PROMISING TROPICAL GRASSES AND LEGUMES AS FEED RESOURCES IN CENTRAL TANZANIA III - EFFECT OF FEEDING LEVEL ON DIGESTIBILITY AND VOLUNTARY INTAKE OF 4 GRASSES BY SHEEP
Rn. Mero et P. Uden, PROMISING TROPICAL GRASSES AND LEGUMES AS FEED RESOURCES IN CENTRAL TANZANIA III - EFFECT OF FEEDING LEVEL ON DIGESTIBILITY AND VOLUNTARY INTAKE OF 4 GRASSES BY SHEEP, Animal feed science and technology, 70(1-2), 1998, pp. 79-95
An experiment was conducted to study the effect of increasing feeding
level on digestibility and voluntary intake of four high yielding gras
ses cut at 6 and 10 weeks. The grasses were fed to Blackhead Persian r
ams (mean age = 72 weeks mean weight = 30 kg) at levels of 600, 900, 1
200, 1500 and 1800 g of hay per day in a split plot design. The grasse
s were Cenchrus ciliaris cv. Biloela (CCB), C. ciliaris cv. Gayndah (C
CG), Panicum coloratum cv. Bambatsi (PCB) and Chloris gayana cv. Mpwap
wa (CGM). In vivo organic matter (OM) digestibility was on average 60%
. Among the species compared, CCB and PCB had lower OM digestibility,
by 3 units, than CCG and CCM (P < 0.05), but CGM had lower intakes (P
< 0.05) than the other species by approximately 20%. Samples taken at
10 weeks regrowth had higher neutral detergent fibre (NDF) and lignin
contents and lower protein contents and in vitro organic matter digest
ibility compared to the 6-week cuts. Intake of OM, but not of NDF was
also lower (P < 0.05) for the 10-week cut. The sheep consumed the gras
ses selectively in favour of the more nutritious parts when offered ex
cess feed. With higher feeding levels, OM digestibility, but not NDF d
igestibility, was significantly improved(P < 0.05). Voluntary intakes
of all species and stages were also improved by increasing feeding lev
els (P < 0.05). The lowest levels of feeding, allowing maximum intakes
of the hays, varied between species and stages of maturity. These fee
ding levels ranged from 900-1500 g of hav per day with refusals betwee
n 15.3-50.8% for PCB (6 weeks) and CGM (10 weeks), respectively. From
calculations of optimal feeding levels to attain maximum daily nutrien
t uptake by producing sheep, we recommend early harvesting and feeding
of the grasses at levels allowing refusals of at least 30%. (C) 1998
Elsevier Science B.V.