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 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|
|Dry matter, kg||12.7||15.1||17.0|
|Crude protein, g||1,524||2,038||2,550|
|Crude fat, g||279||362||459|
|Crude fiber, g||3,048||3,473||3,740|
Source: Lithuania NIR 2017
Lithuania NIR 2017.