Stylosanthes Hamata Supplementation: effects on degradation characteristics, passage rate of rice straw and performance of lactating djallonke ewes and their lambs

Three experiments were conducted to evaluate the effect of sun-dried Styloanthes hamata supplementation on: degradability of rice straw fractions, intake and growth rate of Djallonké ewes and their lambs and passage rates of rice straw tractions. The same diet, consisting of 1000 g rice Straw supplemented with 180, 240, or 360 g of sun dried Stylosanthes hamata per day as given in all the three experiments. In Experiment I (dry matter degradability studies), three-rumen fistulated Djallonké ram weighing about 20 kg, were used in a 3 x 3 Latin Square Design to determine the dry matter degradability of three rice straw fractions (leaf, stein and whole) incubated in the rumen. The factors were rice straw fractions (teat, stem and whole), animals (3) and level of supplement (180. 240 and 360 g Stylosanthes per day). The treatments were designated as T180, T240 and T360. Samples of the straw were incubated and removed over 6 time periods (6, 12, 24, 48, 72 and 96 h). The mean degradation over the 96-hour incubation period showed higher values for T360 in all the three fractions, with the stern traction showing the highest degradation for the T360 (stem; 34.9%, leaf; 29.37%, whole; 32.9%). The mean degradation for each traction taken separately shows the stein as more degradable compared to the other fractions (stem; 32.0% vs leaf; 26% ) and (stem, 32.0% vs whole 29.4%). The mean degradation constant was higher in the stem (0.010) and whole (0.011) than the leaf (0.005) suggesting a higher rate of disappearance of these tractions than the leaf In Experiment 2, passage rate parameters of 3 rice straw fractions were investigated using 2-rumen fistulated Djallonké rams with potassium dichromate as an indigestible marker. The fractional outflow rates of the chromium treated rice straw fractions from the rumen of sheep were 0.022 and 0.98; 0.029 and 1.01; and 0.029 and 0.56 per h for leaf, stem and whole, respectively. The mean retention time (MRT) of the rice straw fractions was 77.27, 68.18 and 62.08 h for leaf, stem and whole respectively. The stem fraction had the highest transit time (TT) (31.85 h) among the 2 fractions. The leaf and the whole fractions had transit times of 29.05 and 25.71 h, respectively. There were differences between the particulate rate parameters of the 3 rice straw fractions, which reiterate the higher degradability of the stem traction. Experiment 3 was conducted in December 2001- February 2002. Thirty lactating Djallonké ewes and their lambs were used in a growth rate study. The ewes were randomly assigned to 3 treatment groups of 10 animals each. The animals were individually housed and each offered I 000 g rice straw basal diet per day. The ewes in the treatment groups were offered supplements of Stylosanthes hamata at the rate of 180, 240 and 360g per day per animal for treatments T180, T240 and T360 respectively. Total dry matter intake significantly (P< 0.01) increased as the level of Stylosanthes in the diet increased. The mean dry matter intake of the highest level of Stylosanthes was significantly (P< 0.001) higher than values tor the two lower levels. Likewise, the total feed intake T360 ewes was significantly (P< 0.01) higher than values for T180 and T240 ewes. However, Increasing the levels of Stylosanthes supplementation had no significant effect (P>0.05) on mean daily dry matter intake of rice straw This suggests there was no substitution effect on rice straw intake due to increasing level of Stylosanthes hamata supplementation. All the ewes maintained their body weights over the experimental period and there was no significant difference (P>0.05) in the body weights of the ewes due to treatment effects. The growth rates of the lamb were significantly (P <0.05) affected by the treatments Growth measurements of the lambs, which were taken at day 30 and 49, indicated that supplementation significantly (P<0.01) affected average daily gains (ADG) on the days of measurements. The ADG at day 30 were 38.33 65.00 and 66.67 g for treatments T180, T240 and T360, respectively. Similarly, at day 49, ADG of lambs was significantly (P<0.() I ) affected by increasing supplementation of ewes. The values obtained were 47.5, 63.4 and 76g for T180, T240 and T360 respectively. In conclusion, it would be inferred that adequate supplementation increases rate of degradation and also reduces the MRT of rice straw. These results suggest supplementation of basal rice straw diets with 360 g per day of Stylosanthes hamata enabled ewes to maintain their body weight in the dry season and also enabled improved ADG of lambs.

Source: KNUST