) in a pelleted diet on ingestive behavior, digestibility, blood metabolites, growth performance, and economic viability of fattening Lohi lambs. A total of thirty male lambs (age: 5months; body weight 20.4 ± 0.24kg) were allotted to one of the three diets (n = 10 lambs/diet) under a completely randomized design. The diets were with 25% RGH inclusion (control), replacing 15% RGH with 15% SH as a fiber source (SH-15), and containing only 25% SH inclusion on a dry basis (SH-25). Ingestive behavior parameters like time spent (min/day), bouts frequency (number/day), and bout length (min/bout) for feeding, drinking, rumination, chewing, standing, and lying were not influenced (P > 0.05) by replacing RGH with SH. The dry matter (DM) and neutral detergent fiber (NDF) chewing rate, rumination rate, and feeding efficiency were also not changed (P > 0.05) by dietary treatments, whereas total dry matter and NDF intakes, and their rumination efficiencies were lower (P < 0.05) for the SH-25 than for the rest of the treatments. The digestibility of NDF and acid detergent fiber (ADF) was higher (P < 0.05) for the SH-25 than for the rest of the treatments. The concentrations of blood metabolites like glucose, blood nitrogen, and cholesterol were not changed (P > 0.05) among the treatment groups. Similarly, performance parameters like dry matter intake, initial and final body weight, average daily gain, and feed conversion ratio were similar (P > 0.05) across the treatments. However, the incidence of loose fecal consistency was higher (P < 0.05) for SH-25 than for the control. The values of economic efficiency were better for SH-25-fed lambs than those fed the rest of the treatments. Based on the results, substituting SH for RGH in a pelleted diet improved the digestibility of fiber fractions, and economics without affecting the growth performance, and blood metabolites of fattening lambs. However, lower rumination efficiency and loos fecal consistency are evidencing less effectiveness of SH fiber.

Effects of Neem (Azadirachta indica) Leaf Powder Supplementation on Rumen Fermentation, Feed Intake, Apparent Digestibility and Performance in Omani Sheep.

The objective of the present study was to evaluate the potential of the dietary addition of neem (Azadirachta indica) leaf powder (NLP) when compared to monensin (MON) on ruminal fermentation, feed intake, digestibility, and performance of growing lambs. Eighteen Omani lambs (22.8 ± 2.18 kg of body weight (BW)) were equally divided into three groups (n = 6 lambs/group) for 90 days. Animals were fed an ad lib basal diet consisting of Rhodes grass (Chloris gayana) hay (600 g/kg) and a concentrated mixture (400 g/kg) offered twice daily. Experimental treatments were control (basal diet without supplements); MON (control plus 35 mg/kg DM as a positive control); and NLP (control plus 40 g/kg DM). Lambs fed NLP had reduced ruminal ammonia nitrogen concentrations, protozoal counts, total volatile fatty acid, and blood urea nitrogen concentrations compared to the control. Compared to MON, lambs fed NLP had increased ruminal acetate and decreased propionate proportions. Inclusion of NLP in the diet increased blood total protein, globulin, and liver enzyme concentrations in comparison with the control, which was similar to MON. The lamb's final BW and average BW gain were also increased with the NLP relative to the control. Further, adding NLP to the diet increased the digestibility of crude protein compared to the control diet. In conclusion, adding NLP to the diet with 40 g/kg DM could be used as a promising phytogenic supplement for growing lambs with no detrimental effects on the ruminal fermentation profile, nutrient intake, or digestibility.

PSVIII-10 In Vitro Incubation with a Bacillus-Based Direct-fed Microbial Improves Forage Digestibility Parameters

