Bermuda grass is suitable for all ruminant species as pasture, hay and haylage. OM digestibility for the fresh forage is comprised between 45 and 65% and slightly lower for the hay. Pasture mass below 8 cm can be considered unavailable for the grazing ruminants (Alvim et al., 2001).
In Florida, under tropical conditions, annual stocking rates of 5 or 6 dairy cows/ha have been achieved under low (100 kg/ha) to high (400 kg/ha) N fertilization, resulting in extremely high milk production per ha, from 26 to 32 t milk/ha depending on the supplementation level (Alvim et al., 2001). Intake levels of Bermuda grass ranged from 9-12 kg DM/cow/day with 6 to 8 kg of concentrate, to 13-15 kg of forage DM/cow/day in late lactation with less than 3 kg of concentrate (Fike et al., 2003).
Due to its limited digestibility and energy value, Bermuda grass is rarely fed alone to lactating dairy cows, particularly in early lactation and with Holstein cows. With Holstein cows, current concentrate supplementation levels are 9, 6 and 3 kg/day in early, mid and late lactation, respectively, enabling a milk production ranging from 20-22 kg in early lactation to 10-12 kg in late lactation (Alvim et al., 2001; Vilela et al., 2002). Marginal milk response to concentrate ranges from 0.8 to 1.1 kg milk per kg concentrate in the range of 3 to 6 kg (Fike et al., 2003; Cardoso et al., 2009).
Average daily gains of 0.3 to 0.9 kg have been achieved in unsupplemented yearling steers intensively grazing Bermuda grass pastures (Horn et al., 1979; Larbi et al., 1990; Prohmann et al., 2004; Corriher et al., 2007; Burns et al., 2008; Cruz et al., 2009). The daily BW gain is largely affected by Bermuda grass pasture quality, being close to 0.3, 0.7 and 1.0 kg at high pasture availability for low (DM digestibility < 53%), medium (53%< DM digestibility < 60%) and high (DM digestibility > 60%) quality pastures (Guerrero et al., 1984). On medium quality pasture, with 3 kg of concentrate/animal/day, daily BW gain exceeded 1.0 kg (Cruz et al., 2009). In calves grazing high quality Bermuda grass pastures, concentrate supplementation of 15 g/kg BW was sufficient to maximize BW gain (+ 0.65 kg/d) (Vendramini et al., 2007). Average daily gain per animal was 25% lower on steers grazing on Bermuda grass than on alfalfa, but, due to higher biomass productivity, the total number of grazing days per ha was 35% greater on the Bermuda grass than on alfalfa (Cassida et al., 2006). In Florida, in a full year, more than 1000 kg of BW gain/ha was achieved with a input of N and intensive grazing (Burns et al., 2008). In Brazil, 150 to 250 kg of BW gain/ha/month was achievable during the summer season (Prohmann et al., 2004). The DM intake of Angus × Hereford cows under intensive grazing conditions on high quality Bermuda grass averaged 120 g/kg BW0.75 (Horn et al., 1979).
Hay and haylage
In lactating dairy cows, the replacement of 10-15% of the alfalfa hay DM in the diet with Bermuda grass hay or haylage had no effect on voluntary intake and milk production (Bernard et al., 2010; Castro et al., 2010). When forage represented 60% of the diet (40% concentrate), the total replacement of alfalfa hay with Bermuda grass hay had no effect on voluntary intake, milk production and DM diet digestibility (Moreira et al., 2001b). However, when Bermuda grass replaced maize silage in the diet there was a reduction in DM intake (-3.3 kg/d), milk yield (-3.5 kg/d) and total diet DM digestibility (-9.3%) (Moreira et al., 2001b). DM intake reached 4.1% BW in Holstein cows or 3.6% BW in Jersey cows with 55% concentrate in the diet (66% of the forage as Bermuda grass hay; West et al., 1997), or 3.2% BW with 40% concentrate (Moreira et al., 2001b).
