
TY  - JOUR
A1  - McLennan, SR 
A1  - Savage, MD 
A1  - Lindsay, JA 
A1  - O'Rourke, PK 
A1  - Murray, RM 
T1  - Effects of sulfur and different sources and levels of nitrogen and energy on the intake and liveweight change of steers fed tropical native pasture hay
JF  - Australian Journal of Experimental Agriculture
JO  - Aust. J. Exp. Agric.
Y1  - 1989
VL  - 29
IS  - 2
SP  - 157
EP  - 163
KW  - 
UR  - https://doi.org/10.1071/EA9890157 
N2  - Weaner steers were fed low quality native pasture hay in pens for 84 days to determine the differences in response to supplements of molasses (280 g/steer.day) and grain sorghum (265 g/steer.day), fed with urea (45 g/steer.day), and to determine the role of sulfur in these differences. The control group consumed 1.63 kg/steer.day organic matter (OM) and lost 277 g/steer.day over the feeding period. Supplements of urea alone or urea + grain did not affect hay intake or liveweight performance but both parameters were markedly improved by supplements of urea + molasses and urea + sodium sulfate. It was concluded that sulfur, in addition to urea, was necessary to increase feed intake and reduce liveweight loss in steers fed the low-protein pasture hay. With an increase in molasses intake from 280 to 1120 g/ steer.day, total OM intake remained constant while roughage OM intake declined (P> 0.05). At the higher molasses intake both roughage and total OM intakes were greater when 37 g/steer.day of supplemental nitroin-was fed (P>0.05), suggesting that energy substitution could be countered by ensuring a non-limiting nitrogen supply. Urea, meat and bone meal or the combination of the 2 were equally effective as the nitrogen source. In a second experiment weaner steers were fed a similar hay in pens for 56 days to compare the effects of either urea or protein meal as the nitrogen source in molasses. Molasses was fed at 1120 g/steer.day. The protein meal was a formaldehyde-treated mix of cottonseed meal, meat and bone meal and fish meal (8:1:1). Unsupplemented animals consumed 2.86 kg/ steer.day OM and lost 210 g/steer.day liveweight. Total OM intake was increased similarly by both nitrogen sources (P<0.05) but, whereas steers fed urea-molasses maintained weight, those given urea molasses plus the formaldehyde-treated protein meal gained weight at 163 g/steer.day (P<0.05). The advantage of providing a protein source protected from rumen degradation was demonstrated. 
ER  -