Abstract Over the years, the use of direct-fed microbials (DFM) has been gaining attention and interest by beef cattle producers and nutritionists, due to health benefits associated with these solutions. Moreover, some bacterial strains currently fed to cattle are also capable of producing and releasing enzymes that might improve nutrient utilization in beef animals. Hence, we hypothesized that the incubation of a Bacillus-based DFM would improve in vitro dry matter (DM) and neutral detergent fiber (NDF) digestibility of ten forage sources (spinifex, buffel grass, Flinders grass, Queensland bluegrass, corn silage, lucerne hay, ryegrass, rhodes grass hay, leucaena, and Mitchell grass hay). Our objective was to evaluate the effects of incubating a Bacillus-based DFM on in vitro forage digestibility. Forage sources were incubated, in triplicate, into the media containing or not Bacillus-based DFM (Bacillus licheniformis and B. subtilis; 3.2 × 109 CFU/g; Bovacillus, Chr. Hansen A/S, Horsholm, Denmark) over a 48-h period. The DAISY-II fermentation technique was used with the buffer and nutrient solution described by Goering and Van Soest (1970). The DFM was added to the rumen fluid of treatment groups to simulate the dose of 3 g/animal per day and filter bags were used to isolate 0.5 g of ground forage samples. All data were analyzed using SAS. Inoculation of a Bacillus-based DFM increased overall mean in vitro DM digestibility in 8 out of 10 forage sources with improvements ranging from 6. 1 to 27.3% (P ≤ 0.01). Similarly, mean in vitro NDF digestibility was improved in 8 out of 10 forage types (P ≤ 0.01). In summary, incubation of a Bacillus-based DFM improved in vitro DM and NDF digestibility in forage sources of varying nutritional profile, demonstrating its feasibility to be used in forage-based beef systems.

Enteric Methane Emission from Sheep Fed with Rhodes Grass Hay (Chloris gayana) Alone or Supplemented with Dried Distillers’ Grains with Solubles

Livestock systems based on subtropical and tropical pastures are characterized by the low productivity of livestock due to the poor nutritional value of the forage (low nitrogen concentration and digestibility, and high fiber and lignin concentrations). These conditions lead to low productivity and, consequently, high absolute emissions of methane (CH4) per unit of product. Dry distilled grains with solubles (DDGS) are the main by-product resulting from ethanol production, and they are characterized by their high-energy fibrous and protein content, thus becoming an option for the supplementation of low-quality forage. This research investigated the effects of dietary DDGS inclusion on dry matter digestibility (DMD) and enteric CH4 emission. Eight adult sheep of 64 ± 8 kg live weight were used. The duration of the study was 54 days, divided into two periods (changeover design), which comprised a 17-day pre-experimental period and 10 days for experimental data collection. Animals were allocated to one of two treatments used: hay (H) as a control treatment, where animals were fed with Rhodes grass hay alone; and H + DDGS, where animals were fed with H supplemented with DDGS. CH4 emissions were estimated using the sulfur hexafluoride (SF6) tracer technique. Diets containing DDGS increased DMI by 22% (p &lt; 0.05) and reduced daily CH4 emissions by 24% (g/d), the CH4 yield by 35% (g/kg DMI), and the average value of CH4 energy per gross energy intake (Ym) by 44%, compared to the control treatment (p &lt; 0.05). The experiment demonstrated that supplementation with DDGS in low-quality roughage reduced daily CH4 emissions, yields, and Ym.

Towards Sustainable Sources of Omega-3 Long-Chain Polyunsaturated Fatty Acids in Northern Australian Tropical Crossbred Beef Steers through Single Nucleotide Polymorphisms in Lipogenic Genes for Meat Eating Quality

This study aimed to identify single nucleotide polymorphisms (SNP) in lipogenic genes of northern Australian tropically adapted crossbred beef cattle and to evaluate associations with healthy lipid traits of the Longissimus dorsi (loin eye) muscle. The hypothesis tested was that there are significant associations between SNP loci encoding for the fatty acid binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD) and fatty acid synthase (FASN) genes and human health beneficial omega-3 long-chain polyunsaturated fatty acids (ω3 LC-PUFA) within the loin eye muscle of northern Australian crossbred beef cattle. Brahman, Charbray, and Droughtmaster crossbred steers were fed on Rhodes grass hay augmented with desmanthus, lucerne, or both, for 140 days and the loin eye muscle sampled for intramuscular fat (IMF), fat melting point (FMP), and fatty acid composition. Polymorphisms in FABP4, SCD, and FASN genes with significant effects on lipid traits were identified with next-generation sequencing. The GG genotype at the FABP4 g.44677239C&gt;G locus was associated with higher proportion of linoleic acid than the CC and CG genotypes (p &lt; 0.05). Multiple comparisons of genotypes at the SCD g.21266629G&gt;T locus indicated that the TT genotype had significantly higher eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids than GG genotype (p &lt; 0.05). Significant correlations (p &lt; 0.05) between FASN SNP and IMF, saturated and monounsaturated fatty acids were observed. These results provide insights into the contribution of lipogenic genes to intramuscular fat deposition and SNP marker-assisted selection for improvement of meat-eating quality, with emphasis on alternate and sustainable sources of ω3 LC-PUFA, in northern Australian tropical crossbred beef cattle, hence an acceptance of the tested hypothesis.

