An preliminary nutritive evaluation of feedstuffs for goats originated from north of Guizhou by in vitro gas production technique
L. Y. Li, W. X. Wu*
College of Animal Science, Guizhou University, Guiyang, China Introduction
The in vitro gas production technique is a useful way to assess the fermentation character of feedstuff for ruminants. Qianbei goat is one of regional goats species in Karst area. However, till now there is little information on the rumen fermentation metabolism characteristic compared with others (Shi, 2008; Mao, 2010;). Therefore, the objective of this study was to investigate the nutritive evaluation of common feedstuffs for Qianbei goats using in vitro gas production technique.
Materials and methods
Five male Qianbei goats were used as the rumen fluid donors. Ruminal content was sampled before the morning meal and was strained through 4 layers of cheesecloth for ruminal fluid collection as described (Menke et al., 1979). The precise 200mg dry matter of feedstuffs material, including ryegrass, green hay, peanut vine, rice straw, alfalfa; and rice bran, soybean meal, rapeseed cake, fish meal, DDGS, corn bran, corn alcohol stillage were placed in a 100ml calibrated glass syringes with each of 4 replicates. The gas production of each syringe was recorded at 2, 4, 9, 12, 24, 36, 48, and 72 h of fermentation.
The in vitro gas production parameters were estimated using the equation GP= a+b(1-e-ct) as described by Φrskov and McDonal (1979). The organic matter digestibility (OMD, %) was expressed as OMD= 0.986GP+0.0606CP+11.03, which was proposed by Menke and Steingass (1988).
Results and Discussion
Gas production rate of concentrate material was quickly increased from 2-24h, reaching a plateau phase. Corn bran was observed to have the highest cumulative gas production (63.9 ml) while rice bran the lowest one (10.8 ml). Otherwise, corn bran had a higher potential gas production(63.0 ml) and OMD (66%) over other feedstuff materials. This result indicated that corn bran might be the easiest material to be fermented in the rumen.
Gas production rate of roughage was similar to the concentrate feeds except for rice straw. The greatest gas production rate (42.9 ml) and OMD (51.1%) was observed on alfalfa, while the highest potential gas production was noted for rice straw (47.8 ml). Unexpectedly, green hay was found to have the lowest cumulative gas production, even lower than rice straw, which had the lowest value of OMD. Further research is needed to investigate the reason.
In summary, corn bran was observed to have the highest fermentation degree
while rice bran to be the lowest one. For the roughage material, alfalfa was found the easiest one to be fermentated in the rumen and green hay being the hardest one. References
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