Research, Policy and Practice
From: Economic losses associated with Peste des petits ruminants in Turkana County Kenya
Parameter description | Methodology for estimation of parameter |
---|---|
Herd age structure | Â |
  G y…a = proportion (%) of sheep/goats in age group young to adult | Proportional piling (PP) of sheep and goat herds by age group (n = 27) |
Losses due to mortality | Â |
  H y…a = PPR mortality (%) of sheep/goats in age group young to adult | PP sheep (n = 43)/goat (n = 44) mortality by disease |
  H a = mortality (%) of pregnant female | Mortality in adult sheep and goats |
  C y…a = value expressed in US$/TLU kg for sheep/goats in age group young to adult | Value of sheep or goat in TLU (C me*W y…a) |
Losses from reduced milk production | Â |
  S m…f = proportion (%) of male and female sheep/goats in the herds | PP sheep (n = 6)/goat (n = 6) |
  L f = proportion (%) of lactating sheep/goats | Derivative of PP from G y |
  P f = proportion (%) of pregnant sheep/goat | Derivative of PP sheep (n = 6)/goat (n = 6) |
  I y…a = prevalence (%) of PPR in sheep/goats in age group young to adult | PP for disease prevalence |
  I af = prevalence (%) of PPR in lactating sheep/goats | PP for disease prevalence I af equals I a in adults |
  V l = volume of milk loss (litres) per day per PPR case | Key informant interviews |
  T r = duration (days) of reduced milk production per acute PPR case | Course of disease as described by Bundza et al. (1988) |
  V a = daily volume (litres) of milk produced per healthy sheep/goat | Key informant interviews and literature (Njanja 1991) |
  T l = lactation period (days) | |
  C m = sale value of milk (US$/l) | Key informant interview with milk sellers |
  C me = TLU value expressed in US$/unit weight of TLU | TLU = 250 kg; cost of TLU is US$ 150. Value of TLU/kg is US$ 0.6 (ILCA 1988; Mude et al. 2010) |
Losses due to weight losses | Â |
  W l = proportion (%) of body weight loss | Key informant interviews |
  W a…y = average body weight (kg) of sheep/goat in age group young to adult | Key informant interviews with livestock officials and keepers |
  K = inter-kidding/lambing interval in days | Key informant interviews and literature (Njanja 1991) |
  B = birth weight (kg) of kid/lamb | Literature (Njanja 1991) |
  N = sheep/goat population in study area in Turkana County | KNBS 2010 Kenya population and livestock census data |
  Q = delay in conception in months due to disease | Key informant interviews and livestock keepers |