Dairy Feeding of
Rice Hay - 2009

 

 

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Project Leader and Principal  Investigators

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

 

 

 

This project continues studies of rice straw used as a feed supplement in dairy rations. A new area of research in 2009 focused on soil plant-nutrient loss from straw removal.

Straw removal

In addition to the cost of baling and removing rice straw for use as a livestock feed supplement, soil plant nutrients important to rice growth and development are being removed from fields. In an effort to quantify the amounts for a better understanding of the true costs of straw removal, scientists examined nutrient levels from rice straw samples taken from multiple years.

The greatest impact was on potassium and silica levels. The analysis showed that on average every ton of rice straw contained 33 pounds of potassium and 100 pounds of silica. This is important for growers in areas that may be deficient in these nutrients. Silica helps form erect leaves that optimize photosynthesis, minimizes transpiration losses, and is important in rice disease prevention.

Straw nutrient levels are not generally used as a diagnostic for fertility management.  Straw analysis from the 2002-2003 season indicated that potassium, copper, phosphorus, and sulfur were below normal levels assumed for maximum grain production. In samples from 2008, some fields indicated low levels of silica.  However, a study of one Colusa County farm that removed 1.5 tons per acre of straw each year did not reveal any deficiencies during a three-year period.  Researchers plan to follow up on these results with fertility plots on some of the operations with low straw-nutrient levels.

Nutritional analyses

A nutritional analysis of 133 stacks of rice straw showed wide variation in nutritional value for livestock. Results from 2008 showed lower acid detergent fiber (better digestibility) and lower crude protein than in the past.

An experiment examined differences in the digestibility of fresh and dried rice plants in relation to silica content. Plants low in silica did not significantly affect digestibility during the drying process.

Laboratory studies also suggest a possible connection between later plant maturity, declining digestibility of straw, and thus nutritional value to livestock.

Future research should focus on the reasons for loss in nutritive value, and ways to prevent it.

Dairy developments

Rice growers were invited to several dairies starting in January 2010 to see how straw was used in replacement heifer rations. Dairies need field-processed straw that is 6 inches or less in length, which allows for mixing in feed wagons with other feeds without chopping at the dairy.

Dairy managers will be surveyed on heifer feeding levels, refusal rates, and other indicators of rice straw acceptance.

Researchers will also work with dairy operators to compare wheat straw and rice straw in heifer rations. Feeding performance factors include body-weight gain, body score, and feed intake.

 

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