Category Archives: Model Structure

Papers for transition matrices

Its difficult to decide what shall I do first
 
But I think I will go through all Dutch condition papers and decide the numbers using the formula.
 
Then I will go for europe papers and decide the numbers
 
Finally I will go for US paper to decide the numbers
 
Then I will make a definition based on DUtch papers and also the assumption and problems with numbers to make an adjustment.
 
I would take the first 3-4 months seriously (more stages) than after 4 months (which may have similar stages).
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Transition matrix numbers

Before I am going back home, I wanted to summarize few points that I have to know in order to get the RISK
 
1) DEFINITION OF NEEDED RISK
  • Mortality; overall and specific
  • Morbidity; overall and specific, prevented
  • Cure rate; treated and not treated
  • transition between states; association between previous history of morbidity

2) DEFINITION BASED BY BOOK (Dohoo)

  • Host attributes (Age: Very week and every 3 weeks, sex: heifer, breed: Dutch Black and white)
  • Specific outcomes (Mortality, morbidity, cure rate, transition rate : Healthy, scours, pneumonia, stomach worm, lungworm)
  • Risk period: based on disease occurence (by age)

3) RISK OF IMPORTANCE

  • INCIDENCE RISK (R)= CUMULATIVE INCIDENCE = SURVIVAL (1-R)= Probability that an individual animal will contract or develop a disease in a defined time period (each disease will have risk period)
  • INCIDENCE RATE (I)=INCIDENCE DENSITY=HAZARD RATE=Number of new cases of disease in a population per unit of animal-time during a given time period.

4) PAPERS TO BE USED

  • Mortality
  • Morbidity
  • Treatment for drugs/anthelmintics/prevention & cure
  • Relationship between diseases
  • Cull
  • Holland, Europe, US

5) FORMULA OF INCIDENCE RISK & FORMULA TO CHANGE TO INCIDENCE RISK

  • Risk of disease: number of new cases of diseased in a defined time period
  •                           Population at risk (open&close, Prevalence(at that point))
  • Rate to risk
  • survival to risk
  • hazard to rate to risk
  • overall risk to specified risk
  • First case risk
  • multiple to 1 disease risk
  • previous disease to disease of interest
  • collapse of clinical signs (but different history: age, mgm, nutrition)

 


Growth curve

Disease reduces growth.  Bodyweight affects puberty and bodyweight at calving.

I already have a growth curve by Koenen and Groen.

But I need to establish the effect of diseases on growth.  I have to identify papers written related to growth in diseased condition.  Surely I will find normal growth, but it is difficult.

Anyway, I am having headache because of the introduction now…

hmm shall I start with methods?