Effects of a Bacillus-based direct-fed microbial on in vitro nutrient digestibility of forage and high-starch concentrate substrates.

Two experiments evaluated the effects of a Bacillus-based direct-fed microbial (DFM) on in vitro dry matter (DM) and neutral detergent fiber (NDF; experiment 1) and starch (experiment 2) digestibility of a variety of ruminant feedstuffs. In experiment 1, 10 forage sources were evaluated: ryegrass, alfalfa hay, leucaena, corn silage, spinifex, buffel grass, flinders grass, Mitchell grass, Rhodes grass hay, and Queensland bluegrass. Experimental treatments were control (forages with no probiotic inoculation; CON) and forage sources inoculated with a mixture containing Bacillus licheniformis and Bacillus subtilis (3.2 × 109 CFU per g; DFM). In vitro DM and NDF digestibility were evaluated at 24- and 48-h post-treatment inoculation. Treatment × hour interactions were noted for IVDMD (in vitro dry matter digestibility) and IVNDFD (in vitro neutral detergent fibre digestibility) (P ≤ 0.05). More specifically, DFM inoculation increased (P ≤ 0.03) IVDMD at 24 h in four forages and increased 48-h IVDMD (P ≤ 0.02) in alfalfa hay, ryegrass, leucaena, and Mitchell grass hay, but opposite results were observed for Queensland bluegrass (P < 0.01). A 24- and 48-h IVNDFD increased following DFM inoculation (P ≤ 0.02) in five forage sources, but reduced for Queensland bluegrass (P < 0.01). When the forages were classified according to their quality, main treatment effects were detected for IVDMD (P ≤ 0.02) and IVNDFD (P < 0.01). In experiment 2, five common cereal grains were evaluated—high-density barley (82 g/100 mL), low-density barley (69 g/100 mL), corn, sorghum, and wheat—under the same treatments as in experiment 1. In vitro starch digestibility (IVSD) was evaluated at 6- and 12-h following treatment inoculation. Treatment × hour interactions were observed for starch digestibility in three out of five concentrate sources (P ≤ 0.001). Inoculation of DFM yielded greater 24-h starch digestibility for high-, low-density barley, and wheat (P ≤ 0.02), but also greater at 48 h in wheat (P < 0.0001). Moreover, mean starch digestibility improved for corn and sorghum inoculated with DFM (P < 0.01). Using a Bacillus-based DFM (B. licheniformis and B. subtilis) improved the mean in vitro DM and NDF digestibility of different forage sources of varying qualities (based on crude protein content). Similarly, IVSD was also greater following DFM inoculation, highlighting the potential of this probiotic to improve nutrient digestibility and utilization in the beef and dairy cattle herd.

Nutritive value of forages and diets in some small-scale dairy farms in Kiambu County, Kenya in the short rains season

