Abstract :
This study estimated economic values (EVs) for disease resistance traits for dairy/crossbred
goats in Kenya. The traits mean somatic cell count (SCC, cells/ l) and faecal worm egg
count (FEC, epg) were taken as indicator traits for the most prevalent diseases in the
smallholder farms i.e., mastitis and helminthiosis, respectively. Economic weights were
objectively assigned to these indicator traits in a selection index such that the overall gains
in the breeding objective traits were maximised. Four options for calculating EVs for SCC
and FEC were considered. Option 1, response from single trait selection was set equivalent
to index response for the trait. Option 2, response from single trait selection was set
equivalent to maximum gains achievable. Option 3, level of FEC/SCC was set to zero; and
option 4, response in FEC/SCC was set to the minimum gains achievable. In all the options,
EVs with/without risk for breeding objective traits 12-month live weight (LW-kg); ADG,
average post-weaning daily gain (ADG-g); DMY, average daily milk yield (DMY-kg) were
used. For each production trait selected for improvement, a less positive response in the
traits FEC and SCC would be desirable. Maximum negative EVs were achieved at a point
where the response in SCC was set at zero (option 3) while EVs for SCC were zero when
response for DMY was maximised (option 2). In addition, considerable differences in EVs
for SCC were obtained when EVs with/without risk were used. Similar results were also
observed for FEC when LW was the objective of improvement. However, more positive EVs
for FEC were estimated relative to ADG and DMY. The results confirm that there is a scope
to incorporate disease resistance traits in a breeding program with objective of reducing
disease incidences and the costs of disease control
