Dairy Feeding of Rice Hay, 2013

 

Project Leader

Glenn Nader, livestock advisor
UC Cooperative Extension
Butte, Sutter, and Yuba counties

This project continues studies of rice straw used as a feed supplement in dairy rations. In 2012, research focused on two areas:

Comparison of rice and wheat straw in dairy heifer rations

Improving the digestibility of rice straw

Heifer rations comparison

Four pens of 120 heifers were randomly assigned to rice or wheat straw. Two pens were fed either rice or wheat straw for 28 days. The next 28 days all four pens were fed wheat straw to determine any compensatory gains by switching from rice to wheat straw. Indicators of animal growth—hip height, hip width, and body scores—were recorded throughout the trial.

Findings indicated no difference in dry matter intake. No differences in skeletal growth were observed. Wheat straw fed in the second 28-day period demonstrated compensatory gains. The same occurred with body condition score. This demonstrated that a short feeding of a higher energy ration could eliminate the energy difference between the two straws.

This experiment showed that rice straw supplies a lower energy level to the diet than wheat straw.  A laboratory analysis of relative energy values is pending.  This will help in valuing the price of rice straw for use in dairy rations.  Dairy producers could use rice straw for short periods with no impact to skeletal growth of heifers.

Digestibility of rice straw

A new area of research is based on the idea that the enzymes involved in rice straw digestion are limited by the time it takes in the rumen for the straw to hydrate before digestion. Drying of straw may affect the activity of rumen microbes. A preliminary experiment involved testing premoistened straw samples on bacterial enzymes. The enzyme’s digestion action was greater following an ethanol treatment. Researchers plan to focus on the rice plant’s water-repelling cutin layer as a possible factor affecting rice straw digestion.