Sixteen selected small-scale dairy farms were investigated in Kiambu County (Kenya) during the short rains seasonto develop a snapshot of the types of rations fed, milk yields obtained and sources of fodder. On average farmers had1 ha of land and 2.2 lactating cows yielding 8.93 kg milk/cow/d with feed intake of 10.5 kg DM/d. Only 35% of feedconsumed was produced on farm. Boma Rhodes grass hay and green Napier grass were the main forage components(37.9 and 28.3% of total DM). Protein forages used were the herbaceous legumes lucerne and desmodium (19.9 and15.9% CP, respectively) and leguminous shrubs (Leucaena, Calliandra and Sesbania with 21.1% CP and 43.4%aNDFom, on average). Grasses had higher aNDFom digestibility (47.1%) than legumes (39.7%). Napier grass, BomaRhodes grass, lucerne and desmodium had fiber digestibility of 51.9, 48.6, 46.8 and 32.6%, respectively. The energyand protein balances (actual vs. requirements) of the cows were on average -19.3 and -16.4%, respectively, indicatingthat cows utilized body tissues to produce the levels of milk obtained. Mutiple correspondence analysis showed that amilk yield higher than 9.1 kg/d was associated with a level of Boma Rhodes grass &lt;5 kg DM/d, concentration of nonfibrous carbohydrates in the diet &gt;22.0% (DM basis), concentrate level &gt;2.63 kg/cow/d and CP% in the ration &gt;9.1%. To improve milk yields during this season farmers should harvest grass forage at a younger age, include leguminous forage in the diets and increase the level of concentrates fed. These strategies should be demonstrated on farms to show possible benefits.

Effect of incremental proportions of Desmanthus spp. in isonitrogenous forage diets on growth performance, rumen fermentation and plasma metabolites of pen-fed growing Brahman, Charbray and Droughtmaster crossbred beef steers.

Desmanthus (Desmanthus spp.), a tropically adapted pasture legume, is highly productive and has the potential to reduce methane emissions in beef cattle. However, liveweight gain response to desmanthus supplementation has been inconclusive in ruminants. This study aimed to evaluate weight gain, rumen fermentation and plasma metabolites of Australian tropical beef cattle in response to supplementation with incremental levels of desmanthus forage legume in isonitrogenous diets. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were pen-housed and fed a basal diet of Rhodes grass (Chloris gayana) hay supplemented with 0, 15, 30 or 45% freshly chopped desmanthus forage on dry matter basis, for 140 days. Varying levels of lucerne (Medicago sativa) hay were added in the 0, 15 and 30% diets to ensure that all diets were isonitrogenous with the 45% desmanthus diet. Data were analyzed using the Mixed Model procedures of SAS software. Results showed that the proportion of desmanthus in the diet had no significant effect on steer liveweight, rumen volatile fatty acids molar proportions and plasma metabolites (P ≥ 0.067). Total bilirubin ranged between 3.0 and 3.6 μmol/L for all the diet treatments (P = 0.67). All plasma metabolites measured were within the expected normal range reported for beef cattle. Rumen ammonia nitrogen content was above the 10 mg/dl threshold required to maintain effective rumen microbial activity and maximize voluntary feed intake in cattle fed low-quality tropical forages. The average daily weight gains averaged 0.5 to 0.6 kg/day (P = 0.13) and were within the range required to meet the target slaughter weight for prime beef markets within 2.5 years of age. These results indicate that desmanthus alone or mixed with other high-quality legume forages can be used to supplement grass-based diets to improve tropical beef cattle production in northern Australia with no adverse effect on cattle health.

Lipid Metabolism, Carcass Characteristics and Longissimus dorsi Muscle Fatty Acid Composition of Tropical Crossbred Beef Cattle in Response to Desmanthus spp. Forage Backgrounding.

Lipid metabolism, carcass characteristics and fatty acid (FA) composition of the Longissimus dorsi (loin eye) muscle were evaluated in tropical crossbred steers backgrounded on Desmanthus spp. (desmanthus) with or without feedlot finishing. It was hypothesized that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce carcasses with similar characteristics and FA composition. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were backgrounded for 140 days on Rhodes grass (Chloris gayana) hay augmented with 0, 15, 30 or 45 percent desmanthus on dry matter basis. Lucerne (Medicago sativa) hay was added to the 0, 15 and 30 percent desmanthus diets to ensure that they were isonitrogenous with the 45 percent desmanthus diet. After backgrounding, the two heaviest steers in each pen were slaughtered and the rest were finished in the feedlot for 95 days before slaughter. Muscle biopsy samples were taken at the beginning and end of the backgrounding phase. Carcasses were sampled at slaughter for intramuscular fat (IMF) content, fat melting point (FMP) and FA composition analyses. Increasing the proportion of desmanthus in the diet led to a linear increase in docosanoic acid (p = 0.04) and omega-6/omega-3 polyunsaturated FA ratio (n-6/n-3 PUFA; p = 0.01), while docosahexaenoic acid decreased linearly (p = 0.01). Feedlot finishing increased hot carcass weight, subcutaneous fat depth at the P8 site and dressing percentage (p ≤ 0.04). The n-6/n-3 PUFA ratio was within the recommended < 5 for human diets. IMF was within the consumer-preferred ≥3% level for palatability. The hypothesis that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce similar carcass characteristics and FA composition was accepted. These findings indicate that a combination of tropical beef cattle backgrounding on desmanthus augmented forage and short-term feedlot finishing produces healthy and highly palatable meat.

