Inventory practice: Use of feed tables to estimate gross energy in Lithuania

Sadie S

Keywords: feed tables | milk yield | dairy cattle

What data needs were addressed? Estimating gross energy intake for dairy cattle.

Why was the data needed? Lithuania’s inventory points out that gross energy and milk yield have a clear positive relationship. Estimation of gross energy in the inventory can be simplified if standards are used to relate annual milk yield data to gross energy intake.

Methods used: feed standards.

How was the data gap addressed? Gross energy estimates for dairy cattle are based on feed standards. National research has established that gross energy intake is related to crude protein, crude fat, crude fibre and nitrogen-free extracts in feed, and identified a relationship between these feed contents and milk yield (Table 1). Gross energy is estimated as a function of these feed contents:

𝐺𝐸=0.0239∙𝐶𝑃+0.0398∙𝐶𝐹𝑎𝑡+0.0201∙𝐶𝐹𝑖𝑏𝑒𝑟+0.0175∙𝑁𝐹𝐸

where:

GE gross energy, MJ kg in DM;
CP crude protein, g/kg in DM;
CFat crude fat, g/kg in DM;
CFibre crude fibre, g/kg in DM;
NFE nitrogen-free extracts, g/kg in DM.

Since the nutrition standards have established the relationship between milk yield and dietary nutrients, inventory estimates of gross energy intake can be made using only data on milk yield. Milk yield values between those shown in the table are interpolated.

Table 1. Nutrition standards for dairy cattle

 Quantity of milk (4% milk fat), kg/day
101520
Dry matter, kg12.715.117.0
Crude protein, g1,5242,0382,550
Crude fat, g279362459
Crude fiber, g3,0483,4733,740
Nitrogen-free extract6,3507,4208,990

Source: Lithuania NIR 2017