Voluntary intake of Bermuda grass hay fed alone is generally between 2.0 and 2.7% BW (Lippke, 1980; Hall et al., 1990; Galloway et al., 1991a; Galloway et al., 1991b; Sun et al., 1991; Garcés-Yépez et al., 1997; Burns et al., 2007; Burns, 2011), but lower intake levels, between 1.5 and 1.8% BW, have been observed (Ribeiro et al., 2001; Itavo et al., 2002; Cavalcante et al., 2004; Cabral et al., 2006; Silva et al., 2007).
An average daily gain of 0.3 kg has been achieved in yearling cattle fed on Bermuda grass hay alone (Lippke, 1980; Garcés-Yépez et al., 1997). Average daily gains of 0.6 kg have been achieved with 10-20% concentrate in the diet (Brake et al., 1989; Garcés-Yépez et al., 1997), and a gain of 0.9 kg was obtained with 40% concentrate in the diet (Garcés-Yépez et al., 1997).
Sheep and lactating ewes
Voluntary DM intake of castrated male sheep fed only on Bermuda grass hay is close to 2.0-2.4% BW, or 50-55 g/kg BW0.75 (Aumont et al., 1995; Moreira et al., 2001a; Gonçalves et al., 2003). Voluntary intake was 20% lower for mature forage (84 days, 2.0% BW) than for younger grass (28 days, 2.4% BW) (Gonçalves et al., 2003). Average DMI decreased by 0.17 g/kg BW0.75 per day of regrowth (Aumont et al., 1995). In vivo OM digestibility of fresh or Bermuda grass hay decreased with maturity, on average by 1 or 2 percentage points per day (Aumont et al., 1995; Gonçalves et al., 2003). The OM digestibility of Bermuda grass was lower than that of alfalfa hay (51 vs. 58%), but its NDF digestibility was similar. Voluntary DMI and average daily weight gain were 24% and 31% lower for Bermuda grass hay than for alfalfa hay, respectively. Average daily weight gain of male sheep fed only on Bermuda grass hay reached 101 g per day. Voluntary DMI of Bermuda grass hay was as high as that of maize silage fed as the sole forage, without any protein supplementation (Moreira et al., 2001a).
Bermuda grass hay could be fed to early lactating ewes as the sole forage, provided that adequate energy and protein were supplied by a concentrate. Total DM intake of early lactating ewes was 2.3 kg DM/d (113 g/kg BW0.75) with a supplementation level of 28% (DM basis), and 2.7 kg DM/d (128 g/kg BW0.75) when the supplementation level was 50% (DM basis) (Araujo et al., 2008).
Voluntary intake of Bermuda grass hay by young goat kids or adult goats was close to that reported in sheep (42 to 56 g/kg BW0.75) (Coleman et al., 2003; Robinson et al., 2006; Patterson et al., 2009). Adult goats fed on Bermuda grass hay showed 50% greater voluntary intake than when fed on tall fescue hay (Festuca arundinacea) even though both forages had a similar chemical composition and DM digestibility, but intake was 25% lower than for goats fed on alfalfa hay (Robinson et al., 2006). Other comparisons between hays showed that Bermuda grass hay was well accepted despite its relatively low DM digestibility (Coleman et al., 2003; Sponheimer et al., 2003).
Young meat goats kids fed on Bermuda grass hay alone achieved only low BW gains (20-60 g/d; Packard et al., 2007), or no gain (Patterson et al., 2009), particularly when compared to a complete pelleted diet or concentrate diet (BW gain of 100 to 250 g/d). Supplementing Bermuda grass hay with concentrate supplementation at 1% of BW (250-300 g DM/d) increased BW gain of kids by 70 g/d (Patterson et al., 2009).
Llamas and alpacas
Compared to goats, voluntary intake of Bermuda grass hay was lower with llamas and much lower with alpacas, though DM digestibility was higher (Sponheimer et al., 2003).