In vitro Fermentation Profile and Methane Production of Kikuyu Grass Harvested at Different Sward Heights

Highly digestible forages are associated with an in vitro low-methane (CH4) rumen fermentation profile and thus the possibility of reducing CH4 emissions from forage-based systems. We aimed to assess the in vitro ruminal fermentation profile, including CH4 production, of the top stratum of Kikuyu grass (Cenchrus clandestinus - Hochst. ex Chiov) harvested at different sward heights (10, 15, 20, 25, and 30 cm). Herbage samples (incubating substrate) were analyzed for their chemical composition, in vitro organic matter digestibility (IVOMD), and morphological components. In vitro incubations were performed under a randomized complete block design with four independent runs of each treatment. Gas production (GP), in vitro dry matter digestibility (IVDMD), CH4 production, total volatile fatty acid (VFA) concentration, and their acetate, propionate, and butyrate proportions were measured following 24 and 48 h of incubation. Herbage samples had similar contents of organic matter, neutral detergent fiber, and crude protein for all treatments. However, a higher acid detergent fiber (ADF) content in taller sward heights than in smaller sward heights and a tendency for metabolizable energy (ME) and IVOMD to decrease as sward height increased were found. Similarly, the stem + sheath mass tended to increase with increasing sward height. Amongst the nutrients, ME (r = −0.65) and IVDMD (r = −0.64) were negatively correlated with sward height (p < 0.001) and ADF was positively correlated with sward height (r = 0.73, p < 0.001). Both the GP and IVDMD were negatively related to the sward height at both incubation times. Sward heights of Kikuyu grass below 30 cm display an in vitro profile of VFAs high in propionate and low in acetate, with a trend toward lower methane production of CH4 per unit of IVDMD. These findings are important to aid decision-making on the optimal sward height of Kikuyu grass and manage animal grazing with the opportunity to reduce CH4 production.

Avena sativa AV25-T (Altoandina) Supplementation as Alternative for Colombia's High-Altitude Dairy Systems: An Economic Analysis

In the Colombian high-altitude tropics (2,200–3,000 m.a.s.l.), Kikuyu grass (Cenchrus clandestinus) is the main feed source for the dairy system. This grass species has good characteristics regarding adaptability and productivity, but is affected by frost, grass bugs (Collaria spp.) and precipitation-related production seasonality. Forage deficits might thus be a problem at several times in a year. As a strategy to maintain production stable, dairy farmers use commercial feed concentrates increasing their production costs. Agrosavia, as a response to this, started in 2005 with the evaluation and selection of new forage species for the Colombian high-altitude tropics. The oat Avena sativa AV25-T was identified as promising alternative to supply the requirements of dry matter in times of deficit and released as cultivar in 2018 under the name Altoandina. The objective of this study was to evaluate the economic viability of Altoandina in Colombia's high-altitude dairy systems. Altoandina (Aa) was provided as silage in two different diets: 35%Aa−65% Kikuyu (Yellow Diet) and 65%Aa-35% Kikuyu (Red Diet). The diet for comparison was traditional grazing with 100% Kikuyu grass (Blue Diet). All diets were supplemented with 6kg commercial feed concentrate, 0.5 kg cotton seeds and 0.5 kg Alfalfa meal per cow/day, respectively. To estimate economic indicators, we used a cashflow model and risk assessment under a Monte Carlo simulation model. Including Altoandina incremented productivity per hectare by 82.3 and 220% in the Yellow and Red Diets, respectively. According to the results of our economic model, the Yellow Diet is the best alternative. Its average Net Present Value (NPV) was superior in >80% and showed a lower variability. The indicators Value at Risk (VaR) and probability (NPV < 0) show the Yellow Diet to have the lowest risk for economic loss under different yield/market scenarios. The Yellow Diet also has the lowest unit production costs and uncertainty of productive parameters. According to our findings, supplementation with Altoandina at 35%, i.e., during critical times, has high potential to improve efficiency and profitability. This information is key for the decision-making process of dairy farmers on whether to adopt this technology.

