Increasing lamb survival and lamb weaning weight through feeding high fecundity crossbred sheep

Abstract

The monitoring of a high fecundity ewe flock in the Te Anau basin demonstrates the process of improved feeding to improve lamb survival and growth to weaning. Feed budgeting was changed from traditional to tailored feed requirements based on measured ewe liveweight with wastage of 15% factored in. Feed allocation was changed from monthly to weekly increases during late pregnancy, and set stocking was delayed until the planned start of lambing. This increased late pregnancy feed allocation from 99 kg DM/ewe to 128 and 144 kg DM/ewe for twin and triplet bearing ewes, respectively. Ewe body condition score was maintained at between 3 and 3.5, with condition score loss between scanning and lambing being reduced to zero. Lamb survival and lamb liveweight gain to weaning increased in both twin and triplet bearing ewes. Pregnancy scanning increased from 200 to 222 lambs per 100 ewes, between 2007 and 2012, while lambing percentage (lambs weaned/ ewe mated) rose from 132% to 165%, with more ewes rearing lambs and rearing multiples. Lamb wastage declined from 37% in 2007 and 2008, to 25% in 2011 and 2012, though scanning percentage rose by 20%. Lamb weights increased from 27.5 to 36 kg/lamb at 100 days of age. The increase in the liveweight of lambs and ewes at weaning reduced the calculated feed requirements over summer and autumn, potentially releasing 70 to 110 kg DM/ewe to provide feed to meet the extra winter feed requirements. Keywords: ewe body condition score, feed allocation, lamb survival, lamb weaning weight

Winter crop choice and body condition loss change the eco-efficiency of sheep flocks

“…Varying impacts of BCS change on reproductive performance have been reported by many authors and these impacts interact strongly with the nutrition available at the time (reviewed by Kenyon et al, 2014). However, practical investigations of the impacts of BCS on commercial farms have generally demonstrated benefits in ewe flock productivity (Morgan-Davies et al, 2008;Stevens et al, 2011;Casey et al, 2013;Everett-Hincks et al, 2013;Mathias-Davis et al, 2013;Johns et al, 2016;McCoard et al, 2020). This study used results from farm practice to quantify the potential impacts of changes in BCS and winter feeding practices on GHG emissions and N and P loss, as well as production of meat and fibre.…”

“…For this reason, data from a commercial flock, over two seasons, using 2200 recorded ewes, was used to measure reproductive performance in relation to changes in BCS, rather than any static BCS parameter. A description of this flock has been published by Johns et al (2016). Using the full data set, the following equations were created to represent ewe mortality and lamb mortality, in response to BCS changes during mid-to-late pregnancy.…”

Using new insights in grazing management to buffer the impacts of climatic variability on pasture resilience

“…This leaves more feed to support ewe lactation and lamb weight gain. Managements like this, which have resulted in higher pasture covers in spring, have been documented to increase overall ewe flock performance and profitability (e.g., Johns et al 2016). Spring productivity may also be significantly increased when winter grazing management is changed from daily to 4-daily shifting, potentially through reduced treading damage and increased post-grazing residuals, without compromising animal intake (Stevens et al 2011).…”

A systems approach to understanding the connection between farm systems resilience and pasture resilience

“…Farmers identified that the genetic potential of the ewe flock was not being met in cases B and C. This directed changes in the timing of both feed supply and demand (Fraser et al 2016, Johns et al 2016, including additional forage resource, supplementation and changing lambing date.…”