Assessment of fodder resources in Ethiopia: Biomass production and nutritional value

AbstractFodders are the major feed resource in Ethiopia. This study was conducted to assess biomass production and nutritive value of fodder resources in Ethiopia. A total of 34 scientific papers and 30 Central Statistical Agency (CSA) (Ethiopia) reports for biomass production, and 249 scientific papers for nutritive value were used for this study. The biomass production of crop residues was greatest followed by grazing biomass, enset [Ensete ventricosum (Welw.) Cheesem.] and banana (Musa spp.) leaves and pseudostems. The crude protein (CP) concentration of vetch (Vicia spp.) hay, alfalfa (Medicago sativa L.) hay, cultivated legume species and many indigenous browse species was &gt;150 g kg−1 dry matter (DM). However, the CP value of natural pasture, crop residues, natural pasture hay, rhodes grass (Chloris gayana Kunth) hay, cultivated grass species, sycamore fig (Ficus sychomorus L.), Indianfig pricklypear [Opuntia ficus‐indica (L.) Mill.] and enset and banana was &lt;150 g kg−1 DM. Natural pasture, crop residues, all parts of enset except enset corm, natural pasture hay, rhodes grass hay, and cultivated grass species contained &gt;550 g kg−1 DM neutral detergent fiber (NDF). Enset corm, vetch hay, alfalfa, Chinese banyan (Ficus thonningii Blume), and bitter leaf (Vernonia amygdalina Delile) contained &gt;10 MJ kg−1 DM metabolizable energy (ME). Crop residues except faba bean straw contained &lt;600 g kg−1 DM in‐vitro digestibility. Methods should be devised for more efficient and effective use of the most widely available crop residues and grazing biomass through better management practices and appropriate supplementation with good quality forages and locally available better quality agricultural and agro‐industrial by‐products.

Response to Climate Change: Evaluation of Methane Emissions in Northern Australian Beef Cattle on a High Quality Diet Supplemented with Desmanthus Using Open-Circuit Respiration Chambers and GreenFeed Emission Monitoring Systems.

Simple SummaryThe beef industry in Northern Australia is characterized by an extensive grazing system in dry tropical rangelands defined by climate change indices of very low rainfall, a prolonged dry season and feeds of low nutritive value. In response, beef cattle need to be more efficient in converting the available drought-tolerant feeds to muscle, in an attempt to minimize greenhouse gas emissions. This study addressed the problem of reducing methane emissions from tropical beef cattle with the goal of decreasing the impact of climate change and greenhouse gas emissions in Northern Australia. The primary objective was to compare the effect of supplementing tropical beef cattle with both good quality lucerne and poor quality hay with increasing levels of different Desmanthus cultivars on in vivo methane emission. The results showed that in tropical beef cattle on high-quality diets, irrespective of cultivar and emission evaluation method, Desmanthus does not reduce methane emissions.The main objective of this study was to compare the effect of supplementing beef cattle with Desmanthus virgatus cv. JCU2, D. bicornutus cv. JCU4, D. leptophyllus cv. JCU7 and lucerne on in vivo methane (CH4) emissions measured by open-circuit respiration chambers (OC) or the GreenFeed emission monitoring (GEM) system. Experiment 1 employed OC and utilized sixteen yearling Brangus steers fed a basal diet of Rhodes grass (Chloris gayana) hay in four treatments—the three Desmanthus cultivars and lucerne (Medicago sativa) at 30% dry matter intake (DMI). Polyethylene glycol (PEG) was added to the diets to neutralize tannin binding and explore the effect on CH4 emissions. Experiment 2 employed GEM and utilized forty-eight animals allocated to four treatments including a basal diet of Rhodes grass hay plus the three Desmanthus cultivars in equal proportions at 0%, 15%, 30% and 45% DMI. Lucerne was added to equilibrate crude protein content in all treatments. Experiment 1 showed no difference in CH4 emissions between the Desmanthus cultivars, between Desmanthus and lucerne or between Desmanthus and the basal diet. Experiment 2 showed an increase in CH4 emissions in the three levels containing Desmanthus. It is concluded that on high-quality diets, Desmanthus does not reduce CH4 emissions.

