Dry Matter and Crude Protein Degradability of Some Common Feeds and Total Mixed Ration in F1 Boran- Fresian Bulls Using in situ Methods

Abstract

The study was conducted at Holeta agricultural research center with objectives to evaluate dry matter and crude protein degradability and degradability parameters of some common feeds (natural pasture hay, wheat bran, cotton seed cake and noug seed cake) and total mixed ration (TMR contained natural pasture hay (50%), wheat bran (14%), noug (Guizotia abyssinica) seed cake (14%), cotton seed cake (8%), molasses (11%), urea (1%) and salt (2%) about 3 g of DM equivalent of samples were weighed in sealed nylon bags (10 x 20cm size and a pore size of 53 μm) that were incubated in the rumen of three ruminally fistulated F1- Boran-Fresian steers (body weight=510±57 kg  and age= 13±3 months ) that fed  natural pasture hay ad libitum and supplemented with 2 kg concentrate mixture contained with 50% wheat bran, 40% noug seed cake, 9 % cotton seed cake and 1% salt on dry matter basis, once per day in the morning. Three ruminally cannulated were housed in 1.5 x 2.0 m pen. The sieve size of the sample was 2mm.  The bags with 3 g sample were placed into the ventral rumen after morning feeding in quadruplicate at each time point in each steer for 6, 12, 24, 48, 72, and 96 h. Washing loss  was determined by washing duplicate feed samples in the water thank for 30 minutes. Wheat bran, noug seed cake and concentrate mixture had the highest DM and CP degradability (P<0.05) but, natural pasture hay had the lowest DM and CP degradability (P>0.05). The lag time of DM and CP were lowest and highest in natural pasture hay and wheat bran, respectively (P<0.05). Wheat bran and concentrate mixture had higher degradable fraction (a, b and a + b), rate and extent of degradation and effective degradability at (P<0.01). In contrast, natural pasture had lower degradability parameters than others feeds (P>0.05). In addition, wheat bran had the highest effective degradability (P<0.05), but hay had the lowest one. Generally, DM and CP degradability and   degradability parameters of TMR were ranged at the degradability values of natural pasture hay and concentrate mixture.

Keywords: Dry matter, Crude protein, In situ degradability, Steers.