Aspects to consider for the brotamotological analysis of grasslands.
Dear readers, in our blog we have described a great diversity of aspects related to grassland, considering that it is a crop of great importance in the livestock sector for the feeding of ruminants, pasture when properly managed can strengthen such economic activity by generating excellent income. In this sense, in order to increase the productivity of meat and milk within agricultural production units, animals must be adequately nourished and to achieve this, grasslands must have acceptable nutritional levels of elements such as protein and fiber.
In this same order of ideas, those who do not know about this area will ask How can I know the nutritional levels of pastures? is certainly an excellent question, because agricultural systems should not be managed in an improvised way and much less of hunches or estimates, that is why, in order to know the nutritional levels of grasses, an analysis of grasses must be carried out in the laboratory of bromatology using different methods, depending on the type of element to be known, In order to take the sample of these plants to the laboratory, a sampling of the plants must be carried out on the sown area, the methodology of which I will share in the following link:
SAMPLING METHOD AND PASTURE QUALITY
Among the analyses that are usually sent to the producers in the pastures are the percentage of proteins and fiber since, the protein intervenes in various essential vital functions, such as metabolism, muscle contraction or immune response of the animal and fibre is essential to maintain rumen functionality (bovine stomach compartment), stimulate chewing, rumination and keeping the pH of the rumen adequate for good health and digestion.
Crude fiber can be determined with proximal analysis but some researchers among them Peter Van Soest (1963), point out that for the determination of fiber in grasslands this analysis is not accurate "because a small part of lignin and hemicellulose is dissolved in the treatment applied", consequently, the raw fibre does not entirely include the elements that make up the fibre, which are cellulose, hemicellulose and lignin. Due to the inaccuracy in the determination of the raw fiber, Van soest thinking about feeding ruminants developed the analysis known today as the van soest method which divides the fiber into: detergent neutral fiber (FND) and detergent acid fiber (FAD).
Particularly when performing some laboratory analyses, I like to use the van soest method, because of the accuracy it has generating effective information; from the plant’s point of view when the levels of detergent neutral fiber increases is an indicator that the crop possibly has a poor agronomic and zootechnical management which causes the plant to reach its level of maturity before being consumed by the animal so that affects its voluntary consumption and decreases the animal’s intake since, Due to the high contents of structural carbohydrates (cellulose, hemicellulose and lignin) the animal will consume less pasture because its stomach cavity will be filled with little plant material.
Also, through the FAD an estimation of the digestibility of the material can be made, an analysis that yields low percentages could be deduced that the fodder material can be easily digested since it has adequate levels of lignin and cellulose, Taking into account that lignin is an indigestible compound that hinders the normal digestion of nutritional elements, that is the pasture evaluated could have little time established therefore, its structures have low percentages of indigestible elements.
Next, I will share a table that I have used in several articles, but it is necessary to incorporate it again because, it clearly visualizes the appropriate percentages of FND and FAD, which will facilitate the analysis of the laboratory results.
As for protein from an agronomic point of view focusing on the plant, when there are low protein values (less than 7%) could be an indicator that the crop has reached maturity, because when fiber levels increase considerably protein percentages decrease, as the cell wall increases its thickness by increasing the structural carbohydrates, That makes it more difficult to degrade the cell wall to easily obtain the elements found within the cell. The appropriate protein levels of a grassland in a tropical zone can vary between 8 and 16% to meet the requirements of the rumen to maintain the microbial biota of it and achieve excellent degradation.
Then, we share the results of a bromatological analysis carried out in the laboratory of the national institute of agricultural research, where we will analyze the levels of protein and fiber depending on the possible management of the crop on the farm.
The results obtained after the bromatological analysis of a forage area cultivated with Megathyrsus maximus cultivar Tanzania and an association with a creeping legume known as Arachis pintoi can be seen in the image above. According to what has been discussed in the article we will make an analysis of the data highlighted in yellow, to infer about what may be happening in this forage area.
Let us begin to evaluate the monoculture values of Tanzania, analysis showed that the grassland contains 9% protein, this value is in a range moderately acceptable for grassland in tropical areas, these are in accordance with the DNF values that are above 60% this is an indicator that grazes either has long established or was simply harvested in an advanced state of maturity, possibly the second option because this pasture had 3 months of sowing, that is to say a new plantation, which is also reflected in the results of FAD which presents very favourable values of 29%, which is an indicator that possibly the fodder can be easily degraded by the animal.
As for the association of Arachis and Tanzania can be evidenced as improved protein levels with 12%, that corroborates the importance of integrating a legume into the ecosystem considering that its leaves contain greater amount of protein, It also significantly improved the values of FND and FAD reflecting the low presence of structural carbohydrates in the vegetative parts of legumes, which favors the voluntary consumption and digestibility of the vegetative parts of the animal plant.
| final considerations |
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Dear readers, it is necessary that the agricultural producer knows the appropriate values that should present their forage crops and the relationship that has with the management that makes it and the effect that can have on the animals. Having this knowledge allows us to infer a little about what is happening, but it is mandatory to diagnose the forage surface to know the elements (soil, fertilization, pests, weeds, zootechnical management, among others) that are influencing the behaviour of plants.
| bibliographic references |
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- Cuesta, P. (2005). Production and Use of Forage Resources in Bovine Production Systems of the Caribbean Regions and Inter-Andean Valleys. Bogotá, Colombia: Corpoica.
- Estrada, J. (2002). Pastures and fodder for the Venezuelan tropico. Manizales, Colombia: Universidad de Cardas.
- Hoffman, P., Lundberg, K., Bauman, L., & Shaver, R. (2007). The effect of maturity on the Digestibility of FDN (Neutral Detergent Fiber). 5. (F. Contreras, Trad.)
- León, G., Martínez, S., Pedraza, R., & González, C. (2012). Indicators of the chemical composition and in vitro digestibility of 14 tropical fodder. Journal of Animal Production.
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After reading this blog, I am quite convinced agricultural producers should know those things. I am however wondering how many actually do, and whether this is applied in practice. Do you have any idea about this? Thanks in advance for your answer!
Cheers!
Greetings dear @lemouth, when you manage the forage resources of a farm you must have knowledge about these aspects that are essential for a producer to nourish their animals. In the area where I am located 45% of producers are interested in carrying out forage planning where they are interested in carrying out sampling of grasslands, fertilizing them, controlling pests among other activities typical of agriculture.
Unfortunately, there is a high percentage that do not see grasses as a crop, this is thought by the benefits that these grasses have to grow again after being cut by the animal, focusing only on green matter and not on the quality of that green matter. Forage culture is interesting because it takes into account within the components of the system the animals, which is a living organism that depends on forage and that causes an effect on it.
So long, I hope you have an excellent start to the week.
Thanks a lot for providing those interesting insights. 45% is not a bad number at all. I would take it as a pretty good result. I am wondering about the similar numbers in France (I live in a very agricultural area). I will try to look for this information.
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