Plasma Metabolites, Productive Performance and Rumen Volatile Fatty Acid Profiles of Northern Australian Bos indicus Steers Supplemented with Desmanthus and Lucerne.

The hypothesis tested was that tropical steers supplemented with the Desmanthus legume and lucerne, a widely characterized temperate legume of high nutritive value, would elicit similar responses in plasma metabolite profiles, productive performance, nitrogen retention, and volatile fatty acids (VFA). The tannin-binding compound, polyethylene glycol-4000 (PEG), was added to the diets (160 g/kg Desmanthus dry matter) with the objective of further exploring nitrogen (N) utilization in the animals supplemented with Desmanthus relative to lucerne. From February to June 2020, sixteen yearling Brangus steers (average liveweight of 232 ± 6 kg) were fed a background diet of Rhodes grass (Chloris gayana) hay for 28 days, before introducing three Desmanthus cultivars (Desmanthus virgatus cv. JCU2, D. bicornutus cv. JCU4, D. leptophyllus cv. JCU7) and lucerne (Medicago sativa) at 30% dry matter intake (DMI). Relative to the backgrounding period, all supplemented steers exhibited similar growth performance. Steers supplemented with Desmanthus recorded a lower DMI and animal growth performance, but higher fecal N concentration than animals supplemented with lucerne. Among the three Desmanthus cultivars, there were no significant differences in N concentrations, VFA, and plasma metabolite profiles. The addition of PEG induced higher rumen iso-acid concentrations and fecal N excretion. However, feeding Desmanthus spp. to tropical Bos indicus steers could be a valuable means of increasing N utilization, which is attributable to the presence of tannins, and, consequently, improve animal productive performance. Since supplementation with lucerne resulted in higher liveweight, daily liveweight gains, and overall animal performance than supplementing with Desmanthus, the tested hypothesis that both supplements will elicit similar animal performance does not hold and must be rejected. Further in vivo investigation is needed to better understand the impact of tannins in Desmanthus on N utilization.

Effect of dietary concentrate content on feed intake, feed efficiency, and meat quality of Holstein steers fattened in a hot environment.

The objective of this study was to investigate the effect of feeding high and low concentrate diets on feed intake and feed efficiency, the morphological characteristics of the rumen papillae, and meat quality of Holstein steers fattened under hot climate conditions in Oman. Ten male Holstein calves, of 5months of age, were selected for the experiment. The animals were fed concentrate and Rhodes grass hay and were divided into two groups of high concentrate (HC, n=5) and low concentrate diets (LC, n=5), in which their feed intake, weight gain, and feed efficiency were evaluated across three growing periods. Feed intake and efficiency and average daily gain (ADG) of the HC group were significantly greater than for the LC group and were affected by the diet (p<.01) and the period (p<.001). Across the fattening periods, ADG declined in both groups, with ADG improved by 35% for steers on the HC diet compared to steers on the LC diet. Carcass meat quality was not affected significantly by the dietary concentrate level. In conclusion, our results can be used to make improvements in feed efficiency of Holstein steers under hot climate conditions.

Supplementing Northern Australian Beef Cattle with Desmanthus Tropical Legume Reduces In-Vivo Methane Emissions.

