Paspalum dilatatum is a valuable forage due to its vigour, persistence and ability to withstand heavy grazing and trampling (Cook et al., 2005). It is ususally grazed, but is suitable for hay and silage. It should be cut before flowering to obtain the best quality hay. It makes good silage with pH reported values of 4.8. Volatile fatty acids account for 5% DM, and ammonia N accounts for 20% of total ammonia (Cook et al., 2005).
Paspalum dilatatum is very palatable when young up to the pre-flowering stage. Its palatability declines with maturity particularly when inflorescences are infected with ergot (Cook et al., 2005). It was found to be more palatable than tall fescue (Festuca arundinacea) and Bahia grass (Paspalum notatum) (Nada et al., 1985). In cattle, density, height, stem horizons and their relative positions in the sward are determinants of bite weight, which accounts for most of the variability of intake rate. Bite weight was reduced in swards with stems compared to those with pseudostems (Laca et al., 1992; Flores et al., 1993).
Digestibility and dry matter intake
Organic matter digestibility is about 60%, corresponding to a ME content of 8.4 MJ/kg DM. Average DM intake is 1.7% LW.
Dallis grass supports up to 25 sheep per ha during the growing season (Cook et al., 2005). With dairy cows, stocking rates of 5 heads/ha in summer pasture (70% dallis grass) and 2.5 heads/ha in winter (temperate species) led to a production of 10 t/ha of milk (Cook et al., 2005). With beef cattle (steer calves), stocking rates between 5.7 and 7.3 heads/ha resulted in optimal net returns, which increased with the rate of application of N fertilizer (Gunter et al., 2005).
As Paspalum dilatatum does not have a high nutritional value, supplementation with maize silage, cereal grains and protein or nitrogen sources is required for dairy cows. Cows grazing unsupplemented Paspalum dilatatum ate less pasture that those grazing white clover (Trifolium repens), and milk yield dropped rapidly until the cows ceased production. Supplementation with maize silage alone or combined with barley grain, urea or cottonseed meal stopped the decline in milk production (Stockdale, 1997). Supplementation is more beneficial when pastures are short in height because this practice minimizes substitution of supplement for pasture and maximizes marginal returns in milk yield (Wales et al., 1999). Dairy cows fed restricted amounts of dallis grass-dominant pasture in autumn gave 1.1 kg of fat-corrected milk per kg of cereal grain-based concentrate when fed 3 kg DM of concentrate per day, but feeding beyond this level resulted in decreasing marginal responses (Walker et al., 2001).
Supplementation with maize silage, of dairy cows grazing dallis grass-dominant pastures of low quality (CP 12% DM), led to high levels of pasture substitution, poor milk responses associated with low rumen ammonia nitrogen and faecal N concentrations. Additional N supplementation was therefore necessary, even at feeding levels as low as 2 or 3 kg DM of maize silage/head/day (Moran et al., 1993). However, in the case of cows supplemented with 8 kg DM of a cereal-based feed, the metabolizable protein was estimated to be sufficient to support 22 kg milk/head/day without requiring additional nitrogen supplementation (Wales et al., 2000).