Docstoc

More versatile Merino muscles up

Document Sample
More versatile Merino muscles up Powered By Docstoc
					                                                                                                                                                                    LIVESTOCK:
                                                                                                                                                                         CATTLE
                                                                                                                                                                shEEp brEEding




                                    More versatile Merino
                                    muscles up
                                             Authors

                                                                                           A shift toward meat production in many Merino flocks during recent years
Photo: CSIRO Livestock Industries




                                                                                           has resulted in a much greater emphasis on reproduction, carcass and growth
                                                                                           traits in Merino breeding programmes. Researchers examined how selecting
                                                                                           for carcass muscling, growth and fat affected maternal performance in
                                         Mark              Mark                            Merino ewes. Muscling, a trait that Merino breeders have largely overlooked,
                                       Ferguson           Filmer
                                                                                           was the big surprise — it can help breeders develop a more versatile and
                                      FOR CSiRO liveSTOCk iNduSTRieS
                                                                                           profitable flock.

                                    Newborn: Researchers examined how selecting for        Carcass muscling, a trait for which              are focussed on meat production, but the
                                    traits such as muscling, growth and fat affected the   there has been low selection pressure in         Merino has a relatively poor reproductive
                                    maternal performance of Merinos.
                                                                                           most Merino breeding programmes, can             performance. There is also a desire to
                                                                                           be used in combination with other key            increase the level of muscling and improve
                                                                                           traits to produce a more versatile and           growth rates in pure Merino or Merino
                                                                                           profitable flock.                                cross lambs to improve lean meat yield
                                                                                              This is one of the key findings of a study    from these animals.
                                                                                           in which researchers examined the impact
                                                                                           of selection for muscling, fat and growth on     Carcass, growth and
                                                                                           the maternal performance of Merinos. The
                                                                                           study has demonstrated that selecting for a      maternal traits vary greatly
                                                                                           combination of higher carcass muscling           within the Australian Merino
                                                                                           and higher growth, while not selecting
                                                                                           against fat, will produce better all–round
                                                                                                                                            flock, due to previously low
                                                                                           results than breeding for either higher          selection pressure.
                                     At a glance                                           muscling or higher growth alone.
                                                                                              The findings also suggest that the Merino,      The study, a collaborative project involving
                                    There has been a shift toward meat                     with some fine–tuning to improve growth,         CSIRO Livestock Industries and Murdoch
                                    production in some Merino flocks                       carcass and reproduction traits, has the         University within the Cooperative Research
                                    during recent years.                                   potential to become the maternal breed of        Centre for Sheep Industry Innovation, was
                                                                                           choice for the prime lamb industry.              established to determine the impact of
                                    Reproductive and maternal traits
                                                                                              Findings from this research project will      selecting for carcass traits on other
                                    are key profit drivers in systems                                                                       productive qualities.
                                    focussed on meat production but                        benefit many producers, particularly those
                                    the Merino has a relatively poor                       who are considering adjusting their                In particular, the focus was on muscling,
                                    reproductive performance.                              enterprise mix by reducing their reliance on     growth and fat and how these traits affected
                                                                                           wool in favour of a more even balance            maternal performance, as measured by
                                    Carcass, growth and maternal traits                    between wool and meat production.                variables such as lamb birth weight and
                                    vary greatly within the Australian                                                                      survival, growth rate, ewe milk production
                                    Merino flock due to previously low                     Background to the study                          and liveweight at weaning. Initially, the
                                    selection pressure.                                      During recent years there has been a           researchers were concerned that selecting
                                                                                           significant shift toward meat production         for carcass traits might have detrimental
                                    Selecting for greater muscling and                     in many Merino flocks and this has               impacts on maternal traits, and so reduce
                                    growth, while not selecting against                    resulted in a much greater emphasis on           the overall profitability of an enterprise.
                                    fat, will produce better all-round                     reproduction, carcass and growth traits in
                                    results than breeding for muscling                     Merino selection programmes.                     On–farm experiments
                                    or growth alone.                                         Reproductive and maternal traits are key         Experiments were carried out at the
                                                                                           drivers of profitability for enterprises that    Billandri Poll Merino stud at Kendenup and

                                                                                                                                  Farming Ahead November 2008 No. 202 www.farmingahead.com.au   61
            LIVESTOCK:
            shEEp brEEding


