What does FI stand for?

6] ejaculate Percentage of active spermatozoids 70-90% Percentage of inactive spermatozoids 10-30% Percentage of normokinetic spermatozoids (a,b) 40-90% Percentage of hypokinetic spermatozoids (a,b) 10-20% Percentage of diskinetic spermatozoids (a) 6-10% Percentage of akinetic spermatozoids (a) 10-20% Farris 1 fertility index > 200 Farris 2 fertility index > 100 (a) Spermatozoids are classified by their mobility as: normokinetic-- fast expedient movement; hypokinetic--movement with poor progress; diskinetic--limp movement and spermatozoids twitching on the same spot; akinetic--absence of movement.

With on-farm conception rates currently falling at a rate of one per cent a year producers will, for the first time, be able to take advantage of a new Fertility Index as an additional selection tool after considering type and production, and select UK proven-sires on the fertility of their daughters.

In my analysis, four indicators related to economic and cultural patterns account for just over half of the variation among counties in the marital fertility index ([ILLUSTRATION FOR FIGURE 1 OMITTED] and Table 1).