The effect of dietary forages in tetanus hyper immunized equine serum production

The determination of local forage in meeting the nutritional requirement of horses and its effect on the antibody titer production is necessary to be conducted. The aim of the study was to determine the effect of dietary forage to antibody titer production of Anti-Tetanus Serum. All procedures performed in this study were approved by the Institutional Animal Care and Use Committee (Ethical Approval No: 01/IACUC-BF/VI/20). A total of 12 Sandalwood horses aged 3-6 years with body weight ranged at 268.4 - 365.8 kg were used in this study. Horses were randomly assigned into four dietary treatment groups for ten weeks (100% Elephant grass; 100% Mott elephant grass; 67% Elephant grass: 33% Kikuyu grass; and 67% Mott elephant grass: 33% Kikuyu grass) which allowed 7.24; 11.45; 11.12; 12.62% crude protein respectively. The titer measurement was carried out once a week during the production period. The data obtained was analyzed using correlation analysis. The results showed that 100% Mott elephant grass group produced the highest titer but the correlation between crude protein levels in the diets and titer were weak (0.44). Thus, it can be concluded that the high protein forage given has no potential to increase the serum antibody titer.

Biodiversity of Kikuyu Grass (Pennisetum clandestinum Hochst. ex Chiov) in Indonesia as high protein forage based on morphology and nutrition compared

Kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov) is tropical grass originates from Eastern Africa, that has been introduced in other tropical and subtropical areas including in Indonesia. Kikuyu used as forage with high protein content and palatable. In Indonesia, Kikuyu still rarely exists, and no data reported yet about Kikuyu growing in Indonesia except data about when it was introduced to Indonesia. The aims of this study were to know the biodiversity of Kikuyu in Indonesia and to compare its morphology and nutrition contents between accession. Exploring Kikuyu accessions was done around West of Java province area. The morphology of each accession was observed with parameters and nutrition content of each accession was analyzed using proximate analysis. The results showed 3 accessions of Kikuyu from Burangrang, Tangkuban Perahu and Bukit Tunggul location. Morphology of the 3 accessions shows not significant different in all parameters. Nutrition contents between accessions namely dry matter, water contents, and fat contents shows not significant different. Crude protein content of Kikuyu accessions was ranged between 18.18 to 21.48 % DM. In this study, Burangrang accession had higher crude protein (21.48%) than other accessions, for that it has potential to be developed as superior variety.

Pennisetum clandestinum (Kikuyu grass).

P. clandestinum is an aggressive perennial plant, spreading by rhizomes below ground, especially by long runners above ground, and it also sets seed. It is native to the highlands of eastern Africa but has been widely introduced elsewhere for forage and for soil conservation. In well managed situations it does not generally spread very far but it is highly tolerant of grazing and mowing and can steadily invade poorly managed plantations. It also readily invades natural vegetation with resultant loss of biodiversity. This has occurred in Australia, New Zealand, South Africa, Hawaii and the Galapagos. It is listed as a Federal Noxious Weed in the USA.

Methane emissions from lambs fed kikuyu hay alone or mixtured with lotus hay

Dietaryinclusionof contain­tanninlegumes mayreduce enteric methane emissioninruminants. Toevaluate methane emissions fromsheep fed with a kikuyu grass (Cenchrus clandestinus) diet partially substitutedwith lotus(Lotus uliginosus), twelve growing lambs, with 23 ± 2 kg average liveweight, were assigned randomly totwo treatments and with three measurement periods in a switchover design. Treatments consisted of 100 %kikuyuhay or 70 %kikuyu hay: 30 %lotus hay and with 6 lambs per treatment. Each of three periods lasted 20 d, where thefirst 15 d were for acclimatization and the last 5 d for measurements. Lambs were placed in metabolic cages and fedonce a day (8 AM) at 90 %of their voluntary feedintake, with free access to drinking water. Feedintake, fecalproductionandfeeddigestibility were determinedat eachperiod. Methane productionwas measuredfor eachtreatment group of 6 lambs using the poly­tunnel technique. Legume addition reduced total methane production(27.6vs.23.1 g animal­1; p < 0.01), methane production per dry matter intake (DMI) (18.8 vs. 12.2 g kg­1DMI; p <0.01), methane production per digestible OM(DOM) (36.1vs. 23.4 g kg­1DOM; p < 0.01) and methane productionper digestible NDF (DNDF) (43.5vs. 34.0 g kg­1DNDF; p < 0.01). In conclusion, lotus inclusion in pasture systemscould be a suitable legume to reduce methane emissions in grazing systems.