    the Merinotech nucleus flock farm at Kojonup,                    Muscling overcomes potential problems                                                             implications for breeding
    both in south–west Western Australia.                               But selecting for growth alone can create                                                        With more Merino producers starting to
       From the Billandri flock, the researchers                     potential problems, such as increased                                                             breed for meat as well as wool, the results of
    selected four groups of 25 maiden ewes that                      mature ewe size, which leads to higher feed                                                       this research project will give these
    had either high or low Australian Sheep                          demand, health and safety issues with                                                             producers (and others considering this
    Breeding Values (ASBVs) for muscling and                         handling larger animals, and higher lamb                                                          option) greater confidence to incorporate
    high or low ASBVs for growth. (ASBVs are                         birth weights, which can cause dystocia                                                           high muscling into their breeding
    an estimate of the value of an animal’s                          (lambing difficulties).                                                                           programmes — knowing there won’t be any
    genotype, based on that animal’s                                                                                                                                   negative impacts on wool production and
    performance and the performance of its                              Muscling can play an important role in
                                                                     helping to overcome such problems. The                                                            there will be positive spin–offs in improved
    relatives. They allow producers to evaluate
                                                                     study found that choosing ewes with high                                                          maternal performance.
    genetic potential and select animals most
    suited to their particular enterprise.)                          muscling was correlated with lower lamb                                                             By selecting for high muscling and high
                                                                     birth weight but, importantly, the reduction                                                      growth, as well as traits such as resistance to
       From the Merinotech flock, the researchers
                                                                     in lamb birth weight did not reduce lamb                                                          worms, low dags and reduced breech
    selected 100 maiden ewes with high
    muscling and high or low fat ASBVs. The                          survival rates. High muscling and growth                                                          wrinkle (and not selecting against fat),
    sheep were divided into two flocks of 50.                        traits have opposite effects and tend to                                                          producers will develop a more versatile
    Each flock was then run at different levels of                   cancel each other out — so breeding for a                                                         Merino that will be both profitable and meet
    nutrition to determine the impact of                             combination of muscling and growth will                                                           consumer expectations. Indeed, the Merino
    selection for, or against, fat in high–muscled                   give producers most of the benefits                                                               could eventually become the maternal breed
    Merino ewes on maternal and fitness traits.                      associated with high growth selection, while                                                      of choice for the prime lamb industry,
    (Muscling was measured using an                                  not affecting lamb birth weights.                                                                 especially in medium and low rainfall areas
    ultrasound scan on the eye muscle site                                                                                                                             — offering $20–$30 worth of wool on top of
    between each animal’s 12th and 13th ribs.                        High muscled ewes also                                                                            income from its lambs.
    This procedure would typically cost Merino                                                                                                                           Reaching this point will require some
    breeders between $3–$4 per head.)                                produce more twin lambs                                                                           improvements in growth, carcass and
       The ewes and lambs at both sites were                         and their lambs have a                                                                            reproduction traits. But the right genetics
                                                                                                                                                                       are available within the Australian Merino
    monitored closely to determine how carcass
    traits affected ewe maternal performance —
                                                                     greater proportion of                                                                             population and producers have access to all
    the researchers measured factors such as                         lean meat.                                                                                        the information needed to identify animals
    lamb birth weight and survival, lamb growth                                                                                                                        with the desirable traits necessary to achieve
    and ewe milk production.                                             They also produce more milk during                                                            such gains.
                                                                     early lactation. The only negative impact of
    Some key findings                                                                                                                                                    Many Merinos are still selected based on
                                                                     selecting for high muscling was slightly
                                                                                                                                                                       appearance, but it will become increasingly
       The three–year study has shown that                           reduced early growth in lambs.
    selection for a combination of high growth                                                                                                                         important for producers to use better
    and high muscling provides a better overall                      Selecting for fatness                                                                             information in their breeding programmes,
    result than breeding for either individual                                                                                                                         particularly when selecting for meat
                                                                        Selecting for fatness could be beneficial
    trait on its own.                                                                                                                                                  production, as some important meat traits
                                                                     during periods of low nutrition. Ewes with
                                                                                                                                                                       can’t necessarily be visualised.
       Selecting ewes that had high growth                           positive breeding values for fatness were
    ASBVs alone in the Billandri Merinos                             better able to provide nutrients for a                                                            More research possible
    resulted in a higher proportion of twin                          growing foetus, and produced heavier
    lambs, improved ewe milk supply and                                                                                                                                  It is hoped this project will be followed by
                                                                     lambs and more milk, and so had lambs                                                             more research, focussing on developing
    better lamb growth rates, leading to a                           with higher early growth rates when
    higher weaning weight. (Lambs from ewes                                                                                                                            selection indices that are both specific to
                                                                     nutrition was limited.                                                                            different production areas and based on
    selected for high growth were about five
    kilograms heavier at weaning than lambs                             Also, increasing fat levels showed some                                                        whole–farm profitability. Such information
    from ‘average growth’ ewes, a result that                        evidence of improved lamb survival but                                                            would help sheep producers achieve an
    has important implications for post–                             flock size was not large enough to prove                                                          optimum match between production
    weaning survival rates).                                         this statistically.                                                                               environment and production genetics.

                                                                                                                                                                       aCkNowledgeMeNts CsIRo, Murdoch
                                                                                                                                                                       University and the Cooperative Research Centre
                                                                                                                                                                       for sheep Industry Innovation supported this
                                                                                                                                                                       research project.
                                                                                                                                                                       this work was carried out under the supervision
                                                                                                                                                                       of the late Norm adams, a CsIRo livestock
                                                                                                                                                                       Industries scientist who sadly passed away
                                                                                                                                                                       earlier this year, and graham gardner and dave
                                                                                                                                                                       Pethick, of Murdoch University.
                                                                                                                                                                       Ian Robertson and family, Bill and geoff
                                                                                                                                                                       sandilands and family and Merinotech wa also
                                                                                                                                   Photo: CSIRO Livestock Industries




                                                                                                                                                                       supported this work.




                                                                                                                                                                        CSiRO research
                                                                                                                                                                        CoNtaCt Mark Ferguson
                                                                                                                                                                           0407 539 208
     Measuring: Ewes at two trial sites were closely monitored. The researchers measured factors such as                                                                   mark.ferguson@csiro.au
     milk production as well as lamb birth weight and survival.                                                                                                            www.csiro.au/org/cli

         This article appeared in the November 2008 edition of the Kondinin Group’s monthly magazine Farming Ahead. The Kondinin Group holds the copyright on the
         article. Reproduction of this text in whole or part by any other publication or for any other purpose is not permitted without permission of the Farming Ahead
         editor. For more information contact the Kondinin Group on (08) 9478 3343.
62 Farming Ahead November 2008 No. 202 www.farmingahead.com.au

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:8
posted:3/7/2010
language:
pages:2
Description: More versatile Merino muscles up