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In 2023, the area dedicated to pastures in Brazil totals 155.5 million hectares, according to an estimate from Scot Consultoria based on data from the Laboratory of Image Processing and Geoprocessing (Lapig). As a result, Brazilian livestock farming predominantly takes place on pasture.
In other words, pastures are a key factor for feeding livestock in our country. However, it is common to encounter situations of pasture scarcity or excess for the animals.
It is essential for farmers to implement an efficient forage budget. To do this, it is necessary to calculate the amount of forage needed during the grazing period, ensuring effective nutrition for the herd, which leads to weight gain without pasture degradation
A Bit of Definition
In pasture-based animal production systems, forage budgeting is an essential tool for strategic planning. It helps producers manage and administer the forage on their property.
The forage budgeting strategy includes a set of calculations designed to estimate the forage mass over a specific period.
These calculations will indicate the amount of forage needed for the entire grazing period, ensuring that the herd has a diet that meets its needs, gains weight, and does not degrade the pasture.
Three Steps to Forage Budgeting
To budget forage, farmers should follow a series of steps:
Image 1. Forage Budgeting Flowchart.
Source: Adapted from Cavalcante, 2015.
Step 1: evaluation of the amount and reserves of available forage
Quantifying the forage stocks is the starting point for projecting the food supplies on the property. These stocks represent the total mass of forage in the area.
For this study, we can adopt a direct or indirect method.
The direct method is the most labor-intensive and reliable. It involves cutting forage samples, between 5 and 25 samples per pasture, preferably at ground level, over an area with a known surface, typically defined by a metal or wooden frame of 1 to 2 m².
After cutting all the forage within the defined area, the collected material should be packaged in paper bags and weighed. Once this information is collected, the producer can extrapolate the weight to the total area, in hectares, determining the amount of “kg/ha” of instant forage in the pasture.
Once this information is determined, the producer can calculate the possible number of grazings, projecting in kilograms per hectare (kg/ha) or tons per hectare (ton/ha) for the entire period of wet or dry season.
The indirect method aims to overcome the limitations inherent in the direct method when evaluating large areas of pasture.
Although this method is often less accurate, its advantage lies in its operational simplicity.
Indirect methods include canopy height measurement, visual estimation, and the use of a measurement disk:
- Canopy height
The canopy refers to the top layer of vegetation. In pastures, the canopy height can be measured as part of the biomass evaluation and grazing condition assessment.
Measuring the canopy height is a widely adopted practice to determine the right time for animals to enter and exit a pasture, using a table that indicates the optimal entry and exit height.
- Visual estimation
This is considered a simple method for estimating the available forage, and although it may seem inaccurate, observer training can provide reliable results.
- Measurement disk
This method is based on the relationship between dry matter production and plant height/density. The equipment consists of a graduated rod connected to a metal disk with a known surface area (ranging from 0.2 to 1.0 m²). By pressing the disk onto the vegetation, the rod indicates the average height of the plants. This height is used to calculate the estimated amount of dry matter per unit area.
After the survey, the calculation should be made using the following formula:
Available forage = number of hectares x production per month/year
Once the forage stocks are defined, the producer moves on to estimate the livestock’s forage needs for a given period.
Step 2: evaluate the forage needs of the livestock
Maintaining the productive levels of cattle, whether for weight gain or milk production, is essential to determine the food demand in the production system and the forage budget.
However, it should be noted that this variable depends on factors such as animal category, weight, sex, physiological stage, quality of the supplied food, among others.
In addition to dry matter intake, it is necessary to consider the forage lost during the grazing process, represented by the difference between the produced (accumulated) forage and the forage actually consumed by the animals.
Kg of forage needed per month = number of animals x % of live weight¹ x weight² x number of days in the month
¹The percentage of live weight can vary from 0.5% to 3.0% depending on the livestock category.
²Average weight of the herd or animal category used.
For forage planning purposes, losses of 60% to 70% are suggested, meaning that 30% to 40% of the forage is utilized. This allows for determining how many animals will be assigned to a particular area.
Step 3: data analysis and strategic planning project
Tabulation and analysis of the information make up the last step in the forage budgeting process.
At this stage, it is possible to identify periods of forage scarcity or surplus on the property, and decisions are made based on this information.
Balance = Step 1 – Step 2
Positive balance: means there is a forage surplus;
Negative balance: means there is a forage shortage.
When making a decision, certain factors should be considered, such as:
- Increasing or decreasing the livestock load on pastures;
- Expanding or reducing the grazing area;
- Searching for forage plants better adapted to regional demands;
- Adapting the livestock diet to meet all nutritional needs (by adding mineral supplements or concentrated feeds).
The forage budget should be initiated at the beginning of each year and adjusted throughout the months, ensuring flexibility and adaptability.
Now that we’ve covered forage budgeting, how about continuing to learn about topics that can make a difference in your business?