Selection for resistance to fungal diseases and other desirable traits in kikuyu grass (Cenchrus clandestinus)

While kikuyu (Cenchrus clandestinus) is an important grass for dairy and beef production in the subtropical region of Australia and the world, the most common cultivar, Whittet, is seriously affected by the fungal diseases, kikuyu yellows (Verrucalvus flavofaciens) and black spot (Bipolaris spp.). Thus resistance to these diseases is a priority in selecting a better kikuyu cultivar, along with higher herbage quality and yield and better winter growth. A study was conducted to identify suitable candidates from kikuyu ecotypes collected along the east coast of Australia plus lines obtained by subjecting Whittet to a mutagenic agent. Initial glasshouse studies identified 19 lines that were resistant to the KY1A strain of kikuyu yellows and 4 of these, with forage quality and yield superior to Whittet, were further evaluated in the field at 2 sites using Whittet as the control. At Site 1, line 12A demonstrated a much higher level of resistance to kikuyu yellows than Whittet, with 85% of plants resisting infection compared with only 15% of Whittet plants. At Site 2, the numbers of 12A and Whittet plants infected were similar. Further tests, using kikuyu yellows inoculum collected from 11 sites along the east coast of Australia, found that only 15% of 12A plants became infected compared with 61% of Whittet plants. Thus, kikuyu line 12A was resistant to most, but not all, strains of the kikuyu yellows pathogen. Annual yield of 12A (19,008 kg DM/ha) was 24% higher than that of Whittet and 12% higher than Acacia, but the difference was significant only for Whittet. During summer, 12A produced 10,212 kg DM/ha (24% higher than Whittet), was more active in early spring, had slightly higher dry organic matter digestibility (66.7 vs. 64.0%) and was resistant to black spot infection.

BASE GROWTH TEMPERATURE AND PHYLLOCHRON FOR KIKUYU GRASS (Cenchrus clandestinus; Poaceae)

In order to estimate the base temperature (Bt) of growth through the appearance of leaves and calculate the phyllochron for kikuyu grass, three plots were established on three farms in the Provincia of Ubaté (Cundinamarca, Colombia) located at different altitudes (2560, 2640, 3143 m. a. s. l.). Measurements were made in four cycles in a period of eight months. The Bt was estimated by the least coefficient of variation method using a second order regression model and the model obtained was validated by the cross-validation method. The Bt values for the first, second, third and fourth leaf were 4.02, 3.68, 3.93, and 3.62 ° C, respectively. For the appearance of the first leaf, the kikuyu required more thermal time (TT) (97.5 accumulated growing degree days (AGDD)) than for the second (74.2 AGDD), third (73.8 AGDD) and fourth leaf (76.0 AGDD) (p<0.05). There were no differences in TT among farms (p> 0.05). There was a tendency to a greater number of days required to reach each leaf stage in the farm located at higher altitude and with lower mean temperature. The validation showed an adequate adjustment (r2 = 0.94) and a substantial concordance (CCC = 0.97) between the observed values and the predicted values for the estimated TT with the Bt value obtained for each leaf stage. The results of Bt for kikuyu grass obtained, will allow to make more precise predictions about the phyllochron and generate growth models close to reality.