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Vasse presentation stephen lee Vasse presentation stephen lee Presentation Transcript

  • Reporting outcomes from social science and industry herd data analysis
    Stephen Lee
    Ian Nuberg
    Wayne Pitchford
  • Maternal Productivity
    Difficult to define:
    • the outputs in the beef production system relative to the inputs
    • weight of calf weaned / MJ energy cow calf unit
    • cow weight change (kg)
    Traits include:
    Reproductive performance (no. of calves weaned per cow exposed)
    Pre-weaning growth of progeny
    Change in size and body composition of the cow
    Motivating concern
    • How does increasing production potential impact on breeding herd efficiency?
  • Research Approach
    In-depth interviews with seedstock breeders on role and key influencers of maternal productivity
    • hypotheses generating – logic of breeding and management
    Maternal Productivity Data from 4500 industry animals over first and second parity
    associations between performance potential (EBVs) and body energy reserves
    genetic parameter estimates
    reproduction differences
    output traits (calf weaning weight, cow weight change)
    Management and breeding implications for cows differing in genetic potential
  • Breeding goals
    Majority of breeders had similar goals:
    low cost of production
    high quality product (marbling and yield)
    multiple end market specifications
    structural soundness
    temperament
    Contrasting on-farm animal management approach
  • Diverse management
  • Controlled input
    ‘I have a real problem with fat and I touched on this before in regard to cow condition. Fat is expensive to put on, you put it on, the animal goes to the processor and they cut if all off. When you feed it (fat) on and it costs you somewhere in the vicinity of 40% of every mega-joule you end up using in the process of putting it on and then re-metabolising it again, that’s just crazy’
    ‘If you couldn’t do it any other way and we were dropping 10% conception rate, then you have to have that fat there. If you can have yield and have efficient cows, then to me the wrong thing for a seedstock business to do is to push positive fat.’
  • Variable input
    ‘We have done a study of what it costs us to produce dry matter during the year and it is about 4 times as cheap during spring compared to autumn. So that says a lot about when you put condition on and when you can let the cows coast through. The ones that have stayed in the system have this ability where they can put weight on quickly in spring when there is compensatory growth and they can draw down on those reserves when things are tougher and then gain weight quickly when the feed is available.’
    ‘I use the carcass traits more for maternal productivity than for carcass. It is huge, rib and rump, whenever I use an AI sire I have a really good look at his fat EBVs. When I use a negative fat bull the drop out rate in our maternal side is too high.’ ‘I know the feedlot buyer wants high yielding steers but I can’t afford that in the cow herd.’
  • Maternal Productivity
    Calving ease
    Calf growth
    Feed Intake (energy)
    Fertility – 365 day breeding cycle
    Pre-calving energy reserves
    P8 and Rib EBVs
    EMA EBV
    600d Wt EBV
    Milk EBV
    Frame
    Maturity pattern
  • EBV Standard Deviations
  • 962 progeny
    77 herds
    623 progeny
    in 20 herds
  • Percentage increase in P8 fat depth for 1mm increase in P8 EBV
    %change in P8 fat depth
    A 1mm increase in P8 fat EBV for Angus at pre-calving first parity (PC1) increased scanned P8 fat depth by 14.6%
  • Maternal Productivity
    Calving ease
    Calf growth
    Feed Intake (energy)
    Fertility – 365 day breeding cycle
    Pre-calving energy reserves
    P8 and Rib EBVs
    EMA EBV
    600d Wt EBV
    Milk EBV
    Frame
    Maturity pattern
  • Relationship between Rib and P8
    EBVs and observed days to calving
    A 1mm increase in P8 EBV resulted in reduced observed DTC by 0.95 days in Spring and 2.45 days in Autumn
  • Relationship between pre-calving rib fat depth and observed days to calving
    In Spring calving cows for every extra millimetre pre-calving scan rib fat depth, observed days to calving was reduced by 0.39 days, this effect was larger in Autumn calving cows (-2.89).
  • Summary
    Cow management approach differed between breeders (CONTROL vs. VARIABLE)
    Cow management approach was linked with attitude to optimal EBVs for traits including fat, growth and milk
    Body composition
    • EBVs for P8 and Rib impact cow fat depth at pre-calving and weaning (approx 15% per standard deviation)
    • Body composition traits are phenotypically repeatable for pre-calving and weaning
  • Summary
    Days to calving and Rib and P8 EBVs
    Approx 1.0 days shorter DTC in spring
    Approx 2.5-2.9 days shorter DTC in autumn
    Pre-calving but not weaning cow fat depth impacts subsequent days to calving
    Approx 2.89 days/mm rib fat in autumn and
    Approx 0.39 days/mm rib fat in spring.
    • For control input management, where it is cost effective to increase inputs (feed), the effect of increasing genetic potential for yield (leanness) is unlikely to compromise observed pre-calving energy reserves
    • However, in variable input systems, the ability for young cows with high potential for leanness and growth to attain sufficient pre-calving energy reserves in adverse seasons may be compromised
  • Acknowledgements
    Ian Nuberg
    Wayne Pitchford
    Angus Australia
    Herefords Australia
    Collaborating herds!