Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs

Abstract

Abstract. The effect on ewe and lamb production by differential management of single-and twin-bearing Merino ewes during pregnancy and lactation was examined. The hypothesis that the survival and productivity of single-and twin-born progeny is not affected by differential management of single-and twin-bearing ewes was tested. To test this hypothesis, two ewe flocks were monitored on a commercial property in the south-east of South Australia. The body condition score of one flock of ewes was managed according to Lifetimewool recommendations for southern Australian (Lifetimewool flock; n = 464). Lifetimewool recommendations are that body condition score should be 3.0 at mating and then allowed to decline to an average of 2.7, which is maintained until lambing. Twin-and single-bearing ewes were managed as separate mobs after pregnancy scanning to meet their energy requirements. The second flock was managed similarly to the commercial ewe flock and was representative of ewe management practices in the region (normal-practice flock; n = 464). At lambing, the condition score of the Lifetimewool flock was 0.7 condition scores units greater than the normal-practice flock. Ewe clean fleece weight and fibre diameter were greater in the Lifetimewool flock and their lambs had higher survival rates to weaning. Over three shearings, progeny from Lifetimewool ewe flocks produced more clean wool (P < 0.0001) but there was no consistent effect on fibre diameter, staple length or staple strength. Twin-born lambs from ewes managed to Lifetimewool guidelines had a similar liveweight and produced similar quantity and quality of wool to single-born lambs managed to Lifetimewool guidelines, but still suffered higher rates of mortality to weaning. This suggests that it is possible to manage ewes pregnant with twins to ensure that their surviving progeny perform at a level similar to single-born progeny managed under similar targets.

On-farm paddock-scale comparisons across southern Australia confirm that increasing the nutrition of Merino ewes improves their production and the lifetime performance of their progeny

“…Coupled with the fact that the larger and longer term difference in the performance of twin progeny compared with single progeny (Hocking Edwards et al 2011;Oldham et al 2011;Thompson et al 2011aThompson et al , 2011b) also indicate that this maternal effect through either nutritional management of the ewe or litter size are real and must be factored into economic analyses of the impacts of nutritional guidelines on whole-farm profit .…”

Successful adoption of new guidelines for the nutritional management of ewes is dependent on the development of appropriate tools and information

“…* South Australia: a demonstration farm was used as a focus for activities with a group of sheep producers who observed the management using the recommendations as reported by Hocking Edwards et al (2011). * New South Wales: a similar approach to South Australia was used based around three demonstration farms.…”

Short term repeatability of body fat thickness measurement and body condition scoring in sheep as assessed by a relatively small number of assessors

“…Nutrition can be optimized by adjusting the feeding according to the body condition of the animals, particularly during early lactation and in late pregnant ewes (Brozos et al, 2011;Rook, 2000). Managing flocks according to recommendations for body condition, for example guidelines developed in the Lifetimewool project in Australia (Dart et al, 2011), also increases wool production of ewes (Ferguson et al, 2011) and wool quality of their progeny (Hocking Edwards et al, 2011). Determining BCS or measuring RFT are also common methods to determine meat quality in sheep (Frutos et al, 1997;van Burgel et al, 2011).The merit of condition scoring for managing the nutrition of sheep and as an alternative to liveweight measuring has been shown by van Burgel et al (2011).…”

“…The assessment of the body condition in ewes is an important tool for a good flock management (Hocking Edwards et al, 2011). With continuous monitoring of the body condition, increasing risks for metabolic diseases, e.g.…”