Author:
Davies H. Lloyd,Southey I. N.
Abstract
Border Leicester x Merino ewes joined to Dorset Horn rams were grazed for 3
years on subterranean clover-based pastures established on virgin ground at
Bakers Hill, Western Australia, at 3 stocking rates and 2 systems of grazing
management (viz. continuous grazing compared with a deferred grazing system
which was designed to ensure that pasture availability met the nutritional
requirements of breeding ewes at critical phases of their reproductive cycle).
Both stocking rate and grazing management affected pasture availability: there
was always a greater amount of pasture available on offer under the deferred
grazing system. However, this extra pasture rarely increased animal
production; the effect of the deferred grazing compared with continuous
grazing was inconsequential for ewe liveweight in late pregnancy and for lamb
growth rate. The deferred grazing system promoted grass dominance at all
stocking rates whereas there was only 24% grass under continuous
grazing at the high stocking rate. Stocking rate on some occasions affected
ewe liveweight at joining but always affected the prelambing weight. The
highest stocking rate on some occasions reduced twinning rate. Stocking rate
(particularly in 1966) affected lamb growth rate. The combination of the
effect of stocking rate on twinning rate, lamb survival and lamb growth rate
resulted in a lower proportion of lambs achieving 30 kg liveweight per lamb
marked at higher stocking rates (3-year mean low stocking rate 106%
lambs marketed; medium stocking rate 95% and high stocking rate
80%). In 1966, total plasma ketones were lower and plasma glucose
(measure of ewe metabolic status) was higher on the deferred system than on
the continuously grazed system.
Subject
General Agricultural and Biological Sciences
Cited by
16 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献