Simple SummaryThe problem addressed in this study is that of mitigating methane emissions by tropical beef cattle with the aim of reducing the impact of climate change and greenhouse gas emissions in Northern Australia. The primary objective was supplementing tropical beef cattle on poor quality hay with incremental levels of Desmanthus leptophyllus cv. JCU1 and Desmanthus bicornutus cv. JCU4 to evaluate their in-vivo antimethanogenic effect. Results showed that, irrespective of cultivar, incremental supplementation with up to 31% of Desmanthus led to a 10% linear decrease in methane emissions without reducing dry matter intake. This finding makes a significant novel contribution to a better understanding of the impact of supplementing beef cattle with Desmanthus on in vivo methane reduction and the role of condensed tannins in rumen fermentation. The practical implication of this finding is that Desmanthus, an adapted tropical legume, has the potential to mitigate in vivo methane emissions by beef cattle in the drier parts of Northern Australia and contribute to the larger global effort of reducing the impact of climate change and greenhouse gas emission.The main objective of this study was to investigate the effect of supplementing beef cattle with incremental levels of Desmanthus leptophyllus cv. JCU1 and Desmanthus bicornutus cv. JCU4 on in vivo methane (CH4) emissions and the role of tannins in rumen fermentation. Fourteen yearling Droughtmaster steers were allocated to each of the two Desmanthus species and offered a basal diet of Rhodes grass (Chloris gayana) hay plus fresh Desmanthus at 0%, 15%, 22%, and 31% of dry matter intake (DMI). The 15% and 31% Desmanthus periods lasted 21 days and the 22 and 0% Desmanthus periods, 14 days. Methane production was measured by open-circuit gas exchange in the last two days of each period. The results showed a linear increase in DMI and reduction in CH4 yield with the increasing level of Desmanthus and subsequently condensed tannins in the diet. The added tannin binder polyethylene glycol-4000 did not affect CH4 yield but increased rumen NH3-N and iso-acid concentrations. Therefore, on a low-quality diet, Desmanthus has the potential to increase intake and reduce CH4 emissions. Even though its tannins can bind rumen proteins, the beef cattle anti-methanogenic response to supplementation with Desmanthus may be a combination of rumen fermentation and tannin effects.

Noug Seed (Guizotia abyssinica) Cake Substituted with Dried Mulberry (Morus indica) and Vernonia amygdalina Mixed Leaves' Meal on Growth Performances of Bonga Sheep at Teppi, Ethiopia.

This study was conducted to evaluate noug seed (Guizotia abyssinica) cake substituted with dried mulberry and Vernonia mixed leaves' meal on feed intake, body weight change, and digestibility of Bonga sheep fed on Rhodes grass hay at Teppi Agricultural Research Center, Ethiopia. The experiment was conducted using 25 yearling lambs with an average initial body weight of 20.83 ± 1.66 kg. Five lambs were allotted per treatment in randomized complete block design. Treatments were isonitrogenous supplements of 100% concentrate (49.5% NSC, 49.5% ground maize grain, and 1% salt) offered at 400 g DM/head/day (T1), 25, 50, 75, and 100 of NSC CP substituted by dried mulberry and Vernonia mixed leaves' meal in T2 = 429.8 g/day, T3 = 459.5 g/day, T4 = 489.3 g/day, and T5 = 519 g/day, respectively. The sheep were fed Rhodes grass hay adlibitum and had free access to water and salt block. Intake and growth trail lasted for 90 days followed by 10 days of digestibility trial. The CP, NDF, and ADF contents of Rhodes grass hay were 7.9, 74.8, and 46.8 percent. The CP content of NSC, ground maize grain, dried mulberry, and Vernonia leaves was 32.4, 8.3, 18.5, and 22.5%, respectively. Total DM intake (g/day) was significantly higher for lambs in T3 (771.4) than in T1 (722.8) and T5 (642.8) but similar to T2 (754.9) and T4 (759.7). The CP intake was highest (P < 0.001) for sheep in T2 and T3, but lowest in T5. The apparent DM digestibility for T1 (70.8%), T2 (68.8%), and T3 (69.1%) was significantly higher than for T5 (64.4%), while T4 (67.9%) and T5 were not significantly different. The attained average daily gain (g/day) of sheep in T1 (87.7), T2 (82.0), T3 (83.4), and T4 (75.2) was higher (P < 0.01) than in T5 (56.0). The result of this study indicated that dried mulberry and Vernonia mixed leaves' meal can substitute NSC as a protein supplement up to 75% inclusion level resulting in optimum DM and nutrient intakes and body weight gain of yearling Bonga sheep. This study also highlights the positive potential of dried mulberry and Vernonia mixed leaves' meal as a supplement to ruminants on a basal diet of fibrous feeds.

