Rumen degradability characteristics of normal maize stover and silage, and quality protein maize silage-based diets offered to cows
Abstract
Rumen degradability characteristics of dry matter (DM), organic matter (OM) and crude protein (CP) of normal maize (NM) stover (T1)-, NM silage (T2)- and quality protein maize (QPM) silage (T3)-based diets were studied using three rumen-fistulated Boran × Friesian non-lactating cows (371 ± 32.00 kg) in 3 × 3 Latin Square Design. Cows were supplemented with a similar concentrate mix. In sacco degradability of DM and OM indicated that the (a) values of DM (128) and OM (114) for NM stover were lower (P < 0.001) than that for NM silage (268 and 253) and for QPM silage (323 and 303), respectively. The (a) value for CP was lower (P < 0.05) for QPM silage (286) than for NM stover (404) and NM silage (326). The (b) values of DM in NM stover (597) and NM silage (535) were higher (P < 0.05) than in QPM silage (499). The (b) value of CP in NM stover (372) was lower (P < 0.05) than in NM silage (655) and in QPM silage (608). Rate of degradation of OM in NM stover and NM silage, each with 0.03, was faster (P < 0.01) than in QPM silage (0.02). Moreover, QPM silage had higher potentially degradable fraction for DM (821) (P < 0.05) and OM (840) (P < 0.01) than DM (725) and OM (712) in NM stover. The mean rumen ammonia concentration (209 mg/l) of QPM silage was higher (P < 0.05) than that of NM stover (179 mg/l) and NM silage (170 mg/l). The average rumen pH (6.1) in cows fed QPM silage was lowest (P < 0.05) compared to pH (6.3) in cows fed either NM stover or silage. The concentration of total volatile fatty acids (116 mmol/l) in the rumen of cows incubated with QPM silage was higher (P < 0.001) than in those incubated with NM stover (113 mmol/l) and NM silage (110 mmol/l). It was concluded that QPM silage-based diet was superior in DM and OM degradability, and had higher ammonia and VFA concentration than NM stover-based diet. No differences have been observed in all parameters measured between QPM and NM silages.
Keywords
Degradability characteristics Normal maize silage/stover Quality protein maize Rumen ammonia Volatile fatty acidAbbreviations
- a
Washing loss
- b
Insoluble but slowly degradable
- c
Degradation rate per hour
- PD
Potential degradability
- L
Lag time in hours
- ED
Effective degradability
- ADF
Acid detergent fibre
- ADL
Acid detergent lignin
- NM
Normal maize
- NDF
Neutral detergent fibre
- OM
Organic matter
- QPM
Quality protein maize
- SEM
Standard error of the mean
- NS
Not significant
Notes
Acknowledgements
We thank the International Livestock Research Institute (ILRI), Debre Zeit Station, for providing financial support and facilities and Haramaya University for facilities. Professor Dr. Allan Degen is highly appreciated for reading and making valuable comments and suggestions.
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