states in the model

Hi Wilma,

probability is calculated= no of diseased (eg Diarrhoea) calf for the age
                                       no of sick calf for that age group

1) Disease that affect growth

1998;  CONCLUSION: Health status of dairy calves and growing heifers
had a significant effect on growth rate-especially during the first 6
months of life. Septicemia and pneumonia slowed growth by 13 to 15 days
(to reach the same weight as healthy calves) during the first 6 months.
Diarrhea had a much-smaller impact on growth. Passive transfer of
colostral antibodies had no direct effect on growth but does influence
weight and height growth through its effects on health, especially
septicemia and respiratory disease (Donovan et al., submitted).

2) Reason of only choosing Bovine respiratory disease state;

van der Fels-Klerx, 2002: BRD is caused by one or more primary
pathogens, including respiratory viruses and Mycoplasma spp., commonly
complicated by a secondary bacterial infection, or by bacteria alone.
Although respiratory agents are responsible for the ensuing clinical
signs, predisposing factors markedly increase their likelihood and
severity, i.e.the disease is multifactorial (Radostits et al., 1994)

The paper classified BRD based on age, type and severity;
Age classes; 0-3months, 3-6 months, 6-24 months
Type; Calf pneumonia (age <3months) commonly by bacteria
          BRD Outbreak (age >3 months, regularly affect age <3months) commonly by Bovine Syncytial Virus
Severity; Mild, Severe, Chronic

the paper made combination for all the classification.  Effect of
productivity was calculated.  It was mortality, weight (3-6-14 months),
age at first calving and 305 days milk production for first lactation.

3) Reason for choosing SCOURS/ DIARRHOEA/ ENTERITIS
Etiology; a) Viral = BVD, Rotavirus, Coronavirus)
                  Bacteria= E.coli, Salmonella, Enterotoxaemia
                  Protozoa=Coccidiosis, cryptosporidium

different age, there is usually different etiology responsible for calf
diarrhoea.  Bacterial diarrhoea usually occur in the first week while
viral diarrhoea more often in 6-24 months.  BVD occur in all stage of
cows life. It also affect reproduction of the animal. 

4) What involved in Septicaemia (Merk Veterinary Manual)
     a) Joint ill/ Arthritis
     b) Navel ill/ Omphalopleibitis
     c) other infectious (viral, bacteria, protozoa)


  • Healthy
  • Scours (Diarrhoea/enteritis)
  • Bovine Respiratory Disease (BRD)
  • Septicaemia (Navel ill/joint ill/omphalophleibitis)
  • Other infectious
  • Culled
  • Death
  • Growth
  • Estrous
  • Estrous detection
  • pregnant

6) Any disease should be separated in 1 state?
7) Should disease being specified like viral diarrhoea, Bacterial diarrhoea etc,  shall scours, enteritis be separated?
8) Probability from being in 1 disease to another disease. Those conditions are interrelated.
there are 2 diseases under 1 generalization, how to combine it? Do I
just add the raw numbers of the calf with those diseases?

10) For the model,  It seems that I have the mortality for each disease
to put under death state, morbidity for each disease.  There are
treatment (cure rate) but I’m not sure type of treatment (eg type of
antibiotic), but I assume probably 50% to 70% of cure by treatment. 
11) The probability of being healthy, can it be (1-total morbidity)?


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