Herbage allowance - intake - production relationships in continuously
stocked winter- and spring-lambing ewes
S.T. Morris, W.J. Parker, D.L. Burnham, C.M.C. Jenkinson, S.N.
McCutcheon
Department of Animal Science, Massey University, Palmerston North,
New Zealand
Proceedings of the New Zealand Society of Animal Production. 1993,
53: 11-14
In a series of studies, relationships between herbage allowance (as
measured by sward surface height (SSH), herbage intake (measured by
intraruminal chromium controlled release capsule) and production were
assessed in continuously stocked winter (June)- and spring (August)- lambing
pregnant and lactating ewes. At SSHs of 2.8, 4.0, 7.1 and 8.5 cm, organic
matter intakes (OMI) of winter-lambing ewes in the last month of pregnancy
were 1.4, 1.7, 1.6 and 1.9 (Pooled SE = 0.1) kg/d (P<0.05), respectively. Ewe
liveweight gain over the last month of pregnancy increased with SSH but
there was no effect of SSH on lamb birthweight or ewe midside wool growth.
Similarly, pregnant spring- lambing ewes had OMI of 1.4, 1.7, 1.8 and 1.9
(PSE = 0.1) kg/d (P<0.05) at SSHs of 2.7, 4.0, 5.9 and 7.8 cm, respectively
and ewe liveweight gain increased with SSH but there was no effect of SSH
on ewe wool growth or lamb birthweight. Results suggest that both winter-
and spring-lambing ewes can tolerate SSH below 3 cm during late pregnancy
without detrimental effects on lamb or wool production.
Winter-lambing lactating ewes (first two months of lactation) had OMI of
1.8, 2.3 and 2.5 (PSE = 0.1) kg/d (P<0.05) at SSHs of 2.6, 4.4 and 7.8 cm
respectively. Sward height did not influence ewe wool production or lamb
growth but ewes on the 2.6 cm sward lost 8-10 kg more liveweight during
lactation than those on the 4.4 and 7.8 cm swards. Spring- lambing ewes had
OMI of 1.8, 2.0, 1.9, 2.0 and 2.0 (PSE = 0.3) kg/d (P<0.1) at SSHs of 3.5,
5.0, 6.0, 7.0 and 8.5 cm, respectively. There were no effects of SSH on ewe
wool growth or lamb growth but ewe liveweight loss was greatest at low
SSH. Results are discussed in the context of feeding recommendations for
winter- and spring-lambing ewes.
Keywords: NZSAPAB;
Winter- and spring-lambing; continuously stocked; herbage intake; ewe
liveweight; wool production; lamb birth weight.
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Last Updated 25-01-1997