Effect of Different Levels of Noug (Guizotia Abyssinica) Seed Cake Supplementation on Growth Performance of Doyogena Sheep Fed Rhodes Grass Hay Basal Diet

The objective of the study was to evaluate the effect of different levels of Noug ( Guizotia Abyssinica ) seed cake supplementation on feed intake, digestibility and body weight change of Doyogena sheep fed Rhodes grass hay basal diet. The experimental period was 112 days including 90 days of feeding trial and 15 days of adaptation period. Twenty four lambs were assigned into six groups based on their body weight and randomly assigned to four treatments with replication of six sheep to each treatment. The experimental animals were fed on Rhodes grass hay as a basal diet. The treatments were: T1 (Hay ad libtium+ 200 g Wheat bran), T2 (Hay ad libtium +200 g Wheat bran + 150 g Noug cake), T3 (Hay ad libtium+200 g Wheat bran+175 g Noug cake) and T4 (Hay ad libtium+200 g Wheat bran+200 g Noug cake). Fecal samples were collected for 7 days after 3 days of familiarizing lambs to carry fecal bags. Significant (p&lt; 0.001) differences were observed in total dry matter, organic matter and crude protein intakes among treatments. Intake increased as level of noug seed cake supplementation increased. The dry matter, organic matter, crude protein digestibility and feed conversion efficiency were significantly (p&lt; 0.001) higher with increased level of noug seed cake. Higher (p&lt; 0.001) final body weight and average daily body weight gains were observed in sheep supplemented with highest level of Noug seed cake. Based on the results of this study, it can be concluded that supplementation of lambs with 200 g of Noug seed cake was potentially feasible and economically beneficial. Key words : Digestibility, Doyogena, Intake, Noug seed cake, Wheat bran, Weight gain DOI: 10.7176/ALST/81-01 Publication date: August 31 st 2020

Effects of Inclusion Levels of Sweet Potato Vine Silage on Feed Intake, Milk Production and Profitability of Lactating Crossbred Dairy Cows

Feed scarcity is a major challenge in smallholder production systems especially during the dry season. Sweet potato vines (SPV) contribute over 40% of the crop residues fed to dairy cattle but they are highly perishable resulting into losses of about 24% per season. Ensiling SPV mitigates seasonal feed shortages and assists in coping with seasonal feed price fluctuations. This study was conducted to evaluate the effect of sweet potato vines silage (SPVS) supplementation on the performance of lactating Ankole × Friesian crossbred dairy cattle. Four primiparous cows in early lactation were randomly allotted a basal diet of Rhodes grass (Chloris gayana) hay supplemented with dairy pellets and four graded levels of SPVS (0, 100, 200 and 300 g/kg of the daily ration) in a 4 × 4 Latin square design. The animals were given a one-week adaptation period followed by a two weeks data collection period for each diet. Dry matter intake (DMI), live weight changes, milk yield and composition were determined. Dry matter intake improved with addition of SPVS (P ≤ 0.05), with intake being highest (11.9 kg) in cows that were fed the highest SPVS level and lowest in cows that were not given SPVS (6.8 kg). Although animals on diets with 0, 100, 200 g of SPVS/kg of daily ration lost weight, there were no significant differences (P ≥ 0.05) in body weight changes across all treatments. Milk yield increased with SPVS supplementation by 1.5 - 1.7 kg per cow per day but there were no significant differences between the different SPVS supplementation levels. Milk fat and solids-non-fat differed (P ≤ 0.05) across the four diets but there was no consistent trend observed. Considering profit margins, supplementing dairy cows with SPVS at a level of 100 g/kg of daily ration was the most profitable at Uganda shillings 1290 (0.344 USD) per cow per day. In conclusion, SPVS supplementation improved DMI and milk yield but supplementation beyond 100 g/kg of the daily feed intake was not cost-effective.