125
promotes higher intake due to an increase in the rate of passage of the ingested feed
by the animal. The negative side of this is that it causes less time for rumination and
less exposure to microbial degradation, thus in turn reducing degradation and
digestibility of the straw components. Uden (1988) observed that grinding and pelleting of grass hay decreased dry matter degradability in cows from 73% to 67%,
which was mainly due to a decreased fermentation rate (9.4–5.1% h
−1
) and decreased
total retention time of the solids from 73 to 54 h, resulting in an increased intake
(Stensig et al. 1994). The use of machines in physical treatment and processing of
crop residues is also not practical for small-scale farms because of their capacity to
buy equipment and the benefits derived may be too low or even negative for the
farmers (Schiere and Ibrahim 1989).
The costs involve can be one of the factors that limit the adoption of chemical
treatment of straw. Although there are significant effects on the improvement of the
nutritive value, animal performance, as well as an increase in income due to treatment of rice straw, the farmers should still balance their decision whether to adopt
or not to adopt using treated straw. Hazard issues, such as toxicity and environmental pollution, are some of the limitations in using chemicals for straw treatment.
For microbial treatment of rice straw, one of the major drawbacks is the strain of
the fungi to be used and its capacity to degrade lignin and other components of the
straw, such as cellulose and hemi-cellulose. Incubation period is another limitation
for its practical application in treating straw. There are species of fungi with very
high affinity to degrade lingo-cellulosic materials, even in just 1 or 2 weeks of incubation and these have to be explored for its optimum incubation time to increase the
feeding value of straw. In addition, some fungi produce toxins that may affect both
human and animals so proper care should be considered in using these for rice straw
treatment.
7.6 Summary and Recommendations
Among agricultural byproducts, rice straw is most abundant, low in cost, and a
practical source of fodder for ruminants. Its utilization as a livestock feed is limited
due to problems in collection, hauling, and storage. Rice straw has low nutritional
value (low protein content and poor digestibility) compared to grasses, thus it cannot support the nutrients required by high-yielding milk cows and buffaloes. There
are technologies that have been developed to increase the nutritive value, nutrient
digestibility, and utilization of rice straw, such as physical processing, pretreatment
using chemicals, and/or biological treatment. However, adoption of these developed
technologies is still low due to farmers’ limited skills and inputs (e.g., farm equipment) and their doubts regarding applicability to the farm situation and the benefits
for the animals and livestock producers. To maximize the utilization of rice straw as
fodder for ruminants, mechanization is most important to facilitate collection, hauling, and stacking or processing all available rice straw from the field.
7 Rice Straw-Based Fodder for Ruminants
promotes higher intake due to an increase in the rate of passage of the ingested feed
by the animal. The negative side of this is that it causes less time for rumination and
less exposure to microbial degradation, thus in turn reducing degradation and
digestibility of the straw components. Uden (1988) observed that grinding and pelleting of grass hay decreased dry matter degradability in cows from 73% to 67%,
which was mainly due to a decreased fermentation rate (9.4–5.1% h
−1
) and decreased
total retention time of the solids from 73 to 54 h, resulting in an increased intake
(Stensig et al. 1994). The use of machines in physical treatment and processing of
crop residues is also not practical for small-scale farms because of their capacity to
buy equipment and the benefits derived may be too low or even negative for the
farmers (Schiere and Ibrahim 1989).
The costs involve can be one of the factors that limit the adoption of chemical
treatment of straw. Although there are significant effects on the improvement of the
nutritive value, animal performance, as well as an increase in income due to treatment of rice straw, the farmers should still balance their decision whether to adopt
or not to adopt using treated straw. Hazard issues, such as toxicity and environmental pollution, are some of the limitations in using chemicals for straw treatment.
For microbial treatment of rice straw, one of the major drawbacks is the strain of
the fungi to be used and its capacity to degrade lignin and other components of the
straw, such as cellulose and hemi-cellulose. Incubation period is another limitation
for its practical application in treating straw. There are species of fungi with very
high affinity to degrade lingo-cellulosic materials, even in just 1 or 2 weeks of incubation and these have to be explored for its optimum incubation time to increase the
feeding value of straw. In addition, some fungi produce toxins that may affect both
human and animals so proper care should be considered in using these for rice straw
treatment.
7.6 Summary and Recommendations
Among agricultural byproducts, rice straw is most abundant, low in cost, and a
practical source of fodder for ruminants. Its utilization as a livestock feed is limited
due to problems in collection, hauling, and storage. Rice straw has low nutritional
value (low protein content and poor digestibility) compared to grasses, thus it cannot support the nutrients required by high-yielding milk cows and buffaloes. There
are technologies that have been developed to increase the nutritive value, nutrient
digestibility, and utilization of rice straw, such as physical processing, pretreatment
using chemicals, and/or biological treatment. However, adoption of these developed
technologies is still low due to farmers’ limited skills and inputs (e.g., farm equipment) and their doubts regarding applicability to the farm situation and the benefits
for the animals and livestock producers. To maximize the utilization of rice straw as
fodder for ruminants, mechanization is most important to facilitate collection, hauling, and stacking or processing all available rice straw from the field.
7 Rice Straw-Based Fodder for Ruminants