TEC-funded MPhil/PhD Student Abstract
| Title | : | Improving milk production by optimising the efficiency of utilisation of available forages for dairy cows |
| Student | : | RAVINA Jean Mathieu |
| Institution | : | Faculty of Agriculture, University of Mauritius |
| Level | : | MPhil - FT Year : 2010 |
| Supervisor | : | Assoc. Prof F. Driver |
| Abstract | : | The impact of nitrogenous (N) fertiliser, seasons of the year and physiological maturity on stargrass (Cynodon plectostachyus) biomass (dry matter yield; DMY) and nutritive value was evaluated in a split plot design. Seasons of the year, N- fertiliser and regrowth maturity impacted significantly (p<0.01) on sward biomass and nutritive value. DMY was fourfold higher with N- fertiliser (60 Ton/ha/yr versus 16 Ton/ha/yr) irrespective of seasons and the DMY of winter sward was three times lower regardless fertiliser treatments. The leaf proportion of sward quadratically declined with physiological maturity while the opposite was recorded with the stem, senescent materials and fibre content (cellulose, hemicelluloses and lignin) of sward. The crude protein (CP) content of fertilised sward was higher and declined from 20.45%± 2.89 and 34.68%± 0.34 to 4.52%± 0.30 and 7.10%± 0.57 in summer and winter respectively. Sward CP and fibre was highly related to sward phenology, and the latter could be used for indexing stargrass quality. The nutritive value of sward declined with sward maturity. The relapse in sward nutritive value was more rapid in summer; therefore, stargrass should be harvested at latest 6 weeks maturity in summer and up week- 10 in winter. Sward production was seasonal and to ensure year round supply of quality sward, about ¼ of the summer biomass should be conserved. Unfertilised sward was unsustainable since land is a limited resource. The stocking rate of fertilised stargrass was estimated to be 12 Livestock Unit, equivalent to 10.3 Dairy Unit. Depending on seasons, fertiliser treatments and animal physiological state, sward- based diet should be supplemented with crude protein, energy and minerals for optimum rumen condition and milk production.
Key words: Stargrass, biomass, nutritive value, maturity, N- fertiliser and seasons
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